螯合树脂研究：ⅩⅩⅡ.用螯合树脂吸附和分离铂和铼

研究了三种含硫氯的凝胶型螯合树脂对铂和铼的吸附和解吸性能。树脂对铂铼的吸附容量随树脂氮含量的增加而增加;随溶液中铂铼浓度的增大而增大;随溶液酸度的增大而下降。含铂和铼的溶液通过树脂柱,两种金属离子可全部被吸附,其饱和吸附容量可达353mgRe/g树脂和319mgPt/g树脂。吸附在树脂上的铂和铼可用解吸能力较弱的洗脱剂先洗脱铼,然后用解吸能力较强的洗脱剂洗脱铂。两者可在洗脱过程中达到有效的分离。洗脱率均在98％以上,树脂可再生重复使用。     

大孔螯合树脂HZ401吸附去除废水中的铅

通过静态吸附实验,研究了大孔螯合树脂HZ401吸附去除废水中铅的性能.探究了时间、树脂用量、废水中铅的初始浓度、p H、温度、转速等条件对树脂吸附铅效果的影响,分析了吸附等温线和吸附动力学过程.结果表明:在研究范围内,HZ401树脂对铅的吸附率可以达到95%以上,返洗率几乎达到100%.树脂对铅的吸附符合Langmuir和Freundlich等温吸附方程,同时符合准一级动力学Lagergren方程和准二级动力学Lagergren方程.HZ401树脂可以用于废水中痕量铅的去除.     

氨基硫脲-甲醛螯合树脂的合成及吸附性能

以氨基硫脲和甲醛为原料,用一步法合成了一种新型的螯合树脂.测定了树脂对几种金属离子的吸附容量和对某些金属离子的吸附率,研究了吸附动力学、等温吸附等静态吸附性能.实验发现,树脂对某些贵金属离子有相当高的吸附容量和吸附率,对金离子有很好的吸附选择性.等温吸附测定表明在稀浓度范围内吸附符合Langmuir方程.     

新型SGN螯合树脂吸附贵金属性能和机理的研究

本文首次研究自制的氨基胍基螫合树脂吸附贵金属的行为。测定了树脂在HCl及H_2SO_4介质吸附贵金属的分配系数和吸附百分率,并研究了各种贵金属的吸附速率、以及酸度和温度等对吸附过程的影响。并提出树脂对贵金属配阴离子的配位和交换共存的吸附历程。     

铜印迹螯合树脂对金属离子的吸附特性

研究了铜印迹螯合树脂与非印迹螯合树脂对金属离子的吸附性能，结果表明：铜印迹树脂对Cu^2 、Ni^2 、Zn^2 的吸附量比非印迹树脂有显著增大,两者对Cu^2 的吸附速率均较快，其表观吸附速率分别为0．044s^-1和0．040s^-1；印迹树脂对Cu^2 的吸附可用Langmuir或Freundlish等温式来描述；其动态吸附曲线与离子的起始浓度相关；用0．5mol／L HCl即可快速洗脱吸附的Cu^2 ，树脂具有较强的再生能力，可以重复使用。     

螯合树脂研究——Ⅺ.一类新的氨基二硫代甲酸型螯合树脂的合成及吸附性能

 本文报道了以多乙烯多胺为主链的巯基胺树脂与二硫化碳反应,合成了四种新型的氨基二硫代甲酸型螯合树脂,这类树脂对贵金属具有高的吸附容量和优良的吸附选择性。并通过红外光谱和X光电子能谱研究树脂及其金属螫合物。     

用螯合树脂富集与分离贵金属元素

本文用放射性示踪法在静态和动态条件下研究贵金属元素在螯合树脂上的吸附行为,发现具有某种螯合基团的树脂3926(Ⅱ)对贵金属元素有很高的吸附选择性,对Pt、Pd、Au、Ir、Os、Ru的吸附率分别为100,99.5,98.3,97.7,93.0和84.3%,树脂不吸附Fe、Co、Zn、Pb、Cs、Sr、Cd、和稀土元素,而且树脂具有很好的辐照稳定性,可用于中子活化分析法测定矿样中痕量贵金属元素。     

