Free chlorine exposure dose (ppm·h) and its impact on RO membranes ageing and recycling potential
| Autor: | Serena Molina, Junkal Landaburu-Aguirre, Amaia Lejarazu-Larrañaga, Laura Rodríguez-Sáez, Eloy García-Calvo, Thomas Ransome, Raquel García-Pacheco |
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| Jazyk: | angličtina |
| Předmět: |
Membrane permeability
Mechanical Engineering General Chemical Engineering Ultrafiltration chemistry.chemical_element 02 engineering and technology General Chemistry 021001 nanoscience & nanotechnology QD Chemistry Desalination 6. Clean water Membrane 020401 chemical engineering chemistry Chemical engineering Thin-film composite membrane Chlorine TD Environmental technology. Sanitary engineering General Materials Science Nanofiltration 0204 chemical engineering 0210 nano-technology Reverse osmosis Water Science and Technology |
| Zdroj: | Desalination |
| ISSN: | 0011-9164 |
| DOI: | 10.1016/j.desal.2019.01.030 |
| Popis: | Spiral wound thin film composite (TFC) polyamide (PA) membranes dominate the desalination market. Despite the proven performance of reverse osmosis (RO) membranes, they are periodically replaced and usually disposed of in landfills. The present study investigates the effect of using a diverse combination of free chlorine solutions (from 1 to 12,240 ppm) and exposure times (from 0.5 to 6500 h) with two purposes, namely: i) to simulate accelerated membrane ageing (low free chlorine concentration solutions) and ii) to optimize the existing recycling process of end-of-life RO membranes. Membrane coupons were taken from 8″ diameter modules (pristine and old). Membrane permeability and rejection coefficients were obtained by filtering synthetic brackish water (BW). Membrane surfaces were characterized by SEM and ATR-FTIR techniques. This work shows distinct PA vulnerability depending on membrane design (brackish water (BWRO) and seawater (SWRO) reverse osmosis membranes). Results reveal that the use of the exposure level parameter (ppm·h) as an independent basis for comparing free chlorine exposure must be carefully employed during ageing assessments and monitoring transition between nanofiltration (NF)-like performance to ultrafiltration (UF)-like performance. However, it can be used consistently to convert end-of-life RO membrane into NF-like recycled membranes using concentrations higher than 10 ppm. |
| Databáze: | OpenAIRE |
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