Ion Exchange Resin Treatment Research Articles

A low-cost and sustainable solution for nitrate removal from secondary effluent: Macroporous ion exchange resin treatment

Macroporous ion exchange resin has excellent selectivity to nitrogen (N), phosphorus (P) and partially soluble refractory organic compounds contained in the secondary effluent of wastewater treatment plants (WWTP). In this study, macroporous ion exchange resins were chosen as an alternative to single biochemical nitrogen removal processes. Various conditions were examined to optimize adsorption performance, and the adsorption mechanism was explored through isotherm fitting, thermodynamic parameter calculation, and kinetic analysis. The experiment demonstrated that the resin exhibited strong selectivity for nitrate (NO3−) and achieved an equilibrium adsorption amount of 9.8924 mg/g and an equilibrium adsorption time of 60 min at 25 °C. The resin denitrification pilot plant demonstrated stable operation for two months and achieved COD<20 mg/L, TN < 1.5 mg/L, and NH4+-N<0.5 mg/L. The removal rates of COD, TP, NH4+-N, NO3−-N, and TN were 41.65%, 42.96%, 55.37%, 91.8%, and 90.81%, respectively. After the resin was regenerated, the removal rates of NO3−-N, TN and the regeneration recovery rate were above 90%. Through cost analysis, the treatment cost of the pilot plant is only 0.104 $/m3. This study presents a practical, low-cost, and efficient treatment method for the deep treatment of secondary effluent from WWTP in practical engineering, providing new ideas and theoretical guidance.

Recent advances in Fenton-like treatment of radioactive ion exchange resins

Ion exchange resins (IERs) are widely used to remove radioactive contaminants from various commercial nuclear power plant systems. After the completion of their useful life cycle, IERs are removed from the nuclear facility and are known as spent resins. In the past few decades, the development of Fenton/Fenton-like treatments for the management of spent resins has received considerable attention because of their potential to completely break down the IER structure into harmless compounds (e.g., carbon dioxide, water, and inorganic salts). In addition, after Fenton-like treatments, the resulting solutions containing radionuclides can be easily immobilized to stable waste. In this review, we critically discuss the key developments in Fenton/Fenton-like dissolution, degradation, and mineralization of spent resins. We describe the important reaction parameters (initial pH, resin dosage, catalyst type and dosage, hydrogen peroxide dosage, flow rates of the catalyst and oxidant, reaction temperature, treatment time, and other specific parameters) for various Fenton/Fenton-like treatments of spent resins. Moreover, this review focuses heavily on the major reaction intermediates generated in Fenton-like treatments. In the final section of this review (conclusions and perspectives), we discuss the major challenges and suggest future research directions need to be addressed to improve the efficiency of Fenton-like treatments of spent resins.

Проведение опытной работы по снижению активности отработавших ионообменных смол

High level decontamination is seen as a method providing the reprocessing of ion-exchange resins: they are treated with specifically selected solutions to achieve high degree of radionuclide elution. In 2021, Research Manufacturing Technological Bureau Onega launched an experimental study aimed at reducing the activity of spent ion-exchange resins unloaded from ships undergoing maintenance. Under the study, a few experiments were performed to select appropriate regenerating solutions, optimal methods for spent ion-exchange resin processing and treatment of regenerating solutions on sorbents of NZрS and TsMPA types. Based on the study, a method was proposed with an appropriate processing flowchart developed to manage spent ion-exchange resins at the ship repair site Zvezdochka.

Experimental study on treatment of mixed ion exchange resins by supercritical water gasification

Nuclear power acts as a significant role in the current world energy supply system. The treatment of radioactive waste from nuclear station is a considerable issue and has attracted more and more attention. Spent ion exchange resins used in nuclear power plants are typical organic nuclear waste which are difficult to deal with. Supercritical water gasification could offer an efficient and clean treatment to spent ion exchange resins. In this study, Supercritical water gasification of mixed ion exchange resins was carried out in a batch reactor with various conditions. Effects of reaction parameters such as temperatures (550oC–750 °C), concentrations (5 wt%-15 wt%), catalysts (K2CO3, Na2CO3, KOH and NaOH) and residence times (10 min–60 min) were investigated. Results showed that high temperature, low concentration, K2CO3 addition and long residence time promote the gasification result. And the carbon gasification efficiency reached up to 97.2% with 10 wt% concentration and K2CO3 catalyst addition at 750 °C. The main intermediate organic component residues in liquid products were trimethylamine, benzene, toluene, ethylbenzene p-xylene styrene benzene, 1-ethyl-4-methyl- and naphthalene. Reaction pathways in supercritical water have been discussed and proposed. And the conversion pathways and distributions of sulfur and nitrogen were disclosed.

