Removal of As(V) from Water by Fe-Chitosan-Modified Composite Microspheres

To address the prevailing issue of arsenic contamination in water bodies, a novel composite microsphere (Fe-CB) was developed for the effective removal of As(V) ions from aqueous solutions. This microsphere was prepared using a sol–gel-titration-freeze-drying method, with chitosan and ferric chloride as raw materials, polyethyleneimine as a modifier and glutaraldehyde as a cross-linking agent. The effects of pH, adsorbent dosage, initial heavy metal concentration, and contact time on the performance of the adsorbent were investigated by a series of adsorption experiments. It was showed that pH played a significant role in determining the adsorption efficiency, while temperature had a relatively minor influence. The adsorption isothermal of As(V) on Fe-CB was best described by Langmuir isotherm model, whereas the dynamic adsorption process fitted the pseudo-second-order or secondary kinetic model well. Notably, the theoretical maximum adsorption capacity was 80.97 mg/g. Furthermore, regeneration experiments demonstrated that Fe-CB maintained a regeneration rate of over 85% even after five cycles, highlighting its excellent recyclability. This study underscores the potential of Fe-CB as an efficient and reusable adsorbent for the removal of As(V) ions from contaminated waters.