Regeneration Of Cation Exchanger Research Articles

Innovative ammonia harvesting from wastewater: A controlled closed-loop process at high pH for enhanced nutrient recovery

This study presents a new, sustainable, high-pH recirculating batch process for the regeneration of NH4+-laden cation exchange resins, while recovering the ammonia as a pure, reusable, solid salt (NH4Cl). The process efficiently recycles a minimal volume of regeneration solution while reducing NaCl consumption between cycles. The regeneration solution, containing a high concentration of NaCl maintained at high pH (pH > 11) allows Na+ to replace the desorbed NH4+, which, due to the high pH, completely transforms into NH3. Real time pH monitoring of the regeneration solution and the column effluent provided accurate tracking of the regeneration rate and allowed concise endpoint determination. Ammonia was recovered by evaporation of the exhausted regeneration solution followed by sublimation (and thereafter deposition) of NH3 and HCl, which produced pure NH4Cl salt.The optimal working conditions for the cation exchange regeneration were identified as 1 M NaCl, pH 12.0, and regeneration solution volume of 1 bed volume. Single-column application of six adsorption-regeneration cycles (no zeolite replacement) showed that the process conditions do not degrade the resin’s adsorption performance. Cost assessment of two possible ammonia recovery options indicated that while stripping NH3 from the regeneration solution and reabsorbing it in an acidic solution is operationally easier, the sublimation-based approach yields a more valuable product. For an optimized sublimation approach, a low regeneration solution volume, combined with a high resin capacity for NH4+, are essential.This process demonstrates a sustainable solution for ammonia salt recovery from wastewater, offering a circular approach that does not only add an important control to the regeneration step, but also harvests ammonia as a reusable product.

Study of the possibilities of integrated treatment of flue gases and waste water from coal-fired heat power plants

The results of laboratory studies carried out to identify the possibility and effectiveness of technologies for the complex recycling of components of flue gases and wastewater from thermal power plants and industrial boilers are presented. The following factors were investigated: the degree of saturation of water solutions with CO2, the efficiency of using these solutions for the regeneration of cation exchangers, the properties of regeneration solutions intended for the regeneration of cation exchange filters prepared using components of flue gases obtained from the combustion of organic fuel in the laboratory by saturating water of various compositions, the degree of saturation of condensate and waste-water with components of flue gases, as well as the degree of regeneration of cation exchangers with such regeneration solutions. After research in the laboratory, a laboratory installation was created in an industrial environment to determine the properties of solutions obtained from wastewater and flue gases obtained after production processes at a power plant. The technologies were developed for the complex recycling of flue gases and waste-water from thermal power plants with the production of CO2 with a purity of 99.9%, technical nitrogen with a purity of 95%, special solutions for the regeneration of cation exchangers in water purification plants of industrial enterprises. The results obtained make it possible to minimize the volume of emissions into the atmosphere and the volume of waste-water from thermal power plants.

Universal Installation for the integrated utilization of flue gases and wastewater from thermal power plants

For 30 years research has been carried out on the use of wastewater from thermal power plants and industrial boilers, as well as on the use and extraction of various components from flue gases such as carbon dioxide, sulfur and nitrogen. Technological solutions were developed and implemented in various productions at various times: use of acid-forming components of flue gases for the regeneration of cation exchangers; carbon dioxide from flue gases of 99.9% purity with “food” quality; technical nitrogen of 95-99 purity from flue gases; wastewater usage to increase the degree of sulfur oxides from flue gases. The article presents a technological solution for the integrated utilization of flue gases and wastewater from a thermal power plant with high-pressure boilers burning solid fuels.

Extraction of Cu2+, Zn2+ and Ni2+ cations from industrial wastewater by ionite KU-2-8

