Selection of membranes and operational parameters aiming for the highest rejection of petrochemical pollutants via membrane distillation
“In search of more sustainable approaches for water reclamation from petrochemical industries, Membrane Distillation (MD) has become an alternative to pressure driven membrane technologies. In the present study, the efficiency of a Direct Contact MD (DCMD) configuration with hydrophobic and oleophobic commercially available membranes was examined, aiming to reject the main petrochemical pollutants such as acetate, propionate, and phenol. The influence of the feed and distillate temperatures, cross-flow velocity and pH on the flux and quality of the obtained distillate was further studied in a systematic way. The highest overall rejection efficiency of acetate, propionate, and phenol of approximately > 97% was obtained with the oleophobic membrane at pH ~ 13. The rejection of phenol was mainly influenced by pH, as this impacts its dissociation and thus its volatility. Moreover, to calculate the rejection of the components a novel mathematical method for lab-scale experiments was developed. This method is based on (dynamic) mass balances and was shown to be superior to state-of-the-art methods, which can greatly overestimate rejection. The method is independent of the experimental time and avoids the dilution effect of the initial water in the distillate vessel. The findings underline the importance of correct calculation of rejection in MD, to obtain results valuable for practical application.”
(Citation: Veleva, I., Vanoppen, M., Hitsov, I., et.al. – Selection of membranes and operational parameters aiming for the highest rejection of petrochemical pollutants via membrane distillation – Separation and Purification Technology 259(2021)art. no.118143 – DOI: 10.1016/j.seppur.2020.118143)
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