Simultaneous Recovery of NH<sub>3</sub>–N and Removal of Heavy Metals from Manganese Residue Leachate Using an Electrodialysis System
Yuyang Yi, Haopeng Feng, Jiajia Wang, Jing Tang, Yangfeng Wu, Xiangmin Liang, Yuyao Guo, Lin Tang
Abstract
The problem of high concentration of NH 3 –N and heavy metals in manganese residue leachate (MRL) needs to be solved urgently as it can harm the surrounding soil, water bodies, and even the ecological system. In this study, a novel electrodialysis system with a self-growing titanium dioxide nanowire (TiO 2 NW) electrode is proposed to recover NH 3 –N and remove heavy metals from MRL. Plant growth experiments and ecotoxicity studies are used to evaluate the ecological risks of the reuse of recovered NH 3 –N. In the electrodialysis system with a proton membrane to separate the two chambers, 87%–97% removal of heavy metals and 95% recovery of NH 3 –N from MRL can be achieved. The obtained recovery solution from the cathode chamber can greatly promote the plant growth. The ecotoxicity experiment results further reveal that the recovered NH 3 –N can optimize the soil microbial community structure by promoting the reproduction of the genus Bacillus and thus improve soil fertility. This work can provide a new perspective on the harmless disposal and resource recovery of MRL.