The object of the research is model solutions of wastewater and wash water from metal processing enterprises containing copper, nickel and zinc ions. One of the most problematic places is that the process of sorption of copper, nickel and zinc cations on the strongly acidic cation exchanger KU-2-8 at high metal concentrations is not well understood.The sorption and desorption processes of Cu2+, Zn2+ and Ni2+ ions on KU-2-8 cation exchanger in the H+ form are studied using model solutions of metal sulfate at high concentrations. The experiments were carried out in an ion-exchange column with a diameter of 2 cm 2 loaded with cation exchanger with a volume of 20 cm 3. During the research, the concentration of metals was measured by titrometric, photometric and instrumental methods (concentration of copper, zinc and nickel ions, acidity, alkalinity, pH). Model solutions of heavy metal ions Cu2+, Zn2+ and Ni2+ with a concentration of 10, 20, and 50 mg-Eq/dm3 were passed through KU-2-8 ion exchanger in the H+ form. During sorption of 0.01 n model solutions, the ion exchanger capacity on average reached 2073 mg-Eq/dm3, at 0.02 n – 2140 mg-Eq/dm3 and at 0.05 n – 2100 mg-Eq/dm3. After metal extraction from model solutions and complete saturation of the ion exchanger, the conditions for the regeneration of cation exchanger in the Cu2+, Zn2+ and Ni2+ form with solutions of 5, 8 and 10 % sulfuric acid were studied. The efficiency of desorption of divalent metal ions from an ion exchanger was almost 100 %.The scientific novelty of the work lies in the fact that metal ions were sorbed for the first time at concentrations of 10, 20, and 50 mg-Eq/dm3 in terms of metal and their desorption of 5, 8, and 10 % sulfuric acid from cation exchanger.After the experiments, a scheme for washing water treatment using ion exchange and electrolysis was proposed, which will allow the organization of environmentally friendly metal processing processes at galvanic enterprises.

STUDY OF THE EFFICIENCY OF SORPTION TREATMENT WATER FROM AMMONIUM IONS ON NATURAL AND ARTIFICIAL SORBENTS

It was studied processes of ion-exchange water purification from ammonium ions from model solutions on cation exchangers and on zeolite. It was established dependencies ammonium sorption on the form of ion exchanger, the ratio of ammonium and calcium in water and the level of ion concentrations in solution. It was shown that the strongly acid cation exchanger KU-2-8 in Na+-form has a low selectivity for ammonium ions, in comparison with the H+-form. It was established that the sorption efficiency of ammonium ions on cation exchangers KU-2-8 and Dowex Mac-3 decreases in the presence of calcium ions. It was determined that regeneration of cation exchanger KU-2-8 was more effective when hydrochloric acid solutions were used. It was shown that ammonium sorption on zeolite from tap water goes in the same way as from model solutions. It was determined the boundary capacity of the zeolite for ammonium ions and it was amounted 40 mg/g. The regeneration of zeolite with a sodium chloride solution was investigated and it was established that the degree of regeneration reached 100 %. Bibl. 16, Fig. 6, Tab. 1.

Environmental fate of Ra in cation-exchange regeneration brine waste disposed to septic tanks, New Jersey Coastal Plain, USA: migration to the water table

Fate of radium (Ra) in liquid regeneration brine wastes from water softeners disposed to septic tanks in the New Jersey Coastal Plain was studied. Before treatment, combined Ra ( 226Ra plus 228Ra) concentrations (maximum, 1.54 Bq L −1) exceeded the 0.185 Bq L −1 Maximum Contaminant Level in 4 of 10 studied domestic-well waters (median pH, 4.90). At the water table downgradient from leachfields, combined Ra concentrations were low (commonly ≤0.019 Bq L −1) when pH was >5.3, indicating sequestration; when pH was ≤5.3 (acidic), concentrations were elevated (maximum, 0.985 Bq L −1 – greater than concentrations in corresponding discharged septic-tank effluents (maximum, 0.243 Bq L −1)), indicating Ra mobilization from leachfield sediments. Confidence in quantification of Ra mass balance was reduced by study design limitations, including synoptic sampling of effluents and ground waters, and large uncertainties associated with analytical methods. The trend of Ra mobilization in acidic environments does match observations from regional water-quality assessments.

Fluidization of cation exchangers with regenerating sulfuric acid solution

Dependences of the bed expansion of cation exchangers (weakly acidic Lewatit CNP 80 and strongly acidic KU-2×8) on the flow velocity, temperature, and concentration of the regenerating sulfuric acid solution were determined. An equation describing the dependence of the bed expansion of cation exchangers on the flow velocity, temperature, and concentration of sulfuric acid, common to the two ion exchangers, was derived, which allows a priori determination of the extent of bed expansion in regeneration of cation exchangers in the fluidization mode.

