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OTHER CHEMICALS > Hydrogen Peroxide

Hydrogen peroxide is the simplest peroxide. It is also a strong oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless.

Formula: 2(HO), Density: 1.45 g/cm³, Melting point: -0.43 °C, Boiling point: 150.2 °C, IUPAC ID: dihydrogen dioxide, Molar mass: 34.0147 g/mol

Uses :

Water treatment

Drinking water treatment

Hydrogen peroxide can be used for cleaning well water or other drinking water sources, by removing odors, organic materials that change the water taste, and the removal of H2S and Iron, while reducing trihalomethanes and haloacetic acids. Hydrogen peroxide can be used to increase or decrease the amount of ozone in drinking water.

Wastewater treatment

Hydrogen peroxide is replacing prechlorination as a way to deal with odors entering wastewater treatment plants:

Sulfide oxidation

Hydrogen peroxide has been utilized to minimize hydrogen sulfide (H2S) formation.

The processing of wastewater sludge (or biosolids) can cause the generation of hydrogen sulfide, a poisonous and odoriferous gas. Hydrogen sulfide can also damage equipment and concrete structures.

Sulfides are found throughout the environment as a result of both natural and industrial processes. Most sulfides found in nature were produced biologically (under anaerobic conditions) and occur as free hydrogen sulfide (H2S) – characterized by its rotten egg odor. Biogenic H2S is encountered in sour groundwaters, swamps and marshes, natural gas deposits, and sewage collection/treatment systems. Man-made sources of H2S typically occur as a result of natural materials containing sulfur (e.g., coal, gas and oil) being refined into industrial products. For a variety of reasons – aesthetics (odor control), health (toxicity), ecological (oxygen depletion in receiving waters), and economic (corrosion of equipment and infrastructure) – sulfide laden wastewater must be handled carefully and go through a remediation process before it can be released to the environment. Typical discharge limits for sulfide are < 1 mg/L.

Hydrogen peroxide is a strong oxidizer effective in controlling sulfide and organic-related odors in wastewater collection and treatment systems. It is typically applied to a wastewater system where there is a retention time of 30 minutes to 5 hours before hydrogen sulfide is released. Hydrogen peroxide oxidizes the hydrogen sulfide and promotes bio-oxidation of organic odors.
BOD and COD removal from wastewater

Hydrogen peroxide decomposes to oxygen and water, adding dissolved oxygen to the system, thereby negating some Biochemical Oxygen Demand (BOD). Typical sewage at its first stage has aerobic organisms quickly consuming the oxygen, then dying and decomposing, and anaerobic organisms usually bacteria, set in, creating a toxic environment through their anaerobic digestion. In order to "re-vitalize" the water, various methods of aeration are typically used.

Hydrogen peroxide has been used to reduce the BOD and COD of industrial waste-water for many years. While the cost of removing BOD/COD through chemical oxidation is typically greater than that through physical or biological means, there are nonetheless specific situations which justify its use. These include:

    Pre-digestion of wastewater which contains moderate to high levels of compounds that are toxic, inhibitory, or recalcitrant to biological treatment (e.g., pesticides, plasticizers, resins, coolants, and dyestuffs);
    Pretreatment of high strength / low flow wastewater – where biotreatment may not be practical – prior to discharge to a Publicly Owned Treatment Works (POTW);
    Enhanced separation of entrained organics by flotation and settling processes; and

Supply of supplemental Dissolved Oxygen (DO) when biological treatment systems experience temporary overloads or equipment failure.

As indicated by these examples, hydrogen peroxide can be used as a stand-alone treatment or as an enhancement to existing physical or biological treatment processes, depending on the situation.
Nitrogen oxide (NOx) abatement

Nitrogen oxides are major pollutants in the atmosphere, being a precursor to acid rain, photochemical smog, and ozone accumulation. The oxides are mainly nitric oxide (NO) and nitrogen dioxide (NO2) both of which are corrosive and hazardous to health, typically created from the decomposition of organic materials, assisted by anaerobic organisms, or released during the combustion of fossil fuels.

With the use of catalytic converters on automobiles, the initial regulatory focus of controlling of mobile NOx emissions has reached the point where further restriction has become economically impractical. Consequently, the stationary sources of NOx emissions are now being subjected to more stringent standards in many areas of the U.S. Stationary sources include nitric acid manufacturing plants, manufacturers of nitrated materials such as fertilizer and explosives, and industrial manufacturers (metallurgical processors, glass manufacturers, cement kilns, power generators, etc.) where high processing temperatures are used.

