School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha 410114, PR China.
School of Hydraulic Engineering, Changsha University of Science & Technology, Changsha 410114, PR China; College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China.
Sci Total Environ. 2020 Sep 1;733:139316. doi: 10.1016/j.scitotenv.2020.139316. Epub 2020 May 11.
Devising new versatile nano-adsorbents for efficient capturing of heavy metals in water represents one important direction for environmental remediation. Here, the application of a novel polyaniline@magnetic chitosan (PANI@MCTS) composite consisting of numerous nitrogen-containing functional groups and magnetic FeO nanoparticles was reported for the efficient treatment of chromium-containing wastewater. This material exhibited a fast adsorption kinetics (80% removal efficiency within 15 min) and strong adsorption capacity (186.6 mg(Cr(VI))•g(PANI@MCTS)) for removing Cr(VI) in water as well as an excellent magnetic separation ability. The adsorption of Cr(VI) was found to follow the Langmuir isotherm model and comply with the pseudo-second-order kinetics. More importantly, the PANI@MCTS could facilitate the in-situ chemical reduction of Cr(VI) to Cr(III) that enabled the detoxification treatment of Cr(VI) in water. XPS analysis revealed the simultaneous adsorption and in-situ chemical reduction of Cr(VI) on the PANI@MCTS, where the coordination and electrostatic interaction between Cr(VI) and the positively charged nitrogen containing functional groups contributed to the adsorption, and the = N-/-NH- groups served as active redox pair triggered the in-situ chemical reduction reaction. The recycle experiment showed an excellent stability of this material with >90% removal efficiency after five repeats of treatment. This work provides a promising alternative material for the effective treatment of chromium-containing wastewater.
设计新型多功能纳米吸附剂以高效捕获水中重金属是环境修复的一个重要方向。本研究中，报道了一种新型聚苯胺@磁性壳聚糖（PANI@MCTS）复合材料的应用，该复合材料由大量含氮官能团和磁性 FeO 纳米粒子组成，可用于高效处理含铬废水。该材料对水中的 Cr(VI) 具有快速的吸附动力学（15 分钟内去除率达到 80%）和强吸附能力（186.6mg(Cr(VI))·g(PANI@MCTS)），以及优异的磁分离能力。Cr(VI) 的吸附符合 Langmuir 等温吸附模型和准二级动力学模型。更重要的是，PANI@MCTS 可促进 Cr(VI)的原位化学还原为 Cr(III)，从而实现水中 Cr(VI)的解毒处理。XPS 分析表明，Cr(VI)在 PANI@MCTS 上同时发生吸附和原位化学还原，Cr(VI)与带正电荷的含氮官能团之间的配位和静电相互作用有助于吸附，而= N-/-NH-基团则作为活性氧化还原对引发原位化学还原反应。循环实验表明，该材料具有优异的稳定性，经过五次处理后去除效率仍保持在 90%以上。这项工作为有效处理含铬废水提供了一种有前途的替代材料。
