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Reverse Osmosis (RO) filtration will be crucial for drinking water treatment in the future due to its ability to remove emerging contaminants such as pharmaceuticals, however RO filtration still faces issues with membrane fouling. Ion exchange has been shown to aide in the pretreatment of water for RO filtration by removing charged constituents in water. However, neutral, hydrophilic portions of organic matter such as proteins remain after ion exchange and are a critical foulant for RO membranes. Removing dissolved protein via coagulation with chitosan would increase the life-span of RO membranes and drive down energy costs associated with fouled membranes. Chitosan is a natural biopolymer derived from the shells of crustaceans and has been shown to bind to proteins. Chitosan is a desirable coagulant for water treatment because it is naturally derived and can be land-applied after use unlike other water treatment coagulants such as alum and ferric chloride. Therefore, the primary goal of this research is to coagulate bovine serum albumin (BSA), a model protein, from solution using chitosan. To achieve this goal the point of zero charge for chitosan will be determined via salt titration, the coagulation process will be seeded using quartz sand and kaolinite clay to encourage larger floc-size, and the effectiveness of chitosan derivatives such as chitosan alginate will be tested. Preliminary results have shown that undissolved chitosan at a dose of 10 mg/L is superior to a more concentrated dissolved dose. Based upon literature review, the point of zero charge of chitosan should occur at a pH of approximately 5, kaolinite clay should perform better than sand when seeding, and chitosan-alginate may be more effective than chitosan alone. |
