Development of composite polyelectrolyte complex membrane for cationic dye and heavy metal sorption

Abstract

The sorption process is most useful in water treatment because it provides high sorption efficiency, low cost and rapid method. Polyelectrolyte complex (PECs) is a novel polymeric membrane prepared by mixing between oppositely charged polyelectrolyte solution of PDADMAC and PSS. Activated carbon (ACs) is used to improved adsorption efficiency in PECs. Non-stoichiometric PDADMAC/PSS membrane were prepared by mixing excess PSS concentration to get the negative charges on the membrane surface. Sorption efficiency was evaluated by methylene blue, cationic dye and heavy metal ions based on the same material, the difference sorption mechanism were observe. In the cationic dye, the adsorption mechanism operated by excess PSS on membrane surface via electrostatic interaction. The maximum adsorption capacity occur in a removal salt 1:2 PDADMAC:PSS mole ratio (R-1:2) without AC which is 4.9 mg g-1 with 10 mg l-1 of methylene blue concentration. Furthermore, R-1-2 fitted with pseudo-second order kinetic model and Temkin isotherm model with physical adsorption type and also regenerated by salt solution. In contrast, the heavy metal ions sorption operated ion exchange mechanism, 1:2 PDADMAC:PSS without AC show highest sorption capacity which is 30 mg g-1 with 50 mg l -1 of Cu2+ ions concentration. The mechanism occur between Na+ on PSS chain and Cu2+ ions in solution. The metal ions sorption fitted with pseudo-second order kinetic model and Freundlich isotherm model with chemical sorption type and bilayer surface sorption and shows high selective of Pb2+ and Cr 3+metal ions.