Adsorption of organic arsenic acids from water over functionalized metal-organic frameworks

• Published in: Journal of hazardous materials 2017-08, Vol.335, p.162-169
• Main Authors: Sarker, Mithun, Song, Ji Yoon, Jhung, Sung Hwa
• Format: Article
• Language: English
• Subjects: Adsorption; Hydrogen bonding; MIL-101(OH)3; p-Arsanilic acid; Phenylarsonic acid
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2017.04.044

[Display omitted] •Functionalized MOFs (with OH) were applied for adsorptive purification of water.•Organic arsenic acids such as phenylarsonic acid were adsorbed most effectively.•The main adsorption mechanism (H-bond) could be confirmed.•The direction of H-bond could be defined (adsorbates: H-acceptor; MOFs: H-donor).•MIL-101(OH)3 was suggested as highly efficient and recyclable adsorbents. Organic arsenic acids (OAAs) are regarded as water pollutants because of their toxicity and considerable solubility in water. Adsorption of OAAs such as phenylarsonic acid (PAA) and p-arsanilic acid (ASA) from water was investigated over functionalized (with OH groups) metal-organic framework (MOF, MIL-101), as well as over pristine MIL-101 and commercial activated carbon. The highly porous MIL-101 bearing three hydroxyl groups (MIL-101(OH)3) exhibited remarkable PAA and ASA adsorption capacities. Based on the effects of pH on PAA and ASA adsorption, hydrogen bonding was suggested as a plausible mechanism of OAA adsorption. Importantly, OAAs and MIL-101(OH)3 can be viewed as hydrogen-bond acceptors and donors, respectively. Moreover, MIL-101(OH)3 could be regenerated by acidic ethanol treatment, being a promising adsorbent for the removal of PAA and ASA from water.