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Zinc oxide is also used as an electrode in supercapacitors.
Zinc oxide is used in products such as baby powder and barrier creams to treat diaper rashes, calamine cream, anti-dandruff shampoos, and antiseptic ointments.
Zinc oxide is widely used in industrial applications: rubber, plastics, ceramics, glass, cement, paints & coatings, pigments, lubricants, electronics (semiconductors, optoelectronics).
CAS Number: 1314-13-2
EC Number: 215-222-5
MDL Number: MFCD00011300
IUPAC name: zinc(II) oxide
Molecular formula: ZnO
Molar mass: ~ 81.39-81.41 g/mol
SYNONYMS:
Zinc oxide, ZnO, Zinc white, Calamine, Chinese white, Zinca, Zinc(II) oxide, Philosopher's wool, Flowers of zinc, Zincum Oxydatum, Zinc paste, Zinci Oxydum, Zinc (as oxide), Zinc oxide emulsion, DTXSID7035016, Zinc (as zinc oxide), SOI2LOH54Z, CI 77947, 215-222-5, 1314-13-2, Actox 14, Actox 16, Actox 216, AI3-00277, Akro-zinc bar 85, Akro-zinc bar 90, Amalox, Azo 22, Azo-33, Azo-55, Azo-55TT, Azo-66, Red Seal 9, Reliamed, Repara, Shield, Snow White, TENDERWRAP, Unichem ZO, Vandem VAC, Vandem VOC, Vandem VPC, White seal-7, XX 203, XX 601, XX 78, Zinc monoxide, Zincoxide, Zinc oxide neutral, Zinc oxide, Puratronic®, Zn 0701T, Zinc hydrate, Zinc;oxygen(2-), Zincum Oxydatum [HPUS], RNWHGQJWIACOKP-UHFFFAOYSA-N, SCHEMBL5899, ZINC OXIDE [II], ZINC OXIDE [MI], ZINC OXIDE [FCC], ZINC OXIDE [JAN], ZINC OXIDE [HSDB], ZINC OXIDE [VANDF], ZINC PASTE [VANDF], ZINC OXIDE [MART.], ZINC OXIDE [USP-RS], ZINC OXIDE [WHO-DD], ZINC OXIDE [WHO-IP], ZINC(2+) OXIDANDIIDE, CHEMBL3988900, ZINC OXIDE [ORANGE BOOK], ZINC OXIDE [EP MONOGRAPH], ZINC OXIDE [USP IMPURITY], VUSION COMPONENT ZINC OXIDE, ZINC (AS OXIDE) [VANDF], AMY14799, ZINC OXIDE EMULSION [VANDF], CALAMINE COMPONENT ZINC OXIDE, ZINCI OXYDUM [WHO-IP LATIN], ZINC (AS ZINC OXIDE) [VANDF], Zinc oxide, 50nm, 50 wt. % in H2O, ZINC OXIDE NEUTRAL [USP MONOGRAPH], NS00074443, Z0046, ZnO, Methicone, snowwhite, ZINC(II)OXIDE, Zinc oxide (ZnO), Zinc oxide, ACS, 99.0% min, ci77947, zincite, Zinkoxid, Zinc white
Zinc oxide is an inorganic compound with the formula ZnO.
Zinc oxide is a white powder which is insoluble in water.
Although it occurs naturally as the mineral zincite, most zinc oxide is produced synthetically.
Zinc oxide is one of the most widely used inorganic compounds in industry and consumer products, thanks to its broad usefulness, relative chemical stability, and multifunctional performance (pigment, skin protectant, UV blocker, semiconductor).
Crude zinc oxide is a yellow-gray granular solid with no odor.
Zinc oxide is insoluble in water.
Zinc oxide is an inorganic compound used in a number of manufacturing processes.
Zinc oxide can be found in rubbers, plastics, ceramics, glass, cement, lubricants, paints, ointments, adhesives, sealants, pigments, foods, batteries, ferrites, fire retardants, and first-aid tapes.
It occurs naturally as the mineral zincite, but most zinc oxide is produced synthetically.
Zinc oxide is also a component in tape (called "zinc oxide tape") used by athletes as a bandage to prevent soft tissue damage during workouts.
The mechanism of Zinc oxide's antibacterial effect has been variously described as the generation of reactive oxygen species, the release of Zn2+ ions, and a general disturbance of the bacterial cell membrane by nanoparticles.
Zincite is a mineral form of zinc oxide, ZnO.
Crude zinc oxide is a yellow-gray granular solid with no odor.
Zinc oxide has a specific gravity of 4.4.
Zinc oxide is insoluble in water.
Zinc oxide slowly decomposed (hydrolyzed) in water.
Zinc oxide is insoluble in water.
Zinc oxide is insoluble in water.
What little solubility Zinc oxide has yields aqueous solutions that are neutral in pH.
Zinc oxide is a mineral-derived sunscreen ingredient.
Ideal for both daily and intense sun exposure because of its ability to block the widest spectrum of UV light, zinc oxide provides broad-spectrum protection against both UVA and UVB rays.
Zinc oxide is a powder, white whencold and yellow when hot, ZnO; r.d.5.606; m.p. 1975°C.
Zinc oxide occurs naturallyas a reddish orange ore zincite,and can also be made by oxidizinghot zinc in air.
Zinc oxide is amphoteric,forming zincates with bases.
Zinc oxide is used as a pigment (Chinese white) and a mild antiseptic in zinc ointments.
Zinc oxide is an archaic name is philosopher’swool.
Zinc oxide is an inorganic compound used in a number of manufacturing processes.
Zinc oxide occurs in nature as mineral zincite.
Zinc oxide is the most important zinc compound and has numerous industrial applications.
Zinc oxide is the pigment in white paints.
Zinc oxide is a white, powdery mineral used for making cosmetic and medical products.
Zinc oxide has antibacterial and anti-inflammatory properties, and it's best known as a primary ingredient in sunscreens.
Current research doesn't show any adverse outcomes from the nano-sized zinc oxide particles that are found in cosmetics or sunscreens.
When applied topically, zinc oxide also offers several other important benefits for skin health.
Zinc oxide is a nutrient supplement.
Zinc oxide is a constituent of cigarette filters for removal of selected components from tobacco smoke.
Zinc oxide is a filter consisting of charcoal impregnated with zinc oxide and iron oxide removes significant amounts of HCN and H2S from tobacco smoke without affecting its flavor.
Zinc oxide is an amphoteric oxide.
Zinc oxide is nearly insoluble in water and alcohol, but it is soluble in (degraded by) most acids, such as hydrochloric acid.
Zinc oxide is an inorganic compound with the formula ZnO.
Zinc oxide usually appears as a white powder, nearly insoluble in water.
Zinc oxide is widely used as an additive into numerous materials and products including plastics, ceramics, glass, cement, rubber (e.g. car tyres), lubricants, paints, ointments, adhesives, sealants, pigments, foods (source of Zn nutrient), batteries, ferrites, fire retardants, first aid tapes, etc.
Zinc oxide is present in the Earth crust as a mineral zincite; however, most ZnO used commercially is produced synthetically.
Zinc white is used as a pigment in paints and is more opaque than lithopone, but less opaque than titanium dioxide.
Zinc oxide is also used in coatings for paper.
Chinese white is a special grade of zinc white used in artists' pigments.
Because it reflects both UVA and UVB rays of ultraviolet light, zinc oxide can be used in ointments, creams, and lotions to protect against sunburn and other damage to the skin caused by ultraviolet light (see sunscreen).
Zinc oxide is the broadest spectrum UVA and UVB absorber that is approved for use as a sunscreen by the FDA, and is completely photostable.
Zinc oxide is also a main ingredient of mineral makeup.
Zinc oxide is a relatively soft material with approximate hardness of 4.5 on the Mohs scale.
Zinc oxide's elastic constants are smaller than those of relevant III-V semiconductors, such as GaN.
The high heat capacity and heat conductivity, low thermal expansion and high melting temperature of Zinc oxide are beneficial for ceramics.
Zinc oxide has been shown to exhibit anti-inflammatory and antibiotic functions.
Zinc oxide belongs to the family of Transition Metal Oxides.
These are inorganic compounds containing an oxygen atom of an oxidation state of -2, in which the heaviest atom bonded to the oxygen is a transition metal.
Zinc oxide is a mild astringent and topical protectant with some antiseptic action.
Zinc oxide is also used in bandages, pastes, ointments, dental cements, and as a sunblock.
Zinc Oxide is a very useful ingredient that has been used for centuries in various skincare and cosmetic formulations.
