Parametric studies on the performance of cation exchange for the ammonium removal

Ion exchange performance to remove ammonium in drinking water was studied experimentally in batch and continuous operation systems under the various conditions. Data were collected using commercially available strongacid cationexchange resins of Na+ and H+ types. The performance was evaluated using equilibrium concentrations for the batch system or the effluent concentration histories for the continuous column system as a function of time or the solution volume passed through the experimental column until resins were exhausted. With high temperature or low initial feed concentration, ammonium removal characteristics of the batch system increase. At the solution concentrations of 0.5, 1.0, and 2.0 mg/L of NH4+-N and the temperatures of 15, 25, and 35 ‡C, the selectivity coefficients of resin were determined between 1.38 and 1.43 for Na+ type resin, and 3.22 and 3.47 for H+ type resin. The selectivity coefficient was correlated as a function of temperature using Kraus-Raridon equation. The breakthrough curves obtained from the continuous column operation give some results; i) with small column diameter or large column height, ii) with low initial feed concentration, iii) with low volumetric flow rate, or iv) with high solution temperature, the ammonium removal for the typical macroporous type resin increase. The results of this study could be scaled up and used as a design tool for the waterpurification systems of the drinking water treatment processes. This paper was presented at The 5th International Symposium on Separation Technology-Korea and Japan held at Seoul between August 19 and 21, 1999.     

Parametric studies on the performance of mixed-bed ion exchange at ultralow concentrations –1. Multicomponent system–

We experimentally evaluated the effects of multicomponent systems of divalent cations on the performance of mixed-bed ion exchange in the concentration range used for ultrapure water processing. Data were collected in the batch and continuous column systems with Dowex Monosphere resins used commercially for ultrapure water applications. The presence of divalent cations in the systems affects significantly the capacity of the units to remove a univalent cation. However, the anion exchange rate increases slightly in the multicomponent systems. The equilibrium and the breakthrough curves of ions, plotted as the ratio of the effluent to influent concentration versus run time or solution volume passed through the experimental column, give detailed results about the effects of the existence of other ionic species on the fate of each ion in MBIE units. The results of the present study are expected to be used to develop and simulate mathematical models and to understand the performance of mixed-bed ion exchange at ultralow concentrations.     

The mixed-bed ion exchange performance at ultralow concentrations 1. Variable feed concentration and incomplete mixing of resins

Experimental data were obtained to evaluate the performance of mixed-bed ion exchange for the cases of variable feed concentration and incomplete mixing of anion and cation resins observed in large scale industrial units. For variable feed concentration, step changes in feed concentration were arbitrarily introduced into a test column. For incomplete mixing, only anion resin was loaded in the upper 20% of the column and more cation resin in the lower portion. Feed concentrations of 5.0× 10⁻⁵−2.0×10^-4 M NaCl were used for the experiments, with flow rates of 0.665-7.0 ml/sec. The effluent from the column was collected periodically and analyzed using on-line/off-line ion chromatography. The step changes in feed concentration affect the breakthrough times of sodium and chloride. Sodium breakthrough curve is more sensitive to the step changes than chloride breakthrough curve. With the same volumes of cation and anion resins, incomplete mixing of resins increases the cation exchange rate slightly and decreases the anion exchange rate slightly. As the cation resin volume increases, the effect of the incomplete mixing of resins decreases. The breakthrough curves of both ions, plotted as the ratio of effluent to the influent concentration versus run time in hour, give some detailed results about the effects of the conditions.     

The effects of amine additives and flow rate on the performance of mixed-bed ion exchange at ultralow concentrations

Experimental data were obtained to evaluate the effects of amine additives for pH control of solution and the volumetric flow rate of feed solution on the performance of mixed-bed ion exchange for the removal of ionic impurities in solution. The experiments were performed under various temperatures and cation resin ratios by using a continuous column system with NaCl solution. The breakthrough curves of ions, plotted as the ratio of the effluent to influent concentration versus run time or treated solution volume, give detailed results about the effects of the existence of the pH controller, such as ammonia and morpholine, and the variable flow rate on the fate of each ion in the units. The experimental results show that the morpholine breakthrough occurs earlier than the ammonia breakthrough and that the effect of ammonia on both sodium and chloride exchange rates is more significant than that of morpholine. The addition of ammonia in solution results in the decrease of cation resin capacity for the sodium removal much more than the addition of morpholine. The step changes in the flow rate affect significantly the shapes of sodium and chloride breakthrough curves. The effluent concentrations of sodium and chloride change according to the flow rate. However, the effect increases with decreasing operation capacity of cation resin, while it becomes serious around the breakthrough time of chloride and negligible after the time.     

