Separation and Recovery of Silver(I) Ions from Base Metal Ions by Melamine‐formaldehyde‐thiourea (MFT) Chelating Resin

Abstract

Melamine‐formaldehyde‐thiourea (MFT) chelating resin were prepared using melamine (2,4,6‐triamino‐1,3,5‐triazine), formaldehyde, and thiourea and this resin has been used for separation and recovery of silver(I) ions from copper(II) and zinc(II) base metals and calcium(II) alkaline‐earth metal in aqueous solution. The MFT chelating resin was characterized by elemental analysis and FT‐IR spectra. The effect of pH, adsorption capacity, and equilibrium time by batch method and adsorption, elution, flow rate, column capacity, and recovery by column method were studied. The maximum uptake values of MFT resin were found as 60.05 mg Ag⁺/g by batch method and 11.08 mg Ag⁺/g, 0.052 mg Zn²⁺/g, 0.083 mg Cu²⁺/g and 0.020 mg Ca²⁺/g by column method. It was seen that MFT resin showed higher uptake behavior for silver(I) ions than base and earth metals due to chelation.     

Synthesis of Chelating Resin PETU and Its Adsorption to Ag(I)

A novel chelating resin (PETU) with thiourea groups in its main chain was synthesized by the reaction of O,O'-butane-1,4-diyl dicarbonisothiocyanatidate and triethylene tetraamine. The adsorption of Ag(I) on PETU was investigated by batch tests. The results showed that adsorption data fitted Boyd's diffusion equation of liquid film and the adsorption was controlled by liquid film diffusion. Under the temperatures between 15～60 ℃, the adsorption capacity decreased with the increase of temperature, and increased with the increase of initial concentration of Ag(I). The experimental data fitted Langmuir and Freundlich equations, and the correlation coefficients for Langmuir equation were between 0.9965～0.9998, and those for Freundlich equation were between 0.8211～0.9810, and increased with the adsorption temperature. △H, △G and △S calculated by thermodynamic formulae were all negative, which meant that the adsorption process was exothermic and spontaneous, and the entropy decreased during the process. XPS results showed that N, S and O atoms were the electron donors to coordinate with Ag.     

三乙烯四胺型螯合树脂微柱分离富集-火焰原子吸收光谱法测定地质样品中痕量银

用新合成含硫三乙烯四胺型螯舍树脂填充微型吸附柱，建立了螯合树脂微柱分离富集一火焰原子吸收光谱法测定地质样品中痕量银的方法。研究了螯合树脂微柱的吸附性能及影响吸附的因素，用酸性硫脲作洗脱剂，以峰面积检测，测定Ag(Ⅰ)的线性范围为0.02～1．0μg／mL，相对标准偏差为2．3％(n=3)，检出限为0．005μg／mL，灵敏度提高20倍，螯合树脂微柱可重复利用。用于地质样品中痕量银的测定，结果满意。     

螯合树脂及其在检测食品中重金属离子的应用

系统地介绍了新型螯合树脂的概念、分离富集金属离子的原理以及螯合树脂的分类,并对合成型螯合树脂的研究进展及其在食品分析检测领域中分离富集金属离子的应用情况进行了综述。     

Separation of Silver(I) and Copper(II) from Aqueous Solutions by Transport through Polymer Inclusion Membranes with Cyanex 471X

In this work the selective transport of silver(I) and copper(II) ions from aqueous nitrate(V) solutions by transport through polymer inclusion membrane (PIM) has been studied. The membrane consisted of cellulose triacatate (CTA) as the polymeric support, o-nitrophenyl pentyl ether (ONPPE) as the plasticizer and Cyanex 471X (triisobutylphosphine sulphide) as the ion carrier. Ag(I) ions were effectively removed from the source phase by transport through PIM into 0.01 M Na₂S₂O₃ as the receiving phase. The influence of membrane composition on the transport of silver(I) ions has been evaluated.     

