P-950哌啶树脂吸附钯的动力学研究

研究了P－950哌啶树脂吸附钯的动力学．结果表明，该树脂从氯化物溶液中吸附钯的动力学符合Boyd液膜扩散方程，吸附速率随盐酸浓度的增加而下降；当温度升高时吸附钯的分配比降低．测得的液膜扩散系数K＝1．34×10-2／s，吸附表现热焓△H＝-13.77kJ／mol，表明该树脂吸咐钯是放热反应.     

浊点萃取-火焰原子吸收光谱法测定乙醛触媒微量钯含量

建立了以1-（2-吡啶偶氮）-2-萘（PAN）为络合剂,以非离子表面活性剂TritonX-100为萃取剂的浊点萃取分离富集-火焰原子吸收光谱法测定痕量钯的新方法。研究了溶液的酸度、络合剂和表面活性剂浓度、平衡温度和时间、离子强度等条件对浊点萃取效果的影响。该方法对钯的检出限为35．3ng／mL,相对标准偏差（RSD）为3．1％（n=8）,回收率97．6％0～106．7％。可用于乙醛催化剂中微量Pd（Ⅱ）的测定。     

从废钯催化剂中回收钯的绿色工艺研究

以双氧水-盐酸混合溶液浸出废催化剂中钯，经离子交换树脂脱出氯钯酸后，循环使用；pH8-9的氢氧化钠和氯化铵溶液为洗脱液。研究了双氧水、盐酸浓度、浸出温度和时间及浸出液循环次数对浸出率的影响，结果表明，最佳浸出条件为：盐酸、双氧水的浓度分别为：1．7，1．1moL／L，72℃反应7h，80℃反应2h，钯平均浸出率98．3％，单程总回收率90.2％；由于浸出液与洗脱液能循环使用，解决了浸出液深度脱钯问题，并避免排放大量废酸液，实现了绿色化生产。     

化学试剂络合对改性活性炭吸附痕量铂、钯的影响

为了更准确地测定土壤中的铂、钯,在体积分数为5%的盐酸介质中,选用不同试剂为络合剂,改性活性炭为吸附剂,电感耦合等离子体质谱法测定土壤中的铂、钯。实验研究表明:经盐酸羟胺改性的活性炭富集,铂、钯的回收率为92.3%~102.4%;8-羟基喹啉为络合剂时,铂的回收率为86.4%~104.9%,钯的回收率为91.7%~100.0%;抗坏血酸为络合剂时,铂的回收率为82.6%~100.9%,钯的回收率为86.2%~98.3%;硫脲为络合剂时,铂的回收率为78.2%~105.1%,钯的回收率为81.9%~95.3%。方法检出限:铂为0.017 ng/mL,钯为0.021 ng/mL。该方法操作简便,分析速度快,灵敏度高,具有良好的测定精密度和准确度,适用于超痕量铂、钯的分析。     

2-氨基苯并噻唑和Amberlite XAD-4树脂分离富集金的研究

金(Ⅲ)-2-氨基苯并噻唑配合物在10%王水介质中能定量地吸附在Amberlite XAD-4树脂柱上,金(Ⅲ)用丙酮-0.1 mol/L 盐酸混合液洗脱后用结晶紫分光光度法测定。除铊,钯外许多金属离子都不被吸附。铊(Ⅲ)能在金洗脱之前用 EDTA 溶液洗去,钯(Ⅱ)不干扰金的测定。树脂对金的吸附容量为12.5 mg/g 千树脂。本法选择性好。已用于矿石中金的测定。     

三烷基氧膦络合萃取一元有机羧酸

络合萃取法对极性有机物稀溶液的分离具有高效性和高选择性。选择甲酸、乙酸、丙酸、丁酸为分离对象 ,三烷基氧膦 (TRPO)为络合剂 ,煤油为稀释剂 ,进行了系统的萃取相平衡实验 ,测定了络合剂浓度、稀释剂组成等因素对萃取平衡分配系数的影响。实验结果表明 ,溶质的亲油性对络合萃取平衡影响起主导作用 ;随TRPO浓度增大 ,萃取平衡分配系数呈增大趋势 ;随溶质初始浓度增大 ,有机相的溶质浓度向饱和萃取量接近 ;饱和萃取量随络合剂浓度的增大而增大。对相平衡分配系数进行拟合 ,精度令人满意。     