Spherical TiO2 /Cr2O3 Composites Synthesized Using Ion-Exchange Resins as a Template

Two samples of TiO2 /Cr2O3 composites were synthesized as spherical grains by stepwise thermal treatment of ion-exchange resins, which were preliminarily saturated with chromium cations Cr3+ and dichromate anions Cr2O7 2– and covered with a film-forming solution of titania. The modes of calcination were based on thermal analysis and determined by the type of ion-exchange resin chosen as a template. The obtained composites consist mostly of the α-Cr2O3 phase, while the content of the TiO2 phase does not exceed 4 %. The composites retain the spherical grain shape of the initial ion-exchange resins with the size from 370 to 660 μm. Grains of the sample based on cationite, which adsorbs Cr3+ ions, have a pore structure with swells and voids. Grains of the sample based on anionite have fractures and cracks over the entire surface due to nonuniform distribution of adsorbed Cr2O72– anions in the initial anionite. The composites exhibit the catalytic activity in the complete oxidation of p-xylene. The sample based on cationite is more active. This may be related to a smaller accessible specific surface area of titania in the anionite-based sample due to formation of the Ti3+ solid solution in α-Cr2O3.

Recent Advances in Fenton-Like Treatment of Radioactive Ion Exchange Resins

Recent Advances in Fenton-Like Treatment of Radioactive Ion Exchange Resins

Исследование осушки и оптимизация кондиционирования отработавших ионообменных смол без включения в матрицу для захоронения

The publication [1] discusses technical issues faced during the conditioning of intermediate- and low-level spent ion exchange resins by thermal vacuum drying to obtain packages that would meet waste acceptability criteria for nearsurface disposal facilities. This article is a continuation of another publication [1] which elaborated on a study of ionexchange resin drying process and provided some proposals on the conditioning optimization using NZK-150-1.5 P containers. It specifies optimal parameters for the pre-disposal treatment and conditioning of dried resins providing their safe storage and disposal. The study presents calculated permissible internal pressure providing adequate strength of the containers. The proposed pre-disposal ion exchange resin treatment and conditioning method can be recommended for industrial use.

Field demonstration of coupling ion-exchange resin with electrochemical oxidation for enhanced treatment of per- and polyfluoroalkyl substances (PFAS) in groundwater

This pilot-scale field demonstration evaluated the remediation of poly- and perfluoroalkyl substances (PFAS) from groundwater contaminated with aqueous film-forming foam (AFFF) from a coupled regenerable ion exchange resin (IXR) and electrochemical oxidation (EO) treatment train. A pilot-scale IXR system was used that incorporates a novel resin regeneration process, and recovers and reuses the majority of the regenerant solution using distillation. The pilot system removed PFAS from ∼1,000,000 L (approximately 260,000 gallons) of contaminated groundwater from a fire training area, and treated effluent from the IXR system was non-detect for PFOA and PFOS. The concentrated waste stream (i.e., still bottom) from IXR was treated on-site by an EO system with Ti4O7 electrodes, achieving 80–98% destruction of PFOA and PFOS. The surface area normalized first-order rate constants (kSA) were 3.96 × 10−7 m s−1 and 7.92 × 10−7 m s−1 for PFOA and PFOS, respectively, with short-chain perfluoroalkyl acids (PFAAs) identified as intermediate degradation products. Based on the fluoride recovered and PFAS mass loss measured at the end of EO treatment, fluoride release ratios were 130% for still bottom sample 1 (SB1) and 215% for still bottom sample 2 (SB2), indicating mineralization of unquantified fluorinated compounds in the waste stream. Overall, the electric energy consumed per order of magnitude reduction in concentration (EE/O) for treating PFOA and PFOS in groundwater by the IXR-EO treatment train was 0.131–0.161 kWh/m3 for PFOA and 0.071–0.094 kWh/m3 for PFOS, which was orders of magnitude lower than the reported EE/O values for stand-alone electrochemical treatment. The results of this field demonstration show the promise of coupling regenerable IXR with EO for cost-effective removal, concentrating, and destroying PFAS from groundwater.