聚乙烯四唑型螯合树脂及其对重金属离子的吸附性能

采用表面引发原子转移自由基聚合(SI-ATRP)方法将丙烯腈(AN) 接枝到氯甲基化聚苯乙烯树脂(PS-CH₂Cl) 表面, 再与叠氮化钠进行3+2环加成反应, 制备了一种聚乙烯四唑型螯合树脂(PVT-g-PS). 用红外光谱和元素分析对PVT-g-PS树脂进行了表征, 考察了该树脂对Pb(Ⅱ), Ni(Ⅱ)和Cd(Ⅱ)的吸附性能. 在一定聚合时间范围内, 丙烯腈接枝率与SI-ATRP时间呈线性关系, 树脂表面四唑含量及树脂对金属离子的吸附容量随丙烯腈接枝率增大而增大, 说明丙烯腈在树脂表面聚合为活性可控聚合, 树脂表面功能团含量和树脂吸附容量可以用聚合时间调控. 通过分析树脂吸附容量与溶液pH值的关系、 吸附等温线和吸附动力学, 证明3种金属离子的吸附主要是基于配位作用的化学吸附. 当SI-ATRP时间为10 h时, 树脂对Pb(Ⅱ), Ni(Ⅱ)和Cd(Ⅱ)吸附容量高达1.57, 1.68和1.92 mmol/g. 经过10次吸附-解吸循环实验, 树脂的吸附容量无显著变化, 表明新型树脂具有较高的吸附量和良好的重复使用性.     

新型螯合树脂聚苯乙烯负载葡糖胺对Pt(Ⅳ)吸附性能

合成了新型螯合树脂聚苯乙烯负载葡糖胺(PS-GA)。研究了树脂对Pt(Ⅳ)的吸附容量、吸附动力学、等温吸附等静态吸附性能及影响吸附的因素。结果表明,该树脂对Pt(Ⅳ)的吸附量较高;吸附动力学研究证明树脂对Pt(Ⅳ)的吸附为液膜扩散控制,吸附的活化能通过计算得10.31kJ/mol;树脂对Pt(Ⅳ)的等温吸附,与Freundlich方程相比,更加符合Langmuir方程;计算了等温吸附过程的热力学参数ΔG,ΔH,ΔS值;升高温度有利于吸附;树脂可用2%硫脲～0.1mol/LHCl溶液清洗再生,5次再生后仍保持良好的吸附能力,适合重复使用。     

氨基膦酸螯合树脂吸附重稀土的研究

研究了重稀土在氨基膦酸树脂的吸附行为.试验结果表明,氨基膦酸树脂对重稀土的吸附在pH=5.0的HAc-NaAc缓冲溶液时最佳;298K时静态饱和吸附容量为332mg/g干树脂;用2mol/L盐酸洗脱,洗脱率为91.2%;等温吸附服从Freundlich经验式;吸附反应中△H=10.76kJ/mol,表观速率常数k298=1.223×10-4s-1,表观活化能Ea=3.2kJ/mol.     

羧甲基二硫代氨基甲酸酯功能化聚氯乙烯树脂的合成及对Ag~+的吸附与选择性能

以聚氯乙烯为大分子骨架,经三乙烯四胺胺化,再与二硫化碳和乙醇钠反应,得到的二硫代氨基羧酸盐改性聚氯乙烯树脂(PV-NS)进一步与氯乙酸钠反应,合成了一种同时舍N,S,O的羧甲基二硫代氨基甲酸酯改性聚氯乙烯树脂(PV-NSO).合成树脂的功能基结构经红外和元素分析确认.对合成树脂的吸附性能研究表明,合成树脂对Ag+、Hg2+、Au<'3+>、Pb2+离子的吸附容量在实验条件下分别达2.058mmol/g、1.514mmol/g,1.125mmol/g和0.415mmol/g,而对Cu2+、Cd2+、Zn2+、Ni2+、Mg2+等离子的吸附容量很小,甚至不吸附.树脂的选择性吸附表明,树脂对Ag+的吸附选择性较好,在有Hg2+、Pb2+、Cd2+、Zn2+、Cu2+或Mg2+共存时,树脂对Ag+的选择性吸附系数分别达4.74、17.33,12.98、∞、7.60和74.14.合成树脂在极性溶剂中的溶胀性能均比在非极性溶剂中好.     

