Adsorption equilibrium, kinetics, and dynamic separation of Ca2+ and Mg2+ ions from phosphoric acid–nitric acid aqueous solution by strong acid cation resin

The separation of Ca2+and Mg2+ions from phosphoric acid-nitric acid aqueous solution is very significant for the neutralization process of nitrophosphate fertilizer.This paper studied the adsorption equilibrium,kinetics,and dynamic separation of Ca2+and Mg2+ions by strong acid cation resin,and the effects of phosphoric acid and nitric acid on the adsorption process were investigated.The results reveal that the adsorption process of Ca2+and Mg2+ions in pure water on resin is in good agreement with the Langmuir isotherm model and their maximal adsorption capacities are 1.86 mmol·g-1 and 1.83 mmol·g-1,respectively.The adsorption kinetics of Ca2+and Mg2+ions on resin fits better with the pseudo-first-order model,and the adsorption equilibrium in pure water is reached within 10 min contact time,while at the present of phosphoric acid,the adsorption rate of Ca2+and Mg2+ions on resin will go down.The dynamic separation experiments demonstrate that the designed column adsorption is able to undertake the separation of metal ions from the mix acids aqueous solution,but the dynamic operation should control the flow rate of mix acid solution.Besides nitric acid solution was proved to be effective to completely regenerate the spent resin and achieve the recyclable operation of separation process.

Mechanism and kinetics study on removal of Iron from phosphoric acid by cation exchange resin

Iron element is one of the main impurities in wet-process phosphoric acid and it has a significant impact on the subsequent phosphorus chemical products. This paper studied the feasibility of using Sinco-430 cation exchange resin for iron removal from phosphoric acid. The specific surface area and the total exchange capacity of resin were 8.91 m2·g-1 and 5.18 mmol·g-1, respectively. The sorption mechanism was determined by FTIR and XPS and the results indicated that iron was combined with-SO3 H in resin. The removal process was studied as a function of temperature, H3 PO4 content and mass ratio between resin and solution. The unit mass of resin to remove iron was 0.058 g·g-1 resin when the operating parameters were T = 50 ℃, H3 PO4 content = 27.61 wt%and S/L = 0.1, respectively. Kinetics study demonstrated that pseudo-second-order reaction model fits this study best and the calculated activation energy of overall reaction is 29.10 kJ·mol-1. The overall reaction process was mainly controlled by pore diffusion.

Kinetic and thermodynamic studies of the esterification of acidified oil catalyzed by sulfonated cation exchange resin

This study describes the kinetics and thermodynamics of the esterification of acidified oil with methanol catalyzed by sulfonated cation exchange resins（SCER）. The effects of the mass ratio of methanol to acidified oil,reaction temperature,and catalyst loading were studied to optimize the conditions for maximum conversion of free fatty acids（FFAs）. The results showed that the optimal conversion rate of FFAs was 91.87% at the mass ratio of methanol to acidified oil of 2.5：1.0,reaction temperature of 65.0 °C,catalyst loading of 5.0 g and reaction time of 8.0 h. The external and internal mass transfer resistances were negligible based on the experimental results and a pseudo-homogeneous kinetic model was proposed for the esterification. The activation energy and thermodynamic parameters including G,S and H were determined. The conversion rates of FFAs obtained from the established model were in good agreement with the experimental data.

Synthesis of cation exchange resin-supported iron and magnesium oxides/hydroxides composite for nitrate removal in water

In this study,we reported on the concept and practical use of cation exchange resin(CER)for removing anions in water via pretreating the CER with metal salts.The cation exchange resinsupported iron and magnesium oxides/hydroxides composite(FeMg/CER)was synthesized and introduced as a new and potential adsorbent for selective removal of nitrate ion in the water environment.Characteristics of FeMg/CER were determined by techniques such as Fouriertransform infrared spectroscopy,scanning electron microscopy,and Xray diffraction.The results showed that FeMg/CER material had a high nitrate adsorption capacity of 200 mg NO_(3)^()·g^(1)with a fast equilibrium adsorption time of 30 min at pH 5.In addition,it had good durability of at least 10 times of regeneration,which could be applied to practical water and wastewater treatment.

Adsorption behavior and mechanism of cadmium on strong-acid cation exchange resin

The adsorption behavior of Cd2+ on 001×7 strong-acid cation exchange resin was studied with the static adsorption method. The adsorption process was analyzed from thermodynamics and kinetics aspects. The influences of experimental parameters such as pH, temperature, initial concentration and adsorption rate were investigated. The experimental results show that in the studied concentration range, 001×7 resin has a good sorption ability for Cd2+, and the equilibrium adsorption data fit to Freundlich isotherms. The adsorption is an exothermic process which runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best adsorption condition is pH 4-5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the desorption efficiency is over 98%. The maximal static saturated adsorption capacity is 355 mg/g (wet resin) at 293 K. The adsorption mechanism of Cd2+ on 001×7 resin was discussed based on IR spectra.

