Synthesis of magnetic carboxymethyl chitosan-g-poly(acrylamide)/laponite RD nanocomposites with enhanced dye adsorption capacity

Abstract

This investigation reports the synthesis of magnetic nanocomposite hydrogels based on carboxymethyl chitosan-g-poly(acrylamide) (CMC-g-PAAm). The magnetic nanoparticles were prepared via in situ co-precipitation of iron salts in the presence of laponite RD nanoclay. Different contents of magnetic nanoclay were utilized to prepare magnetic CMC-g-PAAm nanocomposites. The structure of nanocomposite hydrogels was characterized by transmittance electron microscopy, scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and vibrating sample magnetometer techniques. The obtained magnetic nanocomposites were examined to remove crystal violet (CV) cationic dye from aqueous solutions. By introducing magnetic laponite RD, the nanocomposites showed an enhanced adsorption capacity for CV dye. Equilibrium adsorption data were modeled according to Langmuir and Freundlich isotherm models. The following experimental isotherm data from models was affected by the content of magnetic laponite RD. The maximum adsorption of crystal violet on magnetic nanocomposite hydrogels was 169 mg g−1. In addition to high adsorption capacity of magnetic nanocomposites for CV, the regeneration of obtained adsorbents was effective and the corresponding nanocomposites may be considered as new candidate in the treatment of colored water.