Natural organic matter separation by forward osmosis: Performance and mechanisms

Lin Wang; Tian Li; Huaqiang Chu; Wanzhu Zhang; Weiwei Huang; Bingzhi Dong; Daoji Wu; Feiyong Chen

doi:10.1016/j.watres.2021.116829

Natural organic matter separation by forward osmosis: Performance and mechanisms

Water Res. 2021 Mar 1:191:116829. doi: 10.1016/j.watres.2021.116829. Epub 2021 Jan 10.

Authors

Lin Wang¹, Tian Li², Huaqiang Chu³, Wanzhu Zhang⁴, Weiwei Huang⁵, Bingzhi Dong², Daoji Wu⁶, Feiyong Chen⁷

Affiliations

¹ School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, China; Resources and Environment Innovation Institute, Shandong Jianzhu University, Jinan 250101, China; State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
² State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
³ State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: chuhuaqiang@tongji.edu.cn.
⁴ Beijing General Municipal Engineering Design & Research Institute Co.,Ltb, Beijing 100082, China.
⁵ Eco-Environmental Protection Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai 201403, China.
⁶ School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, China; Resources and Environment Innovation Institute, Shandong Jianzhu University, Jinan 250101, China.
⁷ Resources and Environment Innovation Institute, Shandong Jianzhu University, Jinan 250101, China.

PMID: 33476800
DOI: 10.1016/j.watres.2021.116829

Abstract

The purification performance of a forward osmosis (FO) membrane on natural organic matter (NOM) contained in real surface water by was investigated systematically. FO could reject the natural dissolved organic matter (DOM) effectively with removal efficiencies of approximately 99.0%. When the natural water samples (e.g., raw surface water) had lower fouling tendencies, the active layer facing the draw solution (AL-facing-DS mode) provided a higher water flux than that in the alternative membrane orientation because the isoflux point occurred later in the process. It was found that the concentration of calcium ions had a more severe effect on decreasing the fouling flux of the FO membrane than that of the organic foulant. Furthermore, the concentrated feed solution had a more significant effect on the fouling flux decline of the natural DOM containing more small molecules than natural DOM containing more macromolecules. Additionally, the fouling that occurred in the AL-facing-DS orientation was compensated by the reduced internal concentration polarization (ICP) level based on the occurrence of the critical compensation point. It was also revealed that the permeation drag caused by the water flux and the chemical interactions induced by the feed solution pH and the calcium ion concentration played a significant role in the adsorption of small natural DOM molecules in the porous structure of the FO membrane. Based on the analysis of the interfacial free energies, the interactions between the natural DOM and the surface of the support layer dominated the initial fouling of the FO membrane, while subsequent fouling was controlled by the interaction between the approaching DOM molecules and the already adsorbed DOM.

Keywords: Forward osmosis; Fouling; Interfacial energy; Internal concentration polarization; Surface water.

MeSH terms

Adsorption
Membranes, Artificial*
Osmosis
Water
Water Purification*

Substances

Membranes, Artificial
Water