钯的二苄基硫醚固相萃取分离研究

基于二苄基硫醚与钯的配合反应,建立了一种高选择性固相萃取吸附钯的方法。在0.1 mol/L的盐酸介质中,钯可以被二苄基硫醚树脂吸附富集并形成1∶2稳定配合物,该配合物可用20 g/L酸性硫脲洗脱,洗脱液经处理后用分光光度法测定,柱可以再生和重复使用,且萃取剂流失少。二苄基硫醚对钯的吸附是配位萃取机理;方法用于吸附分离钯选择性高,钯的回收率达95%以上。     

磷酸三丁酯络合萃取丁酸的研究

用络合萃取法分离极性有机稀溶液 ,具有高效性和高选择性。利用磷酸三丁酯 (TBP)为络合剂 ,分别采用甲苯、异丙基甲酮、正辛醇、煤油作为稀释剂萃取丁酸稀溶液 ,系统研究了不同稀释剂对络合萃取平衡的影响 ,最终从效能、毒性、价格等综合因素考虑 ,选用正辛醇作为稀释剂 ;分析了络合剂浓度、丁酸溶液初始浓度、溶液 pH值以及温度对络合萃取相平衡分配系数的影响 ;利用红外光谱测定了负载有机相中萃合物的结构 ;并进行了有机溶剂的再生研究     

阴离子交换树脂-活性炭动态吸附-电感耦合等离子体发射光谱法测定矿石中的铂、钯、金

试验样品经HCl-H_2O_2-KClO_3高效湿法分解体系分解后,采用活性炭-717阴离子交换树脂混合吸附剂进行分离富集矿石中微量的的铂、钯、金,建立了以盐酸为介质电感耦合等离子体发射光谱测定矿石样品中铂、钯、金的方法。通过国家标准物质验证本方法,结果与标准值相符。方法中铂、钯、金的检出限分别为0.021、0.020、0.0050μg/g,测定下限分别为0.050、0.040和0.017μg/g。按照实验方法测定地质标准样品中铂、钯、金,测定结果的相对标准偏差(RSD,n=10)均小于6.7%,相对误差(RE,n=10)均小于3%,可满足地球化学样品中微量铂、钯、金的检测要求。     

金钯合金电镀液(日本专利 特开昭57—47892)

本发明旨在通过电解金和钯以得到淡红色的光亮的金钯合金镀层。由本发明之方法能得到由黄金色到白紫色至淡红色的金钯合金电镀层,其所呈色泽根据金和钯合金的比例组成而异。在本发明的方法上既可以由电解条件及操作来达到需要的色泽也可以自由选择合金组     

The selective adsorption of gold (III) and palladium (II) on new phosphine sulphide-type chelating polymers bearing different spacer arms: Equilibrium and kinetic characterisation

New resins, with a functional group based on triisobutyl phosphine sulphide and containing different spacer arms between the polymeric matrix and the functional group, are evaluated in order to determine and characterise the mechanism of the metal adsorption process. These polymers are selective towards gold and palladium from other noble (Pt, Rh and Ir) and base (Fe, Cu, Ni and Zn) metals. Selectivity is higher in the case of gold (2.8 mmol Au/g resin for polymer 3 and 6.5 for polymer 4) than for palladium (0.5 mmol Pd/g resin for polymer 3 and 0.7 for polymer 4). The application of the Langmuir model to the data permits the determination of the adsorption mechanism, which we found to be a chelating process. The result shows that spacer heteroatoms become involved in the adsorption process. The kinetics of the adsorption is faster for palladium than for gold. The elution of these two metals is accomplished by the use of sodium nitrite and thiourea as eluting compounds.     

THE SEPARATION OF Au(III) AND Pd(II) IN HYDROCHLORIC ACID SOLUTIONS BY STRONG ANION TYPE II EXCHANGE RESINS: THE EFFECT OF COUNTER ION CONCENTRATION AND TEMPERATURE

ABSTRACT

The separation of gold and palladium ions in hydrochloric acid solutions by strong anion Type II exchange resins is studied in batch and column operations. Increases in the hydrochloric acid concentration and the temperature of the adsorption process have the effect of decreasing the adsorption capacity and the separation factor of both metals. A faster kinetics of the adsorption process of both ions results from temperature increase and this effect is higher for gold ions as a result of greater changes in its diffusivity. Although the adsorption capacity of palladium ions is lower at equilibrium conditions, the adsorption isotherms obtained suggest that they are more strongly retained by the polymers.

