Enhancing capture of As(V) through a sulfonic-acid-functionalized 2D crystal Ce-5-SIP-MOF and its insights from DFT calculations

In this study, a novel Ce-5-SIP-MOF was successfully synthesized by the solvothermal method employing sodium isophthalate-5-sulfonic acid as a ligand. Single crystal X-ray diffraction (SC-XRD) revealed that Ce-5-SIP-MOF exhibited a stacked two-dimensional (2D) layered crystal structure. Ce-5-SIP-MOF possessed a significant adsorption capacity of 170.28 mg/g for As(V) and followed the Langmuir isotherm model, indicating that the adsorption process was carried out by single-layer chemical adsorption. Importantly, Ce-5-SIP-MOF had a high As(V) removal efficiency, which can effectively reduce the arsenic concentration of Shimen mining area wastewater and Yangzonghai spring water to below the Class III water standard stipulated in China's Surface Water Environmental Quality Standard (GB3838-2002). Spectral analysis and DFT calculations confirmed that the strong coordination between Ce3+ and HAsO4 2-, electrostatic attraction force and hydrogen bonding played a key role in the capture of As(V). Column experiments showed that Ce-5-SIP-MOF also performed well in continuous mode, removing about 2.5 L of Yangzonghai spring water before exhaustion time. This study provides an effective adsorbent for remediation of arsenic pollution, and a new idea and method for solving the problem of arsenic pollution in water.