Because of the environmental concerns posed by air pollution, much research time and money have been expended to develop methods for controlling NOx emissions. Several 'NOx scrubbing' processes have been developed, using H2O2 as part of the solution, where the nitrogen oxides are converted to nitrate, nitric acid or nitrogen.

Hydrogen peroxide is also used to eliminate nitrogen oxide development 'at the source', by reacting with HNO as it is formed, and eliminating its decomposition into NO or NO2.

Pollutants removal

Hydrogen peroxide is one of the most versatile, dependable and environmentally compatible oxidizing agents. The relative safety and simplicity of its use as an oxidizing agent has led to the development of a number of applications in refinery wastewater systems:

Uncatalyzed hydrogen peroxide

The strong oxidizing power of hydrogen peroxide makes it suitable for the destruction of a variety of pollutants. Optimization of conditions using hydrogen peroxide to destroy these pollutants can involve control of pH, temperature and reaction time. No additional additives are required.

Catalyzed hydrogen peroxide

Pollutants that are more difficult to oxidize require hydrogen peroxide to be activated with catalysts such as iron. Catalyzed oxidation can also be used to destroy easily oxidized pollutants more rapidly.

Under acid pH conditions, the addition of iron salts to a wastewater solution activates hydrogen peroxide to generate free radicals, which can attack a variety of organic compounds. Other metal salts and conditions can apply (e.g. in cyanide destruction, a copper catalyst can be used at a pH of 8.5 – 11.5).

Aeration for fish and plants


Some horticulturalists and users of hydroponics advocate the use of weak hydrogen peroxide solution in watering solutions. Its spontaneous decomposition releases oxygen that enhances a plant's root development and helps to treat root rot (cellular root death due to lack of oxygen) and a variety of other pests.

Fish Aeration

Laboratory tests conducted by fish culturists in recent years have demonstrated that common household hydrogen peroxide can be used safely to provide oxygen for small fish. The hydrogen peroxide releases oxygen by decomposition when it is exposed to catalysts such as manganese dioxide.

Industrial applications
ISO tank container for hydrogen peroxide transportation

Bleaching wood pulp

About 50% of the world's production of hydrogen peroxide in 1994 was used for pulp- and paper-bleaching.

Possible alternative to chlorine bleaches

Other bleaching applications are becoming more important as hydrogen peroxide is seen as an environmentally benign alternative to chlorine-based bleaches. However scientific studies have found hydrogen peroxide to be ineffective in certain cases, and generally instruct hospitals, medical institutions, and other locations where public health is monitored, to use chlorine-based bleaches for disinfection.

Mild bleaches in laundry detergents

Other major industrial applications for hydrogen peroxide include the manufacture of sodium percarbonate and sodium perborate, used as mild bleaches in laundry detergents.

Intermediate processes in the chemical industry

It is used in the production of certain organic peroxides, such as dibenzoyl peroxide, used in polymerisations and other chemical processes.

Hydrogen peroxide is also used in the production of epoxides, such as propylene oxide: Reaction with carboxylic acids produces a corresponding peroxy acid. Peracetic acid and meta-chloroperoxybenzoic acid (commonly abbreviated mCPBA) are prepared from acetic acid and meta-chlorobenzoic acid, respectively. The latter is commonly reacted with alkenes to give the corresponding epoxide.


In the PCB manufacturing process, hydrogen peroxide mixed with sulfuric acid was used as the microetch chemical for copper surface roughening preparation.

Instant steam

A combination of a powdered precious metal-based catalyst, hydrogen peroxide, methanol and water can produce superheated steam in one to two seconds, releasing only CO
2 and high-temperature steam for a variety of purposes.

Bio-decontamination validation

Recently, there has been increased use of vaporized hydrogen peroxide in the validation and bio-decontamination of half-suit and glove-port isolators in pharmaceutical production.
Rapid oxidation for nuclear plant shutdown

Nuclear pressurized water reactors (PWRs) use hydrogen peroxide during the plant shutdown to force the oxidation and dissolution of activated corrosion products deposited on the fuel. The corrosion products are then removed with the cleanup systems before the reactor is disassembled.

