Evaluation of Crosslinking Degree on the Characteristics and Performance of Membranes Formulated from Quaternized Chitosan

Abstract

Chitosan is a polymer produced from chitin that is insoluble in neutral or basic pH conditions. Regarding its biodegradability, nontoxicity, and biocompatibility, chitosan has limited applications due to its low solubility in a neutral or slightly alkaline condition, which increases below pH of 5. Quaternization came out as a way of altering this natural polymer to enhance its solubility over a wide pH range and boost permanent positive charges. For the separation process, quaternized chitosan or QCs can be used as the polymer owing to its high properties, such as high solubility and the capability to be easily formed into a membrane film. In this study, the quaternized chitosan was prepared using 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHTAC), which was then formulated into the integral membrane with a blend with polyvinyl alcohol, polysulfone, and tetraethylorthosilicate (TEOS). The membrane properties and their performance in terms of functional groups, surface charge, surface morphology, pure water flux, and antifouling analysis were analyzed. The results revealed that the incorporation of 1 wt. % TEOS has reduced the pore size of the membranes but did not help much in enhancing hydrophilicity and positive charge of membranes, and slightly better antifouling characteristic in terms of relative flux recovery (RFR) was observed with membrane without crosslinking process. Therefore, further studies need to be conducted to evaluate the potential applications of the produced membrane.