REMOVAL OF BORON FROM BALÇOVA-IZMIR GEOTHERMAL WATER BY ION EXCHANGE PROCESS: BATCH AND COLUMN STUDIES

In this study, the efficiency of boron removal from Balçova geothermal water provided by the Izmir Geothermal Energy Company, Turkey, has been investigated using boron selective ion exchange resins Diaion CRB 02 and Dowex (XUS 43594.00) by batch and column methods. The results of the column studies have been evaluated in terms of type of resin and feed flow rate, and the effects of particle size and temperature have been investigated using the results obtained from batch kinetic studies. The data from the kinetic studies have been evaluated using pseudo-first-order and pseudo-second-order kinetics models. In addition, the classical diffusion models have been used to evaluate the kinetic data obtained to understand the rate-controlling mechanisms.     

Effects of operation variables on the recovery of lactic acid in a batch distillation process with chemical reactions

In this study, the feasibility of recovery of lactic acid by batch reactive distillation using cation exchange resin as a catalyst was investigated. For the recovery of lactic acid, two reactions, esterification and hydrolysis, are involved and hence, an apparatus with two distillation columns was developed and operated in a batch mode to ensure enough residence time in the reboiler and column. The effects of operation variables such as catalyst loading, reactant mole ratio, feed concentration, type of alcohols and partial condenser temperature on the yield were studied. In this study, the reaction products of the esterification (methyl lactate and water) were distilled to the hydrolysis part to be recovered into pure lactic acid. The yield of lactic acid increased as catalyst loading in the esterification part increased and reactant mole ratio and feed lactic acid concentration decreased. Methanol as a reactant gave higher yield than any other alcohols. The yield of recovered lactic acid was as high as 90%. The yield of lactic acid was closely related to the boiling temperature of the reaction mixture in the esterification part     

Zirconium and Hafnium Separation,Part 2. Solid/Liquid Extraction in Hydrochloric Acid Aqueous Solution with Anion Exchange Resins

Abstract

Sorption behavior of zirconium and hafnium on different commercial anion exchange resins with different amine functions; ammonium (Amberjet 4200Cl), pyridine (PVP) and pyridinium (HPQ) was investigated in hydrochloric acid by both batch and column methods. Experiments were studied as a function of the concentration of hydrochloric acid. For all resins, zirconium was preferably extracted. The highest separation factors at equilibrium conditions were obtained by poly(vinyl‐pyridine) (PVP) with a hydrochloric acid concentration of 9.5 M. It was observed that a single contact of the loaded resins with pure water completely back extracted the metal ions from the resins. On the basis of the significant difference between distribution coefficients of Zr and Hf, the separation was performed on a glass column (25×160 mm), packed with the resin. The breakthrough curves showed a competitive sorption and desorption process between Zr and Hf for the three resins studied.     

阳离子交换树脂法制备L-组氨酸钙工艺

采用阳离子交换树脂法制备L-组氨酸螯合钙,测定了D151和110两种弱酸型阳离子交换树脂的钙离子交换容量及其在26℃下的交换动力学曲线,并考察了温度、NaOH与L-组氨酸摩尔比、L-组氨酸初始浓度和树脂量对2种树脂钙交换过程的影响. 结果表明,D151和110的钙交换容量分别为1.12和2.59 mmol/g;交换过程迅速,工业上交换0.5 h即可达到平衡;钙离子交换是一个放热过程,工业生产中可在室温下或低温下进行;适宜的NaOH与L-组氨酸摩尔比为(1~1.25):1;用D151树脂时适宜的L-组氨酸初始浓度和树脂量分别约为0.46 mol/L和0.125 g/mL;用110树脂时分别约为0.4 mol/L和0.15 g/mL.     

催化精馏合成乙酸乙酯

以乙酸、乙醇为原料,阳离子交换树脂为催化剂,在自制精馏塔内催化精馏酯化合成乙酸乙酯.以捆扎包作为催化剂装填方式,并考察了催化剂布包材料、乙醇进料位置、空速、回流比、进料酸醇物质的量之比对乙醇转化率和塔顶产品中乙酸乙酯含量的影响.结果表明,合适的条件为催化剂布包采用尼龙布材料,乙醇进料位置在催化段底部,空速为0.213 h-1,进料酸醇物质的量之比3:1,回流比1.0.该工艺条件下,乙醇转化率为97.16%,塔顶乙酸乙酯的质量分数为95.44%.     

