School of Environment and Energy, Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters (Ministry of Education), Guangdong Engineering and Technology Research Center for Environmental Nanomaterials , South China University of Technology , Guangzhou 510006 , China.
College of Environmental Science and Engineering, Key Laboratory of Marine Environmental Science and Ecology (Ministry of Education) , Ocean University of China , Qingdao 266100 , China.
Environ Sci Technol. 2018 Mar 20;52(6):3466-3475. doi: 10.1021/acs.est.7b05761. Epub 2018 Feb 13.
p-Arsanilic acid ( p-ASA) is an emerging organoarsenic pollutant comprising both inorganic and organic moieties. For the efficient removal of p-ASA, adsorbents with high adsorption affinity are urgently needed. Herein, amine-modified UiO-67 (UiO-67-NH) metal-organic frameworks (MOFs) were synthesized, and their adsorption affinities toward p-ASA were 2 times higher than that of the pristine UiO-67. Extended X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculation results revealed adsorption through a combination of As-O-Zr coordination, hydrogen bonding, and π-π stacking, among which As-O-Zr coordination was the dominant force. Amine groups played a significant role in enhancing the adsorption affinity through strengthening the As-O-Zr coordination and π-π stacking, as well as forming new adsorption sites via hydrogen bonding. UiO-67-NHs could remove p-ASA at low concentrations (<5 mg L) in simulated natural and wastewaters to an arsenic level lower than that of the drinking water standard of World Health Organization (WHO) and the surface water standard of China, respectively. This work provided an emerging and promising method to increase the adsorption affinity of MOFs toward pollutants containing both organic and inorganic moieties, via modifying functional groups based on the pollutant structure to achieve synergistic adsorption effect.
对氨基苯胂酸（p-ASA）是一种新兴的含砷有机污染物，由无机和有机部分组成。为了有效去除 p-ASA，急需具有高吸附亲和力的吸附剂。本文合成了胺改性的 UiO-67（UiO-67-NH）金属有机骨架（MOFs），其对 p-ASA 的吸附亲和力比原始 UiO-67 高 2 倍。扩展 X 射线吸收精细结构（EXAFS）、X 射线光电子能谱（XPS）和密度泛函理论（DFT）计算结果表明，吸附是通过 As-O-Zr 配位、氢键和π-π堆积的组合作用实现的，其中 As-O-Zr 配位是主要作用力。胺基通过增强 As-O-Zr 配位和π-π堆积以及通过氢键形成新的吸附位点，在提高吸附亲和力方面发挥了重要作用。UiO-67-NHs 可以在模拟天然水和废水中去除低浓度（<5mg/L）的 p-ASA，砷含量分别低于世界卫生组织（WHO）饮用水标准和中国地表水标准。这项工作提供了一种新兴且有前途的方法，可以通过基于污染物结构修饰官能团来提高 MOFs 对含有有机和无机部分的污染物的吸附亲和力，从而实现协同吸附效应。
