Rapid polyamide membrane compatibility testing of potential anti-biofouling agents for reverse osmosis membrane systems

Abstract

The detrimental impacts of biofouling on reverse osmosis (RO) membrane (ROM) installations is one of the main technical barriers faced by RO technology to provide potable water. To unveil safer alternatives for biofouling prevention in ROM installations, this work assesses the ROM compatibility of three potential low-hazard anti-biofouling agents (lauroyl arginate ethyl (LAE), phenoxyethanol (PE), and sodium benzoate (SB)) via a proposed rapid membrane degradation test. This study offers a cost-effective screening tool to select biocides for extensive compatibility studies. Attenuated total reflectance – Fourier-transform infrared spectroscopy, atomic force microscopy, and scanning electron microscopy assessed ROM surface damage due to biocide exposure. LAE did not show significant morphological or chemical membrane damage at any experimental conditions (exposure time: 1, 8, and 24 h; pH: 4, 7, 9; concentration: 100 mg/L, 50 g/L, 100 g/L, and 150 g/L). However, results indicated that exposure to PE and SB led to membrane degradation. The proposed rapid membrane degradation test showed to be an excellent tool for improving current membrane compatibility testing practices. It identified two ROM-damaging biocides, SB and PE, streamlining large-scale testing efforts. Additionally, it identified a promising biocide, LAE, with the potential to address biofouling in RO systems, prompting further long-term compatibility studies.