Concentrations and environmental fate of Ra in cation-exchange regeneration brine waste disposed to septic tanks and accumulation in sludge, New Jersey Coastal Plain, USA

Concentrations of Ra in liquid and solid wastes generated from 15 softeners treating domestic well waters from New Jersey Coastal Plain aquifers (where combined Ra ( 226Ra plus 228Ra) concentrations commonly exceed 0.185 Bq L −1) were determined. Softeners, when maintained, reduced combined Ra about 10-fold (<0.024 Bq L −1). Combined Ra exceeded 0.185 Bq L −1 at 1 non-maintained system. Combined Ra was enriched in regeneration brine waste (maximum, 81.2 Bq L −1), but concentrations in septic-tank effluents receiving brine waste were less than in the untreated ground waters. The maximum combined Ra concentration in aquifer sands (40.7 Bq kg −1 dry weight) was less than that in sludge from the septic tanks (range, 84–363 Bq kg −1), indicating Ra accumulation in sludge from effluent. The combined Ra concentration in sludge from the homeowners' septic systems falls within the range reported for sludge samples from publicly owned treatment works within the region.

Separation of effluents from regeneration of a cation exchanger by membrane distillation

The treatment of effluents from the regeneration of cation exchanger by the membrane distillation (MD) process has been investigated. The composition ofthese effluents is complex due to the content ofresidual acid (1-50 g HCl/dm3) and different amounts of various salts (ranging in concentration from 10 to 40 g/dm3) including hardly soluble salts. Therefore, long-term investigations were carried out to evaluate the performance of the MD process and a fouling potential of treated effluents. The MD module exhibited a stable performance in terms of membrane permeability during 300 h of a continuous treatment of these effluents. However, the distillate composition was affected by a feed concentration. A low HCl flux was observed when the feed contained less than 50 g HCI/dm3, which resulted in the concentration of acid in the distillate below 0.5 g HCI/dm3. A significant enhancement of the HCl flux (above 500 mol/m2d) was achieved by increasing the acid concentration in the feed to a level of 150 g HCI/dm3. Therefore, 3–4 fold concentrations were sufficient to achieve a high HCI flux for effluents containing 42–46 g HCI/dm3. A condition of high HCl concentration in the feed implies that the recovery of HCl from the effluent with a low acid concentration (e.g. 1 g HCl/dm3) is a difficult task. Moreover, it was found that the 5042− ion concentrations in the feed was a factor limiting the degree of effluent concentration. The formation of salt deposit was observed after exceeding the concentration of 0.6 g SO42−/dm3, which caused a decrease of the MD module efficiency.

Recovery of acid from cation exchange resin regeneration waste by diffusion dialysis

Sulphuric acid can be selectively separated from the sulphates of calcium, magnesium, sodium and potassium present in cation exchange regeneration waste by diffusion dialysis. Studies were carried out to determine the optimum flow rate which will result in the maximum recovery of acid with minimum salt concentration. Separation factors between salt and acid for various salts present in the cation exchange regeneration waste are also presented.

Correction

Journal AWWAVolume 44, Issue 4 p. 355-355 CorrectionFree Access Correction This article corrects the following: Counterflow Regeneration of Cation Exchanger in Partial Demineralization of Brackish Waters K. S. Spiegler, Walter Juda, Morris Carron, Volume 44Issue 1Journal - American Water Works Association pages: 80-88 First Published online: January 1, 1952 First published: 01 April 1952 https://doi.org/10.1002/j.1551-8833.1952.tb15362.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume44, Issue4April 1952Pages 355-355 RelatedInformation

Counterflow Regeneration of Cation Exchanger in Partial Demineralization of Brackish Waters

Journal AWWAVolume 44, Issue 1 p. 80-88 Article Counterflow Regeneration of Cation Exchanger in Partial Demineralization of Brackish Waters Correction(s) for this article Correction Volume 44Issue 4Journal - American Water Works Association pages: 355-355 First Published online: April 1, 1952 K. S. Spiegler, K. S. SpieglerSearch for more papers by this authorWalter Juda, Walter JudaSearch for more papers by this authorMorris Carron, Morris CarronSearch for more papers by this author K. S. Spiegler, K. S. SpieglerSearch for more papers by this authorWalter Juda, Walter JudaSearch for more papers by this authorMorris Carron, Morris CarronSearch for more papers by this author First published: 01 January 1952 https://doi.org/10.1002/j.1551-8833.1952.tb15299.xCitations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume44, Issue1January 1952Pages 80-88 RelatedInformation