Zinc oxide is a natural ingredient that appears as a white powder in its raw form.
Zinc Oxide provides broad-spectrum protection against UVA and UVB radiation, making it an excellent choice for sunscreens.
Zinc oxide also has anti-inflammatory and antimicrobial properties, making it an excellent ingredient for treating and preventing acne and other skin conditions.
Further, Zinc Oxide is a natural color agent and does not contain any synthetic colorants.
Zinc oxide is a natural alternative to synthetic sunscreens and provides numerous benefits for the skin.
The chemical formula of Zinc Oxide is ZnO.
Zinc Oxide is an inorganic oxide used as a colorant and sunscreen agent.
Zinc oxide is a medicated cream, ointment or paste that treats or prevents skin irritation like cuts, burns or diaper rash.
Some types of zinc oxide protect your skin from the sun’s ultraviolet rays.
You can rub this medication on your affected skin as directed.
Don’t cover the area with a bandage unless your healthcare provider tells you to do so.
Zinc oxide is a fluffy white to yellow-white powder having a very fine physical particle size (99.9% should pass a 325 mesh screen).
Zinc oxide is made using one of two processes that produce different densities.
The French process vaporizes and oxidizes zinc metal, the American process smelts a coal/zinc sulfide mix and oxidizes the zinc fumes.
Zinc oxide is an inorganic compound used in a number of manufacturing processes.
Zinc oxide is soluble in strong alkalies and acids.
Zinc oxide can be an active flux in smaller amounts.
While boron dominates as the key flux in middle temperature glazes, for example, zinc is employed in some base glazes to augment the B2O3 or even replace it entirely.
No combination of the common raw materials feldspar, kaolin, silica, feldspar, calcium carbonate, dolomite and talc will melt properly at cone 6, however, a 5% addition of zinc can transform the mix into a glossy glaze.
5% more and it will be a very fluid glossy glaze.
The zinc can also significantly reduce the thermal expansion of the glaze it is fluxing.
Zinc generally promotes crystalline effects and matteness/softness in greater amounts.
If too much is used the glaze surface can become dry and the heavily crystalline surface can present problems with cutlery marking.
Other surface defects like pitting, pinholing, blistering and crawling can also occur (because its fine particle size contributes to glaze shrinkage during drying and it pulls the glaze together during fusion).
Zinc oxide is thermally stable on its own to high temperatures, however, in glazes it readily dissolves and acts as a flux.
Zinc oxide sublimes at 1800C but it reduces to Zn metal in reduction firing and then boils at around 900C (either causing glaze defects or volatilizing into the atmosphere; note that electric kilns with poor ventilation can have local reduction).
While Zinc oxide might seem that zinc would not be useful in reduction glazes, when zincless and zinc-containing glazes are compared it is often clear that there is an effect (e.g. earlier melting, more crystallization and variegation).
Thus some zinc has either remained or it has acted as a catalyst.
The use of zinc in standard glazes is limited by its price, its hostility to the development of certain colors and its tendency to make glazes more leachable in acids (although zinc itself is not considered a hazardous substance).
Zinc Oxide is amount the purest powdered materials available (its actual chemistry closely matches the theoretical).
USES and APPLICATIONS of ZINC OXIDE:
Zinc oxide can be found in rubbers, plastics, ceramics, glass, cement, lubricants, paints, ointments, adhesives, sealants, pigments, foods, batteries, ferrites, fire retardants, and first-aid tapes.
It occurs naturally as the mineral zincite, but most zinc oxide is produced synthetically.
Zinc oxide is also widely used to treat a variety of other skin conditions, in products such as baby powder and barrier creams to treat diaper rashes, calamine cream, anti-dandruff shampoos, and antiseptic ointments.
The pointed tips of Zinc oxide nanorods could be used as field emitters.
Zinc oxide is a promising anode material for lithium-ion battery because it is cheap, biocompatible, and environmentally friendly.
Zinc oxide has a higher theoretical capacity (978 mAh g−1) than many other transition metal oxides such as CoO (715 mAh g−1), NiO (718 mAh g−1) and CuO (674 mAh g−1).
Zinc oxide is also used as an electrode in supercapacitors.
Dental restoration: When mixed with eugenol, zinc oxide eugenol is formed, which has applications as a restorative and prosthodontic in dentistry.
Zinc oxide highly n-type doped with aluminium, gallium, or indium is transparent and conductive (transparency ~90%, lowest resistivity ~10−4 Ω·cm).
Zinc oxide:Al coatings are used for energy-saving or heat-protecting windows.
The coating lets the visible part of the spectrum in but either reflects the infrared (IR) radiation back into the room (energy saving) or does not let the IR radiation into the room (heat protection), depending on which side of the window has the coating.
Plastics, such as polyethylene naphthalate (PEN), can be protected by applying zinc oxide coating.
The coating reduces the diffusion of oxygen through PEN.
Zinc oxide layers can also be used on polycarbonate in outdoor applications.
The coating protects polycarbonate from solar radiation, and decreases Zinc oxide's oxidation rate and photo-yellowing.
The applications of zinc oxide powder are numerous, and the principal ones are summarized below.
Most applications of Zinc oxide exploit the reactivity of the oxide as a precursor to other zinc compounds.
For material science applications, zinc oxide has high refractive index, high thermal conductivity, binding, antibacterial and UV-protection properties.
Consequently, Zinc oxide is added into materials and products including plastics, ceramics, glass, cement, rubber, lubricants, paints, ointments, adhesive, sealants, concrete manufacturing, pigments, foods, batteries, ferrites, and fire retardants.
Zinc oxide is widely used to treat a variety of skin conditions, including atopic dermatitis, contact dermatitis, itching due to eczema, diaper rash and acne.
Zinc oxide is used in products such as baby powder and barrier creams to treat diaper rashes, calamine cream, anti-dandruff shampoos, and antiseptic ointments.
Zinc oxide is often combined with castor oil to form an emollient and astringent, zinc and castor oil cream, commonly used to treat infants.
Zinc oxide is widely used in industrial applications: rubber, plastics, ceramics, glass, cement, paints & coatings, pigments, lubricants, electronics (semiconductors, optoelectronics).
In pharmaceuticals/consumer products: Zinc oxide is used skin protectant creams/ointments (e.g., diaper rash).
Sunscreen and UV-blocking formulations (due to strong UV absorption/reflection).
As a food/animal feed additive: Zinc oxide is used in zinc supplementation (though with special regulatory status depending on jurisdiction).
Zinc Oxide is used as one of the main raw materials in many industries such as, tire, rubber, ceramics, stabilizers, paint and agriculture.
Zinc oxide facilitates the vulcanization process, promoting the formation of robust cross-links between rubber molecules, resulting in enhanced mechanical strength and stability.
Zinc oxide also acts as a reinforcing agent, bolstering the internal structure of the rubber matrix, leading to improved tear and abrasion resistance.
By mitigating the detrimental effects of oxidation and environmental stressors, zinc oxide extends the lifespan of rubber products, ensuring optimal performance over time.
Zinc oxide optimizes the vulcanization process, leading to the formation of a more robust and well-defined rubber network, further enhancing its durability and resistance to degradation.
Zinc oxide's safety profile in typical consumer uses (e.g., topical skin) is generally good, but care must be taken in industrial use (dust inhalation, nano‐forms, environmental release).
For high‐tech applications of Zinc oxide (optics, electronics), advanced forms (nanostructures) are under active research and regulatory scrutiny.
Zinc oxide is used as an additive in numerous materials and products including cosmetics, food supplements, rubbers, plastics, ceramics, glass, cement, lubricants, paints, sunscreens, ointments, adhesives, sealants, pigments, foods, batteries, ferrites, fire retardants, semi conductors, and first-aid tapes.
Zinc oxide is also widely used to treat a variety of other skin conditions, in products such as baby powder and barrier creams to treat diaper rashes, calamine cream, anti-dandruff shampoos, and antiseptic ointments.
Zinc oxide is added to cotton fabric, rubber, oral care products, and food packaging.
Enhanced antibacterial action of fine particles compared to bulk material is not exclusive to Zinc oxide and is observed for other materials, such as silver.
Zinc oxide is used primarily for its anti-bacterial and fungicidal properties.
Also, in the United States, Zinc oxide is regarded as a Category I skin protectant and a Category III sunscreen.
Zinc oxide is used in a wide range of cosmetics and personal care products, including makeup, nail products, baby lotions, bath soaps and foot powders.
Zinc oxide is also used in skin protectants, such as diaper rash ointments and sunscreen products.
Zinc oxide is used as a bulking agent and a colorant.