Hyperkalaemia management and related costs in chronic kidney disease patients with comorbidities in Spain.

BackgroundHyperkalaemia (HK) is a common electrolyte disorder in patients with chronic kidney disease (CKD) and/or treated with renin–angiotensin–aldosterone system inhibitors (RAASis). The aim of this study is to determine the severity, current management and cost of chronic HK.MethodsWe performed a retrospective cohort study of patients with chronic HK and CKD, heart failure or diabetes mellitus between 2011 and 2018. The study follow-up was 36 months.ResultsA total of 1499 patients with chronic HK were analysed: 66.2% presented with mild HK, 23.4% with moderate HK and 10.4% with severe HK. The severity was associated with CKD stage. Most patients (70.4%) were on RAASi therapies, which were frequently discontinued (discontinuation rate was 39.8, 49.8 and 51.8% in mild, moderate and severe HK, respectively). This RAASi discontinuation was similar with or without resin prescription. Overall, ion-exchange resins were prescribed to 42.5% of patients with HK and prescriptions were related to the severity of HK, being 90% for severe HK. Adherence to resin treatment was very low (36.8% in the first year and 17.5% in the third year) and potassium remained elevated in most patients with severe HK. The annual healthcare cost per patient with HK was €5929, reaching €12 705 in severe HK. Costs related to HK represent 31.9% of the annual cost per HK patient and 58.8% of the specialized care cost.ConclusionsHK was usually managed by RAASi discontinuation and ion-exchange resin treatment. Most patients with HK were non-adherent to resins and those with severe HK remained with high potassium levels, despite bearing elevated healthcare expenditures.

Evaluation of a hybrid process of magnetic ion-exchange resin treatment followed by ozonation in secondary effluent organic matter removal

The presence of effluent organic matter (EfOM) and organic micro-pollutants (OMPs) in secondary effluent is receiving increasing concern due to their potential impacts on the aquatic environment and human health. In this study, the removal characteristics of EfOM by magnetic ion-exchange resin (MIEX), ozonation, and the hybrid process of MIEX followed by ozonation (M + O) were compared by measuring the bulk organic indicators (BOIs), OMPs, bio-toxicity, and fluorescence. Furthermore, the desorption characteristics of MIEX were comprehensively studied. Ozonation could reduce the OMPs, total fluorescence (TF), genotoxicity, and oestrogenic activity more effectively than MIEX, with reductions of 80.3%, 97.8%, 98.9%, and 94.6%, respectively. The M + O process was capable of removing more EfOM than the individual MIEX or ozonation processes and could reduce the genotoxicity and oestrogenic activity to the detection limit. By implementing MIEX as a pre-treatment, the generation of ammonia–nitrogen and nitrate–nitrogen was effectively reduced in the subsequent ozonation process as MIEX adsorbed organic nitrogen and nitrite-nitrogen. The different regenerants influenced the OMP desorption performance of MIEX by changing the desorption mechanisms, and NaCl + NaOH was the best regenerant due to its high total OMP desorption efficiency. Parallel factor analysis coupled with self-organising maps further explained the differences in fluorescence desorption due to the addition of NaOH to the regenerated solution. Pearson correlation analysis indicated the potential of using spectroscopic indicators, such as ultraviolet absorbance and TF, to assess the evolution of OMPs and bio-toxicity during the M + O and MIEX desorption processes.

