Reactive & Functional Polymers, Vol.134, 31-39, 2019
Removal of aqueous copper(II) by using crosslinked chitosan films
Chitosan films crosslinked with sulfuric acid were prepared by using two different methodologies named as homogeneous and heterogeneous. The Cu(II) adsorption capacity of the films was studied by means of kinetic and equilibrium experiments. Neat chitosan (CS) and homogeneously crosslinked samples (CSHA and CSHB) exhibited quite similar performances for aqueous Cu2+ removal (near to 80% for 14 ppm aqueous solutions); whereas the adsorption capacity of heterogeneous films (CSHtA and CSHtB) was significantly lower. The pseudo-second order model adequately reproduced the kinetics curves, while the Freundlich isotherm was preferable for modelling the equilibrium. The capability of the chitosan films for pressure-driven filtration of water solutions was explored by determining pure water permeability along with the flux and rejection of aqueous Cu2+ solutions. Water flux was thoroughly low in the order: CSHA >= CS > > CSHtA. The permeate flux observed for modified chitosan membranes during filtration experiments with aqueous Cu(II) solutions was steady, being significantly higher for the homogeneous samples. All the prepared films exhibited excellent antifouling properties and the crosslinked specimens also enhanced Cu2+ rejection potential (above 95%). The homogeneously crosslinked film CSHA appeared as a promising material for the treatment by adsorption and filtration of aqueous copper streams.
Keywords:Chitin;Sulfuric acid crosslinking;Metal adsorption;Permeability;Copper rejection;Water treatment