Oil and gas exploration fossil analysis

Hydrogen peroxide is also used in the oil and gas exploration industry to oxidize rock matrix in preparation for micro-fossil analysis.
Propylene oxide

A method of producing propylene oxide from hydrogen peroxide has been developed. The process is claimed to be environmentally friendly, since the only significant byproduct is water. Two of these "HPPO" (hydrogen peroxide to propylene oxide) plants came onstream in 2008: One of them located in Belgium is a Solvay, Dow-BASF joint venture, and the other in Korea is an EvonikHeadwaters, SK Chemicals joint venture. A caprolactam application for hydrogen peroxide has been commercialized. Potential routes to phenol and epichlorohydrin utilizing hydrogen peroxide have been postulated.

Therapeutic use

Hydrogen peroxide is generally recognized as safe (GRAS) as an antimicrobial agent, an oxidizing agent and for other purposes by the U.S. FDA. For example, 35% hydrogen peroxide is used to prevent infection transmission in the hospital environment, and hydrogen peroxide vapor is registered with the US EPA as a sporicidal sterilant.

On the other hand many false claims have been made about the therapeutic properties of hydrogen peroxide, some even lethal, as discussed below.

Disinfectant for inanimate objects

Hydrogen peroxide has been used, in sufficient concentrations, to disinfect inanimate objects. As stated above scientific research concluded that chlorine based disinfectants are better used in hospital and other public institutions.

Veterinary practice

Hydrogen peroxide is used as an emetic in veterinary practice.


Hydrogen peroxide mixed with baking soda and salt is used as a toothpaste, but its use was shown to be no more effective than toothpaste.

Acne treatment

Hydrogen peroxide and benzoyl peroxide are sometimes used to treat acne.[56] This too has been challenged by the medical establishment, after research showed that hydrogen peroxide even at minute quantities is harmful to the healing process.[2][4] A fundamental difference from benzoyl peroxide is that hydrogen peroxide is not lipid soluble. Benzoyl peroxide selectively concentrates in the follicles and sebaceous glands because of its lipophilic properties, but hydrogen peroxide is much less soluble in lipids and is a much smaller molecule. This allows it to penetrate at any point in the skin and enter damaged cells relatively easily, leading to the aforementioned harm to the healing process.

Disinfecting wounds

Commonly used as treatment for disinfecting wounds, there is a body of evidence, e.g.[3] and many reports since, that the use of large volumes of hydrogen peroxide over substantial tissue areas can lead to a dangerous oxygen embolism (gas embolism). While judicious use on surface wounds can utilize the catalase-caused "fizzing" effect to assist debridement and cleaning of soil from the wound, clinicians are recommended to consult the literature before using peroxide on wounds and tissue cavities. It has also been shown that hydrogen peroxide, even in dilute solutions and minute quantities can slow the healing process on wounds. Further, hydrogen peroxide applied to wounds can impede healing and lead to scarring because it destroys newly formed skin cells.

Cure for cancer

Following the call by alternative medicine advisors for drinking diluted hydrogen peroxide, and using it in various ways such as in shampoo and as an additive to toothpaste, as a treatment to illness in general and cancer in particular, the American Cancer Society states that "there is no scientific evidence that hydrogen peroxide is a safe, effective or useful cancer treatment", and advises cancer patients to "remain in the care of qualified doctors who use proven methods of treatment and approved clinical trials of promising new treatments."

Inhalation, Oral administration and Injection

For treatment of various illnesses, another alternative medical procedure advocated by this group of medical doctors (now banned from publishing their material) is intravenous injection of hydrogen peroxide, which has been linked to several deaths. Also advocated by this group and its followers are oral administration of "dilute quantities" of H2O2, and inhalation of hydrogen peroxide at a concentration of about 1%. These practices have been challenged by the medical establishment as well.

Domestic uses : Bleach, Fingertips, Skin shortly after exposure to 35% H2O2, Bleaching hair, Diluted H2O2 (between 3% and 8%) is used to bleach human hair when mixed with ammonium hydroxide. The chemical's bleaching property lends its name to the phrase "peroxide blonde".

Bleaching skin

It is absorbed by skin upon contact and creates a local skin capillary embolism that appears as a temporary whitening of the skin.

Bleaching bones for display

It is used to whiten bones that are to be put on display.

