College of Architecture and Engineering, Yunnan Agricultural University, Kunming 650201, PR China.
College of Resources, Environment and Chemistry, Chuxiong Normal University, Chuxiong 675000, PR China.
Chemosphere. 2023 Mar;318:137982. doi: 10.1016/j.chemosphere.2023.137982. Epub 2023 Jan 27.
The simultaneous and efficient removal of various heavy metals from wastewater to satisfy the requirements of zero discharge has been a research hotspot and difficult point. In the laboratory scale (0.5 L), the biocathode microbial electrolytic cells (BCMECs) were constructed with the pre-screened heavy metal-tolerant electroactive bacterial, mainly of the Sphingomonas, Azospira and Cupriavidus. The BCMECs system showed a more satisfactory removal effect for multiple heavy metals and organic pollutants. At the auxiliary voltage of 0.9 V and initial concentration of 20 mg L, the removal efficiency of Cu, Pb, Zn, Cd and COD were 98.76 ± 0.32%, 98.01 ± 0.76%, 73.58 ± 4.83%, 84.39 ± 5.95%, 77.55 ± 1.51%, respectively. It was found by various characterization techniques (CV, EIS, XPS et al.) that the constructed biocathode has the function of electrocatalytic reduction of heavy metal ions in a micro-aerobic, film-free environment. The positive shift (0.030-0.229 V) of the initial potential for heavy metal reduction and the absence of a significant increase (＜ 10 Ω) in the interfacial resistance indicated a reduction in the total free energy of the reduction reaction, which promotes the reaction and improves the efficiency of heavy metal removal. Bacterial community analysis revealed that the Proteobacteria has been dominant in different heavy metal environments. With the increase of heavy metal concentration, Sphingomonas, Azospira and Cupriavidus showed stronger tolerance and became the dominant genus. This study emphasized the important performance of biocathodes and the effective treatment of heavy metal wastewaters by BCMECs and provided a reasonable way for industrial and mining enterprises to innovate the water treatment process.
从废水中同时高效去除各种重金属以满足零排放要求一直是研究的热点和难点。在实验室规模（0.5 L）下，构建了具有预筛选的重金属耐受电活性细菌（主要为鞘氨醇单胞菌、固氮螺菌和铜绿假单胞菌）的生物阴极微生物电解池（BCMECs）。BCMECs 系统对多种重金属和有机污染物表现出更令人满意的去除效果。在辅助电压为 0.9 V 和初始浓度为 20 mg L 的条件下，Cu、Pb、Zn、Cd 和 COD 的去除效率分别为 98.76±0.32%、98.01±0.76%、73.58±4.83%、84.39±5.95%、77.55±1.51%。通过各种表征技术（CV、EIS、XPS 等）发现，构建的生物阴极在微好氧、无膜环境中具有电催化还原重金属离子的功能。重金属还原初始电位的正移（0.030-0.229 V）和界面电阻的显著增加（＜10 Ω）的缺失表明还原反应的总自由能降低，这促进了反应并提高了重金属去除效率。细菌群落分析表明，在不同重金属环境中，变形菌门一直占主导地位。随着重金属浓度的增加，鞘氨醇单胞菌、固氮螺菌和铜绿假单胞菌表现出更强的耐受性，并成为优势属。本研究强调了生物阴极的重要性能和 BCMECs 对重金属废水的有效处理，并为工业和矿业企业创新水处理工艺提供了合理途径。
