Ion exchange removal and resin regeneration to treat per- and polyfluoroalkyl ether acids and other emerging PFAS in drinking water

2021 ◽  
pp. 117781
Author(s):  
Yen-Ling Liu ◽  
Mei Sun
2011 ◽  
Vol 11 (1) ◽  
pp. 107-112 ◽  
Author(s):  
A. Grefte ◽  
M. Dignum ◽  
S. A. Baghoth ◽  
E. R. Cornelissen ◽  
L. C. Rietveld

To guarantee a good water quality at the consumer’s tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research is to measure the effect of NOM removal by ion exchange on the biological stability of drinking water. Experiments were performed in two lanes of the pilot plant of Weesperkarspel in the Netherlands. The lanes consisted of ozonation, softening, biological activated carbon filtration and slow sand filtration. Ion exchange in fluidized form was used as pre-treatment in one lane and removed 50% of the dissolved organic carbon (DOC); the other lane was used as reference. Compared to the reference lane, the assimilable organic carbon (AOC) concentration of the finished water in the lane pretreated by ion exchange was 61% lower. The biofilm formation rate of the finished water was decreased with 70% to 2.0 pg ATP/cm2.day. The achieved concentration of AOC and the values of the biofilm formation rate with ion exchange pre-treatment showed that the biological stability of drinking water can be improved by extending a treatment plant with ion exchange, especially when ozonation is involved as disinfection and oxidation step.


1992 ◽  
Vol 26 (9-11) ◽  
pp. 2269-2272 ◽  
Author(s):  
Š Cerjan-Stefanovic ◽  
M. Kaštelan-Macan ◽  
T. Filipan

Isomorphous substitution of phosphorus into a natural zeolite affords the possibility to change the overall framework charge from negative to positive. The substances so created should be used for purification of waste waters. The work describes the preparation of phosphated zeolite, their characterisation and examples of their anion exchange of NO3 on observed in deionized water, drinking water and in the solution containing varying amounts of nitrate.


2006 ◽  
Vol 6 (3) ◽  
pp. 35-41 ◽  
Author(s):  
R. Baciocchi ◽  
A. Chiavola

This paper provides new insights on the regeneration step of an ion exchange process for the treatment of surface and ground water characterized by high sulphate concentration. Repeated regeneration of ion exchange resin with a sodium chloride solution (brine) did not alter the resin performances with respect to the fresh one. Besides, neither the sodium chloride concentration of the brine, which was varied between 1 and 3 M, nor the presence of sulphates at concentrations up to 20 g/L in the brine, did notably affect the regeneration efficiency. The brine was effectively treated by adding calcium or barium chloride, in order to remove the sulphates and re-establish the original chloride concentration. Calcium chloride was allowed to obtain up to 70% sulphate precipitation, whereas an almost 100% precipitation efficiency was obtained when barium chloride was used. The precipitation step was described by a model based on the mass action, coupled to the Bromley model for the description of the non-ideal behaviour of the electrolytic solution. This model was shown to give correct, or at least conservative, estimates of the equilibrium sulphate concentration when either calcium or barium chloride was used as precipitating agent.


Author(s):  
Tatyana G. Kuzmina ◽  
Valentina A. Nikashina ◽  
Nadezhda Lichareva ◽  
Irina N. Gromjak ◽  
Inna B. Serova ◽  
...  

Previously Sr2+ion-exchange isotherms were obtained from the surface drinking water and the corresponding Sr2+ distribution coefficients (Kd) were calculated for linear part of the isotherms of the studied CLT. The comparative kinetic data of Sr2+ ion-exchange sorption on NH4+- forms of the clinoptilolite-containing tuffs from deposits of Russia and Bulgaria on the sample of the surface drinking water was investigated in detail with the known method of the "thin layer". It was shown, that the kinetic process of the Sr-sorption on the clinoptilolite- containing tuffs is characterized with the features and includes 3 stages. The first stage is described with the particle diffusion law, the second stage –a slowing down, the ion-exchange process reaches a plateau, then an increase of Sr2+ sorption is observed again. The particle diffusion coefficients of Sr2+ describing the first stage of the sorption process on CLT of different deposits were calculated. The obtained data are the initial one for the development of a mathematical model of the dynamic ion-exchange process on NH4+-form of the clinoptilolite- containing tuffs from the surface drinking waters, that makes possible to generate the computer program and thereupon to calculate the break-through curves of Sr2+ sorption on NH4+- clinoptilolite- containing tuffs for the different dynamic conditions, including the sorption dynamic conditions on the permeable reactive barrier


