Adsorption of arsenite by core-shell K-OMS-2@UiO-66 microspheres: performance and mechanism

作者：Yu, Wenyi; Liang, Qianwei; Yin, Yuwei; Geng, Junjie; Chen, Wei; Tan, Xuanyi; Luo, Hanjin^*

来源：New Journal of Chemistry, 2020, 44(34): 14389-14400.

DOI：10.1039/d0nj00868k

• METAL-ORGANIC FRAMEWORKS
• ZEOLITIC IMIDAZOLATE FRAMEWORK-8
• SIMULTANEOUS REMOVAL
• MANGANESE OXIDES
• EFFICIENT REMOVAL
• ARSENATE REMOVAL
• ZIRCONIUM-OXIDE
• WATER
• OXIDATION
• AS(III)

Arsenite (As(iii)) is more toxic and more difficult to remove from water than arsenate (As(v)). A new nano core-shell-structured K-OMS-2@UiO-66 (K-OMS-2, formula KMn8O16 center dot nH(2)O) was fabricatedviaa facile one-step oxidation-coprecipitation method for enhanced As(iii) removal. Results showed that the maximal adsorption capacity of As(iii) achieved was 180.10 mg g(-1). The as-synthesized K-OMS-2@UiO-66 adsorbent functions excellently across a broad pH range of 1.5 to 10.0, and the residual concentrations of As(iii) can drop under 10.0 mu g L-1. Based on XPS and FTIR measurements, it is proposed that the removal mechanism was mainly controlled through a synergistic interaction of surface complexation and hydrogen bonding. As(iii) was sorbed onto the surface of the sorbent by Zr-O bonds and Mn-O bonds. Mn(iv) and Mn(iii) in K-OMS-2@UiO-66 effectively oxidized As(iii) to As(v). Then, some negatively charged As(v) were adsorbed at the positive sites of the adsorbent through electrostatic attraction, while others formed bidentate complexes with the Zr-O bonds. This study develops an attractive sorbent for As(iii) removal from contaminated water and has a facile and low-cost synthesis process, good As(iii) sorption performance, and reusability.

• 单位
  重庆大学