Evaluation of perchlorate removal from aqueous solution by cross-linked magnetic chitosan/poly (vinyl alcohol) particles

Perchlorate is an emerging trace contaminant and has been detected in groundwater, surface water, soil, and food globally. Cross-linked magnetic chitosan/poly (vinyl alcohol) beads (CM-CS/PVA Bs) were synthesized and tested to remove perchlorate from water. The complex was characterized by Fourier transform-infrared spectroscopy, transmission electron microscopy, energy-dispersive spectroscopy, and vibrating sample magnetometry. The influence of pH, co-existing anions, contact time, and temperature on adsorption was investigated. Particles were super-paramagnetic and could be recovered easily using an external magnetic field. The CM-CS/PVA Bs could adsorb perchlorate efficiently in a wide pH range from 4 to 10. Co-existing anions would inhibit the adsorption of perchlorate on CM-CS/PVA Bs. Kinetic data were well-described by the pseudo-second-order model. Langmuir and Freundlich isotherms fitted the equilibrium data well. The negative Gibbs standard free energy and enthalpy show that the adsorption process was spontaneous and exothermic. The exhausted adsorbent could be regenerated efficiently by 0.1% NaCl eluent. Therefore, the magnetic property and reusability of the CM-CS/PVA Bs make it suitable for potential application in perchlorate removal from aqueous solution.