螯合树脂研究——Ⅷ.以聚硫醚为主链的氧杂多乙烯多胺型螯合树脂的合成及其吸附性能

由聚[2′-氯乙基-2,3-环硫丙基醚]和多乙烯声胺反应,合成了四种以聚硫醚为主链的氧杂多乙烯多胺型螯合树脂,它们对贵金属离子Au(Ⅲ)、Pd(Ⅱ)、Pt(Ⅳ)、Ag~+等具有优良的吸附性能。     

负载苯基硫脲酚醛型螯合树脂对Ag+的吸附与实验室应用

在四丁基溴化铵(TBAB)相转移催化条件下,线形环氧酚醛树脂(F44)与苯基硫脲(PTU)发生开环加成,合成了负载苯基硫脲的酚醛型螯合树脂(F44-PTU).研究了该树脂对Cu2 、Ni2 、Pb2 、Hg2 、Au3 的吸附容量及温度、离子浓度、pH值对Ag 吸附性能的影响.结果表明,该树脂对Ag 具有较好的吸附性能,吸附符合Freundlich等温式.吸附树脂在5%硫脲～1mol/L HNO3时可洗脱再生,再生后树脂的吸附能力下降,可能在Ag 的吸附过程中伴随有氧化还原作用.将合成树脂处理实验室含银废液,银的回收率可达93.8%.     

CO adsorption on pure and binary-alloy gold clusters: a quantum chemical study

We performed density-functional theory analysis of nondissociative CO adsorption on 22 binary Au-alloy (Au(n)M(m)) clusters: n=0-3, m=0-3, and m+n=2 (dimers) or 3 (trimers), M=Cu/Ag/Pd/Pt. We report basis-set superposition error corrections to adsorption energies and include both internal energy of adsorption (DeltaU(ads)) and Gibbs free energy of adsorption (DeltaG(ads)) at standard conditions (298.15 K and 1 atm). We found onefold (atop) CO binding on all the clusters except Pd2 (twofold/bridged), Pt2 (twofold/bridged), and Pd3 (threefold). In agreement with the experimental results, we found that CO adsorption is thermodynamically favorable on pure Au/Cu clusters but not on pure Ag clusters and also observed the following adsorption affinity trend: Pd>Pt>Au>Cu>Ag. For alloy dimers we found the following patterns: Au2>M Au>M2 (M=Ag/Cu) and M2>M Au>Au2 (M=Pd/Pt). Alloying Ag/Cu dimers with (more reactive) Au enhanced adsorption and the opposite effect was observed for PdPt dimers. The Ag-Au, Cu-Au, and Pd-Au trimers followed the trends observed on dimers: Au3>M Au2>M2Au>M3 (M=Ag/Cu) and Pd3>Pd2Au>PdAu2>Au3. Interestingly, Pt-Au trimers reacted differently and alloying with Au systematically increased the adsorption affinity: PtAu2>Pt2Au>Pt3>Au3. A strikingly different behavior of Pt is also manifested by the triplet spin state and onefold (atop) binding in Pt3-CO which is in contradiction with the singlet spin state and threefold binding in Pd3-CO. We found a linear correlation between CO binding energy (BE) and elongation of the CO bond. For Ag-Au and Cu-Au clusters, the increase in CO BE (and elongation of the C-O bond which is probably due to the back donation) is accompanied by the decrease in the cluster-CO distance suggesting that the donation (from 5sigma highest occupied molecular orbital in CO to cluster lowest unoccupied molecular orbital) mechanism also contributes to the BE. For Pd-Au clusters, the cluster-CO distance (and CO bond length) increases with increase in the BE, suggesting that the donation mechanism may not be important for those clusters. No clear trend was observed for Pt-Au clusters.     

Application of a macroporous resin containing imidazoline groups to preconcentration and separation of gold, platinum and palladium prior to ICP-AES determination

A new functional resin with a long functional side chain was synthesized by modification of aminated macroporous poly(vinyl chloride) resin with cyanoethylene and ethylenediamine. Traces of Au(III), Pt(IV) and Pd(II) in aqueous solution were quantitatively adsorbed in the acidity range of pH 4 and C(H(+)) 3 M. The rate of equilibration is high; Cu(2+), Fe(3+), Ni(2+), etc. exhibit little interference on the adsorption of the sought noble metals. The saturated adsorption capacities for Au(III), Pt(IV), Pd(II) and Ir(IV) in 2 M HCl were 4.0, 1.57, 2.26, 1.85 mmol g(-1). Adsorbed ions can be quantitatively desorbed by 4% thiourea +0.25 M H(2)SO(4). The resin has good reusability, and can be used for preconcentration and separation of Au(III), Pt(IV) and Pd(II) prior to their determination by ICP-AES with satisfactory results.     