Zinc oxide is used as a bulking agent and a colorant.
In over-the-counter drug products, it is used as a skin protectant and a sunscreen.
Zinc oxide works as a sunscreen by reflecting and scattering UV radiation.
Sunscreens reduce or prevent sunburn and premature aging of the skin.
Zinc oxide is added to paints as a pigment and mold inhibitor and is known as zinc white when it is used as an oil paint by artists.
Zinc oxide is used for cosmetics (ointment to protect nose and lips from ultraviolet sunlight), as a seed treatment, and as a dietary supplement.
Zinc oxide, ZnO, is a reactive white pigment prepared by vaporizing metallic zinc at a temperature of about 900°C in the presence of oxygen.
As a pigment, Zinc oxide is basic in nature and can react with certain types of acidic paint resins resulting in the formation of a brittle film on drying.
Formation of such films leads to premature failure of paint.
For this reason as well as because of its low RI, Zinc oxide cannot compete for the hiding power of TiO2.
Consequently, Zinc oxide is rarely used as the sole pigment in modern coatings, although it finds some use in admixture with other pigments.
Zinc oxide is used in exterior house paints as a fungicide and in some can linings as a sulfide scavenger.
Zinc oxide is used preparation of zinc standard solutions.
Zinc oxide is much inferior to TiO2 in hiding power and is therefore used as a white pigment where some of its other properties are valued.
Zinc oxide can, for instance, act as a fungistat in exterior oil paints.
Zinc oxide absorbs UV radiation and will therefore protect organic polymeric binders from photodegradation and reduce chalking.
The largest use of Zinc oxide is as an activator for vulcanization accelerators in natural and synthetic rubber.
Zinc oxide has been used to protect, soothe, and heal the skin.
Zinc oxide provides an excellent barrier to the sun and other irritants.
Zinc oxide is somewhat astringent, anti-septic, and anti-bacterial.
When used in sunscreen preparations, Zinc oxide provides both UVA and UVB protection, and can contribute to and/or increase SPF.
At the appropriate particle size, zinc oxide is transparent in the visible light spectrum but opaque in the UVC ranges, thereby avoiding a whitening effect when incorporated into sunscreen preparations.
Zinc oxide is included on the FDA’s list of approved sunscreen chemicals.
Zinc oxide demonstrates an impressive synergistic effect when combined with organic sunscreens.
Zinc oxide is also used when a white color is desired for a product.
Zinc oxide is obtained from zinc ore, a commonly found mineral, and is relatively non-allergenic.
Zinc oxide is used to make enamels, white printing inks, white glue, opaque glasses, rubber products and floor tiles.
Zinc oxide is used in cosmetics, soaps, pharmaceuticals, dental cements, storage batteries, electrical equipment, and piezoelectric devices.
Other applications of Zinc oxide are as a flame retardant, as a UV absorber in plastics, and a reagent in analytical chemistry.
A major application of zinc oxide is in the preparation of most zinc salts.
In medicine, Zinc oxide is used as an antiseptic, an astringent and a topical protectant.
Zinc oxide can be found in rubber, plastic, ceramics, glass, cement, lubricants, paints, ointments, adhesives, sealants, pigments, foods, batteries, ferrites, fire retardants, and first aid tapes.
Zinc oxide is used in the following products: polymers, coating products, fillers, putties, plasters, modeling clay, non-metallic surface treatment products, pH regulators and water treatment products, fertilizers and metal surface treatment products.
Zinc oxide is used in the following areas: formulation of mixtures and/or repackaging, construction and civil works, agriculture, forestry and fisheries, and health care.
Zinc oxide is used in the manufacture of: plastic products, machinery and tools, mineral products (eg plasters, cement) and furniture.
Machine wash liquids/detergents, automotive care products, paints and coatings or adhesives, fragrances and air fresheners, flooring, furniture, toys, building materials, curtains, shoes, leather products, paper and cardboard products, electronic equipment, metal, wood and Zinc oxide is used in plastic construction and building materials.
Zinc oxide is a mineral used in cosmetics as a white colourant (CI 77947) or as a UV filter.
Zinc oxide allowed for organic use.
Zinc oxide is used in glass, frits, enamels and ferrites.
Zinc oxide is also used in large quantities in the rubber and paint industries; in insulated wire, lubricants, and advanced ceramics.
Zinc oxide is a largely inert, white compound which is used very widely as a bulking agent or filler, and as a white pigment.
Zinc oxide is found in some rubber, glass and ceramic products, and finds use in the chemical industry as a catalyst.
Zinc oxide is also used in paints as a corrosion inhibitor and for mildew control.
Zinc is an essential trace element, and zinc oxide is added to fertilizers, animal feed, and vitamin supplements.
Zinc oxide is also used in a many cosmetic and medical products and in toiletries, as it has antibacterial and deodorant properties.
Zinc oxide is found in, for example, baby powder and anti-dandruff shampoos, in calamine lotion and in sticking plasters and dental cement.
Zinc oxide's strong absorption of ultra-violet (UV) light has led to its use in sunscreen lotions.
Zinc oxide blocks both UVA (longer wavelength) and UVB (shorter wavelength) radiation, protecting against sunburn, skin damage and cancer.
-UV Protection uses of Zinc oxide:
There are two types of sunscreen protection: chemical and mineral.
Chemical sunscreens absorb the sun's rays to protect the skin.
Mineral sunscreens, like those that contain zinc oxide, create a physical barrier that reflects ultraviolet (UV) light away from the skin's surface.
When UV rays penetrate the skin and damage tissue, Zinc oxide speeds up the aging process and dries out the skin.
Exposure to UV rays, whether from the sun or tanning beds, is also a risk factor for all types of skin cancer.
Sunscreens containing zinc oxide are a good choice for children or adults with sensitive or acne-prone skin, since they're less likely to cause allergic reactions or skin irritation.
They also start working as soon as they're applied.
They do have a thicker texture that can leave a white film on the skin, but some formulations can reduce that effect.
-Burn and Rash Treatment uses of Zinc oxide:
Zinc oxide can protect and soothe your skin in other ways, too.
A topical cream can be used to treat or prevent minor skin irritations, such as burns and cuts.
It's also a key ingredient in many over-the-counter diaper rash creams.
A formulation with 5 percent zinc oxide can be effective and start working within 12 hours.
One review of studies found zinc oxide ointment provides a physical barrier to water absorption, and it reduces bacterial infections in mild dermatitis caused by wet diapers.
The effects are best when Zinc oxide's applied after each diaper change.
-Treating Dark Spots uses of Zinc oxide:
While zinc oxide is white, it doesn't permanently lighten the skin.
Zinc oxide is, however, a common ingredient in sunscreens used for the treatment of melasma, a common skin condition that can cause brown patches on the face.
One study found that people who have melasma reported a reduction in symptom severity after three months of treatment with 10 percent topical zinc sulfate, another type of zinc.
However, current research doesn't support using it as a direct treatment for skin discoloration caused by melasma.
When used daily, broad-spectrum sunscreen with zinc oxide that's SPF 30 or higher can help prevent further skin darkening, though.
Zinc oxide should be worn on all parts of the body that may be exposed to sun, and it should be used even when it's raining or snowing outside.
-Acne Treatment uses of Zinc oxide:
Due to its antibacterial and anti-inflammatory properties, zinc oxide can be an effective acne treatment, although thicker formulations less so.
Applied topically, zinc oxide can help reduce the redness, swelling, and bacteria associated with breakouts.
Research shows it can also boost skin repair, reduce sebum, and prevent scarring.
Oral zinc sulfate may treat acne, too.
Research suggests it can treat mild to moderate papulopustular acne.
This is the type that causes red, raised bumps on the skin as well as those filled with pus.
-Easing Hemorrhoids uses of Zinc oxide:
Zinc oxide is also an active ingredient in many over-the-counter hemorrhoid treatments.
While they may ease discomfort temporarily, these zinc oxide creams have not been studied thoroughly for safety or efficacy for long-term use.
Hemorrhoids are swollen veins around the anal canal that are caused by excess pressure in the pelvic and rectal area.
Zinc oxide can protect skin from such irritation, but the affected area needs to be gently cleaned and dried before applying it.
-Antibacterial uses of Zinc oxide:
Zinc oxide is used in mouthwash products and toothpastes as an anti-bacterial agent proposed to prevent plaque and tartar formation, and to control bad breath by reducing the volatile gases and volatile sulfur compounds (VSC) in the mouth.
Along with zinc oxide or zinc salts, these products also commonly contain other active ingredients, such as cetylpyridinium chloride, xylitol, hinokitiol, essential oils and plant extracts.
