Elucidation of physicochemical scaling mechanisms in membrane distillation (MD): Implication to the control of inorganic fouling

Junghyun Kim, Hye Won Kim, Leonard D. Tijing, Ho Kyong Shon, Seungkwan Hong

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

This study elucidates the physicochemical mechanisms of monovalent and multivalent inorganic scaling and suggests an optimal cleaning strategy for efficient membrane distillation (MD) operation. Three distinct stages of MD inorganic scaling were clearly identified by i) experimentally measuring transient flux, ii) rejection behavior resulted from the deposition of a scale, and iii) SEM-EDX analysis of the membrane. During stage 1, no scale was found over the membrane surface showing almost stable water flux and permeate conductivity. In stage 2, the onset of inorganic scaling resulted in the deposition of scaling on some parts of the membrane surface, partially covering the membrane pores, which lead to a sudden reduction in the water flux despite a steady solute rejection. However, as scaling expands into the pore in final stage 3, the permeate conductivity increased, indicating a reduction in rejection. Then, the pores were completely blocked, and the water flux reached almost zero. To simulate this scaling formation more fundamentally, the saturation index (SI) and supersaturation (S) concepts were introduced. The type and timing of scaling were successfully predicted by the SI value, and the amount of scaling was accurately estimated by the S value. Moreover, through the analysis of this physicochemical mechanism of inorganic scaling, an optimal cleaning strategy for sustainable MD operation was proposed.

Original languageEnglish
Article number115573
JournalDesalination
Volume527
DOIs
Publication statusPublished - 2022 Apr 1

Bibliographical note

Publisher Copyright:
© 2022 Elsevier B.V.

Keywords

  • Inorganic scaling
  • Membrane cleaning
  • Membrane distillation
  • Supersaturation

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • General Materials Science
  • Water Science and Technology
  • Mechanical Engineering

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