Arsenic Adsorption in Subunits of Metal‐Organic Frameworks—A DFT Approach to Assist Water Treatment

Abstract

AbstractThe removal of arsenic compounds from water is classified as an urgent concern by the World Health Organization, since many of these species are hazardous to human health. However, the conventional water treatments are not able to extract them, which makes the development of new methodologies of arsenic removal noteworthy. The application of metal‐organic frameworks (MOFs) as adsorbents to attend this purpose is very promising, because these materials can be intelligently built for the desired application. In this work, the performance of common subunits usually found in MOFs were individually evaluated for the adsorption of some arsenic species through computer simulations based on density functional theory (DFT). Thus, important information at molecular level was obtained, which can assist the design of an optimized adsorbent. Three factors were identified to strengthen the adsorption: ionic coordinate bond, hydrogen bonds, and cycle formation. Furthermore, the evaluated subunits showed to be proper for the removal of HAsO2, once the change in the Gibbs free energy was up to −30.8 kcal mol−1. The comparison with possible coexistent species showed that Cl−, , and can interfere with adsorptive process depending on the MOF composition and on the arsenic species to be removed from water.