Powdered zinc oxide has deodorizing and antibacterial properties.
-Rubber industry uses of Zinc oxide:
Between 50% and 60% of Zinc oxide use is in the rubber industry.
Zinc oxide along with stearic acid is used in the sulfur vulcanization of rubber.
Zinc oxide additives in the form of nanoparticles are used in rubber as a pigment and to enhance its durability, and have been used in composite rubber materials such as those based on montmorillonite to impart germicidal properties.
-Ceramic industry uses of Zinc oxide:
Ceramic industry consumes a significant amount of zinc oxide, in particular in ceramic glaze and frit compositions.
The relatively high heat capacity, thermal conductivity and high temperature stability of Zinc oxide coupled with a comparatively low coefficient of expansion are desirable properties in the production of ceramics.
Zinc oxide affects the melting point and optical properties of the glazes, enamels, and ceramic formulations.
Zinc oxide as a low expansion, secondary flux improves the elasticity of glazes by reducing the change in viscosity as a function of temperature and helps prevent crazing and shivering.
By substituting Zinc oxide for BaO and PbO, the heat capacity is decreased and the thermal conductivity is increased.
Zinc in small amounts improves the development of glossy and brilliant surfaces.
However, in moderate to high amounts, it produces matte and crystalline surfaces.
With regard to color, zinc has a complicated influence.
-Medicine uses of Zinc oxide:
*Skin treatment:
Zinc oxide as a mixture with about 0.5% iron(III) oxide (Fe2O3) is called calamine and is used in calamine lotion, a topical skin treatment.
Historically, the name calamine was ascribed to a mineral that contained zinc used in powdered form as medicine, but Zinc oxide was determined in 1803 that ore described as calamine was actually a mixture of the zinc minerals smithsonite and hemimorphite.
-Agricultural Uses of Zinc oxide:
Zinc oxide (ZnO) is a zinc fertilizer.
Zinc oxide is a white powder when cold and yellow when hot, and contains approximately 78% zinc.
Zinc oxide occurs in nature as a reddish-orange colored zincite, and is made by oxidizing hot zinc in air.
Zinc oxide is an amphoteric oxide forming zincates, by reacting with bases and zinc salts with acids.
Zinc oxide is used as a white pigment and as a mild antiseptic in ointments.
An archaic name of zinc oxide is philosopher's wool.
Foliar applications with zinc oxide reduce the foliage damage.
Zinc oxide, applied by way of seed coatings, root dips or tree injections, corrects the zinc deficiency.
Dipping potato seeds in 2% zinc oxide suspension overcomes zinc deficiency satisfactorily.
A similar method is used for pre-plant dipping of the roots of rice seedlings.
-Pharmaceutical Applications of Zinc oxide:
The pharmaceutical and cosmetic industries use Zinc oxide in powders and ointments because of its bactericidal properties.
Zinc oxide is also used to form dental cements by its reaction with eugenol.
Zinc oxide is used as a raw material for many products: stearates, phosphates, chromates, bromates, organic dithiophosphates, and ferrites (ZnO, MnO, Fe2O3).
Zinc oxide is used as a source of zinc in animal feeds and in electrogalvanization.
Zinc oxide is also used for desulfurizing gases.
-Industrial uses of Zinc oxide:
Zinc oxide has many uses.
By far the most important is in the rubber industry.
Almost half the world’s Zinc oxide is used as an activator for vulcanization accelerators in natural and synthetic rubber.
The reactivity of the Zinc oxide is a function of its specific surface area, but is also influenced by the presence of impurities such as lead and sulfates.
The Zinc oxide also ensures good durability of the vulcanized rubber, and increases its thermal conductivity.
The Zinc oxidecontent is usually 2–5%.
In paints and coatings, zinc oxide is no longer the principal white pigment, although its superb white color is used by artists.
Zinc oxide is used as an additive in exterior paints for wood preservation.
Zinc oxide is also utilized in antifouling and anticorrosion paints [2.82].
Zinc oxide improves film formation, durability, and resistance to mildew (having a synergistic effect with other fungicides) because it reacts with acidic products of oxidation and can absorb UV radiation.
In the field of glass, ceramics, and enamels, Zinc oxide is used for its ability to reduce thermal expansion, to lower the melting point, and to increase chemical resistance.
Zinc oxide can also be used to modify gloss or to improve opacity.
-Materials Uses of Zinc oxide:
The highest purity material is calcined with additives such as Bi2O3 and used in the manufacture of varistors.
The photoconducting properties of Zinc oxide are used in photoreproduction processes.
Doping with alumina causes a reduction in electrical resistance; hence, Zinc oxide can be used in the coatings on the master papers for offset reproduction.
Zinc oxide is used as a catalyst in organic syntheses (e.g., of methanol), often in conjunction with other oxides.
Zinc oxide is present in some adhesive compositions.
-Corrosion prevention in nuclear reactors use of Zinc oxide:
Zinc oxide depleted in 64Zn (the zinc isotope with atomic mass 64) is used in corrosion prevention in nuclear pressurized water reactors.
The depletion is necessary, because 64Zn is transformed into radioactive 65Zn under irradiation by the reactor neutrons.
*Methane reforming
Zinc oxide (ZnO) is used as a pretreatment step to remove hydrogen sulfide (H2S) from natural gas following hydrogenation of any sulfur compounds prior to a methane reformer, which can poison the catalyst.
At temperatures between about 230–430 °C (446–806 °F), H2S is converted to water by the following reaction:
H2S + ZnO → H2O + ZnS
-Electronics use of Zinc oxide:
Zinc oxide has wide direct band gap (3.37 eV or 375 nm at room temperature).
Therefore, Zinc oxide's most common potential applications are in laser diodes and light emitting diodes (LEDs).
Moreover, ultrafast nonlinearities and photoconductive functions have been reported in Zinc oxide.
Some optoelectronic applications of Zinc oxide overlap with that of GaN, which has a similar band gap (~3.4 eV at room temperature).
Compared to GaN, ZnO has a larger exciton binding energy (~60 meV, 2.4 times of the room-temperature thermal energy), which results in bright room-temperature emission from Zinc oxide.
Zinc oxide can be combined with GaN for LED-applications.
For instance, a transparent conducting oxide layer and Zinc oxide nanostructures provide better light outcoupling.
Other properties of Zinc oxide favorable for electronic applications include its stability to high-energy radiation and its ability to be patterned by wet chemical etching.
Radiation resistance makes Zinc oxide a suitable candidate for space applications.
Nanostructured Zinc oxide is an effective medium both in powder and polycrystalline forms in random lasers, due to its high refractive index and aforementioned light emission properties.
-Gas sensors use of Zinc oxide:
Zinc oxide is used in semiconductor gas sensors for detecting airborne compounds such as hydrogen sulfide, nitrogen dioxide, and volatile organic compounds.
Zinc oxide is a semiconductor that becomes n-doped by adsorption of reducing compounds, which reduces the detected electrical resistance through the device, in a manner similar to the widely used tin oxide semiconductor gas sensors.
Zinc oxide is formed into nanostructures such as thin films, nanoparticles, nanopillars, or nanowires to provide a large surface area for interaction with gasses.
The sensors are made selective for specific gasses by doping or surface-attaching materials such as catalytic noble metals.
-Aspirational applications of Zinc oxide:
*Transparent electrodes:
Aluminium-doped Zinc oxide layers are used as transparent electrodes.
The components Zn and Al are much cheaper and less toxic compared to the generally used indium tin oxide (ITO).
One application which has begun to be commercially available is the use of Zinc oxide as the front contact for solar cells or of liquid crystal displays.
Transparent thin-film transistors (TTFT) can be produced with Zinc oxide.
As field-effect transistors, they do not need a p–n junction, thus avoiding the p-type doping problem of Zinc oxide.
Some of the field-effect transistors even use Zinc oxide nanorods as conducting channels.
-Piezoelectricity uses of Zinc oxide:
The piezoelectricity in textile fibers coated in Zinc oxide have been shown capable of fabricating "self-powered nanosystems" with everyday mechanical stress from wind or body movements.
*Photocatalysis
Zinc oxide, both in macro- and nano- scales, could in principle be used as an electrode in photocatalysis, mainly as an anode in green chemistry applications.
As a photocatalyst, Zinc oxide reacts when exposed to UV radiation and is used in photodegradation reactions to remove organic pollutants from the environment.
Zinc oxide is also used to replace catalysts used in photochemical reactions that would ordinarily require costly or inconvenient reaction conditions with low yields.
-Sunscreen uses of Zinc oxide:
Zinc oxide is used in sunscreen to absorb ultraviolet light.
