Highly efficient and selective nitrate and Hg(II) removal from wet oxidation flue gas purification wastewater using bifunctional MXene nanofiltration membrane
Runlong Hao , Jiabin Gao , Xinran Chen , Wei He , Shiwei Guo , Mengyuan Wu , Xin Tong , Zhiwei Wang , Lidong Wang
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引用次数: 0
Abstract
The wet oxidation process is a promising method for simultaneously removing SO2, NO, and Hg0 from coal-fired flue gas. However, the resource utilization of the resulting wastewater, which is enriched with complex ions such as Hg2+, NH4+, NO3−, and SO42−, remains a significant challenge. To achieve the simultaneous goals of concentrating NH4+/NO3−/SO42− ions, adsorbing and separating Hg2+ ions, and reusing wastewater, a bifunctional MXene composite nanofiltration membrane with large interlayer spacing and excellent electrostatic repulsion was developed. The membrane was prepared by co-depositing MXene nanosheets, carboxylated multi-walled carbon nanotubes (MWCNTs), and sodium dodecyl sulfate (SDS) onto an NF-90 membrane. The resulting MXene-MWCNTs-SDS (MMS-COOH) composite membrane demonstrated exceptional salt rejection of 84.4 % for NO3−, 89.0 % for NH4+, 99.8 % for SO42−, and 99.7 % for Hg2+. After 30 cycles, the membrane structure remained stable, maintaining good reusability, with NH4+ and SO42− rejection still reaching 90.0 %. Moreover, the maximum adsorption capacity for Hg2+ was 2869.6 mg g−1, while the capacities for Cr6+ and Pb2+ were 577.6 and 316.8 mg g−1, respectively. The MMS-COOH composite membrane introduces an innovative method for the benign treatment of wet oxidation flue gas purification wastewater and facilitates the recovery of (NH4)2SO4 and NH4NO3 as fertilizers, holding a promising application prospect.
期刊介绍:
The Journal of Membrane Science is a publication that focuses on membrane systems and is aimed at academic and industrial chemists, chemical engineers, materials scientists, and membranologists. It publishes original research and reviews on various aspects of membrane transport, membrane formation/structure, fouling, module/process design, and processes/applications. The journal primarily focuses on the structure, function, and performance of non-biological membranes but also includes papers that relate to biological membranes. The Journal of Membrane Science publishes Full Text Papers, State-of-the-Art Reviews, Letters to the Editor, and Perspectives.