Cleaning blood stains 3% H2O2 is effective at treating fresh (red) blood-stains in clothing and on other items. It must be applied to clothing before blood stains are "set" with heated water. Cold water and soap are then used to remove the peroxide-treated blood.

As floor bleach

Hydrogen peroxide can be used to clean tile and grout on floors. It is sometimes recommended to clean with both hydrogen peroxide and baking soda together.

Skunk odor removal

Mixed with baking soda and a small amount of hand soap, hydrogen peroxide is effective at removing skunk odor.

Other uses

Glow sticks

Hydrogen peroxide is used with phenyl oxalate ester and an appropriate dye in glow sticks as an oxidizing agent. It reacts with the ester to form an unstable CO2 dimer, which excites the dye to an excited state; the dye emits a photon (light) when it spontaneously relaxes back to the ground state.

In the Chemical industry

Hydrogen peroxide can be combined with vinegar and table salt to form a substitute for industrial chemicals such as ferric chloride, ammonium persulfate, or hydrochloric acid as a hobbyist's printed circuit board etchant.

Alcoholic beverage industry

Hydrogen peroxide may be used in accelerated aging of alcoholic spirits. Some hobby distillers advocate adding small amounts of hydrogen peroxide to distilled spirits, on the theory that the oxygen released will accelerate the oxidation of compounds that occurs naturally when spirits are aged in somewhat permeable oak barrels.[68] This has not been proven scientifically.

For more details on this topic, see High-test peroxide.
Rocket Belt hydrogen peroxide propulsion system used in a jet pack

High concentration H2O2 is referred to as High Test Peroxide (HTP). It can be used either as a monopropellant (not mixed with fuel) or as the oxidizer component of a bipropellant rocket. Use as a monopropellant takes advantage of the decomposition of 70–98+% concentration hydrogen peroxide into steam and oxygen. The propellant is pumped into a reaction chamber where a catalyst, usually a silver or platinum screen, triggers decomposition, producing steam at over 600 °C (1,112 °F), which is expelled through a nozzle, generating thrust. H2O2 monopropellant produces a maximum specific impulse (Isp) of 161 s (1.6 kN·s/kg), which makes it a low-performance monopropellant. Peroxide generates much less thrust than hydrazine. The Bell Rocket Belt used hydrogen peroxide monopropellant.

As a bipropellant H2O2 is decomposed to burn a fuel as an oxidizer. Specific impulses as high as 350 s (3.5 kN·s/kg) can be achieved, depending on the fuel. Peroxide used as an oxidizer gives a somewhat lower Isp than liquid oxygen, but is dense, storable, noncryogenic and can be more easily used to drive gas turbines to give high pressures using an efficient closed cycle. It can also be used for regenerative cooling of rocket engines. Peroxide was used very successfully as an oxidizer in World War II German rocket motors (e.g. T-Stoff, containing oxyquinoline stabilizer, for the Me 163B), most often used with C-Stoff in a self-igniting hypergolic combination, and for the low-cost British Black Knight and Black Arrow launchers.

In the 1940s and 1950s, the Walter turbine used hydrogen peroxide for use in submarines while submerged; it was found to be too noisy and require too much maintenance compared to diesel-electric power systems. Some torpedoes used hydrogen peroxide as oxidizer or propellant, but this was dangerous and has been discontinued by most navies. Hydrogen peroxide leaks were blamed for the sinkings of HMS Sidon and the Russian submarine Kursk. It was discovered, for example, by the Japanese Navy in torpedo trials, that the concentration of H2O2 in right-angle bends in HTP pipework can often lead to explosions in submarines and torpedoes. SAAB Underwater Systems is manufacturing the Torpedo 2000. This torpedo, used by the Swedish navy, is powered by a piston engine propelled by HTP as an oxidizer and kerosene as a fuel in a bipropellant system.

While rarely used now as a monopropellant for large engines, small hydrogen peroxide attitude control thrusters are still in use on some satellites.They are easy to throttle, and safer to fuel and handle before launch than hydrazine thrusters. However, hydrazine is more often used in spacecraft because of its higher specific impulse and lower rate of decomposition.
Improvised explosive device / home-made bomb precursor

Hydrogen peroxide was the main ingredient in the 7 July 2005 London bombings that killed 52 London Underground and bus passengers. The bomb-making ingredients are reported to be easier to buy than large numbers of aspirin pills. It was used again in other terrorist attacks.