Separation of Clay Minerals from Host Sediments Using Cation Exchange Resins

Classic physical and chemical treatments applied to separating clay minerals from the host sediments are often difficult or aggressive for clay minerals. A technique using cation exchange resins (amberlite IRC\|50H and amberlite IR\|120) is used to separate clay minerals from the host sediments. The technique is based on the exchange of cations in the minerals that may be associated clay minerals in sediments, such as Ca and Mg from dolomite; Ca from calcite, gypsum and francolite with cations carried by resin radicals. The associated minerals such as gypsum, calcite, dolomite and francolite are removed in descending order. Separation of clay minerals using cation exchange resins is less aggressive than that by other classic treatments. The efficiency of amberlite IRC\|50H in the removal of associated minerals is greater than that of amberlite IR\|120.

Elements, Structure and Electrochemical Property of Carbon Derived from La^(3+) Adulterating Polystyrene Cation Exchange Resin

The polystyrene cation exchange resin was exchanged by La 3+ and then were carbonized to make resin carbon material. The electrochemical properties of the resin carbon material as the electrode of the lithium ion cell were investigated. The test results show that comparing with the polystyrene cation exchange resin without adulterating, the contents of hydrogen, oxygen and sulfur are changed obviously for the resin carbon material derived from the La 3+ adulterating polystyrene cation exchange resin. The contents of hydrogen and oxygen are increased, and the one of sulfur is decreased. The test results also indicate that it is more easily to form the stratum graphite minicrystal structure with bigger diameter for the La 3+ adulterating resin. According to the electrochemical test results, the electrode derived from La 3+ adulterating polystyrene cation exchange resin has much better electrochemical property, and the capacity of charge and discharge of the electrode is increased about 30 mAh·g -1 in average.

USE OF CATION EXCHANGE RESIN IN SYNTHESIS OF N-SUBSTITUTED-1-AMINOALKANEPHOSPHONATE AND-PHOSPHINIC ACIDS

Strongly acidic cation exchange resin(1x1,H form)has been successfully used as a catalyst in synthesis of diphenyl N-benzyloxycarbonyl-1-aminobenzylphosphonate, N-benzyloxycarbonyl-1-aminobenzylphenylphosphinic acid and N-p-tolylsulfonyl-1-aminobenzyl phenylphosphinic acid in high yields.

Elution Behaviour of Monocarboxylic Acids on a Cation-exchange Resin Column

The retention mechanism of monocarboxylic acids on a cation-exchange resin column was investigated. It was assumed that both Donnan membrane equilibrium and adsorption equilibrium were involved in the chromatographic process. On the basis of the proposed mechanism, an equation was derived for correlating distribution coefficient, Kd, dissociation constant, Aa, and adsorption equilibrium constant, K, of the analyzed acid. By this approach, retention data for some aliphatic acids under different operating conditions were predicted. Results are reasonably in agreement with experiment.

Cationized Melamine-formaldehyde Resin for Improving the Wet Strength of Paper

In this work, melamine-formaldehyde resin was cationized by adding modifiers so that the fibers closely bonded to improve their usability and the wet strength of paper was greatly improved. Triethanolamine and dimethylamine were added to modify the melamine-formaldehyde resin,respectively.The mechanism of the cationized resin was explored and the possible chemical reactions were deduced. It was concluded that,with the use of triethanolamine,the most optimum product was obtained by hydroxymethylation for 30 min with a temperature of 85℃ and p H of 9. 0 where n( melamine) ∶ n( formaldehyde) ∶ n( methanol) ∶ n( triethanolamine) was 100 ∶ 330 ∶ 450 ∶ 15. With the combined use of dimethylamine and methanol,the optimal product was acquired by condensation for 30 min at a temperature of 50℃ and p H of 2. 0 at melamine, formaldehyde, methanol, and dimethylamine molar ratio of100∶ 330∶ 350∶ 20. With the only use of dimethylamine,the optimal product was obtained by condensation at melamine,formaldehyde,dimethylamine molar ratio of 100∶ 330∶ 10. The wet tensile strength of fruit-bagging paper was improved by adding cationized melamine-formaldehyde resin. The zeta potential,charge density,and conductivity of the melamine-formaldehyde resin were also studied.