The effect of ion-exchange resin treatment on grape must composition and fermentation kinetics

The aim of this study was to determine the influence of ion-exchange resin treatments of white grape must for the production of sparkling base wines, on the grape must chemical composition and fermentation kinetics. The experiment included an untreated grape must with a pH of 3.2, and resin-treated musts with pH 3.14, 3.07, and 3.01. Analysis of pH, total acidity, optical density (O.D.) at 420 nm, total phenolic content, tartaric acid, ammonium-nitrogen (AN) and cations (Ca2+, Mg2+, Cu2+, K+, and Na+) was performed. The fermentations were monitored by mass reduction (CO2 release g/L), and fermentation parameters obtained from a modified non-linear sigmoidal equation. The analyses of the musts showed differences in the concentration of metals, total acidity, tartaric acid, AN and O.D. 420 nm. The kinetic parameters of the fermentation showed significant changes between the control must and the ion-exchange treatments. This study showed that the treatment with cationic resins at the tested level significantly affects the chemical composition of the musts, interfering with the fermentation kinetics. In addition, reductions in the must pH index close to 0.1 unit can lead to positive results in the characteristics of the base must of sparkling wines.

Combined membrane and thermal desalination processes for the treatment of ion exchange resins spent brine

The disposal of industrial wastewater effluents represents a critical environmental issue. This work focuses on the treatment of the spent brine produced by the regeneration of ion exchange resins employed for water softening. For the first time, a comprehensive techno-economic assessment and an analysis of the energy requirements of the treatment chain are carried out, via the simulation of ad hoc implemented models. The chain is composed of nanofiltration, double-stage crystallization and multi-effect distillation. The valuable product is the brine produced by the multi-effect distillation, which can be re-used for the regeneration. Therefore, the treatment chain’s economic feasibility is evaluated via the Levelized Brine Cost, which includes the terms of cost and revenue of every unit in the chain. Varying the nanofiltration recovery, the treatment system always turns out to be economically competitive, since the Levelized Brine Cost is lower than the current cost of the fresh regenerant solution (8 $/m3). In particular, the lowest value of 4.9 $/m3 is found for a nanofiltration recovery of 25%. Moreover, the cost of the reactant used in the crystallization and the revenues of Mg(OH)2 and Ca(OH)2 play a prominent role in all scenarios. Regarding the energy demand, the thermal energy required by the evaporator is the main contribution and covers more than 30% of the operating costs (excluding the cost of the crystallization reactant, which is balanced by the hydroxides revenues). Therefore, the costs can be significantly reduced when waste heat is available in the industrial site. Overall, the treatment chain is economically feasible and allows reducing the industrial environmental impact by recycling waste streams and waste heat.

Xylitol production from prehydrolysis liquor of kraft-based dissolving pulp by Candida tropicalis

Xylitol production from the hemicelluloses of prehydrolysis liquor (PHL) is of practical interest from both economic and environmental standpoints. The removal of the inhibitors, e.g., lignin, acetic acid, and furfural, is the key to improving the conversion of xylose to xylitol when Candida tropicalis fermentation is used. For this purpose, a full chain process involving activated carbon adsorption, ion exchange resin treatment, acidolysis, and fermentation was considered in this work. The results showed that 72.6% of lignin and 67.1% of furfural were removed using an activated carbon dosage of 20 mg/g PHL. Additionally, 61.2% of acetic acid was also removed at a resin dosage of 100 mg/g PHL. Subsequently, acidolysis using sulfuric acid and pH adjustment with lime was performed on the treated PHL to convert the oligosaccharides into monosaccharides; a yield of 0.40 g xylitol/g xylose was achieved via treating the PHL with Candida tropicalis fermentation at 30 °C, 200 rpm, and 96 h. In addition, a material balance was determined for the full chain process.

The use of combined treatments for reducing parabens in surface waters: Ion-exchange resin and nanofiltration

In this study, the removal of parabens from waters, using a combined treatment of magnetic ion exchange resins and subsequent filtration through nanofiltration membranes, was investigated. The selected parabens were methylparaben, ethylparaben, propylparaben and butylparaben. Two different magnetic anionic exchanger resins, MIEX® DOC and MIEX® GOLD, and two nanofiltration membranes (NF), NF-90 and DESAL-HL, were tested. The study was carried out using mono and multicomponent systems, using deionized water and natural waters sampled from two different rivers. In this way, competitive and matrix effects could be evaluated. The results showed, that with the combined treatments, higher elimination rates were obtained. The best removal efficiencies were obtained when the DOC resin was combined with both NF-90 and DESAL-HL membranes. Thus, butylparaben and propylparaben reached removal yields around 100% with both membranes, whereas the corresponding values for methylparaben were 91%, when the NF-90 membrane was employed, or 92% when DESAL-HL membrane was utilized. The elimination rates of ethylparaben with the same treatments were 96% with the NF-90 and 97% when the DESAL-HL membrane was combined with the DOC resin. The elimination percentages were higher as the paraben alkyl chain length increased. In addition, no competitiveness or matrix effects were detected. When the MIEX® GOLD resin was used for pre-treatment, membrane fouling worsened which indicated that resin selection needs to be carefully considered to achieve the best results.

