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Industrial Ecology for Waste Minimization, Utilization, and Treatment
Published in Stanley E. Manahan, Environmental Chemistry, 2022
Ion exchange is a means of removing cations or anions from solution onto a solid resin, which can be regenerated by treatment with acids, bases, or salts. The greatest use of ion exchange in hazardous waste treatment is for the removal of low levels of heavy metal ions from wastewater: 2H+-{CatExchr}+Cd2+→Cd2+-{CatExchr}2+2H+
Chromatography
Published in Jerome Greyson, Carbon, Nitrogen, and Sulfur Pollutants and Their Determination in Air and Water, 2020
Ion exchange resins are polymeric materials with ionic functional groups attached to them. Typical resins have the structures [|−R′−SO3−H+|]nand[|−R′−NR3+Cl−|]n
Removal of Inorganic Contaminants
Published in Samuel D. Faust, Osman M. Aly, Chemistry of Water Treatment, 2018
Anion exchange is similar to cation exchange processes, except, of course, that anions are exchanged rather than cations. Also, nitrate is not the most preferred common ion involved in the multicomponent ion exchange process with contaminated groundwaters. The ion selectivity series for anions is: SO42−>I−>NO3−>CrO42−>Br. Consequently, SO42− is a major interference in the removal of NO3 by the Cl− form of strong base anion (SBA) exchange resins.
Recovery of copper from industrial sludge as a sustainable resource: A review
Published in Geosystem Engineering, 2022
Ha Bich Trinh, Seunghyun Kim, Taehun Son, Jaeryeong Lee
Ion exchange has been widely used in metal separation/purification processes because of its high selectivity, high capacity, and fast reaction kinetics, and has been used to treat a variety of solutions containing low metal tenor (Junior et al., 2019; Nguyen et al., 2009). A simplified reaction occurring during IX process is written as Eq. 24 Specifically discussing copper, the IX process has been used to recover the metal from acids, alkalis, and even organic acid solutions. In one study, six different IX resins ((TP214-thiourea, MTS9100-amidoxime, MTS9507-phosphonic/sulfonic acid combination, MTS9301-iminodiacetic acid, MTS9501-aminophosphinic acid, C107E-carboxylic acid) were used to separate Cu from acetic, lactic, and citric acid solutions that simulated weak acid leachate from wastewater sludge (Bezzina et al., 2019). The results show that TP214 has the highest selectivity for Cu in all of these acidic media due to its thiourea functional group. Puromet MTS914, another thiourea based resin, demonstrated the same tendency of high selectivity to Cu (>90%) from a multi-metal solution (Riley et al., 2021). Despite the promising results, the IX process is not recommended for treating leach liquor from Cu-containing industrial sludge, which typically has a high Cu concentration. If that is the case, the leach liquor must be diluted, which will increase the amount of wastewater generated.
Hydrometallurgical processes for heavy metals recovery from industrial sludges
Published in Critical Reviews in Environmental Science and Technology, 2022
Viraj Gunarathne, Anushka Upamali Rajapaksha, Meththika Vithanage, Daniel S. Alessi, Rangabhashiyam Selvasembian, Mu. Naushad, Siming You, Patryk Oleszczuk, Yong Sik Ok
Resins that contain chelating functional groups to form complexes with metal ions can be used for selective separation of targeted metal ions. Impregnated resins are developed by adsorbing solvent extraction reagents onto polymer beads (Tavlarides et al., 1987). The first hydrometallurgical application of ion exchange resins was for uranium recovery. However, their usage became widespread with the development of chelating and impregnated ion-exchange resins. The effectiveness of an ion-exchange resin is typically expressed as the equilibrium loading capacity or exchange capacity. Other characteristics of resins are functional groups, their selectivity ratio, cross-linking, porosity, and matrix geometry. Ion exchange can successfully be used for selective separation and recovery of metal ions by changing the properties of resins, specifically their functional groups. The ease of operation, no reagent losses, no disengagement of phases, economic feasibility for use in low concentrations of metal ions, and environmental safety can be considered as the advantages of using ion-exchange resins for metal recovery (Nikoloski & Ang, 2014; Tavlarides et al., 1987).
Arsenic exposure from groundwater: environmental contamination, human health effects, and sustainable solutions
Published in Journal of Toxicology and Environmental Health, Part B, 2021
Elida Cristina Monteiro De Oliveira, Evelyn Siqueira Caixeta, Vanessa Santana Vieira Santos, Boscolli Barbosa Pereira
As part of the United States Environmental Protection Agency’s (US EPA) Arsenic Treatment Demonstration Program, Chen et al. (2020) investigated the performance of a full-scale ion exchange technology in water from different wells. Results demonstrated that As was effectively removed from drinking water supplies by coupling ion exchange with strong base anionic resins. However, various factors may affect the efficiency of ion exchange technology, including co-occurring contaminants, As concentration, pH, and resin type. For example, Chen et al. (2020) noted that a chromatographic peaking of As due to the presence of sulfate and more preferred anions, thus interfering in the efficiency removal of the metalloid. Despite the efficacy of ion exchange system in reducing As, additional studies may be warranted in order to explore the most appropriate resin type and parameters of this technology, also taking into account operational cost, maintenance, and capital investment (Sorg, Wang, and Chen 2014).