title: Effects of colloidal fouling and gas sparging on microfiltration of yeast suspension.
abstract: Cross-flow microfiltration is an important step in separating Baker's yeast (Saccharomyces cerevisiae) from aqueous suspension in many processes. However the permeate flux often declines rapidly due to colloidal fouling of membranes and concentration polarisation. The present work explores the possibility of maintaining acceptable permeate flux by co-current sparging of gas along with the feed, which would scour away colloidal deposits and reduce concentration polarisation of membranes. In this work, both washed and unwashed yeast were used to study the effect of washing to reduce protein fouling of membranes. It was found that permeate flux increased by 45% for liquid throughput of 75 kg/h for a feed concentration of 2.0 kg/m3 of washed yeast as compared with unwashed yeast suspension without gas sparging. For washed yeast suspension, the increase in gas flow rate from 0.5 lpm to 1.5 lpm (30 l/h to 90 l/h) had beneficial effect on permeate flux. It is concluded that in the present case, the gas flow rate should be less than or equal to the liquid flow rate for enhancement of permeates flux.
authors.affiliation: School of Chemical Engineering, Queen's University Belfast, BT9 5AG, Northern Ireland, UK. B.Sengupta@qub.ac.uk.
authors.forename: B Sen
authors.initials: BS
authors.lastname: Gupta
authors.affiliation: Department of Nuclear Engineering, University of Missouri-Columbia, Columbia,.
authors.forename: S
authors.initials: S
authors.lastname: Hasan
authors.affiliation: Department of Chemical Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia.
authors.forename: M A
authors.initials: MA
authors.lastname: Hashim
authors.affiliation: Department of Engineering Science, University of Oxford, OX1 3PJ, Oxford, UK.
authors.forename: Z F
authors.initials: ZF
authors.lastname: Cui
mesh_terms: D002469:Cell Separation / Q000295:instrumentation* / Q000379:methods; D003102:Colloids / Q000737:chemistry / Q000302:isolation & purification*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005740:Gases / Q000737:chemistry; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods; D010865:Pilot Projects; D012441:Saccharomyces cerevisiae / Q000302:isolation & purification*; D014462:Ultrafiltration / Q000295:instrumentation* / Q000379:methods
chemical_list: D003102:Colloids; D005740:Gases