Oxidation of poly(ethylene terephthalate) track-etched membranes for using in direct osmosis

Abstract

This study is the first to analyze the oxidation of track-etched membranes with a unique "large well – porous bottom" pore geometry. Their physical and chemical characteristics including strength, air, water performance, and hydrophobicity-hydrophilicity properties were studied. The study covered the analysis of the effect of pore shape and size on membrane performance in direct osmosis processes, encompassing the variation of filtration flux as a function of solution concentration and pore geometry. Membranes with this pore structure exhibit high performance in direct osmosis due to their mechanical properties and permeability. Optimal oxidation conditions contributed to a 28% increase in performance by improving the hydrophilicity of the membranes, leading to an increase in their filtration capacity. In addition, it was found that the level of water purification evaluated by electrical conductivity reached approximately 100%. The membrane performance increases with increasing concentration difference due to the rise in partial pressure. Nevertheless, after direct osmosis, the membranes show fouling of the channels with salt deposits, according to scanning electron microscopy data. These findings may contribute to the development of new approaches to the design of membranes specifically adapted to different applications in the field of liquid purification and filtration. This could result in more efficient and cost-effective use of membrane technologies in industry and utilities.