High Performance of Asymmetric Alumina Hollow Fiber Membranes for the Clarification of Genipap (Genipa americana L.) Fruit Extract

Membrane filtration processes represent a suitable alternative for fruit juice treatment, but the applied membrane should present high stability and permeability. Here, we propose the development and application of ceramic asymmetric hollow fiber membranes for genipap extract clarification. Genipap is an exotic fruit from Central and South America with considerable concentration of phenolic and iridoid compounds. The dual-layer ceramic hollow fiber membrane was fabricated by a single-step co-extrusion and co-sintering process. The developed hollow fibers presented the desired asymmetric structure, with an inner finger-like region that guaranteed a suitable permeate flux (191Lh(-1)m(-2) at 1bar), while the outer sponge-like layer was responsible for solid retentions and for the membrane mechanical resistance. Reductions in turbidity, total polyphenol content, and genipin concentration were of 52, 17, and 4%, respectively. Mathematical modeling of the experimental flux decay showed that pore blocking was the main fouling mechanism during filtrations of genipap extract through the asymmetric hollow fibers. The presence of microchannels with larger pore size in the inner surface of the fiber probably mitigated cake formation. The increase in the transmembrane pressure from 1 to 2bar did not improve the permeation flux through the membrane since the fouling layer resistance was considerably higher at 2bar than at 1bar. Thus, asymmetric ceramic hollow fibers are suggested for juice fruit clarification with improved permeate flux and clarification degree.