Chemical techniques chloramine

The following sections discuss the primary biocide used today, chlorine, and alternative physical and chemical techniques to address membrane biofouling control. The most common alternative techniques examined here include chloramine, chlorine dioxide, ozone, UV, and non-oxidizing biocides such as DBNPA and isothiazolone. Table 8.12 summarizes advantages and limitations of these techniques (adapted from Kim, 2009). It is important to note that some of these biocides/disinfectants can contact the membranes, and others must be removed or destroyed before the water is introduced to the membrane system itself. 

When the crystal structure of a protein is not available, other techniques can be employed to identify the amino acids that are involved in its structure and function. Commonly used techniques include chemical cross-linking, site-specific chemical modifications, and mutagenesis. Chemical modifications of Met residues using oxidizing agents such as hydrogen peroxide, t-butyl hydroperoxide, chloramine T, and sodium periodate have been useful in identifying structure and function relationships in many proteins (1-7). 

Chlorination is also carried out to modify the NR surface of finished products. It produces chemical and physical changes on the modified surface, for example improving oil resistance, and reducing the tackiness and frictional resistance in household NR gloves. Many techniques such as plasma chlorination, acidified hypochlorite solution, chloramines solution and trichloroisocyanuric acid solution have been used to modify the NR surface. The treatment is usually performed using acidified hypochlorite. It was reported that undesirable reactions, e.g. cyclization and chain scission, may also occur. However, the cyclized structures of the NR molecules are absent in the case of NR latex films chlorinated in the aqueous phase. 

---