Efficient methodology for the preparation and fabrication of cation exchange membranes using trichloroacetic acid and cellulose biopolymer

This article presents a new method for preparing enhanced cation exchange membrane (CEM) for water treatment using cellulose biopolymer. The preparation methodology of CEM membranes was performed in two steps; functionalization followed by fabrication. Firstly, cellulose powder was functionalized with trichloroacetic acid at different reaction times to prepare carboxymethyl tricellulose (CMTC). In the second step, the exchange memberane was fabricated via phase inversion technique using the functionalized cellulosic material and polyethylene glycol as a pore former. The prepared CEM was fully characterized using FTIR, SEM, mechanical properties, and degree of substitution (DS) determination. The morphological microstructure of the CEM membrane was investigated and discussed. The microstructural analysis by FTIR confirmed the functionalization process. The tensile values obtained at different reaction times showed the effectiveness of using trichloroacetic acid in the carboxymethylation and consequently, the stability of the obtained functionalized cellulose. The obtained DS values are higher than that of the commercial CMC and also the published values. It has been observed that the prepared CEM have an average DS value of 1.5 and therefore much higher than the DS value of commercial CMC whose DS ranges between 0.7 and 1.2. The prepared CEM membranes were morphologically investigated by SEM. The SEM photos showed homogeneously distributed small pores on the entire surface of the membrane, and its cross-section is a multilayer with large pores.