In most cases, the corrosivity imparted a process water by adding H2O2 is due to dissolved oxygen which is a natural decomposition product of H2O2. Oxygen has known corrosive properties toward ferrous metals, with well documented pH, temperature, pressure and salinity effects. For dilute solutions of H2O2 (< 1%), Perry’s Chemical Engineering Handbook indicates corrosion rates of < 0.02 in. per yr (< 0.5 mpy). In coupon tests involving oil field brine, corrosion rates on 1030 carbon steel were 6 mpy after 30 days exposure to a few hundred mg/L H2O2 – Brine is known to be corrosive when oxygenated and the corrosion rate for most applications of H2O2 will be less. The study developed a model which related corrosivity to (soluble) iron content, pH and H2O2 dose. Iron level and pH were found to be far more significant than H2O2 dose, and when the iron levels were low, there was virtually no effect attributable to H2O2. Still, it is prudent to consider corrosivity when designing injection assemblies, where H2O2 concentrations will be greatest.

Two scenarios warrant special note: applications involving H2S or Fenton’s Reagent. Sulfide-laden waters are typically devoid of oxygen and often provide a protective iron sulfide coating on the submerged portions of the metal (corrosion rates < 1 mpy), while severe corrosion occurs at and above the air-water interface (corrosion rates >20 mpy). While H2O2 use in these applications may increase corrosion below the water surface, corrosion above the water surface is virtually nil. The second special note involves strong catalytic H2O2 processes (especially Fenton’s Reagent) which are very corrosive and should be performed in stainless or lined reactors.

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The primary factors contributing to H2O2 decomposition include: increasing temperature (2.2 factor increase for each 10 deg-C); increasing pH (especially at pH > 6-8); increasing contamination (especially transition metals such as copper, manganese or iron); and to a lesser degree, exposure to ultraviolet light. In most cases, pH and contamination work in tandem as the dominant factors.

See also Question #3. Up to Topic Index Up to Question Index

Commercial grades of H2O2 contain stabilizers designed to minimize its decomposition during normal transportation and storage. In some cases, these stabilizers may also improve the performance of H2O2 in the application. Matching the H2O2 grade to your application is thus the first step. Second, select and prepare construction materials according to manufacturer guidelines (see Safety and Handling Guidelines). The procedure of passivating the piping assembly with dilute nitric acid removes surface contaminants and imparts a protective oxide layer to the surface metal. Third, limit exposure of the product to environmental stresses such as heat, sunlight or dust. And fourth, control the degree of contamination introduced by carrier (or dilution) waters, or even the process water into which it is being applied. If excessive decomposition is remains a problem, contact us for more specific guidance regarding supplemental stabilizer addition to your process.

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Most commercial grades of H2O2 contain chelants and sequestrants which minimize its decomposition under normal storage and handling conditions. In some applications (e.g., copper etching or cosmetic formulations) a high degree of stabilization is needed; whereas, in others (e.g., drinking water treatment or semiconductor manufacture) product purity is more important. For most environmental applications, H2O2 stabilization does not affect product performance.

The types of stabilizers used in H2O2 vary between producers and product grades. Colloidal stannate and sodium pyrophosphate (present at 25 - 250 mg/L) are the traditional mainstays, although organophosphonates (e.g., Monsanto’s Dequest products) are increasingly common. Other additives may include nitrate (for pH adjustment and corrosion inhibition) and phosphoric acid (for pH adjustment). Certain end-uses -- which depend on the bleaching ability of H2O2 in alkali – utilize colloidal silicate to sequester metals and thereby minimize H2O2 decomposition.

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H2O2 has been a commercial product since the 1880's, when it produced in the U.K. by burning barium salts to produce barium peroxide which, when dissolved into water, yields H2O2. The early market was largely for bleaching straw hats, which were very much en vogue at the turn of the century. From the 1920's through the 1950's the primary production route was electrolytic, which produced a higher purity, higher strength grade. As demand grew, the need for greater economies of scale led to the process used today for virtually all commercial H2O2 production -- the "auto-oxidation" or AO process, which uses hydrogen as its raw material. The process consists of:

Crude production. A working solution of alkylated anthraquinones which is alternately hydrogenated (using either nickel or palladium catalyst) and then air oxidized to split off H2O2. Each producer has its proprietary collection of anthrquinones, and maintaining the integrity of this working solution is key to safe and efficient H2O2 production.

