Modification of regenerated cellulose ultrafiltration membranes with multi-walled carbon nanotubes for enhanced antifouling ability: Field test and mechanism study

Jun-Cheng Han; Yi-Kang Zhu; Long-Fei Wang; Yang Mu; Guo-Guang Feng; Kun-Qiao Liu; Cai-Huan Tong; Zhen-Xun Yu

doi:10.1016/j.scitotenv.2021.146657

Modification of regenerated cellulose ultrafiltration membranes with multi-walled carbon nanotubes for enhanced antifouling ability: Field test and mechanism study

Sci Total Environ. 2021 Aug 1:780:146657. doi: 10.1016/j.scitotenv.2021.146657. Epub 2021 Mar 22.

Authors

Jun-Cheng Han¹, Yi-Kang Zhu¹, Long-Fei Wang², Yang Mu³, Guo-Guang Feng⁴, Kun-Qiao Liu¹, Cai-Huan Tong⁵, Zhen-Xun Yu⁶

Affiliations

¹ Department of Civil and Environmental Engineering, School of Civil and Environmental Engineering, Ningbo University, Ningbo 315211, China.
² Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China.
³ CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei 230026, China.
⁴ Ningbo Urban Planning & Design Institute, Ningbo 315211, China.
⁵ Centre Testing International (Ningbo) Corporation, Ningbo 315211, China.
⁶ Department of Civil and Environmental Engineering, School of Civil and Environmental Engineering, Ningbo University, Ningbo 315211, China. Electronic address: yuzhenxun@nbu.edu.cn.

PMID: 34030319
DOI: 10.1016/j.scitotenv.2021.146657

Abstract

Although ultrafiltration (UF) has been extensively employed for drinking water purification, it is crucial to further develop novel membrane materials to improve the antifouling capacity and satisfy the practical usage. Multi-walled carbon nanotubes (MWCNTs) have characteristics that could potentially improve the membrane antifouling performance. Therefore, in this study, modified cellulose UF membranes were prepared using MWCNTs of various outer diameters ranging from 10 to 20 nm to 40-60 nm. The antifouling properties of the modified membrane and natural organic matter (NOM) removal mechanism were investigated while treating water from a local drinking water source river. Overall, the antifouling ability increased by more than one-fold when the nascent cellulose membrane was coated with MWCNTs (outer diameter of 40-60 nm) at a loading of 17.4 g/m². The molecular weight distribution profiles of the NOM in the raw water and permeates suggest the superior performance of the modified membranes in removing two major NOM fractions with molecular weights ranging from approximately 5 k-30 k and 500 k-1000 k. Based on its hydrophobicity, the NOM of the raw water was fractionated into the strong hydrophobic (SHPO), the weak hydrophobic, the strong hydrophilic and the moderately hydrophilic (MHPI) fractions. The WHPO fraction caused the highest fouling compared with the other fractions under consistent experimental conditions. Meanwhile, the modified membranes showed a preference for removing the MHPI and SHPO fractions. These results imply that MWCNTs can be employed to improve the antifouling property of cellulose UF membranes and have the potential to selectively remove moderately hydrophilic contaminants from water.

Keywords: Drinking water source; Hydrophobicity; Multi-walled carbon nanotube; Natural organic matter; Ultrafiltration membrane.