Preliminary study of sulphide removal using ion exchange resin

The paper presents the investigation of sulphide removal via ion exchange resin. Sulphidic spent caustic (SSC) is a dark brown to black effluent generated from petrochemical and oil refinery industries. Typically, SSC has a pH of 13-14, and sulphide concentration of 0.5-4.0wt%. The large amount of sulphide content in SSC leads to its toxic property, obnoxious odor and hazardous nature. This will threaten health and safety of workers, and may pollute the environment. The SSC may not be discharged to wastewater treatment facilities untreated as the high sulphide content will cause corrosion in the pipes especially in aqueous condition. In fact, the Malaysia Department of Environment has limited the acceptable sulphide discharge in industrial effluent at 0.5 mg/L as stated in the Environmental Quality (Industrial Effluent) Regulation 2009. Hence, it is desirable to remove sulphide in the SSC. This research focused on the removal of sulphide from synthetic SSC via strongly basic anion exchange resin. A synthetic SSC was simulated to represent the SSC. The static method was applied, where the synthetic SSC was allowed to stay in a column of resin for several retentions time. The synthetic SSC was characterised for its sulphide content, chemical oxygen demand (COD) and pH before and after the treatment in order to analyse the effect of ion exchange resin treatment. The resin was also characterised for its moisture retention, exchange capacity, and pore size. The treatment was able to remove about 95.8% of the sulphide and the COD was reduced by 94.5%

Study of plasma off-gas treatment from spent ion exchange resin pyrolysis

Polystyrene divinylbenzene-based ion exchange resins are employed extensively within nuclear power plants (NPPs) and research reactors for purification and chemical control of the cooling water system. To maintain the highest possible water quality, the resins are regularly replaced as they become contaminated with a range of isotopes derived from compromised fuel elements as well as corrosion and activation products including 14C, 60Co, 90Sr, 129I, and 137Cs. Such spent resins constitute a major proportion (in volume terms) of the solid radioactive waste generated by the nuclear industry. Several treatment and conditioning techniques have been developed with a view toward reducing the spent resin volume and generating a stable waste product suitable for long-term storage and disposal. Between them, pyrolysis emerges as an attractive option. Previous work of our group suggests that the pyrolysis treatment of the resins at low temperatures between 300 and 350°C resulted in a stable waste product with a significant volume reduction (>50%) and characteristics suitable for long-term storage and/or disposal. However, another important issue to take into account is the complexity of the off-gas generated during the process and the different technical alternatives for its conditioning. Ongoing work addresses the characterization of the ion exchange resin treatment's off-gas. Additionally, the application of plasma technology for the treatment of the off-gas current was studied as an alternative to more conventional processes utilizing oil- or gas-fired post-combustion chambers operating at temperatures in excess of 1000°C. A laboratory-scale flow reactor, using inductively coupled plasma, operating under sub-atmospheric conditions was developed. Fundamental experiments using model compounds have been performed, demonstrating a high destruction and removal ratio (>99.99%) for different reaction media, at low reactor temperatures and moderate power consumption. The role of H2O as an important participant of the oxidation mechanisms in plasma conditions was established. The combination of both processes could represent a simple, safe, and effective alternative for treating spent ion exchange resins with a large reduction of generated gaseous byproducts in fuel cycle facilities where processes that utilize open flames are undesirable.

Green synthesis of bacterial cellulose via acetic acid pre-hydrolysis liquor of agricultural corn stalk used as carbon source

Herein, bacterial cellulose (BC) was synthesized by acetobacter xylinum via organic acid pre-hydrolysis liquor of agricultural corn stalk used as carbon source. Acetic acid was applied to pretreat the corn stalk, then, the prehydrolysate was detoxified by sequential steps of activated carbon and ion exchange resin treatment prior to use as carbon source to cultivate acetobacter xylinum. Moreover, the recovery of acetic acid was achieved for facilitating the reduction of cost. The results revealed that the combination method of detoxification treatment was very effective for synthesis of BC, yield could be up to 2.86g/L. SEM analysis showed that the diameter size of BC between 20 and 70mm. In summary, the process that bacterial cellulose was biosynthesized via prehydrolysate from agricultural corn stalk used as carbon source is feasible, and the ability to recover organic acid make it economical, sustainable and green, which fits well into the biorefinery concept.