It is the broadest spectrum UVA and UVB absorber that is approved for use as a sunscreen by the U.S. Food and Drug Administration (FDA), and is completely photostable.
When used as an ingredient in sunscreen, zinc oxide blocks both UVA (320–400 nm) and UVB (280–320 nm) rays of ultraviolet light.
Zinc oxide and the other most common physical sunscreen, titanium dioxide, are considered to be nonirritating, nonallergenic, and non-comedogenic.
Zinc from zinc oxide is, however, slightly absorbed into the skin.
Many sunscreens use nanoparticles of zinc oxide (along with nanoparticles of titanium dioxide) because such small particles do not scatter light and therefore do not appear white.
The nanoparticles are not absorbed into the skin more than regular-sized zinc oxide particles are and are only absorbed into the outermost layer of the skin but not into the body.
-Food additive uses of Zinc oxide:
Zinc oxide is added to many food products, including breakfast cereals, as a source of zinc, a necessary nutrient.
Zinc may be added to food in the form of zinc oxide nanoparticles, or as zinc sulfate, zinc gluconate, zinc acetate, or zinc citrate.
Some foods also include trace amounts of Zinc oxide even if it is not intended as a nutrient.
-Pigment uses of Zinc oxide:
Zinc oxide (zinc white) is used as a pigment in paints and is more opaque than lithopone, but less opaque than titanium dioxide.
Zinc oxide is also used in coatings for paper.
Chinese white is a special grade of zinc white used in artists' pigments.
The use of zinc white as a pigment in oil painting started in the middle of 18th century.
Zinc oxide has partly replaced the poisonous lead white and was used by painters such as Böcklin, Van Gogh, Manet, Munch and others, though it is being phased out by some artists paint manufacturers because of its tendency to form brittle and unstable paint films in oils.
Zinc oxide is also a main ingredient of mineral makeup (CI 77947).
-UV absorber use of Zinc oxide:
Micronized and nano-scale zinc oxide provides strong protection against UVA and UVB ultraviolet radiation, and are consequently used in sunscreens, and also in UV-blocking sunglasses for use in space and for protection when welding.
-Coatings use of Zinc oxide:
Paints containing zinc oxide powder have long been utilized as anticorrosive coatings for metals.
They are especially effective for galvanized iron.
Iron is difficult to protect because its reactivity with organic coatings leads to brittleness and lack of adhesion.
Zinc oxide paints retain their flexibility and adherence on such surfaces for many years.
CHARACTERISTICS & BENEFITS of ZINC OXIDE:
*Broad utility:
Because of Zinc oxide's high melting point, chemical stability (in many conditions), wide band-gap semiconductor behaviour (for electronics/optics) and good UV-absorbing/reflection properties, ZnO is a very versatile material.
*In skin/consumer health products:
Zinc oxide acts as a physical barrier to UV radiation, provides mild skin protection, antimicrobial/antibacterial properties in some contexts (especially nano-forms) and irritant-soothing benefits.
*Pigment/white pigment (“zinc white”):
Low toxicity compared to lead or cadmium whites historically, good whiteness/reflection, used in coatings and paints.
*Environmental benefit:
Some suppliers highlight recycling/residue usage in ZnO production (e.g., converting galvanizing industry residues to ZnO).
ELECTRONIC AND OPTICAL PROPERTIES of ZINC OXIDE:
Favourable properties of zinc oxide include good transparency, high electron mobility, wide band gap, and strong room-temperature luminescence.
Those properties make Zinc oxide valuable for a variety of emerging applications: transparent electrodes in liquid crystal displays, energy-saving or heat-protecting windows, and electronics as thin-film transistors and light-emitting diodes.
Zinc oxide is a semiconductor of the II-VI semiconductor group and it has a relatively wide direct band gap of ~3.3 eV at room temperature.
Advantages associated with a wide band gap include higher breakdown voltages, ability to sustain large electric fields, lower electronic noise, and high-temperature and high-power operation.
The band gap of Zinc oxide can further be tuned to ~3–4 eV by its alloying with magnesium oxide or cadmium oxide.
Due to this large band gap, there have been efforts to create visibly transparent solar cells utilising Zinc oxide as a light absorbing layer.
However, these solar cells have so far proven highly inefficient.
Most Zinc oxide has n-type character, even in the absence of intentional doping.
Nonstoichiometry is typically the origin of this n-type character, but the subject remains controversial.
An alternative explanation has been proposed, based on theoretical calculations, that unintentional substitutional hydrogen impurities are responsible.
Controllable n-type doping is easily achieved by substituting Zn with group-III elements such as Al, Ga, In or by substituting oxygen with group-VII elements chlorine or iodine.
Reliable p-type doping of Zinc oxide remains difficult.
This problem originates from low solubility of p-type dopants and their compensation by abundant n-type impurities.
This problem is observed with GaN and ZnSe.
Measurement of p-type in "intrinsically" n-type material is complicated by the inhomogeneity of samples.
Current limitations to p-doping limit electronic and optoelectronic applications of Zinc oxide, which usually require junctions of n-type and p-type material.
Known p-type dopants include group-I elements Li, Na, K; group-V elements N, P and As; as well as copper and silver.
However, many of these form deep acceptors and do not produce significant p-type conduction at room temperature.
Electron mobility of Zinc oxide strongly varies with temperature and has a maximum of ~2000 cm2/(V·s) at 80 K.
Data on hole mobility are scarce with values in the range 5–30 cm2/(V·s).
Zinc oxide discs, acting as a varistor, are the active material in most surge arresters.
Zinc oxide is noted for its strongly nonlinear optical properties, especially in bulk.
The nonlinearity of Zinc oxide nanoparticles can be fine-tuned according to their size.
MANUFACTURING PROCESS of ZINC OXIDE:
Most of the Zinc oxide used today is produced from sphalerite, ZnS, as the starting ore by either the direct, US process, or the indirect, French process.
In the US process a compound containing Zinc oxide is reduced with coal to zinc vapor, which is oxidized to ZnO powder.
The French process takes place in two steps.
Zinc metal is first vaporized and the vapor is then oxidized with the Zinc oxide powder being collected.
WHAT IS ZINC OXIDE USED FOR?
Thanks to its many beneficial properties, Zinc oxide can be found in a variety of cosmetic and personal care products.
Most commonly Zinc oxide is present in sunscreens, and it also has other benefits for the skin, including anti-inflammatory and antimicrobial properties.
*Sun care & skin care:
Zinc oxide is added to skin care products because of its ability to treat and prevent acne, soothe irritated skin, and promote wound healing.
Zinc oxide is also an effective natural sunscreen that provides broad-spectrum protection against UVA and UVB rays.
Zinc oxide also acts as a natural colorant and a thickening agent.
Zinc oxide can be found in foundations, powders, and other makeup products to provide a matte finish and even out skin tone.
ORIGIN of ZINC OXIDE:
Zinc Oxide is a natural ingredient that is derived from the mineral zincite.
Zinc oxide is made by heating the mineral to a high temperature and vaporizing it.
The vapor is then oxidized to form Zinc Oxide particles, which are then collected and purified.
The size of the particles can be controlled to produce different grades of Zinc Oxide with varying properties.
WHAT DOES ZINC OXIDE DO IN A FORMULATION?
*ANTIMICROBIAL
*BULKING
*SKIN PROTECTING
*UV ABSORBER
Zinc Oxide is a safe ingredient and is good for the skin as it is non-toxic and non-comedogenic.
However, Zinc oxide is important to note that some people may have a high sensitivity or allergic reaction to the ingredient.
Therefore, a patch test is highly recommended prior to full usage, especially in the case of sensitive skin.
Additionally, Zinc oxide is biodegradable and good for the environment, making it quite a popular choice in many formulations.
Zinc Oxide is also vegan and halal.
ALTERNATIVES of ZINC OXIDE:
*TITANIUM DIOXIDE
*CI 77491
SYNTHESIS of ZINC OXIDE:
Zinc ore is roasted and purified at 1000°C.
The two methods of manufacture are (1) French, an indirect method and (2) American, a direct method.
ZnO is in the form of transparent hexagonal crystals.
The refractive index of this material is 2.0 with whiteness due to the scattering of light by the ultrafine particles.
The coverage on the skin of ZnO is subordinate to that of TiO2.8
This material is soluble in acid and alkali with good heat and light stability.
PREPARATION of ZINC OXIDE:
Zinc oxide is obtained as an intermediate in recovering zinc from minerals (See Zinc, Recovery).
Zinc oxide is prepared by vaporizing zinc metal and oxidation of the zinc vapors with preheated air (French process).