Separation. The (water insoluble) working solution is then separated from the H2O2 by solvent extraction, and then concentrated and returned to the hydrogenator. The crude H2O2 (about 40% w/w) is sent to distillation.

Purification. Crude H2O2 is purified by distilling to about 60% w/w. This storage product may then be diluted to 35% or 50%, distilled to 70%, and/or purified for high-purity uses (e.g., food processing or semiconductor manufacture).

Stabilization. Since H2O2 decomposition is accelerated by trace levels of contaminants (esp. transition metals) stabilizers are added prior to shipping and storage. The type and level of stabilizer depends on the product grade, but generally consists of chelants/sequestrants such as inorganic and organic phosphates, and/or stannate and silicate.

More information on the AO process can be found in Kirk-Othmer’s Encyclopedia of Chemical Technology or other process papers prepared by SRI International (Stanford Research Institute).

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Peracetic acid (or peroxyacetic acid) is an equilibrium product obtained by mixing H2O2 with acetic acid (vinegar).

As a product, it is typically sold as a 5% or 15% active solution for disinfection/sterilization purposes, particularly in the food processing industry. While used for decades in the chemical industry as a selective epoxidizing agent, peracetic acid has more recently been considered as a delignification and bleaching agent for the paper industry.

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Caro’s acid (or peroxymonosulfuric acid) is an equilibrium product obtained by mixing H2O2 with sulfuric acid.

It is used in the mining and hydrometallurgy industries for digesting ores and separating components, and for destroying cyanide residuals. Caro’s acid is not sold as product but is produced onsite at the point of application. FMC has developed several models of generators used for on-site production of Caro’s acid.

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Sodium percarbonate (or sodium carbonate peroxyhydrate) is a non-hazardous granular product developed as an alternative to perborate bleaches in household detergents. When dissolved into water, its releases H2O2 and soda ash (sodium carbonate).

The pH of the resulting solution is typically alkaline, which activates the H2O2 for bleaching. The dry powder contains about 30% w/w H2O2 and finds specialty use as a wood brightener and general cleaning aid. Check with a local supplier to industrial laundries for sourcing.

See also Question #9. Up to Topic Index Up to Question Index

Both calcium and magnesium peroxide (CaO2) are a solid peroxygens (classified Oxidizers) which slowly decompose to release oxygen at a "controlled" rate. They find use in bioremediation and composting operations, and in coating seeds to improve germination and seedling survival rates.

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By itself, H2O2 is a rather poor microbiocide compared to chlorine, bromine, ozone, and other commonly used disinfectants. Consequently, it is not approved by regulatory agencies as a stand-alone treatment in these applications. However, there are a number of technologies which use H2O2 as part of the treatment program. These include: UV disinfection + H2O2; ozone + H2O2; silver salts + H2O2; and quaternary ammonium salts + H2O2. The first three of these are in various stages of commercialization (depending on the state), while the latter is available under the Baquacil label. You are advised to contact the Pool & Spa Association to learn the status of these treatments in your area.

US Peroxide is unable to offer assistance for pool and spa applications of H2O2.

See also Question #18. Up to Topic Index Up to Question Index

As a producer of H2O2, FMC deals primarily in full truckload quantities of bulk chemical (4,000 gallons) in concentrations of 35, 50, and 70% by weight. Through US Peroxide (which provides mini-bulk storage and dosing modules), we are able to deliver less-than-full-truckload quantities (500 - 2500 gallons) in concentrations of 35 or 50% by weight. Packaging of 35 and 50% into 55-gallon drums (and in some cases 300-gallon totes) is available from most industrial chemical distributors. Certain of these distributors (e.g., those serving the textile, food or metal finishing industries) offer product in 5-gallon or 15-gallon carboys. Smaller quantities (pint or gallon containers) of 30 or 35% H2O2 can be purchased through laboratory supply houses that handle chemical reagents. Since chemical distribution is largely a regional business, please let us know your location and requirements, and we will direct you to the appropriate source.

Note to household users: Concentrations > 8% H2O2 (by weight) are classified Oxidizers and are not recommended for household use (see Safety and Handling Guidelines). You should seek out a regional source for this dilute solution, or consider a safe, non-hazardous alternative (see Question #8).

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The problem with using H2O2 to treat household water supply is one of controlled dosage -- overdosage may present health risks. This problem is common to other water treatment chemicals as well, which is why most household treatment systems either rely on "passive" devices (e.g., filters, ion exchange resins, etc.), or are designed and serviced by companies specializing in the field. It is recommended that you contact the Water Quality Association which services that portion of the industry focusing on "point of use" treatment systems.

