Concurrent adsorption and micro-electrolysis of Cr(VI) by nanoscale zerovalent iron/biochar/Ca-alginate composite.
Concurrent adsorption and micro-electrolysis of Cr(VI) by nanoscale zerovalent iron/biochar/Ca-alginate composite.
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DOI：
10.1016/j.envpol.2019.01.047
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发表时间：
2019-04
影响因子：
8.9
通讯作者：
Zhonghao Wan;Dong-wan Cho;Daniel C W Tsang;M. Li;Tan Sun;F. Verpoort
中科院分区：
文献类型：
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作者：
Zhonghao Wan;Dong-wan Cho;Daniel C W Tsang;M. Li;Tan Sun;F. Verpoort
本研究提出了一种在纳米级零价铁（nZVI）介导的反应中同时提高Cr（VI）去除性能和减轻溶解铁释放的新方法。将浸渍了nZVI的生物炭（BC）包埋在海藻酸钙（CA）珠状基质中，对复合材料的理化性质进行了表征，结果表明：nZVI/BC颗粒包埋在海藻酸钙（CA）珠状基质中，其外层呈球形，并有若干裂纹。由还原剂（nZVI）、多孔吸附剂（BC）和外屏蔽层（CA）组成的复合材料具有多官能性，对Cr（VI）的去除效果较好，最大吸附量为86.4 mg/g（基于Langmuir等温线），溶解铁的释放量很小。通过XPS分析和拟二阶动力学和等温线（Redlich-Peterson模型）拟合结果表明，nZVI/BC/CA复合材料对Cr（VI）的去除机制可能是吸附和微电解同时发生。通过固定床柱实验进一步验证了nZVI/BC/CA复合材料的实用性。这些结果为设计用于废水处理的高性能工程生物炭提供了新的见解。
This study introduced a new approach for simultaneously enhancing Cr(VI) removal performance and mitigating release of dissolved Fe during nanoscale zero-valent iron (nZVI)-mediated reactions. After entrapping nZVI-impregnated biochar (BC) in the matrix of calcium-alginate (CA) bead, the physicochemical characterization of nZVI/BC/CA composites revealed that nZVI/BC particles were embedded inside CA having a spherical shape and several cracks on its outer layer. The multi-functionality of nZVI/BC/CA composites consisting of reductant (nZVI), porous adsorbent (BC), and external screening layer (CA) enhanced the removal of Cr(VI) with the maximum adsorption capacity of 86.4 mg/g (based on the Langmuir isotherm) and little release of dissolved Fe. With the XPS analysis and fitting results of kinetics (pseudo second order) and isotherms (Redlich-Peterson model), plausible removal mechanisms of Cr(VI) were simultaneous adsorption and micro-electrolysis reactions by nZVI/BC/CA composites. The practical applicability of nZVI/BC/CA composites was further demonstrated through the fixed-bed column experiments. These results provide new insights into the design of high-performance engineered biochar for wastewater treatment.