The high capacities of these resins for both metals permits their use in the preconcentration of gold and palladium but their application in quantitative separation is restricted by the co-elution of up to% of the interfering ion during the desorption process. The best method for ion desorption is sequential elution with% ammonia for palladium recovery followed by 0·5M thiourea in HCI 1M for the recovery of gold.     

Methods for correction of selectivity of N-(2-sulfoethyl)chitosan-based materials towards platinum(IV) and palladium(II) ions

In this paper, we report methods for correction of selectivity of sorbents based on N-(2-sulfoethyl)chitosan towards platinum(IV) and palladium(II) in HCl solutions. The common method for correction of selectivity of the sorbents is variation of their modification degree with complexing groups. An increase in the degree of sulfoethylation of the chitosan leads to the significant increase in selectivity of sorption of palladium(II) over platinum(IV). Application of the N-(2-sulfoethyl)chitosan with the highest degree of sulfoethylation allows for selective separation palladium(II) from platinum(IV) (рН = 5.0). Palladium is quantitatively desorbed from the surface of the N-(2-sulfoethyl)chitosans by 3.5 mol/dm³ solution of HCl.     

Palladium Recovery from Dilute Effluents using Biopolymer‐Immobilized Extractant

Abstract

Cyanex 301‐immobilized material (prepared by immobilization into an alginate matrix) was tested for Pd sorption in 1 M HCl solutions with a special attention to sorption isotherms and uptake kinetics. This immobilized extractant had great affinity for Pd, as shown by the initial slope of the sorption isotherms. Sorption capacities as high as 150 mg Pd g^?1 were obtained in 1 M HCl solutions. However, kinetics was slow, compared to conventional resins. The main limiting step in the process is the diffusion of metal ions into the matrix. The influence of parameters such as HCl concentration, NaCl addition, presence of Pt (as a competitor metal) has been checked. It appeared that sorption performance of Cyanex 301‐immobilized material was hardly influenced by the addition of NaCl and by HCl concentration (below 2.5 M). The resin was remarkably selective for Pd, versus Pt, especially at 1 M HCl concentration. Loaded resins can be desorbed using thiourea solutions.     

The Development of Palladium(II)-Specific Amine-Functionalized Silica-Based Microparticles: Adsorption and Column Separation Studies

The adsorption and separation of platinum(IV) and palladium(II) chlorido species ([PtCl₆]^2? and [PdCl₄]^2?) on silica-based microparticles functionalized with ammonium centers based on ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetriamine (TETA) and tris-(2-aminoethyl)amine (TAEA) were investigated. The functionalized sorbent materials were characterized using SEM, XPS, BET, and FTIR. The sorbents were used in the batch and column study for adsorption and selective separation of [PtCl₆^2? and PdCl₄]^2?. The adsorption model for both [PtCl₆]^2? and [PdCl₄]^2? on the different sorbent materials fitted the Freundlich isotherm with R² values > 0.99. The S-TETA sorbent material was palladium(II) specific. Pd(II) loaded on the silica column was recovered using 3% m/v thiourea solution as the eluting agent. Separation of platinum and palladium was achieved by selective stripping of [PtCl₆]^2? with 0.5 M of NaClO₄ in 1.0 M HCl while Pd(II) was eluted with 0.5 M thiourea in 1.0 M HCl. The separation of palladium (Pd) from a mixture containing platinum (Pt), iridium (Ir), and rhodium (Rh) was successful on silica functionalized with triethylenetriamine (TETA) showing specificity for palladium(II) and a loading capacity of 0.27 mg/g. S-TETA showed potential for use in the recovery of palladium from platinum group metals such as from solutions of worn out automobile emission control catalytic convertors and other secondary sources.     

