Fabrication of chitosan-based MCS/ZnO@Alg gel microspheres for efficient adsorption of As(V)

Groundwater contaminated by arsenic endangers our health. Therefore, in this work, a novel composite adsorbent consisting of magnetic chitosan (MCS), zinc oxide (ZnO), and sodium alginate (Alg) was prepared to remove arsenic from groundwater. First, chitosan was coated on the surface of Fe3O4 nanoparticles by coprecipitation. Then, MCS/ZnO@Alg gel beads were fabricated by combining MCS with ZnO and Alg, and crosslinking the composite material in the presence of Ca2+ ions. The MCS/ZnO@Alg beads were characterized by SEM, FTIR spectroscopy, XRD, VSM, and XPS. The adsorption experiments revealed that the MCS/ZnO@Alg magnetic gel beads have high stability and As(V) adsorption capability, and adsorbed As(V) through chemical adsorption. The maximum As(V) adsorption capacity as determined from the Langmuir model was 63.69 mg/g. In addition, MCS/ZnO@Alg exhibited good recyclability and high sustainability. This work proves that the MCS/ZnO@Alg gel beads are an ideal candidate for addressing the grievous environmental threats caused by water pollution.