Ultrasonic stimulation on enhancement of air gap membrane distillation

C. Zhu, G. L. Liu, Chun Shun Cheung, Chun Wah Leung, Z. C. Zhu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

41 Citations (Scopus)

Abstract

An ultrasonic irradiation technique was applied to an air gap membrane distillation (AGMD) system to enhance the permeability for the membrane distillation of various aqueous solutions. In this study, an ultrasonic stimulation of resonance frequency of 20kHz and irradiation power up to 90W was applied to a flat-plate AGMD system of 1μm PTFE membrane with a membrane distillation temperature difference up to 55°C. The feed solutions tested include tap water and various sodium chloride solutions. Permeate mass flow rate, heating and cooling temperatures, irradiation power and acoustic intensity in feed solutions are directly measured. It was found that the permeate flow rate with the ultrasonic stimulation increases up to 25% than that without ultrasonic irradiation. The permeate flow rate also increases with an increase of irradiation power. Experimental investigation of basic mechanisms pertaining to the ultrasonic enhancement of AGMD was also attempted via both intermittent ultrasonic irradiation and study of the effect of ultrasonic irradiation on surface temperature of membrane. The results suggest that, for a continuous ultrasonic stimulation, the domination mechanisms are microstreaming and cavitation. The significant reduction of temperature polarization is validated by both temperature measurements and ultrasonic intensity measurements.
Original languageEnglish
Pages (from-to)85-93
Number of pages9
JournalJournal of Membrane Science
Volume161
Issue number1-2
DOIs
Publication statusPublished - 1 Aug 1999

Keywords

  • Membrane distillation
  • Membrane permeation
  • Ultrasonic irradiation

ASJC Scopus subject areas

  • Biochemistry
  • Materials Science(all)
  • Physical and Theoretical Chemistry
  • Filtration and Separation

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