Enhancing the removal of organic micropollutants by nanofiltration membrane with Fe (III)-tannic acid interlayer: Mechanisms and environmental implications

Wenyu Liu; Li Long; Zhe Yang; Li Wang; Qimao Gan; Shenghua Zhou; Pulak Sarkar; Hao Guo; Chuyang Y Tang

doi:10.1016/j.watres.2023.120623

Enhancing the removal of organic micropollutants by nanofiltration membrane with Fe (III)-tannic acid interlayer: Mechanisms and environmental implications

Water Res. 2023 Oct 15:245:120623. doi: 10.1016/j.watres.2023.120623. Epub 2023 Sep 11.

Authors

Wenyu Liu¹, Li Long¹, Zhe Yang¹, Li Wang¹, Qimao Gan¹, Shenghua Zhou¹, Pulak Sarkar¹, Hao Guo², Chuyang Y Tang³

Affiliations

¹ Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
² Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China. Electronic address: guohao@sz.tsinghua.edu.cn.
³ Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China. Electronic address: tangc@hku.hk.

PMID: 37729696
DOI: 10.1016/j.watres.2023.120623

Abstract

Nanofiltration technology has been applied in a variety of water treatment scenarios. However, conventional thin-film composite (TFC) membranes fail to remove emerging organic micropollutants (OMPs) efficiently. Here we applied thin-film nanocomposite membrane with an interlayer (TFNi) of Fe (III)-tannic acid to remove various types of OMPs, such as endocrine disrupting chemicals (EDCs), pharmaceutically active compounds (PhACs), and perfluoroalkyl substances (PFASs). Compared to the pristine TFC membrane, TFNi membrane exhibited crumpled morphology and its rejection layer was denser, better cross-linked and possessed smaller average pore size with narrower distribution. Significant enhancement in water-OMPs selectivity of PhACs and PFASs was observed. The mechanism lies in the effects of interlayer in improving the membrane permeance to water and meanwhile reducing the permeance to some OMPs by enhancing size exclusion effects. This work confirms the effectiveness of using TFNi membrane to simultaneously enhance the OMPs rejection and water permeance. The unraveled mechanism might inspire the future development of high-performance nanofiltration membranes targeting OMPs removal.

Keywords: Fe (III)–tannic acid; Interlayer; Nanofiltration membranes; Organic micropollutants.