State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, PR China; School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, PR China.
UK Biochar Research Centre, School of GeoSciences, University of Edinburgh, Edinburgh EH9 3FF, UK.
J Environ Manage. 2019 Apr 1;235:276-281. doi: 10.1016/j.jenvman.2019.01.045. Epub 2019 Jan 24.
To address inorganic and organic contaminants in the environment, economic new adsorbents are required. Here we test magnetic biochar for efficient capture of the typical pollutants Cr(VI) and trichloroethylene (TCE) from solution. We used a simple synthesis using 2M FeCl solution and peanut hull biomass to prepare magnetic ZVI biochar at alternate pyrolysis temperatures between 650 and 800 °C. The physicochemical character of the biochars were assessed using X-ray diffraction (XRD) and the Brunauer-Emmett-Teller (BET) method for surface area. The magnetic ZVI biochars were highly effective in the removal of Cr(VI) and TCE. The most effective magnetic biochar produced at 800 °C was further examined using scanning electron microscopy (SEM), revealing a high and even loading of ZVI. After sorption the same magnetic biochar was examined by X-ray photoelectron spectroscopy (XPS) to ascertain the underlying mechanisms. The dependence of Cr(VI) capture on solution pH was also examined. Our interpretation suggests that when pH < pH (2.5) electrostatic attraction and redox reactions dominated the adsorption of Cr(VI). When pH > pH the removal process was controlled mainly by redox reaction and substitution of chromate anions for hydroxyl (OH) groups. Capture of TCE in contrast involved hydrophobic partitioning, pore-filling and reductive degradation. Overall our results suggest that simple synthesis of magnetic ZVI biochar could offer an economic and effective option to address water contamination issues.
为了解决环境中的无机和有机污染物问题，需要经济的新型吸附剂。在这里，我们测试了磁性生物炭，以从溶液中高效捕获典型污染物六价铬 (Cr(VI)) 和三氯乙烯 (TCE)。我们使用简单的合成方法，使用 2M FeCl 溶液和花生壳生物质，在 650 到 800°C 的不同热解温度下制备磁性 ZVI 生物炭。使用 X 射线衍射 (XRD) 和 Brunauer-Emmett-Teller (BET) 方法评估了生物炭的物理化学特性，以评估表面积。磁性 ZVI 生物炭对 Cr(VI) 和 TCE 的去除非常有效。在 800°C 下制备的最有效的磁性生物炭进一步通过扫描电子显微镜 (SEM) 进行了检查，结果显示 ZVI 的负载量高且均匀。吸附后，使用 X 射线光电子能谱 (XPS) 检查相同的磁性生物炭，以确定潜在的机制。还研究了 Cr(VI) 捕获对溶液 pH 的依赖性。我们的解释表明，当 pH<pH(2.5)时，静电吸引和氧化还原反应主导了 Cr(VI)的吸附。当 pH>pH 时，去除过程主要由氧化还原反应和铬酸盐阴离子取代羟基 (OH) 基团控制。相比之下，TCE 的捕获涉及疏水性分配、孔填充和还原降解。总的来说，我们的结果表明，磁性 ZVI 生物炭的简单合成可能为解决水污染问题提供一种经济有效的选择。
