Adsorption of hydrogen arsenate and dihydrogen arsenate ions from neutral water by UiO-66-NH2

• Published in: Journal of environmental management 2019-10, Vol.247, p.263-268
• Main Authors: Chang, Zu-Wei, Lee, Yu-Jen, Lee, Duu-Jong
• Format: Article
• Language: English
• Subjects: Acid treatment; Adsorption; Arsenate; Capacity; UiO-66-NH2
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2019.06.068

The metal-organic framework (MOF) UiO-66-NH2 was synthesized with different substrate to solvent ratios and its morphology, surface area, pore distributions, and NMR, XRD, and TGA-FTIR patterns were obtained. Adsorption tests at pH 7 and 25 °C showed that the produced UiO-66-NH2 has a hydrogen arsenate adsorption capacity of 76.9 mg/g. With the affinity onto Zr clusters, this MOF also can adsorb phosphate ions from water. Treatment with 1–4 M hydrochloric acid (HCl) protonated the amine groups in the MOF. Treatment with 1 M HCl at 25 °C for 6 h maximized the adsorption capacity of UiO-66-NH2 to 161.3 mg/g, such that the protonated amine groups accounted for 53.7% of the adsorption of arsenate from the water. The use of excessively strong acid at elevated temperature reduced the adsorption capacity. •Metal-organic framework (MOF) UiO-66-NH2 was synthesized and characterized.•Adsorption capacity at pH 7 and 25 °C is 76.9 mg/g of hydrogen arsenate.•1M HCl treatment at 25 °C for 6 h increases adsorption capacity to 161.3 mg/g.•Protonated amine groups accounts for enhanced adsorption of arsenate ions.