Cerium-doped MIL-101-NH2(Fe) as superior adsorbent for simultaneous capture of phosphate and As(V) from Yangzonghai coastal spring water

A series of novel cerium-doped MIL-101-NH2 materials were synthesized using the solvothermal method for the simultaneous efficient removal of phosphate and As(V). According to the characterization results, cerium was successfully loaded onto MIL-101-NH2 and that Ce-MOFs might be generated during the loading process, which modified the crystal structure of MIL-101-NH2 and resulted in MOFs with different microstructures. In single-uptake systems containing only phosphate or As(V), isothermal adsorption experiments showed that 1Ce-MIL-101-NH2 exhibited better adsorption properties of phosphate and As(V) than MIL-101-NH2. Furthermore, the uptake amounts of phosphate and As(V) reached 341.5 mg/g and 249 mg/g, respectively. Superior uptake amounts for binary phosphate (167.36 mg/g) and As(V) (87.55 mg/g) were achieved with 1Ce-MIL-101-NH2. Kinetic experiments revealed a higher uptake rate of phosphate than of As(V). FT-IR and XPS analyses showed that the main mechanism for the removal of phosphate and As(V) from water by 1Ce-MIL-101-NH2 was the formation of an Fe/CeOP inner complex through ligand complexation and electrostatic attraction. Furthermore, 1Ce-MIL-101-NH2 exhibited high selectivity and excellent efficiency in removing phosphate and As(V) in contaminated spring water in the presence of competing anions; this further confirms the application potential of the novel adsorbent.