Surface Treatment by Physical Irradiation for Antifouling, Chlorine-Resistant RO Membranes

Marwa S Shalaby; Heba Abdallah; Ralph Wilken; Schmüser Christoph; Ahmed M Shaban

doi:10.3390/membranes13020227

Surface Treatment by Physical Irradiation for Antifouling, Chlorine-Resistant RO Membranes

Membranes (Basel). 2023 Feb 13;13(2):227. doi: 10.3390/membranes13020227.

Authors

Marwa S Shalaby¹, Heba Abdallah¹, Ralph Wilken², Schmüser Christoph², Ahmed M Shaban³

Affiliations

¹ Chemical Engineering Department, Engineering Research & Renewable Energy Institute, National Research Centre, 33-El Buhouth Street, Dokki, Cairo 12622, Egypt.
² Plasma Technology and Surface Treatment Department, Fraunhofer Institute for Manufacturing Technologies and Advanced Materials (IFAM), Wiener Straße 12, 28359 Bremen, Germany.
³ Water Pollution Research Department, Environmental Research Institute, National Research Centre, 33-El Buhouth Street, Dokki, Cairo 12622, Egypt.

Abstract

Reverse osmosis (RO) membranes represent a strategic tool for the development of desalination and water treatment processes. Today's global needs for clean water supplies show stressing circumstances to secure this supply, relying upon desalination and wastewater treatment and reuse, especially in Egypt and the Middle East. However, chlorine attack and fouling of polyamide layers, the active (selective) layers of RO membranes, are representing a great obstacle to seriously spreading the use of this technology. One promising way of fouling control and chlorine resistance is surface modification using grafting by plasma or vacuum ultraviolet (VUV) irradiation as a layer-by-layer assembly on polyamide membranes. Several studies have shown the effect of grafting by plasma using methacrylic acid (atmospheric pressure plasma) and showed that grafted coatings can improve PA membranes toward permeation compared with commercial ones with fouling behavior but not chlorine resistance. In this work, the techniques of layer-by-layer (LBL) assembly for previously prepared PA RO membranes (3T) using a mixed-base polymer of polysulfone and polyacrylonitrile in the presence of nanographene oxide (GO) without chemical grafting and with chemically grafted poly-methacrylic acid (3TG) were used. Membranes 3T, 3TG, a blank one (a base polymer membrane only was surface modified using VUV activation (AKT), and one with a grafted layer with polyethylene glycol (VUV-PEG) were prepared. These were then compared with polydimethylsiloxane (VUV-PDMS) and another surface modification with low-pressure plasma using acrylic acid (acryl) and hexadimethyl siloxane (GrowPLAS). The tested membranes were evaluated by short-term permeation and salt rejection experiments together with fouling behavior and chlorine resistance. A clear improvement of chlorine resistance and antifouling was observed for 3T membranes under plasma treatment, especially with the grafting with polyacrylic acid. Better antifouling and antichlorine behaviors were achieved with the vacuum UV treatment.

Keywords: chlorine resistance; fouling behavior; plasma treatment; thin-film composite; vacuum UV.

Grants and funding

This work was fully funded and financially supported through Science, Technology & Innovation Funding Authority (STIFA) formerly STDF in EGYPT as a GERF call-Cycle 5 ID number 33633 and BMBF from Bremen-GERMANY which was funded by the Federal Ministry for education and research under grant number 01DH20016. The responsibility for the content of this publication lies with the authors.