Influence of solution composition on fouling of anion exchange membranes desalinating polymer-flooding produced water

https://doi.org/10.1016/j.jcis.2019.09.029Get rights and content
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Abstract

Hypothesis

Anion exchange membranes (AEMS) are particularly prone to fouling when employed to desalinate polymer flooding produced water (PFPW), an abundant sub-product from the oil and gas industry. The formation of fouling on an AEM will be affected by the composition of the solution, which includes various dissolved salts, partially hydrolyzed polyacrylamide (HPAM), crude oil, and surfactants.

Experiments

Electrodialysis experiments were performed to desalinate feed solutions with different compositions, aiming to distinguish between their individual and combined effects. The solutions contained diverse mono- and divalent ions. The analysis included data collected during the desalination and characterization of the fouled AEMs by diverse analytical techniques.

Findings

HPAM produced the most severe effects in terms of visible fouling and increase of resistance. This polyelectrolyte fouls the AEM by adsorbing on its surface and by forming a viscous gel layer that hampers the replenishment of ions from the bulk solution. Ca and Mg have a large influence on the formation of thick HPAM gel layers, while the oily compounds have only a minimal influence acting mainly as a destabilizing agent. The membranes also presented scaling consisting of calcium precipitates. The effects of the gel layer were minimized by applying current reversal and foulant-free solution.

Keywords

Membrane fouling
Electrodialysis
Polymer-flooding produced water
Partially hydrolyzed polyacrylamide
Polyelectrolyte
Concentration polarization
Gel layer
Crude oil

Abbreviations

AEM
Anion exchange membrane
AFM
Atomic force microscopy
BW
Brackish water
CEM
Cation exchange membrane
CTAB
Cationic cetyltrimethylammonium bromide
DBL
Diffusion boundary layer
ED
Electrodialysis
EDX
Energy-dispersive X-ray spectroscopy
HPAM
Partially hydrolyzed polyacrylamide
IEM
Ion exchange membrane
PFPW
Polymer-flooding produced water
SEM
Scanning electron microscopy
TMEP
Transmembrane electric potential

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