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Title: Piezoelectrically assisted ultrafiltration

The authors have demonstrated the feasibility of using piezoelectrically assisted ultrafiltration to reduce membrane fouling and enhance the flux through ultrafiltration membranes. A preliminary economic evaluation, accounting for the power consumption of the piezoelectric driver and the extent of permeate flow rate enhancement, has also shown that piezoelectrically assisted ultrafiltration is cost effective and economically competitive in comparison with traditional separation processes. Piezoelectric transducers, such as a piezoelectric lead zirconate titanate (PZT) disc or a piezoelectric horn, driven by moderate power, significantly enhance the permeate flux on fouled membranes, presumably because they promote local turbulence. Several experiments were conducted on polysulfone and regenerated cellulose UF membranes fouled during filtration of model feed solutions. Solutions of poly(ethylene glycol) and of high-molecular weight dextran were used as models. The authors found that they could significantly increase the permeate flux by periodically driving the piezoelectric transducer, horn or PZT disc, by application of moderate power over short periods of time, from 20 to 90 seconds. Enhancements as high as a factor of 8 were recorded within a few seconds, and enhanced permeate fluxes were maintained over a prolonged period (up to 3 hours). The prolonged flux enhancement makes it feasible to drive themore » piezoelectric transducer intermittently, thereby reducing the power consumption of the piezoelectric driver. As piezoelectric drivers of sonically assisted ultrafiltration, PZT disc transducers are preferred over the piezoelectric horn because of their small size and ease of adaptability to ultrafiltration test cells. The horn transmits sonic energy to the UF membrane through a titanium element driven by a separate piezoelectric transducer, but a piezoelectric ceramic disc transmits energy directly to the UF membrane.« less
Authors:
; ; ; ; ;  [1]
  1. SRI International, Menlo Park, CA (United States)
Publication Date:
OSTI Identifier:
138553
Report Number(s):
CONF-911049--
Journal ID: SSTEDS; ISSN 0149-6395; TRN: TRN: 93:000018-051
DOE Contract Number:
FC02-89ID12906
Resource Type:
Journal Article
Resource Relation:
Journal Name: Separation Science and Technology; Journal Volume: 28; Journal Issue: 1-3; Conference: 7. symposium on separation science and technology for energy applications, Knoxville, TN (United States), 20-24 Oct 1991; Other Information: PBD: Jan-Feb 1993
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; ULTRAFILTRATION; ECONOMICS; MEMBRANES; FOULING; WASTE PROCESSING; TRANSDUCERS; ENERGY CONSUMPTION; PZT