Zinc oxide can be produced by other processes.
Another method involves roasting franklinite and other ores with coal and then oxidizing Zinc oxide in air.
WHAT IS TOPICAL ZINC OXIDE USED FOR?
Topical zinc oxide is commonly used to protect irritated skin.
Zinc oxide is also used to prevent and treat rashes caused by exposure to wetness, such as the following.
**Diaper rash
Rash caused by leakage of urine (pee) or stool (poop), also called incontinence
Topical zinc oxide may also be used for other conditions as determined by your health care provider.
Zinc is also available as a dietary supplement in various strengths and dosage forms.
Zinc is also available as a prescription product to treat Wilson’s disease, a genetic disorder that causes excessive buildup of copper in the body.
Zinc oxide is a mineral.
Zinc oxide topical (for the skin) is used to treat diaper rash, minor burns, severely chapped skin, or other minor skin irritations.
Zinc oxide rectal suppositories are used to treat itching, burning, irritation, and other rectal discomfort caused by hemorrhoids or painful bowel movements.
There are many brands and forms of zinc oxide available.
Not all brands are listed on this leaflet.
Zinc oxide topical may also be used for purposes not listed in this medication guide.
FUNCTION(S) of ZINC OXIDE IN COSMETIC PRODUCTS
*ANTIMICROBIAL
Zinc oxide helps control the growth of micro-organisms (eg bacteria and fungi)
*BULKING
Zinc oxide reduces the density of cosmetic products by swelling
*LIGHT STABILIZER
Protecting the cosmetic product from deterioration effects of light
*ORAL CARE
Zinc oxide cleans, deodorises and / or protects the oral cavity or teeth
*SKIN PROTECTING
Zinc oxide protects the skin from external influences
*UV ABSORBER
Zinc oxide protects the cosmetic product from damage caused by UV light
*UV FILTER
Zinc oxiderotects skin or hair from harmful UV radiation
MECHANICAL PROPERTIES of ZINC OXIDE:
Zinc oxide is a relatively soft material with approximate hardness of 4.5 on the Mohs scale.
Zinc oxide's elastic constants are smaller than those of relevant III-V semiconductors, such as GaN.
The high heat capacity and heat conductivity, low thermal expansion and high melting temperature of Zinc oxide are beneficial for ceramics.
The E2 optical phonon in Zinc oxide exhibits an unusually long lifetime of 133 ps at 10 K.
Among the tetrahedrally bonded semiconductors, it has been stated that Zinc oxide has the highest piezoelectric tensor, or at least one comparable to that of GaN and AlN.
This property makes Zinc oxide a technologically important material for many piezoelectrical applications, which require a large electromechanical coupling.
Therefore, Zinc oxide in the form of thin film has been one of the most studied and used resonator materials for thin-film bulk acoustic resonators.
PHYSICAL PROPERTIES of ZINC OXIDE:
Structure
Zinc oxide crystallizes in two main forms, hexagonal wurtzite[31] and cubic zincblende.
The wurtzite structure is most stable at ambient conditions and thus most common.
The zincblende form can be stabilized by growing Zinc oxide on substrates with cubic lattice structure.
In both cases, the zinc and oxide centers are tetrahedral, the most characteristic geometry for Zn(II).
Zinc oxide converts to the rocksalt motif at relatively high pressures about 10 GPa.
Hexagonal and zincblende polymorphs have no inversion symmetry (reflection of a crystal relative to any given point does not transform it into itself).
This and other lattice symmetry properties result in piezoelectricity of the hexagonal and zincblende Zinc oxide, and pyroelectricity of hexagonal Zinc oxide.
The hexagonal structure has a point group 6 mm (Hermann–Mauguin notation) or C6v (Schoenflies notation), and the space group is P63mc or C6v4.
The lattice constants are a = 3.25 Å and c = 5.2 Å; their ratio c/a ~ 1.60 is close to the ideal value for hexagonal cell c/a = 1.633.
As in most group II-VI materials, the bonding in Zinc oxide is largely ionic (Zn2+O2−) with the corresponding radii of 0.074 nm for Zn2+ and 0.140 nm for O2−.
This property accounts for the preferential formation of wurtzite rather than zinc blende structure, as well as the strong piezoelectricity of Zinc oxide.
Because of the polar Zn−O bonds, zinc and oxygen planes are electrically charged.
To maintain electrical neutrality, those planes reconstruct at atomic level in most relative materials, but not in Zinc oxide – its surfaces are atomically flat, stable and exhibit no reconstruction.
However, studies using wurtzoid structures explained the origin of surface flatness and the absence of reconstruction at ZnO wurtzite surfaces in addition to the origin of charges on Zinc oxide planes.
CHEMICAL PROPERTIES of ZINC OXIDE:
Pure Zinc oxide is a white powder.
However, in nature, Zinc oxide occurs as the rare mineral zincite, which usually contains manganese and other impurities that confer a yellow to red color.
Crystalline zinc oxide is thermochromic, changing from white to yellow when heated in air and reverting to white on cooling.
This color change is caused by a small loss of oxygen to the environment at high temperatures to form the non-stoichiometric Zn1+xO, where at 800 °C, x = 0.00007.
Zinc oxide is an amphoteric oxide.
Zinc oxide is nearly insoluble in water, but it will dissolve in most acids, such as hydrochloric acid:
ZnO + 2 HCl → ZnCl2 + H2O
Solid zinc oxide will also dissolve in alkalis to give soluble zincates:
ZnO + 2 NaOH + H2O → Na2[Zn(OH)4]
Zinc oxide reacts slowly with fatty acids in oils to produce the corresponding carboxylates, such as oleate or stearate.
When mixed with a strong aqueous solution of zinc chloride, Zinc oxide forms cement-like products best described as zinc hydroxy chlorides.
This cement was used in dentistry.
Zinc oxide also forms cement-like material when treated with phosphoric acid; related materials are used in dentistry.
A major component of zinc phosphate cement produced by this reaction is hopeite, Zn3(PO4)2·4H2O.
Zinc oxide decomposes into zinc vapor and oxygen at around 1975 °C with a standard oxygen pressure.
In a carbothermic reaction, heating with carbon converts the oxide into zinc vapor at a much lower temperature (around 950 °C).
ZnO + C → Zn(Vapor) + CO
PRODUCTION of ZINC OXIDE:
For industrial use, Zinc oxide is produced at levels of 105 tons per year by three main processes:
*Indirect process
In the indirect or French process, metallic zinc is melted in a graphite crucible and vaporized at temperatures above 907 °C (typically around 1000 °C).
Zinc vapor reacts with the oxygen in the air to give ZnO, accompanied by a drop in its temperature and bright luminescence.
Zinc oxide particles are transported into a cooling duct and collected in a bag house.
This indirect method was popularized by Edme Jean LeClaire of Paris in 1844 and therefore is commonly known as the French process.
Its product normally consists of agglomerated zinc oxide particles with an average size of 0.1 to a few micrometers.
By weight, most of the world's zinc oxide is manufactured via French process.
*Direct process
The direct or American process starts with diverse contaminated zinc composites, such as zinc ores or smelter by-products.
The zinc precursors are reduced (carbothermal reduction) by heating with a source of carbon such as anthracite to produce zinc vapor, which is then oxidized as in the indirect process.
Because of the lower purity of the source material, the final product is also of lower quality in the direct process as compared to the indirect one.
*Wet chemical process
A small amount of industrial production involves wet chemical processes, which start with aqueous solutions of zinc salts, from which zinc carbonate or zinc hydroxide is precipitated.
The solid precipitate is then calcined at temperatures around 800 °C.
*Laboratory synthesis
Numerous specialised methods exist for producing Zinc oxide for scientific studies and niche applications.
These methods can be classified by the resulting Zinc oxide form (bulk, thin film, nanowire), temperature ("low", that is close to room temperature or "high", that is T ~ 1000 °C), process type (vapor deposition or growth from solution) and other parameters.
Large single crystals (many cubic centimeters) can be grown by the gas transport (vapor-phase deposition), hydrothermal synthesis, or melt growth.
However, because of the high vapor pressure of Zinc oxide, growth from the melt is problematic.
Growth by gas transport is difficult to control, leaving the hydrothermal method as a preference.
Thin films can be produced by a variety of methods including chemical vapor deposition, metalorganic vapour phase epitaxy, electrodeposition, sputtering, spray pyrolysis, thermal oxidation, sol–gel synthesis, atomic layer deposition, and pulsed laser deposition.
