Abstract
Tricomponent polyelectrolyte complex (PEC) composite cryogels, with remarkable sorption capacity of multiple contaminants and self-antibacterial properties were fabricated from chitosan (CS) and aromatic ionene type polycations evenly dispersed in carboxymethyl cellulose (CMC) aqueous solution. Fast cryostructuration at 196 degrees C (5 min) and overnight at 18 degrees C conducted to pre-PECs ...
Abstract
Tricomponent polyelectrolyte complex (PEC) composite cryogels, with remarkable sorption capacity of multiple contaminants and self-antibacterial properties were fabricated from chitosan (CS) and aromatic ionene type polycations evenly dispersed in carboxymethyl cellulose (CMC) aqueous solution. Fast cryostructuration at 196 degrees C (5 min) and overnight at 18 degrees C conducted to pre-PECs which, after exposure to a source of H+ and freeze-drying, led to PEC composite sponges. The PECs were characterized by FTIR, SEM, EDX, streaming potential titrations, swelling kinetics, swelling at equilibrium as a function of pH, and compressive tests. These PECs were able to simultaneous adsorb oxyanions (HCrO4, (HPO4)-P-2, HAsO42), and heavy metal ions (HMIs) (Cu2+, Cd2+, Pb2+), and to kill similar to 100 % of Gram+ (Staphylococcus aureus) bacteria. Only the tricomponent PECs were able to kill 100 % of Gram- (Escherichia coli) bacteria, while the bicomponent PECs (containing only CS and CMC) were less efficient in this case (only 70 % inhibition of bacteria). The pseudo-first-order kinetic model fitted the best the kinetic data, suggesting the sorption of pollutants by physisorption. In multicomponent systems, HCrO4 ions are preferred, the selectivity coefficients being higher in the case of tricomponent PECs than in the case of bicomponent PECs, while in the case HMIs, Pb2+ ions were preferentially selected. The sustainability of the PEC composite cryogels was demonstrated by their reuse up to five sorption/desorption cycles, with a decrease of the sorption capacity in the fifth cycle of 7 % for H2PO4, 8.1 % for HCrO4, and 6.9 % for HAsO42 when tricomponent PEC cryobeads were used as sorbents. All these abilities recommend the PEC composite cryogels as potential materials for filters suitable for point-of-use water purification.
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