Emulsion synthesis of cellulose/lanthanum alginate /La (Ⅲ) composite microspheres for efficient and selective adsorption of phosphate

Phosphorus exceeding the standard will destroy the ecological environment of the freshwater resources and endanger the survival of aquatic animals. Due to the intrinsic complexation between La(Ⅲ) and alginate, in this study, lanthanum hydroxide was first prepared from lanthanum nitrate, the chemical crosslinking agent was replaced by La(Ⅲ), and cellulose/lanthanum alginate/La(OH)3 composite microspheres (CSPGs-La) were synthesized using polyethyleneimine (PEI) as a crosslinking agent through the emulsification process in one pot. In comparison, the adsorption capacity of 80 mg/L PO43− treated with CSPGs-La, CSPGs-Ech (Samples where the chemical crosslinking agent was not replaced by La(Ⅲ)) and La(OH)3 was 159.5 mg g−1, 57.51 mg g−1 and 137.4 mg g−1, respectively. CSPGs-La has good swelling performance, unique three-dimensional structure and mass transfer efficiency, which are the important reasons for its strong ability to capture phosphate. In the presence of coexisting anions, CSPGs-La can still accurately adsorb PO43−, showing good adsorption selectivity. Intra-surface spherical complexation and electrostatic adsorption play an important role. When the dose of CSPGs-La is 1.35 g/L, the phosphorus pollutants in the actual domestic sewage can be reduced to 10 μg/L below. After five adsorption cycles, the retention rate of phosphorus removal performance is 87.7 %. This study provides a green, easy to implement, and promising solution for the preparation of efficient and selective phosphorus removal adsorbent.