Bleach electrochemical production

Licht S Advanced materials (2011) Efficient solar-driven synthesis, carbon capture, and desalinization, STEP solar thermal electrochemical production of fuels, metals. Bleach doi 10.1002/adma.201103198... 

The current efficiency of Traube s method was pushed to 92% [94] with the introduction of pressurized electrolysis. In 1939, Rubio [93] developed another process for producing H202 by the reduction of 02 in 50% KOH using an active carbon cathode and a Ni anode, with no industrial success. Today, most H202 are produced chemically by the anthraquinone process, which is unsuitable for small-scale production [91]. Another electrochemical process involving 02 reduction on carbon-based cathodes developed by Dow Chemical [2,95] has found a marketplace for on-site production of alkaline H202 for pulp bleaching. 

Chlor-alkali production — With a 63% production volume of the total world chlorine capacity of about 43.4 million tons (in 1998), the chlor-alkali (or chlorine-caustic) industry is one of the largest electrochemical technologies in the world. Chlorine, Cl2, with its main co-product sodium hydroxide, NaOH, has been produced on industrial scale for more than a century by -> electrolysis of brine, a saturated solution of sodium chloride (-> alkali chloride electrolysis). Today, they are among the top ten chemicals produced in the world. Sodium chlorate (NaC103) and sodium hypochlorite (NaOCl, bleach ) are important side products of the... 

During and following World War I, it became possible to ship liquid chlorine and concentrated caustic soda solutions economically, allowing convenient local production of NaClO solutions as needed for on-site textile and wood pulp bleaching. At about the same time, again facilitated by the ability to make the finished product regionally from bulk NaOH and CI2 produced electrochemically in areas with cheap power, household jug bleach (alkaline 3—6 wt% NaClO, most commonly 5.25 wt% in the United States) started to become a familiar, inexpensive, and effective household commodity with a wide variety of everyday uses (see Chap. 17). 

The enzymatic and electrochemical activity of the native or modified enzymes as a function of time was determined by incubating these in 30 mM glucose. Periodically retrieved samples were subjected to gel-filtration-chromatography, in order to eliminate all low-molecular-weight decomposition-products. Following such separation, the enzymes were assayed for their iron or ruthenium content. The enzymatic activity of the samples was determined by measuring the time required to bleach a blue (oxidized) indophenol solution. The rate of decrease of the electrochemical activity, i.e., the drop in the Faradaic current at 30 mM glucose concentration, was then measured by cyclic voltammetry. 

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