Importance of origin and characteristics of biopolymers in reversible and irreversible fouling of ultrafiltration membranes

The present work compares the chemical properties of isolated biopolymers of different origins and their fouling potential during ultrafiltration (UF). The biopolymers were extracted from secondary wastewater effluent as effluent organic matter (EfOM) and from surface water as natural organic matter (NOM). Multiple analytical techniques were used to characterize the isolates. The characterization results revealed that EfOM biopolymers were more enriched in protein-type structures compared to the NOM organics, and they presented significant differences in the reversibility of membrane fouling. Dissolved in pure water, EfOM biopolymers led to more irreversible fouling than that caused by NOM isolates. Dosing divalent cations (e.g., Ca2+) into the solutions increased the irreversibility of both types of fouling, while aggravating NOM fouling more significantly. Further investigation was conducted to understand the interaction between EfOM and NOM biopolymers during formation of the fouling layer. The results showed that the interaction between these two types of organics was negligible in the absence of salts. These findings highlight the importance of a comprehensive understanding of biopolymers from different origins, considering their chemical properties and water chemistry, which have valuable implications for selecting suitable membrane fouling control strategies for treating water from different origins. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study compared the chemical properties and fouling potential of biopolymers extracted from secondary wastewater effluent and surface water during ultrafiltration. It was found that EfOM biopolymers were enriched in protein structures and caused more irreversible fouling compared to NOM biopolymers. Additionally, the presence of divalent cations increased the irreversibility of fouling, with a more significant impact on NOM fouling.