Efficient Capture of Phosphate From Aqueous Media Using Bimetallic La-Zr-MOF

Deposition of excessive phosphate in natural water column caused several issues, like the eutrophication and destruction of aquatic ecosystems. Adsorption has been an effective and convenient method for phosphate elimination. Herein, a novel bimetallic metal–organic framework adsorbent, namely, La-Zr-MOF, was prepared, and the morphology, crystallite, characteristic functional groups, specific surface area, and composite material surfaces were analyzed using XRD, FT-IR, SEM-EDS, and BET. The adsorption performance of the adsorbent was systematically evaluated by batch adsorption experiments, and the adsorption thermodynamic and kinetic properties were analyzed. The results reveal that La-Zr-MOF exhibits a high selectivity and sorption performance for phosphate, and the adsorption of La-Zr-MOF follows the Langmuir and pseudo–second-order models; the phosphate removal procedure is a chemisorption accompanied by an endothermic reaction, and the maximum capacity was 127.7 mg g −1 . Combined with batch adsorption experiments, kinetic and thermodynamic studies and various characterization analyses together revealed the phosphate removal mechanism, mainly ligand exchange and electrostatic interactions.