Silver(I)-Ion-Mediated Cytosine-Containing Base Pairs: Metal Ion Specificity for Duplex Stabilization and Susceptibility toward DNA Polymerases

Spectroscopic characterization of Ag^I-ion-mediated C-Ag^I-A and C-Ag^I-T base pairs found in primer extension reactions catalyzed by DNA polymerases was conducted. UV melting experiments revealed that C-A and C-T mismatched base pairs in oligodeoxynucleotide duplexes are specifically stabilized by Ag^I ions in 1:1 stoichiometry in the same manner as a C-C mismatched base pair. Although the stability of the mismatched base pairs in the absence of Ag^I ions is in the order C-A≈C-T>C-C, the stabilizing effect of Ag^I ions follows the order C-C>C-A≈C-T. However, the comparative susceptibility of dNTPs to Ag^I-mediated enzymatic incorporation into the site opposite templating C is dATP>dTTP≫dCTP, as reported. The net charge, as well as the size and/or shape complementarity of the metal-mediated base pairs, or the stabilities of mismatched base pairs in the absence of metal ions, would be more important than the stability of the metallo-base pairs in the replicating reaction catalyzed by DNA polymerases.     

螯合树脂对铜离子的吸附动力学和热力学

针对以谷氨酰胺-铜(II)配合物为供体酶法制备茶氨酸体系,研究了D401螯合树脂对Cu2+的吸附,探讨了吸附过程的热力学和动力学,通过红外光谱鉴定了树脂的配位结构. 结果表明,树脂吸附量随离子浓度和温度升高而增加,当pH为5.6时吸附量最大,达1.887 mmol/g. 不同温度下Langmuir方程均呈现很好的拟合度. 热力学平衡方程计算得DG<0, DH=21.5 kJ/mol, DS>0,表明该吸附过程是自发的、吸热、熵增加的过程. 动力学研究表明,该过程符合准二级动力学模型,吸附反应速率由颗粒扩散和液膜扩散共同控制. 该树脂在较宽的pH范围内对Cu2+具有很好的选择吸附性,可用于酶转化茶氨酸体系中Cu2+的去除.     

Synthesis,Characterization, and Applications of a New Chelating Resin Containing 4-2-(Thiazolylazo) Resorcinol (TAR)

A new phenol–formaldehyde based chelating resin containing 4-(2-thiazolylazo) resorcinol (TAR) functional groups has been synthesized and characterized by Fourier transform infrared spectroscopy and elemental analysis. Its adsorption behavior for Cu(II), Pb(II), Ni(II), Co(II), Cd(II), and Mn(II) has been investigated by batch and column experiments. The chelating resin is highly selective for Cu(II) in the pH range 2 ～ 3, whereas alkali metal and alkaline earth metal ions such as Na(I), Mg(II), and Ca(II) are not adsorbed even at pH 6. Quantitative recovery of most metal ions studied in this work except Co(II) is achieved by elution with 2M HNO₃ at a flow rate of 0.2 mL min^?1. A similar trend is observed for distribution coefficient values. The quantitative separations achieved on a mini-column of chelating resin include Cd(II) – Cu(II), Mn(II) – Pb(II), Co(II) – Cu(II), Mn(II) – Ni(II), and Mn(II) – Co(II) – Cu(II). The recovery of copper(II) is quantitative (98.0–99.0%) from test solutions (10–50 mg/L) by 1 mol/L HNO₃-0.01 mol/L EDTA. The chelating resin is stable in acidic solutions below 2.5 M HNO₃ or HCl as well as in alkaline solution below pH 11. The adsorption behavior of the resin towards Cu(II) was found to follow Langmuir isotherm and second order rate.     

Sequential Separation and Trace Enrichment of Thorium(IV) and Uranium(VI) on Chelating Resin Amberlite XAD-2-ortho-vanillinthiosemicarbazone (o-VTSC)

ABSTRACT

Polystyrenc-divinylbenzene-based Amberlite XAD-2 was funetionalized with ortho-vanillinthiosemicarbazone and its analytical properties were investigated. The resin was used successfully for the separation and preconcentration of thorium(IV) and uranium(VI) ions prior to their determination by spectrophotometry and by ICAP-AES and GF-AAS, respectively. The influence of several ions as interferents is discussed. The resin exhibits good chemical stability, reuseability, and a faster rate of equilibration for their determination. The proposed method has been applied to sequential chromatographic separation of thorium(IV) and uranium(VI) on river water samples with good analytical reliability such as recovery of 97–98%, relative standard deviation of 2–3%, and a detection limit of 100 ng-mL^-1. The present method is also used for their determination in monazite sand and some standard geological materials.     

