Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China.
Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
Environ Res. 2023 Jan 1;216(Pt 2):114616. doi: 10.1016/j.envres.2022.114616. Epub 2022 Oct 20.
Cr(VI) has drawn growing concern because of its acute toxicity and strong carcinogenic properties to most organisms. Metal-organic frameworks (MOFs) have attracted broad interest in removing Cr(VI) as a novel porous adsorbent. In this work, a novel modified Cu@MIL-53(Fe) material and its derivatives have been successfully synthesized via solvothermal and calcination methods and applied for Cr(VI) removal. Experimental parameters, such as the amount of the added Cu, the calcination temperature, the pollutant concentrations, the pH value of solution, etc. were optimized. The Cu@MIL-53(Fe) optimized synthesis parameters were determined as a 0.5 M ratio of Cu/Fe and 800 °C of calcination temperature. The Cr(VI) removal capacities were 20.65 mg/g at 180 min and 13.35 mg/g in 15 min, and 45.55% of total chromium and 99.05% of Cr(VI) were removed at a dose of 0.5 g/L, pH = 3, 25 °C. Batch experiments revealed that the reaction process applied for Langmuir adsorption isotherm and pseudo-second-order models most suitable with q = 724.6 mg/g. Additionally, Cr (VI) could be reduced to less toxic Cr(III) by Fe and Cu during redox reactions. According to further mechanism analysis, the process was primarily monolayer chemical adsorption, followed by electrostatic interaction, redox reaction co-precipitation and coordination effect, etc. A novel promising method of Cr(VI) removal from acidic water by MOFs adsorption is presented in this study.
六价铬因其急性毒性和对大多数生物的强致癌特性而引起了越来越多的关注。金属有机骨架（MOFs）作为一种新型多孔吸附剂，在去除六价铬方面引起了广泛的关注。在这项工作中，通过溶剂热和煅烧方法成功合成了一种新型改性 Cu@MIL-53(Fe)材料及其衍生物，并将其应用于去除 Cr(VI)。优化了实验参数，如添加的 Cu 量、煅烧温度、污染物浓度、溶液 pH 值等。确定了 Cu@MIL-53(Fe)的最佳合成参数为 Cu/Fe 摩尔比为 0.5 和煅烧温度为 800°C。在 180 分钟时，Cr(VI)去除率为 20.65mg/g，在 15 分钟时为 13.35mg/g，在 0.5g/L、pH=3、25°C 时，总铬的去除率为 45.55%，Cr(VI)的去除率为 99.05%。批量实验表明，反应过程最适合应用 Langmuir 吸附等温线和拟二级模型，q=724.6mg/g。此外，Fe 和 Cu 在氧化还原反应过程中可以将 Cr(VI)还原为毒性较低的 Cr(III)。根据进一步的机理分析，该过程主要是单层化学吸附，然后是静电相互作用、氧化还原反应共沉淀和配位作用等。本研究提出了一种从酸性水中去除 Cr(VI)的新型 MOFs 吸附方法。