Electrochemical decomposition of fluorinated wetting agents in plating industry waste water

Electrochemical decomposition of fluorinated surfactants (PFAS, perfluorinated alkyl substances) used in the plating industry was analyzed and the decomposition process parameters optimized at the laboratory scale and production scale of a 500-liter reactor using lead electrodes. The method and system was successfully demonstrated under production conditions to treat PFAS) with up to 99% efficiency in the concentration range of 1,000-20,000 μg/l (1 ppm-20 ppm). The treatment also reduced hexavalent chromium (Cr(6+)) ions to trivalent chromium (Cr(3+)) ions in the wastewater. If the PFAS-containing wastewater is mixed with other wastewater streams, specifically from nickel plating drag out solution or when pH values >5, the treatment process is ineffective. For the short chain PFAS, (perfluorobutylsulfonate) the process was less efficient than C6-C8 PFAS. The process is automated and has safety procedures and controls to prevent hazards. The PFAS were decomposed to hydrogen fluoride (HF) under the strong acid electrochemical operating conditions. Analytical tests showed no evidence of organic waste products remaining from the process. Conventional alternative PFAS removal systems were tested on the waste streams and compared with each other and with the-E-destruct (electrochemical oxidation) process. For example, ion exchange resin (IX resin) treatment of wastewater to complex and remove PFAS was found to be seven times more efficient when compared to the conventional activated carbon absorption (C-treat) process. However, the E-destruct process is higher in capacity, exhibits longer service life and lower operating costs than either IX or C-treat methods for elimination of PFAS from these electroplating waste streams.

Miscanthus × giganteus xylooligosaccharides: Purification and fermentation

A procedure was developed to recover xylooligosaccharides (XOS) from Miscanthus×giganteus (M×G) hydrolyzate. M×G hydrolyzate was prepared using autohydrolysis, and XOS rich fractions were acquired using activated carbon adsorption and stepwise ethanol elution. The combined XOS fractions were purified using a series of ion exchange resin treatments. The end product, M×G XOS, had 89.1% (w/w) total substituted oligosaccharides (TSOS) composed of arabinose, glucose, xylose and acetyl group. Bifidobacterium adolescentis and Bifidobacterium catenulatum (health promoting bacteria) were cultured in vitro on M×G XOS and a commercial XOS source, which was used as a comparison. B. adolescentis grew to a higher cell density than B. catenulatum in both XOS cultures. Total xylose consumption for B. adolescentis was 84.1 and 84.8%, respectively for M×G and commercial XOS cultures; and for B. catenulatum was 76.6 and 73.6%, respectively. The xylobiose (X2), xylotriose (X3) and xylotetraose (X4) were almost utilized for both strains. Acetic and lactic acids were the major fermentation products of the XOS cultures.

Production of furfural from an industrial pre-hydrolysis liquor

Pre-Hydrolysis Liquor (PHL) produced from the prehydrolysis kraft-based (PHK) dissolving pulp production process can be considered as a potential source for the production of biomaterials and biochemicals. Several dissolved organics such as hemicelluloses, lignin and acetic acid can be recovered and converted to valuable products. Xylan/xylose, a 5-carbon sugar and the major component of the hardwood PHL can be utilized to produce furfural. Pretreatment is necessary to increase the furfural yield, mainly by removing lignin, facilitating processing and minimizing the side reactions. In this research, adsorption by activated carbon, ion exchange resin treatment, and concentration by membrane filtration were utilized as pretreatments of PHL for furfural production. It was found that a furfural yield of 57% was achieved from the PHL at 190°C, using sulfuric acid as a catalyst. An overall process, integrated into the existing PHK dissolving pulp production process, was proposed to produce furfural from the PHL which fits well to the Integrated Forest Biorefinery concept.