Pervaporative separation of corrosive liquids is always challenging in terms of finding a suitable polymeric membrane that can withstand the harsh environment especially when concentrating an aqueous solution of a highly oxidizing liquid such as hydrogen peroxide (H 2O 2). H 2O 2 is one of the most powerful oxidizers known and is a stronger oxidant than chlorine, chlorine dioxide and potassium permanganate; hydroxyl radical (OH) generated from H 2O 2 has a very high reactivity. The choice of membrane material is potentially limited to fluoro polymers and perfluoro polymers considering membrane stability in such a harsh system. Perfluorodimethyldioxole-tetrafluoroethylene (PDD-TFE) copolymer membranes (CMS-3 and CMS-7) were used to concentrate hydrogen peroxide from its aqueous solutions. The feed solution composition was varied between 4 and ~40wt% H 2O 2; the process was studied at 25°C, 30°C and 35°C. CMS-7 displayed a higher flux than CMS-3; a reverse trend was observed for water-H 2O 2 selectivity for the same feed concentration. The highest water-H 2O 2 selectivity of ~12 was observed in CMS-3 membrane at an H 2O 2 concentration of 43wt% with a total flux of 6.15×10 -3g/hcm 2; for CMS-7, values of 9.2 and 9.6×10 -3g/hcm 2 were found for water-H 2O 2 selectivity and total flux, respectively, at the same H 2O 2 concentration. The total permeated flux increased with temperature at the cost of selectivity for both membranes. Extended-term behaviors of CMS-3 and CMS-7 membranes studied at 35wt% H 2O 2 concentration indicated that both are quite stable for tests carried out over periods of 162 and 145 days respectively.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Physical and Theoretical Chemistry
- Filtration and Separation
- Hydrogen peroxide concentration
- Membrane selectivity
- PDD-TFE copolymer membranes