Magnetically responsive chitosan-based nanoparticles for remediation of anionic dyes: Adsorption and magnetically triggered desorption

Chitosan-based nanoparticles (PGMA/mCHT) were prepared for the adsorption of anionic Reactive Red 120 (RR120) and Indigo Carmine (IC). The morphology and characteristics were clarified by using SEM-EDX, XRD, VSM, and FTIR. The adsorption of RR120 and IC on PGMA/mCHT was carried out in a batch process to determine the influence of initial dye concentration (5-600 mg/L), initial pH (3-9), temperature (5, 25, 35, and 45 degrees C) and contact time. Under acidic conditions, higher adsorption efficiencies of the PGMA/mCHT nanoparticles due to intermolecular interactions of dye molecules between the protonated amine groups and the sulfonyl groups. Bi-solute adsorption was also investigated revealing between dye molecules has no competitive effect at the same initial concentration. The kinetic results of RR120 and IC adsorption onto PGMA/mCHT nanoparticles fit well to the pseudo-second-order model. The desorption of dye molecules from PGMA/mCHT nanoparticles was also studied using an alternating magnetic field which is caused the superior desorption behavior demonstrating the magnetic nanoparticles can be acted as a nanoheater.