Characteristics of arsenate removal from water by metal-organic frameworks (MOFs)

Contamination of arsenic in groundwater and surface water occurs frequently across the globe, requiring an effective purification technology. Among the common technologies, the adsorption method is widely used for the merits of low cost and easy operation. Nevertheless, the development of efficient adsorbents remains one of the central challenges in this field. In this article, one kind of typical porous metal-organic framework material (MIL-53(Al)) was explored for the removal of arsenate from water. MIL-53(Al) has a maximum removal capacity of 105.6 mg/g and a conditional capacity of 15.4 mg/g at a low equilibrium concentration (10 mu g/L). The optimum initial pH value is 8.0. Except for PO43-, other coexisting anions do not show a notable influence on the adsorption capacity of MIL-53(Al). In general, MIL-53(Al) is a promising new material for arsenate removal from water. Investigation of the effects of electrical charges, Fourier transform infrared spectroscopy spectra, and X-ray photoelectron spectroscopy (XPS) spectra revealed that electrostatic attraction and hydrogen bond might be involved in the adsorption process of arsenate onto MIL-53(Al).