College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, Shanxi, People's Republic of China.
Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, 712100, Shanxi, People's Republic of China.
Environ Sci Pollut Res Int. 2020 Nov;27(32):40826-40836. doi: 10.1007/s11356-020-10120-8. Epub 2020 Jul 16.
In this paper, metallic copper (Cu) was supported on nanoscale zero-valent iron (nZVI) to form a nanoscale bimetallic composite (nZVI-Cu), which was used to activate persulfate (PS) to simultaneously remove the compound contaminants Cr(VI) and tetracycline hydrochloride (TCH) in simulated wastewater. nZVI, nZVI-Cu, and nZVI-Cu-activated PS (nZVI-Cu/PS) were characterized by SEM, TEM, XRD, and XPS. The effects of the bimetallic composite on Cr(VI) and TCH removal were compared in the nZVI, nZVI-activated PS (nZVI/PS), nZVI-Cu, and nZVI-Cu/PS systems. The results showed that nZVI and Cu can form a nanobimetallic system, which can create galvanic cells; thus, the galvanic corrosion of nZVI and the transfer of electrons are accelerated. For a single contaminant, the removal efficiency of Cr(VI) and TCH is the highest when nZVI is loaded with 3 wt% and 1 wt% Cu, respectively. The ratio of nZVI-Cu with 3 wt% Cu to PS is 7:1, and the removal efficiency of Cr(VI) and TCH compound contaminants is ~ 100% after 60 min under acidic conditions, which indicates that the Cr(VI) reduction and TCH oxidation were complete in the nZVI-Cu/PS system. The mechanisms of simultaneous removal of Cr(VI) and TCH in the nZVI-Cu/PS system are proposed. The removal of Cr is because of the adsorption-reduction effects of the nZVI-Cu bimetallic material. The degradation of TCH is mainly due to the action of oxidative free radicals generated by Fe-activated PS. The free radical capture experiments showed that SO- 4· plays a major role in the process of TCH degradation.
在本论文中，将金属铜（Cu）负载到纳米零价铁（nZVI）上形成纳米双金属复合材料（nZVI-Cu），并将其用于激活过硫酸盐（PS）以同时去除模拟废水中的复合污染物六价铬（Cr(VI)）和盐酸四环素（TCH）。通过 SEM、TEM、XRD 和 XPS 对 nZVI、nZVI-Cu 和 nZVI-Cu 激活 PS（nZVI-Cu/PS）进行了表征。在 nZVI、nZVI 激活 PS（nZVI/PS）、nZVI-Cu 和 nZVI-Cu/PS 体系中比较了双金属复合材料对 Cr(VI)和 TCH 去除的影响。结果表明，nZVI 和 Cu 可以形成纳米双金属系统，从而可以产生原电池；因此，nZVI 的电偶腐蚀和电子转移得到加速。对于单一污染物，当负载 3wt%的 nZVI 和 1wt%的 Cu 时，Cr(VI)和 TCH 的去除效率最高。当 nZVI-Cu 中 Cu 的负载量为 3wt%，且 nZVI-Cu 与 PS 的比例为 7:1 时，在酸性条件下 60min 后，Cr(VI)和 TCH 复合污染物的去除效率达到~100%，这表明在 nZVI-Cu/PS 体系中，Cr(VI)的还原和 TCH 的氧化是完全的。提出了 nZVI-Cu/PS 体系中同时去除 Cr(VI)和 TCH 的机理。Cr 的去除是由于 nZVI-Cu 双金属材料的吸附还原作用。TCH 的降解主要归因于 Fe 激活 PS 产生的氧化自由基的作用。自由基捕获实验表明，SO- 4·在 TCH 降解过程中起主要作用。
