School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China.
School of Environment, Jinan University, Guangzhou, 510632, PR China.
Chemosphere. 2019 Jun;224:220-227. doi: 10.1016/j.chemosphere.2019.02.121. Epub 2019 Feb 19.
Activated carbon-coated α-FeO nanoparticles (nFeO@AC) were synthesized by a facile impregnation method to enhance hexavalent chromium (Cr(VI)) removal from water. The SEM images confirmed that α-FeO particles ranging from 90 to 500 nm were dispersedly loaded on the AC, which successfully amended Cr(VI) removal. The nFeO@AC was able to remove Cr(VI) with a 3 times higher efficiency of 94% in comparison with the AC. After adsorption, Cr(VI) reduction coupled with AC oxidation and low soluble (CrFe)(OH) precipitates were eventually formed. The Cr(VI) removal process was pH-dependent and could be well fitted to pseudo second-order kinetics. The nFeO@AC could be easily regenerated by 0.1 M HCl and showed a good stability as an 80% Cr(VI) removal efficiency was recorded after 4 desorption-adsorption cycles. In addition, this composite had a promising potential for repeated utilization because the AC of the adsorbed nFeO@AC could be refreshed and remodified with nFeO after stripping all the nFeO and (CrFe)(OH) precipitates from its surface by 1 M HCl and a Cr(VI) removal efficiency of 86% could be achieved. Our results demonstrated that the use of nFeO is an efficient and promising method to modify AC and enhance Cr(VI) removal form aqueous solutions.
活性碳负载α-FeO 纳米粒子（nFeO@AC）通过简便的浸渍法合成，以增强从水中去除六价铬（Cr(VI)）。SEM 图像证实，90-500nm 的α-FeO 颗粒分散负载在 AC 上，成功地改进了 Cr(VI)的去除效果。与 AC 相比，nFeO@AC 能够以 3 倍的效率（94%）去除 Cr(VI)。吸附后，Cr(VI)的还原伴随着 AC 的氧化和低溶解度的（CrFe）（OH）沉淀的形成。Cr(VI)的去除过程依赖于 pH 值，并且可以很好地拟合准二级动力学。nFeO@AC 可以很容易地通过 0.1M HCl 再生，并且在 4 次脱附-吸附循环后，记录到 80%的 Cr(VI)去除效率，表现出良好的稳定性。此外，由于从其表面剥离所有 nFeO 和（CrFe）（OH）沉淀以及用 1M HCl 重新填充和重塑吸附的 nFeO@AC 的 AC 后，该复合材料具有重复利用的良好前景，仍可以达到 86%的 Cr(VI)去除效率。我们的结果表明，使用 nFeO 是一种有效且有前途的方法来修饰 AC 并增强从水溶液中去除 Cr(VI)。
