Journal of Membrane Science
2020
B.R. OLIVEIRA; S. SANCHES; R.M. HUERTAS; M.T. BARRETO CRESPO; V.J. PEREIRA
Highlights
• A new photocatalytic membrane reactor was used to treat surface water.
• A. fumigatus was retained and inactivated using the hybrid treatment.
• Scanning electron microscopy displayed morphology changes in the spores.
• Flow cytometry showed effects on membrane permeability and enzymatic activity.
Abstract
Coupling UV photolysis, stable photoactive TiO2 layers and water filtration in a single photocatalytic membrane reactor can be beneficial to achieve high quality drinking water since the membrane retains microorganisms and chemical pollutants whereas the photocatalytic treatment decreases fouling components and treats the concentrated retentate.
In this work, a newly designed photocatalytic membrane reactor combining filtration with UV photolysis/photocatalysis under a low pressure mercury lamp (wavelength emission at 254 nm) using ceramic modified membranes was used to treat filtered surface water inoculated with Aspergillus fumigatus. The photocatalytic membranes used in this study were produced using an environmental friendly modification process. Results showed high percentages of adsorption and retention of the spores for both the unmodified and modified membrane. The lower pore size of the modified membrane has the advantage of retaining the spores at the surface instead of trapping the spores inside as observed for the unmodified membrane. Direct photolysis achieved retentate treatment percentages up to 99% after 60 min of treatment. The effect of the combined treatment showed that direct photolysis and photocatalysis were able to cause the deformation of spores and led to changes in membrane permeability and enzymatic activity.
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Membrane modification
The sol solution obtained was sonicated for 20 min. The membranes were mounted into a glass support to be modified on one side using the dip-coating method conducted at room temperature. The substrates were coated three times using a dip coater (Nadetech Innovations, Spain) at a speed of 150 mm/s for immersion and withdrawal.