Separation,Preconcentration, and Recovery of Pd(II) Ions using Newly Modified Silica Gel with Bis(3-Aminopropyl)Amine

Bis(3-aminopropyl)amine bonded silica gel (BAPA-SG) was synthesized and characterized by elemental analysis and FT-IR spectroscopy, and tested for adsorption, preconcentration, and recovery of Pd(II) ions. The effective parameters on the preconcentration of Pd(II) ions such as pH, volume, and flow rate of the Pd(II) solution, and the type and volume of eluent solution, and also matrix ions such as alkaline and heavy metals were investigated. Flame atomic absorption spectrometry was used for the determination of Pd(II) concentration. The modified silica gel could adsorb Pd(II) ions quantitatively from the solutions up to 400 mL at pH 1.0 by the flow rate of 5 mL/min. The retained Pd(II) ions could be easily eluted by using 5 mL of 1% (m/v) thiourea in 1.0 M HCl solution. The recovery of Pd(II) ions was 95 ± 2% at 95% confidence level. The analytical detection limit of Pd was found to be 0.36 µg L^?1 at the preconcentration factor of 80. Selective adsorption of Pd(II) ions over some base metal ions was also investigated. The developed method was applied to spent auto catalyst for palladium recovery, and a certified ore sample for the determination of palladium content.     

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     

Selective Separation of Uranium using Alizarin Red S (ARS)-Modified Anion-Exchange Resin or by Flotation of U-ARS Chelate

ABSTRACT

An alizarin red S (ARS)-modified anion-exchange resin was prepared by a simple reaction of ARS with the anion exchanger Doulite A101 and used for the efficient sorption of uranium from aqueous media. The effect of various parameters on the sorption of U(VI) (pH effect, sorption kinetics, resin capacity and breakthrough curves) was investigated. The modified resin sorbs U(VI) over a wide range of pH (2·8–5) with a maximum sorption capacity of 0·68 mmol.g^?1 at pH 3·2 to 4·0. Iron (III), Zr(IV), Ti(IV), Cu(II), and Th(IV) ions are also sorbed to different extents, but Be(II), Bi(III), Ca(II), Mg(II), Pb(II), Hg(II), Zn(II), Cd(II), AI(III), Mn(II), Co(II) and Ni(II) are not sorbed; thus, conditions for separating U(VI) from these metal ions have been identified. For eluting U(VI) from the resin, 0·2 mol.L^?1 HCl was used and the recovery recorded was as high as 99.9%. The use of ARS is extended to float uranium quantitatively and selectively from aqueous media at pH = 4 by using oleic acid as a surfactant. The different parameters affecting the flotation process have also been investigated. Uranium(VI) has been effectively separated from natural water samples and certified uranium ores using both procedures.     

Synthesis of Chelating Resin PETU and Its Adsorption to Ag(I)

A novel chelating resin (PETU) with thiourea groups in its main chain was synthesized by the reaction of O,O'-butane-1,4-diyl dicarbonisothiocyanatidate and triethylene tetraamine. The adsorption of Ag(I) on PETU was investigated by batch tests. The results showed that adsorption data fitted Boyd's diffusion equation of liquid film and the adsorption was controlled by liquid film diffusion. Under the temperatures between 15~60℃, the adsorption capacity decreased with the increase of temperature, and increased with the increase of initial concentration of Ag(I). The experimental data fitted Langmuir and Freundlich equations, and the correlation coefficients for Langmuir equation were between 0.9965~0.9998, and those for Freundlich equation were between 0.8211~0.9810, and increased with the adsorption temperature. DH, DG and DS calculated by thermodynamic formulae were all negative, which meant that the adsorption process was exothermic and spontaneous, and the entropy decreased during the process. XPS results showed that N, S and O atoms were the electron donors to coordinate with Ag.     

Solvent extraction of silver(I) from nitrate media using thiourea derivatives

Liquid–liquid extraction of Ag(I) from nitrate solutions using N‐(N′,N′‐diethyl thiocarbamoyl)‐N″‐phenylbenzamidine (TCBA) and 1‐6,‐diethylcarbamoyl imino‐1,6‐diphenyl‐2,5 dithiahexane (TCTH) dissolved in cumene has been studied. The extraction of Ag(I) from 1 mol dm⁻³ NO₃⁻ solutions by TCTH and TCBA was investigated as a function of several variables: equilibration time, organic phase diluent, pH of aqueous phase, Ag(I) and NO₃⁻ concentration in aqueous phase as well as TCBA and TCTH concentrations. Experimental equilibrium data were analysed numerically using the programs LETAGROP‐DISTR and LETAPL and the results showed that Ag(I) extraction could be explained assuming the formation of AgL and AgNO₃HL with TCBA (HL) and AgNO₃S with TCTH (S). The metal extraction was not influenced significantly by the structures of the thiourea derivatives used as extractants. The back extraction of Ag(I) from loaded organic phase was performed using different strippants and 0.5 mol dm⁻³ NaSCN was found to be efficient for this purpose. © 2000 Society of Chemical Industry     

