School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China.
School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China.
Chemosphere. 2021 Jun;272:129606. doi: 10.1016/j.chemosphere.2021.129606. Epub 2021 Jan 11.
Reduction and recycling of Cr(VI) can offer environmental governance and sustainable development. Polypyrrole/sugarcane bagasse composites (PPy/SCB) for efficient adsorption and reduction of Cr(VI) in wastewater were prepared by in-situ polymerization. The effects of the initial pH, Cr concentration, adsorbent dosage, contact time, composition ratio and temperature on adsorption capacity were explored. The optimal Cr(VI) adsorption capacity of PPy/SCB was achieved when the pH value was 2.0. The adsorbents before and after adsorption were characterized, which confirmed that adsorption process affects the morphology, composition and structure of the PPy/SCB surface. The adsorption kinetics data of Cr(VI) were best fitted by the pseudo-second-order model, which indicated that Cr(VI) concentration gradient played a driving role in this process. The adsorption isotherm data were consistent with the Langmuir isotherm model with the adsorption capacity of 156-251 mg/g. Synergic effect of PPy and SCB during the processes of electrostatic adsorption and ion exchange, in-situ reduction of electron donors, and coordination were found to be responsible for the rapid removal and toxicity reduction of total Cr in aqueous solution. Cr(VI) anions can be chelated by oxygen-containing functional groups on SCB surface after reduction to simple cations, which was confirmed by Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy results. This study provides a reasonable scheme for the targeted use of waste biomass for heavy metal pollution control.
还原和回收六价铬 (Cr(VI)) 可以提供环境治理和可持续发展。通过原位聚合制备了用于高效吸附和还原废水中六价铬的聚吡咯/甘蔗渣复合材料 (PPy/SCB)。探讨了初始 pH 值、Cr 浓度、吸附剂用量、接触时间、组成比和温度对吸附容量的影响。当 pH 值为 2.0 时，PPy/SCB 对 Cr(VI) 的最佳吸附容量。对吸附前后的吸附剂进行了表征，证实吸附过程会影响 PPy/SCB 表面的形态、组成和结构。Cr(VI) 的吸附动力学数据最好由伪二阶模型拟合，这表明 Cr(VI) 浓度梯度在此过程中起推动作用。吸附等温线数据与 Langmuir 等温模型一致，吸附容量为 156-251 mg/g。在静电吸附和离子交换、电子供体原位还原和配位的协同作用下，被发现可以快速去除和降低水溶液中总铬的毒性。还原后，SCB 表面的含氧官能团可以螯合 Cr(VI) 阴离子，形成简单的阳离子，傅里叶变换红外光谱和 X 射线光电子能谱结果证实了这一点。这项研究为利用废生物质进行重金属污染控制提供了合理的方案。