Zinc oxide can be produced in bulk by precipitation from zinc compounds, mainly zinc acetate, in various solutions, such as aqueous sodium hydroxide or aqueous ammonium carbonate.
Synthetic methods characterized in literature since the year 2000 aim to produce Zinc oxide particles with high surface area and minimal size distribution, including precipitation, mechanochemical, sol-gel, microwave, and emulsion methods.
NANOSTRUCTURES of ZINC OXIDE:
Nanostructures of Zinc oxide can be synthesized into a variety of morphologies, including nanowires, nanorods, tetrapods, nanobelts, nanoflowers, nanoparticles, etc.
Nanostructures can be obtained with most above-mentioned techniques, at certain conditions, and also with the vapor–liquid–solid method.
The synthesis is typically carried out at temperatures of about 90 °C, in an equimolar aqueous solution of zinc nitrate and hexamine, the latter providing the basic environment.
Certain additives, such as polyethylene glycol or polyethylenimine, can improve the aspect ratio of the Zinc oxide nanowires.
Doping of the Zinc oxide nanowires has been achieved by adding other metal nitrates to the growth solution.
The morphology of the resulting nanostructures can be tuned by changing the parameters relating to the precursor composition (such as the zinc concentration and pH) or to the thermal treatment (such as the temperature and heating rate).
Aligned Zinc oxide nanowires on pre-seeded silicon, glass, and gallium nitride substrates have been grown using aqueous zinc salts such as zinc nitrate and zinc acetate in basic environments.
Pre-seeding substrates with Zinc oxide creates sites for homogeneous nucleation of ZnO crystal during the synthesis.
Common pre-seeding methods include in-situ thermal decomposition of zinc acetate crystallites, spin coating of ZnO nanoparticles, and the use of physical vapor deposition methods to deposit Zinc oxide thin films.
Pre-seeding can be performed in conjunction with top down patterning methods such as electron beam lithography and nanosphere lithography to designate nucleation sites prior to growth.
Aligned Zinc oxide nanowires can be used in dye-sensitized solar cells and field emission devices.
PRODUCTION METHODS of ZINC OXIDE:
(1) At present, used methods are the indirect method for zinc ingots as raw materials (also known as the French law), zinc ore as raw material direct method (also known as the United States) and wet.
Indirect method.
Reaction equation:2ZnO+O2→2ZnO
Operation method: The zinc ingots produced by the electrolysis method are heated to 600-700 ° C and melted, placed in a high temperature crucible, melted and vaporized at a temperature of 1250-1300 ° C, introduced into hot air for oxidation, and the resulting zinc oxide is cooled, cyclone separation, the fine particles with a bag to collect, that is, zinc oxide products.
***Direct method.
Reaction equation:
C+O2→CO2
CO2+C→CO
ZnO+CO→Zn(Steam）+CO2
Zn(Steam）+CO+O2→ZnO+CO2
Operation method: Roasted zinc ore powder (or zinc material) and anthracite (or coke quietly), limestone formulated into a ball in the ratio of 1: 0.5: 0.05.
After reduction and smelting at 1300 ℃, the zinc oxide in the ore powder is reduced to zinc vapor, then oxidized by air, and the produced zinc oxide is collected to obtain the zinc oxide product.
***Wet method.
Zinc sulfate and sulfuric acid reaction to get zinc sulfate, and then reaction with sodium carbonate and ammonia respectively, the obtained zinc carbonate and zinc hydroxide were used as raw materials to produce zinc oxide.
The reaction equation is as follows:
Zn+H2SO4→ZnSO4+H2↑
ZnSO4+Na2CO3→ZnCO3+Na2SO4
ZnSO4+2NH3•H2O→Zn(OH)2+(NH4)2SO4
Using zinc carbonate as raw material, after washing, drying, calcining and crushing to obtain products of Zinc Oxide.
ZnCO2→ZnO+CO2↑
With zinc hydroxide as raw material, after washing, drying, calcination, precipitation, cooling and crushing to obtain products of Zinc Oxide.
Zn(OH)2→ZnO+H2O
(2) Basic zinc carbonate calcination method: production methods of active zinc oxide are more, Most of the low-grade zinc oxide or zinc ore as raw materials, and reaction with dilute sulfuric acid solution, made of zinc sulfate solution, the solution heated to 80~90 ℃, removing iron and manganese with joining Potassium Permanganate oxide, and then heated to 80℃, adding zinc, replacing the liquid copper, nickel, cadmium, after replacement, for second oxidation removal of impurities with Potassium Permanganate in 80 to 90℃, refined zinc sulfate solution, use soda ash and, until the pH value is 6.8, the formation of basic zinc carbonate, filtered, rinsed to remove the sulfate and excess alkali, and then dried and calcined at 500~550 ℃ to get active zinc oxide.
ZnO+H2SO4→ZnSO4+H2O
3ZrSO4+3Na2CO3+3H2O→ZnCO3.2Zn(OH)2.H2O+3Na2SO4+2CO2↑
ZnCO3.2Zn(OH)2.H2O→3ZnO+C02++3H2O
HISTORY of ZINC OXIDE:
Early humans probably used zinc compounds in processed and unprocessed forms, as paint or medicinal ointment; however, their composition is uncertain.
The use of pushpanjan, probably zinc oxide, as a salve for eyes and open wounds is mentioned in the Indian medical text the Charaka Samhita, thought to date from 500 BC or before.
Zinc oxide ointment is also mentioned by the Greek physician Dioscorides (1st century AD).
Galen suggested treating ulcerating cancers with zinc oxide, as did Avicenna in his The Canon of Medicine.
Zinc oxide is used as an ingredient in products such as baby powder and creams against diaper rashes, calamine cream, anti-dandruff shampoos, and antiseptic ointments.
The Romans produced considerable quantities of brass (an alloy of zinc and copper) as early as 200 BC by a cementation process where copper was reacted with zinc oxide.
The zinc oxide is thought to have been produced by heating zinc ore in a shaft furnace.
This liberated metallic zinc as a vapor, which then ascended the flue and condensed as the oxide.
This process was described by Dioscorides in the 1st century AD.
Zinc oxide has also been recovered from zinc mines at Zawar in India, dating from the second half of the first millennium BC.
From the 12th to the 16th century, zinc and zinc oxide were recognized and produced in India using a primitive form of the direct synthesis process.
From India, zinc manufacturing moved to China in the 17th century.
In 1743, the first European zinc smelter was established in Bristol, United Kingdom.
Around 1782, Louis-Bernard Guyton de Morveau proposed replacing lead white pigment with zinc oxide.
The main usage of zinc oxide (zinc white) was in paints and as an additive to ointments.
Zinc white was accepted as a pigment in oil paintings by 1834 but it did not mix well with oil.
This problem was solved by optimizing the synthesis of ZnO.
In 1845, Edme-Jean Leclaire in Paris was producing the oil paint on a large scale; by 1850, zinc white was being manufactured throughout Europe.
The success of zinc white paint was due to its advantages over the traditional white lead: zinc white is essentially permanent in sunlight, it is not blackened by sulfur-bearing air, it is non-toxic and more economical.
Because zinc white is so "clean" it is valuable for making tints with other colors, but it makes a rather brittle dry film when unmixed with other colors.
For example, during the late 1890s and early 1900s, some artists used zinc white as a ground for their oil paintings.
These paintings developed cracks over time.
In recent times, most zinc oxide has been used in the rubber industry to resist corrosion.
In the 1970s, the second largest application of ZnO was photocopying.
High-quality Zinc oxide produced by the "French process" was added to photocopying paper as a filler.
This application was soon displaced by titanium.
FUNCTIONS (INCI) of ZINC OXIDE:
Antimicrobial :
Zinc oxide helps slowing the growth of micro-organisms on the skin and counteracts the development of microbes
*Bulking :
Zinc oxide reduces apparent cosmetics density.
*Cosmetic colorant :
Color cosmetics and / or give a color to the skin
*Oral care/hygiene agent :
Zinc oxide provides cosmetic effects to the oral cavity (cleaning, deodorization and protection)
*Skin protecting :
Zinc oxide helps to avoid the harmful effects of external factors on the skin
*Stabilising :
Zinc oxide improves ingredients or stability of the formula and shelf life
*Uv absorber :
Zinc oxide protects the cosmetic product from UV-light effects
*Uv filter :
Zinc oxide filters certain UV rays to protect the skin or hair from the harmful effects of these rays.
ZINC OXIDE IS PRESENT IN:
Zinc oxide is present in 1.7% of cosmetics.
