Rejection of submicron sized particles from swimming pool water by a monolithic SiC microfiltration membrane: Relevance of steric and electrostatic interactions

The rejection of submicron sized particles from swimming pool water by a ceramic silicon carbide (SiC) microfiltration membrane in monolithic configuration was investigated and mechanisms elucidated. Physicochemical properties showed that the surrogates used in challenge tests (i.e. MS2 bacteriophages and 50-500 nm fluorescent microspheres) are adequate surrogates for viruses commonly found in pool water. The log-removal value (LRV) of the SiC membrane strongly depended on the size and electrostatic properties of the surrogates. Experiments with swimming pool water showed that organic matter and salts present in the pool water decreased the surface potential of the surrogates which in turn increased the LRV of the SiC membrane. Long-term experiments revealed, that the removal effectivity of the SiC membrane, over the course of a filtration cycle (similar to 150 min), increased for large surrogates (500 nm microspheres), while the removal effectivity remained unchanged for small surrogates (MS2 phages). This effect was explained by progressive and permanent blockage of large mesopores ( > 500 nm) in the active membrane layer by particles present in the pool water. (C) 2015 Elsevier B.V. All rights reserved.