Enhanced removal of Cr(VI) from wastewater by nanoscale zero valent iron supported on layered double hydroxides
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Enhanced removal of Cr(VI) from wastewater by nanoscale zero valent iron supported on layered double hydroxides Shifeng Zhao2 · Xin Fan2 · Junshan Yang2 · Hanhan Huang2 · Caifeng Xia2 · Ruisen Jing2 · Mi Wu2 · Zhilei Zhang3 · Aiju Liu1 · Qian Zhang1 · Zilin Meng1
© Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract The application of nanoscale zero-valent iron (NZVI) in a promising remediation strategy was challenged by easy aggregation and surface passivation. To enhance their performance of Cr(VI) removal, layered double hydroxides (LDHs) supported NZVI (NZVI@LDH) with different loading amount via an in-situ way was successfully synthesized. The structural characterization and morphology revealed LDHs could stabilize and uniformly disperse NZVI on the surface of LDHs layer, however, superabundant NZVI still leaded to a visibly aggregation. Cr(VI) removal by NZVI@LDH was higher than that of the sum of NZVI and LDHs, revealing a synergistic effect within this system. The results of Cr(VI) removal displayed with the growth of iron loading amount, the removal efficiencies were raised firstly but declined afterwards. Kinetics studies for all samples showed Cr(VI) removal well fitted pseudo-second-order model and isotherm data was well described by Langmuir model. The effects of initial concentration and pH on Cr(VI) removal were also examined. Cr(VI) in the wastewater was reduced by NZVI to Cr(III), NZVI was oxidized into Fe(II) and Fe(III). The excellent removal performance suggested a promising strategy in sewage water remediation. Keywords NZVI · Ldhs · Cr(vi) · Synergistic effect
1 Introduction Large amounts of wastewaters with hexavalent chromium (VI) are generated in the effluents of electroplating, leather tanning, textile, and many other industries [1–4]. Due to improper storage and inadequate disposal, Cr(VI) has caused Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10934-020-00947-4) contains supplementary material, which is available to authorized users. * Qian Zhang [email protected] * Zilin Meng [email protected] 1
School of Resources and Environmental Engineering, Shandong University of Technology, Zibo, People’s Republic of China
2
School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo, People’s Republic of China
3
CNPC Engineering Technology R&D Company Limited, Beijing, People’s Republic of China
many contamination in water and soil [1, 5]. Cr(VI), known to be mobile, soluble and poisonous, causes a series of health problems from simple skin irritation to lung carcinoma [6]. Therefore, the treatment of Cr(VI)-contaminated wastewater by an effective way is an urgent and well-recognized environmental issue. Nowadays, various techniques like ion exchange, chelation, reverse osmosis, sulfide precipitation and activate carbon adsorption method have been proposed for the Cr(VI) removal from wastewater and among these methods, nanoscale zero-valent iron (NZVI) has been attracted in
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