Reduced graphene oxide membrane with small nanosheets for efficient and ultrafast removal of both microplastics and small molecules

• Published in: Journal of hazardous materials 2025-04, Vol.487, p.137078, Article 137078
• Main Authors: Yan, Linghui, Chen, Junjie, Zhang, Zehui, Liu, Zhengyang, Ding, Tao, Shi, Guosheng
• Format: Article
• Language: English
• Subjects: Microplastic; Mixed system; Permeability; Reduced graphene oxide membrane; Water transport channels
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.137078

The clogging of sieving pores due to the complex sewage system of mixed molecules and nanoparticles of different scales is a difficulty in the membrane-based separation process. When the holes are reduced to the point where they can repel small molecules in the contaminants, large-molecule contaminants can adsorb to the holes and decrease the permeability. A similar question remains in new promising graphene oxide (GO) membranes. In this study, we prepared a small lateral-sized reduced graphene oxide (S-rGO) membrane with short Z-type water transport pathways and a lower adsorption energy for pollutant molecules. The S-rGO membrane presented an ultrahigh permeability for large size microplastics (MPs) of 236.2 L m–2 h–1 bar–1 (99.9 % rejection rate) and small dye molecules of 234.2 L m–2 h–1 bar–1, which was 40 and 25 times higher than the permeability of traditional GO membranes with larger sized sheets, respectively. We evaluated the long-term stability of the membrane in cross-flow system. The membrane maintained more than 212.8 L m–2 h–1 bar–1 permeability and a 99.9 % rejection rate under 16 h. Our findings provided a new strategy to address the difficulty of efficient membrane use for complex water pollutants. [Display omitted] •The small lateral size reduced graphene oxide (S-rGO) membrane with short Z- type water transport pathways and lower adsorption energy was prepared for pollutant molecules removal.•The S-rGO membrane showed an excellent high water permeance of 236.2 L m−2 h−1 bar−1 with a rejection rate up to 99.9 % or MPs removal in water for the first time.•The S-rGO membranes demonstrated exceptional mechanical stability, retaining their integrity even in highly acidic or alkaline environments, and maintaining superior separation performance following membrane surface cleaning.