*Diaper cream (73.44%)
*Cc cream (33.26%)
*Bb cream (18.96%)
*Talc and powder (18.89%)
*Cream deodorant (17.42%)
HISTORY of ZINC OXIDE:
Humans have long learned to use zinc oxide as a coating or topical medicine, but the history of human discovery of zinc oxide has been difficult to trace.
In the "Chakra" which is Ancient India medical literature recorded in a later identified as zinc oxide drugs, used to treat eye diseases and trauma.
The first century AD, the Greek doctor Dioscorides also referred to use zinc oxide to do the ointment.
Avicenna completed in 1025 the "Hui prescription" in Zinc Oxide described for the treatment of various skin diseases, including skin cancer drug of choice.
Nowadays, people no longer use zinc oxide to treat skin cancer, but still widely used in the treatment of other common skin diseases.
As early as 200 BC, the Romans learned how to react with copper and zinc ore containing zinc oxide to make brass.
Zinc oxide into zinc vapor in the shaft furnace, rolled into the flue reaction.
Dioscorides also introduced this.
Since the 12th century, the Indians have known zinc and zinc ore, and began to make zinc using the original way.
Zinc smelting technology introduced in China in seventeenth Century.
1743, Bristol, Britain established the first zinc smelting plant in Europe.
Another major use of zinc oxide is used as a coating, called zinc white.
In 1834, zinc white became the Chinese watercolor paint for the first time, but insoluble in oil.
But soon the problem was solved by the new zinc oxide production process.
In 1845, Leclerc began to manufacture pigment of zinc white oil painting on a large scale in Paris, to 1850, zinc white popular throughout Europe.
The purity of zinc white was so high that some artists painted zinc-white as a background at the end of the nineteenth century, but these paintings were cracked after a hundred years.
In the second half of the 20th century, zinc oxide used in the rubber industry.
In the 1970s, the second major use of zinc oxide is the additives of copy paper, but in the 21st century, the approach of zinc oxide has been eliminated as a copy paper additive.
CHEMICAL PROPERTIES of ZINC OXIDE:
Zinc oxide is a white hexagonal crystal or powder.
Zinc oxide is a tasteless, fine quality.
Zinc oxide is dissolved in acid, sodium hydroxide, ammonium chloride, do not dissolve in water, ethanol and ammonia.
REACTIONS of ZINC OXIDE:
Zinc oxide reacts with mineral acids to yield corresponding zinc salts when the solution is evaporated.
Thus, with sulfuric acid it forms zinc sulfate (hydrated):
ZnO + H2SO4 → ZnSO4 + H2O
Reactions with organic acids such as acetic or propionic acid yields zinc acetate, (CH3COO)2Zn, or zinc propionate, (CH3CH2COO)2Zn, upon concentration.
Fusion of zinc oxide with fatty acids at elevated temperatures produces fatty salts.
Thus, fusion with oleic or linoleic acid forms zinc oleate, Zn(C17H33COO)2, or zinc linoleate, Zn(C17H31COO)2.
Reaction with tellurium powder in alkaline solution yields red crystalline zinc telluride, ZnTe.
Zinc oxide reacts with potassium dichromate in solution in the presence of sulfuric acid to form a greenish-yellow pigment, zinc yellow or citron yellow [11103-86-9], 4ZnO•4CrO3•K2O•3H2O.
PHYSICAL and CHEMICAL PROPERTIES of ZINC OXIDE:
CAS Number: 1314-13-2.
EC / EINECS Number: 215-222-5.
Molecular formula: ZnO.
Molar mass: ~ 81.39-81.41 g/mol.
IUPAC name: zinc(II) oxide
Appearance: White (to pale yellowish) powder or crystalline solid.
Odour: Odourless.
Density / Specific gravity: ~ 5.6 g/cm³ (solid).
Melting point: ~ 1975 °C (decomposes rather than true melting) for ZnO.
Boiling point / decomposition: ~ 2360 °C (or higher) when decomposes rather than truly boils.
Solubility: Practically insoluble in water (very low solubility ~1.6 mg/L at 29 °C reported).
Crystal structure: Commonly hexagonal wurtzite structure under ambient conditions.
Other chemical behaviours: Amphoteric oxide (reacts with acids and strong bases) — dissolves in dilute acids and alkalis.
Refractive index: ~2.008–2.029 reported for certain forms.
Additional: For nanoforms, specific surface area, pore volume, crystallite size etc vary significantly.
Hydrogen Bond Donor Count: 0
Hydrogen Bond Acceptor Count: 1
Rotatable Bond Count: 0
Exact Mass: 79.924056 Da
Monoisotopic Mass: 79.924056 Da
Topological Polar Surface Area: 1 Ų
Heavy Atom Count: 2
Formal Charge: 0
Complexity: 0
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 2
Compound Is Canonicalized: Yes
Physical state: powder
Color: white
Odor: odorless
Melting point/freezing point: > 1,000 °C at ca.1.013,25 hPa
Initial boiling point and boiling range: No data available
Flammability (solid, gas): No data available
Upper/lower flammability or explosive limits: No data available
Flash point: Not applicable
Autoignition temperature: No data available
Decomposition temperature: No data available
pH: 6.72
Viscosity, kinematic: No data available
Viscosity, dynamic: No data available
Water solubility: 0.0029 g/L at 20 °C - slightly soluble
Partition coefficient (n-octanol/water): Not applicable for inorganic substances
Vapor pressure: No data available
Density: 5.68 g/cm³ at 22 °C
Relative density: 5.68 at 22 °C - Regulation (EC) No. 440/2008, Annex, A.3
Relative vapor density: No data available
Particle characteristics: No data available
Explosive properties: No data available
Oxidizing properties: none
Other safety information: No data available
Molecular Formula: OZn (ZnO)
Molecular Weight: 81.39 g/mol
MDL Number: MFCD00011300
MOL File: 1314-13-2.mol
Physical Properties:
Melting point: 1975 °C
Boiling point: 1949.9 °C (estimate)
Density: 5.6 g/cm³
Bulk density: 200–700 kg/m³
Refractive index: 2.008–2.029
Flash point: 27 °C
Storage temperature: Store at +5 °C to +30 °C
Solubility: 0.0016 g/L, practically insoluble
Form: nanopowder
Color: White to pale yellow
Specific Gravity: 5.61
pH: 7 (50 g/L, H₂O, 20 °C, slurry)
Odor: White to gray powder or crystals, odorless, bitter taste
Viscosity: 3 cP
Water Solubility: 1.6 mg/L (29 °C)
Crystal Properties:
Crystal structure: ZnO type
Crystal system: Hexagonal (six sides)
Space group: P63mc
Merck: 14,10147
FIRST AID MEASURES of ZINC OXIDE:
-Description of first-aid measures
*General advice:
Show this material safety data sheet to the doctor in attendance.
*If inhaled:
After inhalation:
Fresh air.
*In case of skin contact:
Take off immediately all contaminated clothing.
Rinse skin with
water/ shower.
*In case of eye contact:
After eye contact:
Rinse out with plenty of water.
Call in ophthalmologist.
Remove contact lenses.
*If swallowed:
After swallowing:
Immediately make victim drink water (two glasses at most).
Consult a physician.
-Indication of any immediate medical attention and special treatment needed.
No data available
ACCIDENTAL RELEASE MEASURES of ZINC OXIDE:
-Environmental precautions:
Do not let product enter drains.
-Methods and materials for containment and cleaning up:
Cover drains.
Collect, bind, and pump off spills.
Observe possible material restrictions.
Take up dry.
Dispose of properly.
Clean up affected area.
FIRE FIGHTING MEASURES of ZINC OXIDE:
-Extinguishing media:
*Suitable extinguishing media:
Carbon dioxide (CO2)
Foam
Dry powder
*Unsuitable extinguishing media:
For this substance/mixture no limitations of extinguishing agents are given.
-Further information:
Prevent fire extinguishing water from contaminating surface water or the ground water system.
EXPOSURE CONTROLS/PERSONAL PROTECTION of ZINC OXIDE:
-Control parameters:
--Ingredients with workplace control parameters:
-Exposure controls:
--Personal protective equipment:
*Eye/face protection:
Use equipment for eye protection.
Safety glasses
*Body Protection:
protective clothing
*Respiratory protection:
Recommended Filter type: Filter A
-Control of environmental exposure:
Do not let product enter drains.
HANDLING and STORAGE of ZINC OXIDE:
-Conditions for safe storage, including any incompatibilities:
*Storage conditions:
Tightly closed.
Dry.
STABILITY and REACTIVITY of ZINC OXIDE:
-Chemical stability:
The product is chemically stable under standard ambient conditions (room temperature).
-Possibility of hazardous reactions:
No data available
