Alkaline Earth Metal Cation Exchange: Effect of Mobile Counterion and Dissolved Organic Matter

Abstract

The goal of this research was to provide an improved understanding of the interactions between alkaline earth metals and DOM under conditions that are encountered during drinking water treatment with particular focus on cation exchange. Both magnetically enhanced and nonmagnetic cation exchange resins were converted to Na, Mg, Ca, Sr, and Ba mobile counterion forms as a novel approach to investigate the exchange behavior between the cations and the interactions between the cations and DOM. The results show that cation exchange is a robust process for removal of Ca(2+) and Mg(2+) considering competition with cations on the resin surface and presence of DOM. DOM was actively involved during the cation exchange process through complexation, adsorption, and coprecipitation reactions. In addition to advancing the understanding of ion exchange processes for water treatment, the results of this work are applicable to membrane pretreatment to minimize fouling, treatment of membrane concentrate, and precipitative softening.

Diclofenac removal in urine using strong-base anion exchange polymer resins

“…Several samples had final phosphate (or citrate) concentrations greater than initial phosphate (or citrate) concentrations; in these cases, the final concentration was set equal to the initial concentration and yielded 0% removal. Chloride, sulfate, and potassium concentrations were measured using ion chromatography (Dionex ICS-3000) as described elsewhere (Indarawis and Boyer, 2012). Samples from E.7 (Table 3) for fresh urine and ureolyzed urine were measured for chloride and sulfate and required a 1:31 dilution and ureolyzed urine measured for potassium required a 1:1000 dilution.…”

Enhanced adsorption and antifouling performance of anion-exchange resin by the effect of incorporated Fe3O4 for removing humic acid

“…Improved antifouling of hybrid membrane is attributed to changes in hydrophilicity, pore size, electrical charge, and catalysis (self-cleaning) effect after incorporating inorganic particles, as reviewed by Kim and Van der Bruggen (2010), Kang and Cao (2012). Regarding MIEX resin, Indarawis and Boyer recently suggested that magnetite particles incorporated into magnetic resin (MIEX WA172) provide magnetism for the fast settling or separation of resin beads and interaction with metaleorganics complexes because of their negative charge at pH above its average zero-charge point (Indarawis and Boyer, 2012). However, the effects of incorporated iron oxide on the hybrid resin structure and its influence on resin adsorption and/or regeneration performance have not been studied.…”

Removal of Dissolved Organic Matter by Magnetic Ion Exchange Resin

“…These results do not agree with magnetic polymer beads containing magnetic particles such as maghemite [14••], which is ferrimagnetic [19]. Indarawis and Boyer investigated the magnetic properties of magnetically enhanced cation exchange resin from Orica Watercare, which was assumed to be produced in a similar manner as MIEX resin [14••], and suggested that cationic MIEX resin contained magnetite [20], which is more consistent with the patented process for MIEX resin. In summary, the magnetic characteristics and behavior of MIEX resin remains an open research question.…”