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H2O2 is added to the leach field distribution piping to improve drainage and filtration through the soil. It does this in two ways: 1) it oxidizes microbial slimes that block the leach pores; and 2) it decomposes once permeated into the soil, liberating oxygen – its conversion from a liquid to a gas represents a volume expansion whereby the compacted soil is "lifted" and air space restored to the soil structure. There are a few things to be aware of regarding this application:

1. Many states have regulations regarding what can be added to septic systems. You should check with your local environmental/health department to learn the status of such restrictions;
2. Add the H2O2 to the leach distribution piping -- not the septic tanks! Septic tanks rely on anaerobic biology which is poisoned by oxygen -- H2O2 decomposes into oxygen and water. You should install a positive barrier (e.g., valving) between the septic tank and H2O2 injection point to ensure that no H2O2 enters the tank. Suggested application rates are about one gallon of 1% H2O2 solution per square foot of leach field.
3. Consider employing a firm which specializes in this field. One such firm is Arcan Enterprises which also sells a peroxygen based cleaning agent for the application. They can be reached at 888/ 35-ARCAN (in New Jersey) or www.arcan.com.

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It depends on the specifics of the requirement (e.g., H2O2 strength and grade, volume per year, packaging and delivery volumes, and location/proximity to production plant or terminal, etc.). Within the continental U.S., the list price for 50% Technical Grade (standard industrial grade), delivered in full tank trucks (40,000 lbs), and freight equalized from the nearest production plant, is as follows.

The freight-equalized production plants are located at or near: Houston, TX; S.Charleston, WV; Mobile, AL; Columbus, MS; Memphis, TN; Vancouver, WA; Gibbons, Alberta; Becancour, Quebec: Maitland, Ontario; and Prince George, British Columbia.

For multiple tank truck deliveries, the competitive situation may allow off-list pricing. Drum pricing (in 55-gallons) is typically 20-30% more than truckload pricing, excluding freight. We would be happy to provide a firm quotation if you could provide us with information regarding your needs.

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It depends upon a number of factors discussed below. But first ... a few points on what pH means. pH is a logarithmic measure -- pH = log10 1/[H+]. Hence, if you mix equal parts of a pH 2 solution and pH 4 solution, you will not necessarily end up with a pH 3 solution -

Hence, to anticipate the resulting pH, it is useful to measure the relative buffering capacities of the two solutions in addition to their pH. The measures used to define buffering capacity (acidity and alkalinity) are derived from the amount of acid or base needed to bring the solutions to neutrality (pH 7).

With this background, the following factors influence the pH of commercial solutions of H₂O₂:

1. Industrial strength solutions of H2O2 (30-70%) depress the pH readings obtained when using a combination glass electrode. The difference between this "apparent pH" and "real pH" varies from about 1.3 pH units for 35% H2O2 to about 2.7 pH units for 70% H2O2.
2. Correcting for apparent pH deviations, solutions of pure H2O2 and water exhibit a pH which varies with concentration of H2O2 as follows:
   

   % H2O2 Conc.	0	10	20	30	40	50	60	70	80	90	100
   pH @ 25-deg C	7.0	5.3	4.9	4.7	4.6	4.5	4.5	4.5	4.6	4.9	6.2

   
   
3. Virtually all commercial production of H2O2 now utilizes a process based on the auto-oxidation of anthraquinones. The degradation by-products of this reaction are typically acidic and, depending on subsequent purification steps, will typically result in a more acidic product than suggested in the above table (by 2-4 pH units), and add significantly to the acidity of the product.
4. Because H2O2 solutions are generally more stable at low pH, some producers may add mineral acids (e.g., phosphoric or nitric acids) to further lower the pH - either in the production process or afterwards.
5. The water used to prepare commercial solutions of H2O2 is generally of very high quality (i.e., deionized, with low acidity), and so does not significantly affect the (real) pH of the product.
6. Most commercial solutions of H2O2 contain stabilizers (chelating and sequestering agents) which have been added to minimize decomposition of the product through transport and storage. While some stabilizers (such as stannate) are alkaline, most (such as phosphonic acids) are acidic and exhibit buffering properties which add acidity to the product. The amount and type of stabilizers varies between producers, product grades, and H2O2 concentration. Electronic and Reagent grades are more pure (less stabilizers, less acidity) while Dilution and Cosmetic grades have among the highest levels of stabilizers - more on this below.

