Biosorption of Cu²⁺ on magnetic calcium alginate immobilized Phanerochaete chrysosporium

Phanerochaete chrysosporium were immobilized in magnetic Fe₃O₄ nanoparticles and calcium alginate to form MC microspheres. The obtained MC microsphere was characterized by SEM, EDS, XRD, BET, VSM and TGA. The results indicated that MC microsphere was a three-dimensional structure with relatively large specific surface area and good porosity. MC microspheres had excellent magnetic recovery performance and thermal stability. The characteristics and performance of MC microspheres on adsorption of Cu²⁺ were evaluated based on batch adsorption experiments. The maximum adsorption capacity of Cu²⁺ by MC microspheres was 35.07 mg g^-1 at pH of 5.0, temperature of 35 °C and adsorption time of 8 h. MC microspheres can still effectively adsorb Cu²⁺ at 400 mg L^-1. Integrating simulation results from pseudo-second-order kinetic model, Intra-particle diffusion model and Freundlich model, the process was mainly dominated by chemical adsorption, and it is a multi-molecular layer adsorption. The results of XPS and FTIR showed that complexation, ion replacement, and reduction are important mechanisms for adsorption of Cu²⁺ on MC microspheres. -OH and C-O/C=O mainly complexes with Cu²⁺ in the biosorption process. After five adsorption-desorption cycles, the adsorption efficiency can still reach 32.40 %. Therefore, MC microspheres are a potential adsorbent that can achieve effective recovery.