FACTORS AFFECT THE RELEASE OF PSEUDOEPHDRINE HYDROCHLORIDE FROM THE UNCOATED CATION EXCHANGE RESIN-BASED DRUG DELIVERY SYSTEM IN VITRO

In this paper, it was investigated that the effect of parameters such as the ionic strength, pH, counter-ion type of release medium, particle size, and cross linkage of cation exchange resin on the release of model drug pseudoephedrine hydrochloride (PE) from uncoated drug-resin complex. The drug-resin complex was prepared by the reaction of PE with strongly acidic cation exchange resin (001×4, 001×7, 001×14). The result showed that the loading of PE increased with the increase of temperatures. The release of PE from drug-resin complex at 37℃ was monitored in vitro. From the experiments, it was found that the release rate of PE depends on the pH, composition of the releasing media, increased at lower pH media or with increase of ionic strength of media. Moreover, the release rate of PE was inversely proportional to the cross-linkage and particle size of the cation exchange resin.

三羟甲基丙烷棕榈油酸酯的合成及其润滑性能研究

为替代矿物基润滑油,制备出稳定性好、易降解、环境友好的植物油基润滑油,采用天然产物棕榈油酸,以三羟甲基丙烷为原料,酸性阳离子树脂Amberlyst为多相催化剂制备润滑剂三羟甲基丙烷棕榈油酸酯(TMPTO),研究了制备条件对TMPTO酯化率的影响,并筛选出最佳合成参数。测试了TMPTO的运动黏度、黏度指数、闪点等物理性质,采用NMR、FTIR、DSC、TG对TMPTO的结构和热氧化稳定性进行了表征;采用四球试验机、接触角测量仪、XRF对TMPTO的抗磨损性能、润湿性和防铝腐蚀性能进行了测试。结果表明:在反应温度180℃,真空度0.09 MPa,醇酸摩尔比1.0∶3.1,反应时间5 h,催化剂用量0.2%(质量分数)的条件下,棕榈油酸的酯化率达到81.53%,催化剂重复使用4次后的酯化率仍保持在81.15%。制备的三羟甲基丙烷棕榈油酸酯的酸值仅为1.87 mg KOH/g,具有较高的闪点(238℃),具有优异的防铝腐蚀性能、润湿性、热氧化稳定性和极压抗磨性能:最大无卡咬负荷P_B为88 kg,最大烧结负荷P_D为620 kg。

磺酸型阳离子树脂的元素分配行为及高精度同位素分析应用

不同元素在离子交换树脂的分配系数是元素纯化和分离的基础,不同酸中各元素分配系数差异可用于设计高效的元素提纯流程,从而被广泛应用于现代高精度同位素分析。本文以AG®50W-X8阳离子树脂为研究对象,以分配系数(Kd)作为量化指标,通过系统实验研究不同元素在该树脂中的分配行为。在前人研究基础上,本实验增加了元素数量和酸的种类,涵盖了金属、类金属、非金属和稀土元素。结果表明:在盐酸和硝酸介质中,几乎所有元素的Kd都与酸度呈负相关,当酸度达到6mol/L时,除Th和Ca以外的所有元素都会被酸洗脱。稀土元素(REEs)和高场强元素在0.1~0.5mol/L稀硝酸和稀盐酸中强烈吸附在树脂上;而一些过渡金属、类金属和非金属元素(如Mo、W、Re、Ir、Sb、Ge、As、Se、Te等)在酸溶液中会形成含氧阴离子,不与阳离子树脂发生吸附。Al、Fe、Se、Pd、Cd、In等元素在盐酸中易与氯离子形成配位化合物或离子团,导致这些离子在盐酸中的分配系数显著降低。在硝酸和盐酸与氢氟酸的混合酸中,除稀土元素外,绝大部分元素随酸度增加Kd迅速降低。稀土元素在盐酸-氢氟酸混合介质中,随着盐酸的浓度增加(从0.1mol/L盐酸-0.2mol/L氢氟酸至6mol/L盐酸-0.2mol/L氢氟酸),稀土元素分配系数(KdREE)具有先增加后降低的趋势。氢氟酸的加入可显著降低Be、Al、Sc、Fe、Sn、Th、U、Ti、Zr、Hf等元素在稀盐酸和稀硝酸中的分配系数,使这些元素几乎不与树脂发生吸附。本研究揭示了不同酸介质中各类元素在阳离子交换树脂上的分配行为存在差异,尤其是氢氟酸的加入可显著改变高场强元素、部分过渡金属和稀土元素的分配系数,为应用该树脂开发和优化适用于高精度金属稳定同位素分析的元素提纯流程(如Li、Mg、K、Sr、Ce、U等)提供了数据支撑,并可有效地减少后续实验设计的工作量。

