Hybrid coagulation-NF membrane processes for brackish water treatment

Effect of pH and salt/calcium concentration

W. L. Ang, A. W. Mohammad, A. Benamor, N. Hilal

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

In order to reduce membrane fouling propensity, membrane technologies in water treatment and desalination processes have been coupled with coagulation process. However, the fouling issues still persisted. It is believed that coagulation might affect the fouling mechanisms involved. Hence, this study was intended to investigate the influence of water chemistry (solution pH, calcium concentration, and total dissolved solids) on hybrid coagulation-nanofiltration membrane processes. Assessment will be done based on permeate flux, salt rejection trend, and foulant layer autopsy. It was discovered that coagulation process altered the properties of the foulants in the solution and resulted in distinct membrane fouling phenomena compared to most of the standalone membrane fouling studies. This situation prevailed in the presence of calcium ions in the solution. It was postulated that coagulation process weakened the interaction between the oppositely charged calcium ions and foulants. Therefore, instead of forming complex with the foulants, calcium ions had higher affinity towards more negatively charged membrane. Consequently, calcium salts precipitated and formed scales on the membrane surface, as supported by membrane performance and SEM-EDX analysis. This indicated that membrane fouling study should consider the impact of pretreatment process for better understanding about the fouling mechanisms involved.

Original languageEnglish
Pages (from-to)25-32
Number of pages8
JournalDesalination
Volume390
DOIs
Publication statusPublished - 15 Jul 2016
Externally publishedYes

Fingerprint

Coagulation
Water treatment
brackish water
Membrane fouling
coagulation
Calcium
water treatment
Salts
calcium
fouling
membrane
salt
Membranes
Fouling
Ions
Nanofiltration membranes
Membrane technology
Desalination
ion
Energy dispersive spectroscopy

Keywords

  • Brackish water
  • Hybrid process
  • Membrane fouling
  • Nanofiltration
  • Water chemistry

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Chemistry(all)
  • Materials Science(all)
  • Water Science and Technology

Cite this

Hybrid coagulation-NF membrane processes for brackish water treatment : Effect of pH and salt/calcium concentration. / Ang, W. L.; Mohammad, A. W.; Benamor, A.; Hilal, N.

In: Desalination, Vol. 390, 15.07.2016, p. 25-32.

Research output: Contribution to journalArticle

Ang, W. L. ; Mohammad, A. W. ; Benamor, A. ; Hilal, N. / Hybrid coagulation-NF membrane processes for brackish water treatment : Effect of pH and salt/calcium concentration. In: Desalination. 2016 ; Vol. 390. pp. 25-32.
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