title: Mechanisms of mineral membrane fouling growth modulated by pulsed modes of current during electrodialysis: evidences of water splitting implications in the appearance of the amorphous phases of magnesium hydroxide and calcium carbonate.
abstract: Experiments revealed the fouling nature evolutions along different electrodialysis (ED) trials, and how it disappears when current pulsation acts repetitively on the interfaces of ion-exchange membranes (IEMs). Fouling was totally controlled on the diluate side of cation-exchange membrane (CEM) by the repetitive pulsation frequency of the higher on-duty ratios applied. They created steady water splitting proton-barriers that neutralized OH(-) leakage through the membrane, decreasing the interfacial pH, and fouling of the concentrate side. The anion-exchange membrane (AEM) on the diluate side was similarly protected, but it was fouled once water splitting OH(-) generation became either intense enough or excessively weak. Interestingly, amorphous magnesium hydroxide (AMH) stemmed on the CEM-diluate side from brucite under intense water splitting OH(-) generation, and/or strong OH(-) leakage electromigration through the membrane. Water dissociation and overlimiting current regimes triggered drastic water molecule removal from crystal lattices through an accelerated cascade water splitting reaction. Also, amorphous calcium carbonate (ACC) appeared on CEM under intense water splitting reaction, and disappeared once intense OH(-) leakage was allowed by the water splitting proton-barrier dissipation. Our findings have implications for membrane fouling control, as well as for the understanding of the growth behavior of CaCO3 and Mg(OH)2 species on electromembrane interfaces.
authors.affiliation: Institute of Nutrition and Functional Foods (INAF) and Dairy Research Center (STELA), Department of Food Sciences and Nutrition, Pavillon Comtois, Université Laval, Sainte-Foy, QC G1V 0A6, Canada.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Cifuentes-Araya
authors.affiliation: Escuela de Alimentos, Pontificia Universidad Católica de Valparaíso, Waddington 716, Valparaíso, Chile.
authors.forename: Carolina
authors.initials: C
authors.lastname: Astudillo-Castro
authors.affiliation: Institute of Nutrition and Functional Foods (INAF) and Dairy Research Center (STELA), Department of Food Sciences and Nutrition, Pavillon Comtois, Université Laval, Sainte-Foy, QC G1V 0A6, Canada. Electronic address: Laurent.Bazinet@fsaa.ulaval.ca.
authors.forename: Laurent
authors.initials: L
authors.lastname: Bazinet
mesh_terms: D002119:Calcium Carbonate / Q000737:chemistry*; D003956:Dialysis; D055664:Electrochemical Techniques / Q000379:methods*; D008276:Magnesium Hydroxide / Q000737:chemistry*; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D033362:Powder Diffraction; D014867:Water / Q000737:chemistry*
chemical_list: D008567:Membranes, Artificial; D014867:Water; D002119:Calcium Carbonate; D008276:Magnesium Hydroxide
keywords: Amorphous calcium carbonate; Amorphous magnesium hydroxide; Anion-exchange membrane; Cation-exchange membrane; Electrodialysis; Mineral fouling; Pulsed electric field; Water splitting reaction