A Thesis submitted in partial fulfilment of the requirements for the degree of Master of Science, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology, 1989

Tangerine (Citrus reticulata blanco) juice was clarified by crossflow microfiltration (CFMF) and ultrafiltration (CFUF} with a polysulphonic membrane. The membranes used were of mw.cut-off 25000, 50000, 100000 and 0.1 æm, 0 . 2 æm pore sizes. The juice was filtered by using a laboratory filtration module made of acrylic resin,120 mm long and 70 mm wide. The transmembrane pressure used was 93 to 194 kPa and a crossflow velocity used was 0.96 to 3.54 m/s at 25 °C . Juice was treated with hydrochloric acid and polygalacturonase before filtration. The performance of both membrane types was determined in terms of quality and quantity of the permeate. Ultrafiltration membrane of pore size 0.1 æm gave the maximum permeate flux and accepted quality by ANOVA based on its clarity. Highest transmembrane pressure of 194 kPa gave maximum filtrate production and quality of permeate flux showed non significant with the lower transmembrane pressure of 137 kPa. Similar to transmembrane pressure, the highest feed crossflow velocity of 3.54 m/s also gave maximum filtrate rate but the permeate was not as clear as the others. These results could be explained by apparent membrane and gel resistance, the concentration polarization, mass transfer coefficient and real rejection of each operating parameter.