Effect of Ring-Size Variation within Dibenzocrown Ether Resins upon Ion-Pair Sorption of Alkali-Metal Cations from Aqueous and Aqueous Methanol Solutions

Abstract

A batch analysis method has been developed for evaluation of metal salt sorption by crown ether polymers. Selectivity in competitive alkali-metal chloride sorption by a series of formaldehyde condensation polymers of dibenzocrown ethers is influenced by the relationship between the crown ether cavity size and metal ion diameter, as well as the degree of hydration of the metal salt. Effective and selective sorption of KCl from the other alkali-metal chlorides was obtained with a dibenzo-18-crown-6 resin. Excellent sorption selectivity for the monovalent metal chlorides was noted for competitive ion-pair sorption of NaCl, KCl, MgCl₂, and CaCl₂ by this resin. This resin was examined as a stationary phase for selective column separation of KCl from alkali-metal chlorides and of KCl and NaCl from alkali-metal and alkaline-earth chloride mixtures in 80% methanol—20% water.     

The use of a rotating cylinder electrode to selective recover palladium from acid solutions used to manufacture automotive catalytic converters

The reduction of palladium, rhodium and neodymium ions at concentrations of 0.94, 0.97 and 0.69 mol dm⁻³, respectively was studied in 1 mol dm⁻³ HNO₃ or 1 mol dm⁻³ HCl, at a stainless steel and a vitreous carbon electrode, at 25 °C. At a vitreous carbon electrode in a solution containing rhodium and palladium ions in 1 mol dm⁻³ HCl electrolyte, the reduction of metal ions occurred at a similar potential to the formation of hydrogen gas, which impeded the selective separation of the two metals. At a stainless steel cathode in 1 mol dm⁻³ HNO₃, palladium deposition occurred at a potential ≈0.35 V less negative than that of rhodium allowing the selective recovery of palladium. Neodymium ions were not electroactive in acidic chloride or nitrate media at pH 0. Using a solution obtained from a catalytic converter manufacturer containing palladium, rhodium and neodymium ions in 1 mol dm⁻³ HNO₃, palladium ions were preferentially removed at 0.15 V versus SHE at an average cumulative current efficiency of 57%.     

负载型钯酞菁催化剂上CCl2F2的选择性加氢脱氯反应

负载型钯酞菁能有效催化CCl₂F₂的选择性加氢脱氯反应,在氟化物为载体的钯酞菁催化剂上,CCl₂F₂转化成CH₂F₂的选择性可达75％以上.对比研究表明,负载型钯酞菁催化剂上CCl₂F₂选择性加氢脱氯的稳态催化活性要高于普通的负载型金属钯催化剂.在钯活性中心引入环状酞菁配体能有效提高催化剂在高腐蚀性反应条件下的稳定性.红外光谱、X射线衍射和紫外-可见光谱表征揭示了负载型钯酞菁催化剂具有良好催化活性和催化稳定性的可能原因.     

Separation of gold(III) ions from copper(II) and zinc(II) ions using thiourea–formaldehyde or urea–formaldehyde chelating resins

Thiourea–formaldehyde (TF) and urea–formaldehyde (UF) chelating resins were synthesized and these resins were used in the separation of gold(III) ions from copper(II) and zinc(II) base metal ions. In the experimental studies, the effect of acidity on gold(III) uptake and gold(III) adsorption capacities by batch method, and loading and elution profiles of gold(III) ions, gold(III), copper(II), and zinc(II), dynamic adsorption capacities and the stability tests of TF and UF resins by column method were examined. By batch method, the optimum acidities were found as pH 2 and 0.5M HCl, and gold(III) adsorption capacities in the solutions including copper(II) and zinc(II) ions were obtained as 0.088 and 0.151 meq Au(III)/g for UF and TF resins, respectively. On the other hand, by column method, the dynamic adsorption capacities were calculated as 0.109 meq Au(III)/g with TF, 0.023 meq Au(III)/g with UF, 0.015 meq Cu(II)/g with TF, 0.0057 meq Cu(II)/g with UF, and under 6.1 × 10^?5 meq Zn(II)/g with TF or UF. TF resin was more effective in the separation and the concentration of gold(III) ions from copper(II) and zinc(II) ions than UF resin. It was seen that sulfur atoms contributed the gold(III) adsorption comparing with oxygen atoms. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

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。