Effect of Electric Field on Membrane Fouling and Membrane Performance in Reverse Osmosis Treatment of Brackish Water

Abstract

One of the most important applied technologies in water treatment is reverse osmosis (RO). However, membrane fouling and flux reduction pose significant challenges. The electric field, as an effective preventive measure, has received limited attention in RO applications. In this study, we added electric fields to finished rolled RO membranes to investigate their effect on membrane fouling and desalination performance. Experimental results indicated that higher electric fields were associated with higher concentrations of treated brine, resulting in a more significant effect. Permeate flux ratios increased with increasing voltage, with peaks of 1.02% (1000 mg/L, 25 V), 1.23% (2000 mg/L, 25 V), and 1.37% (3000 mg/L, 25 V), respectively. Additionally, the maximum reduction in the specific energy consumption (SEC) was 31% (2000 mg/L, 25 V) and 59% (3000 mg/L, 25 V), respectively. Notably, electric fields had a retarding effect on Ca2+ and humic acid (HA) fouling, with a stronger effect on HA, and higher permeate flux was maintained even after 120 h of operation. While this study visually demonstrates the direct effect of electric fields on RO, further quantification of the economic benefits of this method and a comprehensive understanding of the mechanisms behind how the electric field enhances permeate flux and mitigates membrane fouling are needed.