Advancements in superwetting metal foam materials for oily sewage treatment: From theoretical development to separation device design

Abstract

The multi-type oily wastewater has caused severe aquatic pollution, posing threats to ecological security and human health. To treat oil-contaminated wastewater, special wettability materials have been studied over the past decades for efficiently separating oil-water mixtures. Fundamentally, the synergistic effect of surface chemical composition and morphology is considered a key factor in achieving opposite wettability towards oil and water, thereby governing the wettability or selective adsorption of oil and water. Among various wettability materials, metal foam materials (MFs) exhibit significant advantages such as high open-cell porosity, high mechanical strength, high separation efficiency, and self-cleaning properties. This paper first describes the fundamental mechanisms of surface wettability, including contact angles in air. Subsequently, this paper elaborates on the surface wettability modification of MF materials, covering a spectrum of wettability traits: superhydrophobic-superoleophilic, air-exposed superhydrophilic-superoleophobic, underwater superhydrophilic-superoleophobic, and switchable wettability properties. It further summarizes the key performance metrics of specially wetted MFs, including oil absorption capacity, selective separation efficiency, reusability, and physichemical durability under severe operating conditions. Moreover, the current challenges confronting MFs in oily wastewater remediation are dissected, with corresponding outlooks for their future development and practical deployment presented.

Keywords

Special wettability / Metal foams / Oil/water separation / Separation mechanism / Fabrication methods / Separation device

Decleration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

CRediT authorship contribution statement

Zhengping Fang: Writing – review & editing, Writing – original draft, Conceptualization. Yuyan Fan: Writing – original draft. Wenhan Xu: Methodology, Funding acquisition. Liyan Chen: Investigation. Sixuan Meng: Methodology, Investigation. Yandong Wu: Methodology, Investigation. Fengping Xiao: Methodology. Xianggao Meng: Methodology, Investigation. Huiling Wang: Methodology. Lingzi Zuo: Methodology, Conceptualization. Zhicheng Yu: Methodology, Conceptualization. Yong Liu: Writing – review & editing, Conceptualization. Jiahao Wang: Writing – original draft, Conceptualization. Yan Liu: Writing – review & editing, Conceptualization. Daili Peng: Writing – review & editing, Conceptualization.

Acknowledgements

This work was partially supported by the Opening Project of the Key Laboratory of Bionic Engineering (Ministry of Education) of Jilin University (K202406), and National Natural Science Foundation of China (No. 22305090). Specially, thanks for the summary of physical structure detection by Dr. Fang Zhengping and Dr. Zuo Lingzi, the summary of chromatographic detection by Dr. Wenhan Xu, Dr. Liyan Chen, Dr. Sixuan Meng, Dr. Xianggao Meng, and Dr. Zhicheng Yu, and the summary of spectral detection by Dr. Huiling Wang, Dr. Yandong Wu, and Dr. Fengping Xiao.

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