Reverse osmosis membrane composition, structure and performance modification by bisulphite, iron(III), bromide and chlorite exposure. (15th October 2016)

• Record Type: Journal Article
• Authors: Ferrer, O.; Gibert, O.; Cortina, J.L.
• Is Part Of: Water research. Volume 103(2016)
• Page Start: 256
• Page End: 263
• Publication Date: 2016-10-15
• Subjects: Reverse osmosis -- Degradation -- Bisulphite -- Iron -- Bromide -- Rutherford backscattering spectrometry; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2016.07.013
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Reverse osmosis (RO) membrane exposure to bisulphite, chlorite, bromide and iron(III) was assessed in terms of membrane composition, structure and performance. Membrane composition was determined by Rutherford backscattering spectrometry (RBS) and membrane performance was assessed by water and chloride permeation, using a modified version of the solution-diffusion model. Iron(III) dosage in presence of bisulphite led to an autooxidation of the latter, probably generating free radicals which damaged the membrane. It comprised a significant raise in chloride passage (chloride permeation coefficient increased 5.3–5.1 fold compared to the virgin membrane under the conditions studied) rapidly. No major differences in terms of water permeability and membrane composition were observed. Nevertheless, an increase in the size of the network pores, and a raise in the fraction of aggregate pores of the polyamide (PA) layer were identified, but no amide bond cleavage was observed. These structural changes were therefore, in accordance with the transport properties observed. Graphical abstract: Highlights: Bisulphite and Fe(III) caused an increased chloride passage in RO membranes. Bisulphite, Fe(III) and chlorite modified the membrane pore size distribution. In Fe(III) presence, bisulphite in excess to chlorite led to greater chloride passage. Chlorite in excess to bisulphite caused RO membrane chlorination. Bisulphite, Fe(III), chlorite (in excess) and bromide led to membrane bromination.