2018 ◽  
Vol 170 ◽  
pp. 04003 ◽  
Author(s):  
Svetlana Fedorova ◽  
Anatolii Kryzhanovsky

The urgency of the conducted studies is dictated by the problem of Urban Territories’ sub-surface waters purification providing in the Republic of Sakha (Yakutia) population with drinking water, which can be partly solved by involving the sub-surface waters of the Yakutian artesian basin in the domestic and drinking water supply systems. The chemical composition feature of the under-ground waters under consideration, which substantially complicates their widespread use for domestic and drinking purposes, is the increased content of lithium, fluorine and sodium. The main research objective is to develop an effective method for clearing the sub-permafrost waters of the Yakutian artesian basin from lithium compounds, which can be used in water treatment systems for domestic and drinking purposes. As a result of the experimental studies on the sub-permafrost water purification of casting by the ion exchange method, its content reduced from 0.5 to 0.01 mg / l, which fully met the requirements for drinking water. On the basis of the results obtained, a comprehensive scheme for the sub-permafrost waters purification of the Yakutian artesian basin from lithium, fluorine and sodium was developed for the purpose of household and drinking water supply.


1999 ◽  
Vol 40 (2) ◽  
pp. 69-76 ◽  
Author(s):  
T. Viraraghavan ◽  
K. S. Subramanian ◽  
J. A. Aruldoss

The current United States maximum contaminant level for arsenic in drinking water is set at 50 μg/l. Because of the cancer risks involved, Canada has already lowered the maximum contaminant level to 25 μg/l; the United States Environmental Protection Agency is reviewing the current allowable level for arsenic with a view of lowering it significantly. Various treatment methods have been adopted to remove arsenic from drinking water. These methods include 1) adsorption-coprecipitation using iron and aluminum salts, 2) adsorption on activated alumina, activated carbon, and activated bauxite, 3) reverse osmosis, 4) ion exchange and 5) oxidation followed by filtration. Because of the promise of oxidation-filtration systems, column studies were conducted at the University of Regina to examine oxidation with KMnO4 followed by filtration using manganese greensand and iron-oxide coated sand to examine the removal of arsenic from drinking water; these results were compared with the data from ion exchange studies. These studies demonstrated that As (III) could be reduced from 200 μg/l to below 25 μg/l by the manganese greensand system. In the case of manganese greensand filtration, addition of iron in the ratio of 20:1 was found necessary to achieve this removal.


2003 ◽  
Vol 38 (1) ◽  
pp. 169-182 ◽  
Author(s):  
Ashref Darbi ◽  
Thiruvenkatachari Viraraghavan ◽  
Yee-Chung Jin ◽  
Larry Braul ◽  
Darrell Corkal

Abstract Sulfate occurs naturally in groundwater. Concerns regarding the health effects from sulfate in drinking water have been raised because of reports that diarrhea may be associated with water that contains high levels of sulfate. In the livestock production industry, there is a concern that high levels of sulfate in water can adversely affect productivity. Different methods can be used to remove sulfate from water. Proven technologies are ion-exchange, nanofiltration, reverse osmosis, and electrodialysis. A few earlier studies have shown that the use of bentonite/kaolinite for sulfate removal has produced encouraging results. Experimental work was undertaken to examine in detail the feasibility of such processes. Laboratory studies using bentonite showed poor or no removal in the case of high sulfate water. Ion exchange and nanofiltration were found to be very effective in removing sulfate. Ion exchange is likely to be more reliable than nanofiltration because of the sensitivity of the nanofiltration process to total dissolved solids and biofouling.


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