乙酸甲酯催化精馏水解工艺研究

采用阳离子交换树脂为催化剂 ,研究了乙酸甲酯催化精馏水解工艺。反应区充填离子交换树脂催化剂捆束包 ,提馏段充填Mo Ti金属板波纹丝网填料。在小试、中试 (塔径为 2 0 0mm)和工业化 (塔径为1 0 0 0mm)实验中 ,系统地研究了水酯摩尔比、回流进料比和空速对酯分解率和分解液中酸水质量比的影响 ,获得不改变现有聚乙烯醇生产中乙酸甲酯分解回收工艺流程的最佳分解率为 50 %— 60 % ,由此导致比原工艺节能约 30 %和原有设备利用率成倍提高     

离子交换法连续流处理受硝酸盐污染的地下水

采用普通阴离子交换树脂（Purolite A 300E）和硝酸盐选择性离子交换树脂（Purolite A 520E）处理受硝酸盐污染的模拟地下水,通过树脂床层的水流速度越慢,相应的穿透体积越大;用氯化钠水溶液再生饱和的离子交换树脂时,需要的再生液体积随氯化钠浓度的下降而增加,但实际消耗的氯化钠量却随其浓度的下降而减少,氯化钠适宜浓度在3％左右;当地下水中硫酸盐含量较高时,应采用硝酸盐选择性离子交换树脂,但该树脂比普通树脂难再生;树脂再生过程中产生的废液可用SBR工艺进行反硝化脱氮,硝态氮浓度为550m#L的再生废液在SBR池中搅拌反应10h,就能实现完全反硝化。     

Synthesis of High‐Purity Methylal via Extractive Catalytic Distillation

An integrated continuous process, which combines catalytic distillation and extractive distillation in one column, is investigated for the synthesis of high‐purity methylal from methanol and formalin in the presence of a cation‐exchange resin catalyst. A feed with methanol:formaldehyde 2:1 molar ratio is chosen to evaluate the effects of operating parameters, such as extractant feeding position, ratio of extractant to feed, reflux ratio, and reboiler temperature, on the continuous synthesis of methylal. Under the optimum operating conditions and with water as extractant, the extractive catalytic distillation process operated continuously, producing a methylal purity of 98.7 % (H₂O: < 1.30 %) with 98.0 % formaldehyde conversion.     

乙酸甲酯与甲醇共沸物催化精馏水解工艺

以乙酸甲酯与甲醇共沸物为原料,采用阳离子交换树脂为催化剂,研究了乙酸甲酯催化精馏水解工艺。在实验中以捆扎包作为催化剂的装填方式,系统地研究了催化精馏段和提馏段的高度、进料位置、进料中含甲醇、水酯物质的量比、回流进料比和空速等对酯分解率的影响,获得了最佳的工艺条件。分析了传统的水解分离工艺,提出了可行的新工艺。在最佳工艺条件下,新工艺系统的能耗比传统的固定床工艺降低39.99%。     

Characterization of SuperLig® 639 Rhenium and Technetium Resin with Batch Contact and Column Tests

Two new (2013) lots of SuperLig^® 639 ion exchange resin (IBC Advanced Technologies, American Forks, UT) were tested for the first time above typical sodium concentrations (7.8 M sodium, along with typical 5 M concentration) in highly alkaline solutions. Batch contact and ion exchange column tests characterized rhenium (perrhenate) adsorption as a surrogate for pertechnetate. The work supports technetium removal options for Supplemental Low Activity Waste processing at the Hanford River Protection Project Waste Treatment Plant (WTP). The current work found that the resin performs well in the 7.8 M sodium simulant despite complete floating of the beads. A notable difference in performance between the two new resin lots was found. Resin loading overall versus temperature, potassium concentration, and rhenium/nitrate ratios is consistent with previous data and expectations despite the high sodium concentration and floating of the resin beads.     

Adsorptive Removal of Nitrate and Phosphate from Water by a Purolite Ion Exchange Resin and Hydrous Ferric Oxide Columns in Series

Elevated concentrations of nitrate and phosphate in surface and ground waters can lead to eutrophication, and nitrate can also cause health hazards to humans. The adsorption process is generally considered to be an efficient technique in removing these ions provided that the adsorbent is highly selective for these ions. Removal of nitrate and phosphate from a synthetic water (50 mg N/L as nitrate, 15 mg P/L as phosphate) and a wastewater (12.9 mg N/L as nitrate, 5.9 mg P/L as phosphate) using a Purolite A500P anion exchange resin and a hydrous ferric oxide (HFO) columns (60 cm height, 2 cm diameter, flow rate 1 m/h) in series containing 1–10% (w/w) of these adsorbents and the remainder anthracite (90–99%) were studied. Data from batch adsorption experiment at various concentrations of adsorbents satisfactorily fitted to Langmuir adsorption isotherm for nitrate and phosphate on Purolite with adsorption maxima of 64 mg N/g and 7 mg P/g and only for phosphate on HFO with adsorption maxima of 14 mg P/g. Both batch and column experiments showed that Purolite selectively removed nitrate and HFO selectively removed phosphate. The Purolite column BTC time was greater for nitrate than for phosphate. At the highest percentage by weight of Purolite almost all nitrate was removed in batch study and up to 1000 min in column study, but it was not able to remove a comparatively high percentage of phosphate. However, when the effluent from the Purolite column was passed through the HFO column almost all phosphate was removed. The two columns when set up in series also removed almost all nitrate and phosphate from the wastewater.     

