LPAC Compatibility of MP membranes and O 3 Membranes as O 3 contactors Materials under study Experimental Procedure Compatible or not compatible ? Conclusions

LPAC Membranes for O 3 contacting: Several benefits! O 3 in water treatment: MP membranes feasible for O 3 mass transfer? production mass transfer water treatment off-gas treatment - Different contactor types, characteristics & performance - Membrane contactors: off-gas can be recycled, bubble-free, scaling, moderate to fast mass transfer (high k L a values)

LPAC Compatibility of MP membranes and O 3 Membranes as O 3 contactors Materials under study Experimental Procedure Compatible or not compatible ? Conclusions

LPAC Original and chemically modified membrane materials under study MP polymeric ultra-filtration membrane tubes Membrane test assembly: PVC outer tube, MP membranes inside Water flow inside the membranes, O 2 /O 3 flow outside the membranes 1 Assembly with original membrane tubes 1 Assembly with chemically modified membranes water O 2 /O 3

LPAC Compatibility of MP membranes and O 3 Membranes as O 3 contactors Materials under study Experimental Procedure Compatible or not compatible ? Conclusions

LPAC Methods: Ozonation of membrane tubes Set-up: Batch ozonation of MP membrane tubes O2O2 pump MFC OG OS FC2 FC1

LPAC Methods: Ozonation of membrane tubes Experimental conditions: 5 pieces from 3 different membrane tubes Visual observation of damage +  weigth before - after Milli-Q water, near-neutral pH, RT Ozonation: hours, [O 3 ] liq = 8.2–8.6 mg/L Monitoring of pH, ORP, conductivity, [O 3 ] gas, [O 3 ] liq, T, UV/VIS

LPAC Methods: Test assembly Test assembly: Milli-Q water, near-neutral pH, RT Water flow: peristaltic pump [O 3 ] gas = ~ 50 g/m 3 Set-up: O2O2 pump MFC OG OS FC2 FC1

LPAC Compatibility of MP membranes and O 3 Membranes as O 3 contactors Materials under study Experimental Procedure Compatible or not compatible ? Conclusions

LPAC Ozonation of membrane tubes: clear indication of degradation Visual observations (after ± 17 hours ozonation): Dispersion of white particles in solution Increased surface roughness, loss of flexibility Mass balance: mass loss after ozonation periods points at degradation UV/VIS + Conductivity: build-up of degradation products in solution pH: decrease in pH caused by formation of carboxylic acids (?)

LPAC Test assemblies: MP membranes incompatible with O 3 Both test assemblies: damage after < 50 minutes O 3 flow!

LPAC Compatibility of MP membranes and O 3 Membranes as O 3 contactors Materials under study Experimental Procedure Compatible or not compatible ? Conclusions

LPAC MP membranes and O 3 incompatible  Nor original, neither modified MP ultra-filtration membranes are resistant to O 3 MP membranes cannot be used for O 3 contacting despite low [O 3 ] liq in disinfection (typically 0.1 – 1 mg/L)  degradation = concentration + exposure ! Ozonated water streams need to be separated from filter units in the dishwashers!