Analysis of zwitterionic membrane fouling mechanism caused by HPAM in the presence of electrolytes

Abstract

The foulant HPAM and electrolyte CaCl2 are used to investigate the fouling mechanism of zwitterionic membrane dealing with HPAM in saline wastewater.

Investigation of membrane fouling using molecular dynamics simulation

“…4-9. It is evident that divalent ions were strongly coordinated with EfOMs with a dominant first solvation shell located at around 𝑟 = 4.25 Å, which was also observed in past studies [37,102].…”

“…Simulation models have to be validated against experiments to ensure reliability and accuracy. Composition of feed/membrane [92,93] Conductivity [36,94] Cross-linking degree [95,96] Contact angle [97,98] Density of grafting sites on the membrane surface [26,29] DOTM A [55] Density of membrane [30,40,99,100] Flux decline profile [30,33,37,101] Spectroscopy (e.g., XPS B , FTIR C ) [35,102,103] Isotherm of static adsorption (e.g., by QCM-D D ) [104][105][106] Zeta potential [107] Rejection of foulant [35,102] SEM E…”

“…Moreover, adsorption was mainly controlled by ionic interactions between cationic intercalant and terminal oxygen atoms in PFASs, as well as lateral interactions (e.g., fluorophilic attraction) among PFASs. Jiang et al [37] studied hydrolyzed poly(acrylamide) as the model foulant, and found that a positive ion layer was formed between this foulant and a zwitterionic-grafted PVDF membrane. Therefore, strong electrostatic repulsion contributes to the excellent antifouling property of the membrane, which corresponds to an approximately 100% flux recovery ratio observed in experiments.…”

A comparison of three modification methods for polyvinylidene fluoride membrane grafting

“…Liu et al [6] utilized UV-initiated grafting polymerization to prepare IOP Publishing doi:10.1088/1742-6596/2783/1/012062 2 silsequioxane modified PVDF membranes, and the obtained PVDF membrane possessed excellent mechanical, thermal, and dimensional stability. Jiang et al [7] grafted zwitterionic polymers on the pristine PVDF membrane surface via UV-induced grafting. Ozone-activated grafting can introduce peroxy groups uniformly on PVDF membranes' surfaces.…”