Tangential microfiltration of lime and pineapple juices using inexpensive tubular ceramic membrane and analysis of fouling mechanism

Abstract

A non-thermal tangential filtration of lime and pineapple juices using an indigenously elaborated inexpensive bentonite-based tubular ceramic membrane (96 $/m2) is discussed in the present work. The fabricated membrane exhibited a porosity of 37% with 0.11 µm pore size and possessed adequate flexural stability of 18 MPa. Microfiltration experiments were conducted for both centrifuged juice (CJ) and Enzymatic treated centrifuged juice (ETCJ) of lime and pineapple at various operating pressures (69 – 345 kPa) and crossflow rates (110 – 150 Lph) to evaluate their effects on the resulting permeate flux and clarified juice properties. The membrane provided a maximum permeate flux of both ETCJ of lime and pineapple juices as 2.22 × 10−5 m3/m2s and 1.31 × 10−5 m3/m2s, respectively, at operating conditions of 345 kPa pressure and 150 Lph flowrate. Enzymatic pretreatment considerably enhanced the permeate fluxes of both juices. Also, comparatively a high clarity and complete removal of alcohol-insoluble solids were observed for permeate streams of ETCJ. In all the cases, the desirable characteristics of citrus juices, including pH, total soluble solids, and citric acid content, were unaltered, ensuring the uniqueness of the membrane separation processes. Furthermore, fouling analysis was carried out using Hermia's models, revealing experimental data best fits into the cake filtration model for pineapple juice and intermediate pore blocking model for lime juice clarification are identified as dominant mechanisms, respectively.