Surface Chitosan-coated Fe3O4 immobilized lignin for adsorbed phosphate radicals in solution

The design of green, efficient, and conveniently recyclable biomass-based adsorbents is of great importance, but little has been reported. Therefore, magnetic Fe3O4 doped lignin-chitosan based microspheres (CS-Li@Fe3O4) was prepared by emulsion crosslinking for phosphate removal in water. The prepared CS-Li@Fe3O4 shows a spherical structure with a diameter of 5–40 µm. Benefiting from its unique morphological structure and the abundant functional groups on the surface, CS-Li@Fe3O4 exhibits excellent phosphate adsorption capacity and is applicable in environments with a pH of 2–10. More importantly, the CS-Li@Fe3O4 retains excellent adsorption capacity after 6 adsorption/desorption cycles, demonstrating remarkable recyclability and stability. The adsorption isotherm was well described by the Langmuir model, the adsorption kinetics accords with the pseudo-first order kinetic model, which indicates that the adsorption process is monolayer chemisorption. Hence, CS-Li@Fe3O4 holds promising future for water remediation owing to its green raw material and excellent phosphate capture properties. [Display omitted] •CS-Li@Fe3O4 with spherical structures of micron dimensions is developed.•The maximum P element adsorption capacity of CS-Li@Fe3O4 reaches 98 mg/g.•The adsorbents can be easily manipulated by external magnetic fields to achieve simple and efficient solid-liquid separation.