Consequently, it is not possible to state with any certainty the pH of commercial H2O2 solutions. However, it is likely that the apparent pH will be pH 4-5 for the more dilute products (3-10% H2O2) and pH 1-4 for the more concentrated products (35-70%). In terms of buffering capacities, one would expect to find an inverse correlation with product purity. Thus, a general ranking of H2O2 grades might be as follows:

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US Peroxide does not have any knowledge of this area. Any person considering such use is advised to carefully study the Safety and Handling Guidelines (see here), and to use only dilute solutions of H2O2 (3% or less) for topical use. Ingestion of H2O2 at any concentration is strongly discouraged without the supervision and guidance of a licensed medical practicioner.

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There have been reported a number of developing applications for H2O2 in both animal husbandry (e.g., fiber pre-digestion for ruminant feed) and horticulture (adjuvant for foliar feeding, fertigation, irrigation, etc.). These applications are currently outside our realm of expertise, so we can offer no advice or guidance as to their efficacy or application directions. You are advised to contact your local farm bureau or agricultural college for further information.

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Compared to chlorine (or ozone, chlorine dioxide, or uv-light), H2O2 is a rather poor disinfectant and is not approved as a stand-alone treatment for microbial control in water systems. Consequently, it is unlikely that any stand-alone process will be available in the foreseeable future. On the other hand, H2O2 can be used to improve the performance of certain other disinfection methods (e.g., ozonation and UV-photolysis). For non-potable water treatment (e.g., cooling water circuits), there is active development and commercialization of both H2O2-derived disinfectants (e.g., peracetic acid) and combination treatments with biguanide-type quaternary ammonium compounds. We will be adding more information about this area to our website in the near future -- stay tuned.

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Generally no. The ammonium ion is extremely resistant to any common oxidant except active halogens (chlorine, bromine, iodine). While free radical oxidation of undissociated NH3 is possible (using catalytic H2O2), the high pH required is such that the primary removal mechanism is volatilization. Methods typically used for ammonia removal include: biological nitrification/denitrification, air stripping (at high pH), adsorption onto selective ion exchange resins or clinolite (a natural mineral), or super-chlorination.

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This is an area that requires extreme caution since high-strength H2O2 is used. US Peroxide does not support this application by hobbyists given the potential dangers and logistics of transporting the material. You can learn more of the application by contacting the National Association of Rocketry -- Technical Services (NARTS) Group at P.O. Box 1482, Saugus, MA 01906 (CompuServe account: 73320,1253) or The Pacific Rocket Society at P.O. Box 662, Mojave, CA 93502 (661-824-1662). A good technical article on hybrid engines using H2O2 is David Andrews, "Advantages of Hydrogen Peroxide as a Rocket Oxidant", Journal of the British Interplanetary Society, vol 43, number 7, page 319-328, July 1990.

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Currently, this website is devoted to applications of H2O2 for environmental (pollution control/clean-up) purposes. We cannot provide information in other areas at this time.

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Yes. H2O2 is produced by both animal and plant cells -- being associated with the mitochondrial respiratory chain, as well as various hydroxylation and oxygenation reactions. For example, the popular free-radical dietary supplement, superoxide dismutase (SOD), serves to convert the toxic superoxide radical (O2^-) into H2O2, as do the flavin-linked oxidases. A number of other enzymes such as the heme-containing catalase (located in mitochondrial peroxisomes) then decompose the H2O2 to oxygen in order to protect the cells from subsequent damage. You can see these enzymes in action for yourself when you apply H2O2 topically to a cut or wound and witness the intense foaming. Also, the whitening of skin when exposed to more concentrated H2O2 is due to trapped oxygen beneath the epidermis caused as a result of H2O2 permeating through the skin and being decomposed by epidural enzymes. Saliva is another source for H2O2-decomposing enzymes -- hence the foaming when brushing with H2O2-containing tooth pastes. H2O2 is also an active intermediate in the bioluminescence reaction involving the luciferase enzyme (from fireflies).

We have only recently begun to explore how these enzymatic reactions utilizing H2O2 may be harnessed for environmental use. Two examples of active research (and field testing) involve the peroxidase-H2O2 reaction (from the white rot fungus) to degrade toxic organic compounds and to delignify / bleach wood pulp.

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Our goal at H2O2.com is provide all of our information and knowledge online. As a result, there is no additional information ready to be sent out that is not already on our website. We do not currently mail out print versions of pages at this site.

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