Polyacrylamide modified kaolin enhances adsorption of sodium alginate/carboxymethyl chitosan hydrogel beads for copper ions

A simple polyacrylamide modification method was developed to improve the adsorption capacity and anti-interference of kaolin, which enhanced the adsorption performance of sodium alginate/carboxymethyl chitosan composite hydrogel. Fourier transform infrared spectroscopy, Scanning electron microscopy and energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy were used to determine the composition and adsorption mechanism of the adsorbent. In addition, the adsorption effect of the adsorbent on Cu2+ was measured. The results showed that the adsorption rate conformed to the pseudo-second-order kinetic model and the Langmuir isotherm model, and the maximum adsorption capacity of the adsorbent was 5.5157 mg/g. In addition, adding modified kaolin reduced the interference of certain coexisting ions and the influence of pH. After five reuse cycles, its adsorption capacity was more than 82%. Therefore, this study provides a theoretical basis for improving the adsorbent of biomass-based materials.