Microfiltration of kiwifruit juice and fouling mechanism using fly-ash-based ceramic membranes

Three different low-cost inorganic membranes prepared from fly-ash precursor have been used for the clarification of centrifuged kiwifruit juice. The prepared membranes have been characterized by SEM analysis, average pore diameter and porosity determinations, and pure water permeation experiments. Dead-end microfiltration experiments have been performed on centrifuged kiwifruit juice to evaluate the effect of pore diameters (d_m) and porosities (ε) on the permeation characteristics (permeate flux and juice quality). A membrane of pore diameter 1.25 μm proved to be optimal for the clarification of kiwifruit juice. Different membrane pore blocking models have been used to analyze the observed decline in permeate flux. Analysis of the fouling mechanism results has revealed that the three membranes were controlled by different filtration mechanisms.