Novel and efficient microspheres adsorbent (MCA-E0.7/CMC-g- PDMDAAC), based on monochloroacetic acid (MCA) modified epichlorohydrin (ECH) cross-linked carboxymethyl cellulose (CMC), then grafting by dimethyldiallylammonium chloride (DMDAAC), was synthesized and its adsorption properties on cationic and anionic dyes were investigated. The results demonstrated that such MCA-E0.7/CMC-g-PDMDAAC microspheres showed pH-sensitive and could effectively adsorb cationic dye methylene blue (MB) or anionic dye orange II (OR II), at near neutral (pH>4) or acidic (pH<3) condition, respectively. Moreover, it could selectively adsorb the cationic dye MB from the cationic/anionic dye mixture at neutral pH condition. The desorption experiments were mainly performed under acidic (pH 3) or basic (pH 11) condition, over 98.54% of MB and 83.07% of OR II can be desorbed within 20min, respectively. The pseudo-second-order kinetic model and Langmuir isotherm provide better correlation with the experimental data for the adsorption of dyes onto MCA-E0.7/CMC-g-PDMDAAC microspheres.
Keywords: Carboxymethyl cellulose; Dimethyldiallylammonium chloride; Dyes; Selective adsorption; pH-sensitive.
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