Fixed‐Bed Adsorption Study for Fumaric Acid Removal from Aqueous Solutions by Amberlite IRA‐400 Resin

A fixed‐bed adsorption study was carried out by using a strong base anion‐exchange resin (Amberlite IRA‐400) for the removal of fumaric acid from aqueous solutions. The breakthrough curves were obtained as a function of flow rate, temperature, feed pH, and inlet fumaric acid concentration. The total adsorption capacity and the percent fumaric acid removal of the resin were calculated. The Yoon‐Nelson model was applied to the experimental data to predict the breakthrough curves and to determine the characteristic column parameters required for process design. The breakthrough curves fit the model predictions well.     

Static adsorption properties of Ni（Ⅱ）by IDA resin and U-shaped continuous countercurrent desorption

研究了亚胺基二乙酸型螯合树脂R604对模拟含镍废水中镍离子静态交换吸附性能的主要影响因素,包括废水浓度、pH值、温度等,还研究了吸附平衡态、吸附过程的动力学、热力学,并给出了相应的模型,这些模型均与实验结果有很好的符合度。最后研究了独创的U形解吸柱系统对吸附饱和树脂的解吸性能,探讨了树脂停留时间、解吸液树脂流量比对解吸率和金属浓缩液浓度在柱体内分布的影响。研究表明,亚胺基二乙酸型树脂在废水金属离子镍的去除中有着高效、独特的性能,连续逆流U形解吸系统能提高重金属浓缩液浓度,并大幅度节省解吸液用量,减少解吸时间。     

亚胺基二乙酸树脂对金属镍的静态吸附及连续逆流U形解吸系统

研究了亚胺基二乙酸型螯合树脂R604对模拟含镍废水中镍离子静态交换吸附性能的主要影响因素,包括废水浓度、pH值、温度等,还研究了吸附平衡态、吸附过程的动力学,热力学,并给出了相应的模型,这些模型均与实验结果有很好的符合度,最后研究了独创的U形解吸柱系统对吸附饱和树脂的解吸性能,探讨了树脂停留时间、解吸液树脂流量比对解吸率和金属浓缩液浓度在柱体内分布的影响.研究表明,亚胺基二乙酸型树脂在废水金属离子镍的去除中有着高效、独特的性能,连续逆流U形解吸系统能提高重金属浓缩液浓度,并大幅度节省解吸液用量,减少解吸时间.     

Batch and column adsorption of perfluorooctane sulfonate on anion exchange resins and granular activated carbon

Perfluorooctane sulfonate (PFOS) has been detected widely in the natural water matrix and is persistent, bioaccumulative, and toxic. To prevent the adverse effects of PFOS contamination on human health and the environment, effective removal techniques are needed. Adsorption is considered an effective technique for PFOS removal. In this study, five anion exchange resins and granular activated carbon (GAC) were examined to evaluate their performance for the removal of PFOS in both batch and column experiments. Experimental adsorption data for all of the adsorbents exhibited a high correlation with the Freundlich isotherm (R² = 0.95 – 0.98). Most of the anion exchange resins demonstrated a higher adsorption capacity than the GAC. PFA300 had the highest adsorption capacity (455 mg/g). Continuous adsorption of PFOS was performed in column experiments using the same adsorbents that had been used in the batch experiments. The experimental breakthrough curves were set at C/C₀ = 0.1. PFA300 showed the longest operation time before reaching the breakthrough point. The Yoon and Nelson model was used to predict the half‐saturation time of the anion exchange resins. Moreover, the anion exchange resins exhibited high recovery of PFOS by an organic solvent. Continuous PFOS adsorption on a column can be achieved using anion exchange resins for water/wastewater treatment. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39782.     

用于盐湖卤水吸附法提锂的连续离子交换工艺研究

采用连续离子交换技术用于盐湖卤水的吸附法提锂。针对青海一里坪盐湖老卤体系,开发了连续离子交换吸附提锂工艺,研究了操作参数对连续离子交换系统提锂性能的影响,并在优化的工艺条件下进行了长周期的稳定性评价。结果表明,在转动步进周期为20 min、卤水进料量为3.2 BV/h、淋洗水量为2.9 BV/h、解吸水量为9.3 BV/h、解吸温度为15~25 ℃时,连续离子交换系统可以稳定获得镁锂质量浓度比（简称镁锂比）在3左右、锂质量浓度接近1.1 g/L的合格液,锂回收率为98.5%以上。