超声浸提-电感耦合等离子体发射光谱法测定石灰性土壤中的有效磷

采用超声浸提-电感耦合等离子体发射光谱法(ICP-AES)实现了石灰性土壤中有效磷的快速、准确、批量化分析要求.将水土混合液在400 W超声功率下于25℃浸提10 min,用3.50 g苯乙烯阳离子交换树脂降低基体干扰.分析谱线P 214.914 nm,射频功率1150 W,载气流量0.6 L/min,采用ICP-AES测定有效磷.结果显示:磷在0~5.00 mg/L范围内校准曲线线性良好(相关系数0.9996),检出限为0.072 mg/kg.方法用于4种不同碱性土壤有效态标准物质的分析,测定值相对误差小于±7%,相对标准偏差小于10%,且和标准方法(NY/T 1121.7—2014)测定值接近.

乙二胺改性聚苯乙烯树脂对水体中铅(Ⅱ)、铬(Ⅵ)的吸附研究

采用乙二胺对氯甲基化聚苯乙烯树脂进行改性,利用改性后的树脂去除溶液中的铅(Ⅱ)和铬(Ⅵ)。通过改变pH、时间、浓度和吸附剂投加量,确定最佳吸附实验条件,得到改性后的树脂对铅(Ⅱ)和铬(Ⅵ)的最大吸附容量分别为119.60mg/g和128.28mg/g。动力学研究表明,该模型符合Langmuir模型。

Decomposition mechanisms of nuclear-grade cationic exchange resin by advanced oxidation processes:Statistical molecular fragmentation model and DFT calculations

The treatment and disposal of radioactive waste are presently facing great challenges.Spent ion exchange resins have become a focus of attention due to their high production and serious environmental risks.In this paper,a simplified model of cationic exchange resin is proposed,and the degradation processes of cationic resin monomer initiated by hydroxyl radicals(·OH)are clarified by combining statistical molecular fragmentation(SMF)model and density functional theory(DFT)calculations.The prediction of active sites indicates that the S-O bonds and the C-S bond of the sulfonic group are more likely to react during the degradation.The meta-position of the sulfonic group on the benzene ring is the most active site,and the benzene ring without the sulfonic group has a certain reactivity.The C11-C14 and C17-C20 bonds,on the carbon skeleton,are the most easily broken.It is also found that dihydroxy addition and elimination reactions play a major role in the process of desulfonation,carbon skeleton cleavage and benzene ring separation.The decomposition mechanisms found through the combination of physical models and chemical calculations,provide theoretical guidance for the treatment of complex polycyclic aromatic hydrocarbons.

树脂载钯双功能催化剂的制备及其催化碳四烯烃临氢叠合反应

基于碳四烯烃叠合反应工艺,设计并制备了酸性树脂(KC110、Amberlyst35)载钯双功能催化剂,用于一步法催化1,3-丁二烯选择性加氢和异丁烯叠合反应。借助电子微区探针分析(EPMA)、N 2物理吸附-脱附(BET)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)等手段对其物化性质进行表征,并进一步考察了双功能催化剂在碳四烯烃临氢叠合反应过程中的催化性能。结果表明:0.10%Pd/KC110双功能催化剂负载的钯纳米颗粒主要分布在树脂大孔表层结构,平均粒径为3~10 nm,且树脂载体本身的酸性和孔结构保存完好;在反应温度为25℃、压力为1.4~1.6 MPa、质量空速为2.7 h-1、氢气/丁二烯摩尔比为1.5的条件下进行0.10%Pd/KC110催化碳四烯烃临氢叠合反应,1,3-丁二烯可以完全脱除,异丁烯转化率高于81.5%,叠合产物中碳八选择性为75.1%。

果蔬产品中多组分有机磷农药残留测定新方法研究与应用

建立了QuEChERS-气相色谱仪测定蔬菜水果中20种有机磷农药残留的检测方法。净化包用阳离子交换树脂,代替PSA、GCB,在色谱柱前面加2米保护柱,20种有机磷农药残留的线性范围均为10~400g·L-1,线性相关系数(r2)均大于0.998,方法的检出限为0.01mg·kg-1。在3个不同添加水平下的加标回收率为70.0%~120%,RSD为1.2%~10%。该法操作简单、成本较低,可对蔬菜水果中多农药残留进行快速筛查。成本由一个样品50元降为5元。

氯化苯副产盐酸的精制工艺方法研究

利用树脂吸附和脱吸附原理,对氯化苯生产过程中产生的盐酸进行脱色和去除有机物,从吸附和脱附工艺流程、树脂配比、盐酸吸附定量等方面展开分析,设计相应模拟实验进行过程探索,形成了一套比较完善的氯化苯副产盐酸精制的工艺流程。