D401螯合树脂柱分离富集ICP—OES法测定水中的痕量Cu^2＋、Pb^2＋、Cd^2＋

提出了采用自制的D401螯合树脂柱分离富集一电感耦合等离子体原子发射光谱（ICP—OES）法测定水中痕量Cu^2＋、Pb^2＋、Cd^2＋的分析方法。探讨并确定了分离富集和仪器的最佳条件。试验表明,在优化的试验条件下Cu^2＋、Pb^2＋、Cd^2＋可被D401螯合树脂柱定量吸附,可采用25mLl．5mol／L的HNO,溶液完全洗脱,动态饱和吸附容量分别为101．9、205．3、176．7mg／g,方法测定Cu^2＋、Pb^2＋、Cd^2＋的检出限（3σ）分别为0．00041、0．00083、0．000361xg／mL,相对标准偏差（RSD,n=7）分别为2．3％、2．8％、3．1％,加标回收率在93．0％～104．0％之间,测定结果与电感耦合等离子体质谱法基本一致。     

Recovery of Silver from X-Ray Film Processing Effluents Using Trimercapto-s-triazine (TMT)

In this study, the recovery of silver from waste X-ray photographic solutions by precipitation using trimercapto-s-triazine (TMT) was studied. Taguchi L₂₅ (5³) orthogonal design was adopted for the study. The effects of concentration of thiosulphate (5.2–200 g/L), TMT (Ag:TMT = 6.6–2.2), temperature (20–60°C) and pH (4.37–8.00) on the extent of the precipitation of silver were investigated. The findings have shown that the concentration of TMT and pH are the most significant factors affecting the recovery of silver while the effect of temperature (20–60°C) is insignificant under the conditions tested. The increase in the concentration of TMT and pH was found to improve the extent of precipitation of silver. TMT was also found to be an effective agent to reduce silver concentrations below the regulatory limit value of 5 ppm. Characterization of the precipitates was performed to identify silver-TMT compounds formed.     

Adsorption of Silver and Gold Ions from their Aqueous Solutions using a Magnetic Chelating Resin Derived from a Blend of Bisthiourea/Thiourea/Glutaraldehyde

A magnetic chelating resin was obtained from copolymerization of a blend of bisthiourea/thiourea/glutaraldehyde in the presence of magnetite (Fe₃O₄). The uptake of Ag(I) and Au(III) by the resin using batch and column techniques was studied. The maximum uptake capacity showed 6.2 and 5.78 mmol/g for Ag(I) and Au(III), respectively. Breakthrough curves showed critical bed height values of 0.03 cm and 0.04 cm for Ag(I) and Au(III), respectively, indicating the higher affinity of resin to Ag(I) relative to Au(III). Regeneration of the resins was achieved using acidified thiourea at efficiency of 98% over five cycles with no appreciable change in durability. The investigated resin was found to be able to remove 13 different metal ions from a real wastewater matrix at efficiency of 91%.     

Separation and Purification of Flavonoid from Ginkgo Extract by Polyamide Resin

An efficient separation process of flavonoid from Ginkgo extract was developed in this study. Polyamide resin offered the fine adsorption capacity, and its adsorption rate at 25°C fitted well to the Langmuir isotherm. Dynamic adsorption and desorption experiments were conducted to optimize the separation process of total flavonoids from the Ginkgo extract. After one run, the content of total flavonoids increased from 24.0% to 55.0%. The method will provide a potential approach for large-scale separation and purification of flavonoid for its wide pharmaceutical use.     

Mannich反应制备胺基树脂及由其制备的螯合树脂的吸附性能初探

以乙酰化聚苯乙烯微球为原料经非均相Mannich反应制备了胺基树脂,氮含量可达13．1mmol／g。由该胺基树脂制备了氨基羧酸型树脂(AC)和氨基膦酸型鳌合树脂(AP),采用静态吸附法,测试了两种鳌合树脂对Cu^2 、Zn^2 、Ni^2 的吸附性能。结果表明：AP树脂对Cu^2 、Ni^2 的鳌合容量较高,分别达到1．1mmol／g、0．69mmol／g,AC树脂对Zn^2 的吸附容量最高,达到1．35mmol／g。