Composite membranes with organic materials

Monochloramine is approximately 200 times less effective than free chlorine as a disinfectant. However, it is still used as an alternative to chlorine because chloramines do not react as readily with organic materials to form trihalomethanes (THMs). In theory, due to the less aggressive nature of chloramines, the tolerance of polyamide composite membranes to chloramine is about 300,000 ppm-hrs. However, chloramines are usually in equilibrium with free chlorine, making it difficult to use chloramine in RO pretreatment, as the free chlorine will degrade polyamide composite membranes. 

In order to achieve more control of methanol crossover, composite membranes are synthesized. Organic-inorganic composite membranes comprising Nafion with inorganic materials silica, mesoporous zirconium phosphate (MZP) and mesoporous titanium phosphate (MTP) are made as proton-exchange-membrane electrolytes for direct methanol fuel cells (DMFCs) [206] with increase in proton conductivity and low methanol crossover. Composite membranes with mordenite incorporated in polyvinyl alcohol-polystyrene sulfonic acid blend tailored with varying degree of sulfonation also retards the methanol release kinetics considerably [199]. 

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