Elaboration of new ceramic membrane from spherical fly ash for microfiltration of rigid particle suspension and oil-in-water emulsion

Spherical-fly-ash-based membrane is a new kind of ceramic membrane which is recently developed. It is not only a low-cost but also a theoretically low resistance membrane due to the formal spherical raw particles. The factual filtration performance of this new membrane has not been reported. In this paper, the permeability and anti-fouling property of this new membrane for microfiltration of rigid particle suspension and oil-in-water emulsion were evaluated. The effects of operating conditions and feed properties were investigated by measurements of permeate flux, pollutant rejection, and membrane fouling resistances. The results revealed that after continuously running for 10h without backwashing, high permeate flux of 2270Lm^-2h^-1 and 159Lm^-2h^-1 were obtained in the microfiltration of rigid particle suspension and oil-in-water emulsion at a low transmembrane pressure of 0.10MPa, respectively. The rejection of rigid particles and oil-droplets were more than 99% and 95%. The fouling mechanisms of spherical-fly-ash-based membrane in the microfiltration were analyzed based on the resistance-in-series models and pore-blocking models. Analysis results showed that spherical-fly-ash-based membrane exhibited lower membrane fouling resistances in both filtration processes. Spherical-fly-ash-based ceramic membrane exhibited a higher competition comparing to the other available inorganic membranes in both filtration processes.