First-principles investigation of transition metal atom M (M = Cu, Ag, Au) adsorption on CeO2(110)

Transition metal atom M (M = Cu, Ag, Au) adsorption on CeO(2)(110), a technologically important catalytic support surface, is investigated with density-functional theory within the DFT+U formalism. A set of model configurations was generated by placing M at three surface sites, viz., on top of an O, an O bridge site, and a Ce bridge site. Prior to DFT optimization, small distortions in selected Ce-O distances were imposed to explore the energetics associated with reduction of Ce(4+) to Ce(3+) due to charge transfer to Ce during M adsorption. Charge redistribution is confirmed with spin density isosurfaces and site projected density of states. We demonstrate that Cu and Au atoms can be oxidized to Cu(2+) and Au(2+), although the adsorption energy, E(ads), of Au(2+) is less favorable and, unlike Cu(2+), it has not been experimentally observed. Oxidation of Ag always results in Ag(+). For M adsorption at an O bridge site, E(ads)(2NN) > E(ads)(3NN) > E(ads)(1NN) where NN denotes the nearest neighbor Ce(3+) site relative to M. Alternatively, for M adsorption at a Ce bridge site, E(ads)(3NN) > E(ads)(2NN) > E(ads)(1NN). The adsorption behavior of M on CeO(2) (110) is compared with M adsorption on CeO(2)(111).     

聚乙烯苄硫脲大孔型螯合树脂的合成及其对金离子螯合性的研究

合成了对Au~(3+)具有高吸附容量的聚乙烯苄硫脲大孔型螯合树脂(硫脲树脂)。大孔型交联的氯甲基化聚苯乙烯以1,4-二氧六环为溶胀剂,无水乙醇为溶剂与硫脲反应,功能基转化率达理论值的98.8％。树脂对Au~(3+)的吸附容量为819mgAu~(3+)/g树脂,最佳时达920mgAu~(3+)/g树脂。硫脲功能基与Au~(3+)的螯合比是1,探讨了pH对Au~(3+)吸附率的影响,研究了硫脲树脂对Au~(3+)的吸附速率。红外光谱、元素分析探讨了树脂的结构。硫脲树脂可从电镀的废水中回收纯金,回收率≥95.7％,纯度为99.98％。     

Fast recovery of Au (III) and Ag(I) via amine-modified zeolitic imidazolate framework-8

In this paper, zeolitic imidazolate framework-8 modified by the ethanediamine (NH₂-ZIF-8) was employed for adsorbing Au (III) and Ag(I) from aqueous solutions. The adsorption capacities of NH₂-ZIF-8 towards Au (III) and Ag(I) were found to be significantly affected by the pH values of the solution. The adsorption kinetics studies show that NH₂-ZIF-8 presents a fast adsorption property towards metals, attaining 93% of adsorption equilibrium uptake for Au (III) within the first 30 min. This phenomenon can be ascribed to the coordination interaction between the amino group and Au (III). The thermodynamic data suggest that the adsorption of NH₂-ZIF-8 towards Au (III) is endothermic process, while that for Ag(I) is exothermic. The maximum adsorption capacities of NH₂-ZIF-8 toward Au (III) and Ag(I) can be achieved to 357 mg·g⁻¹ and 222.25 mg·g⁻¹, respectively. The metal ions interference results show that Cu (II) and Ni (II) hardly have no interference on Au (III) adsorption in e-waste containing 1500 mg·l⁻¹ Cu (II),100 mg·l⁻¹ Ni (II) and 10 mg·l⁻¹ Au (III); while for Ag(I), Cd (II) and Zn (II) have little interference on Ag(I) adsorption in the hybrid solutions containing Ag(I), Ni (II), Cd (II) and Zn (II) with equal concentration (50 mg·l⁻¹), but Ni (II) interference most. The XPS study shows that partial Au (III) was reduced to Au(I), and that Ag(I) was completely reduced to Ag(0) during the adsorption process. The abundant of active sites of NH₂-ZIF-8 containing C=N, N-H, and Zn-OH groups play a key role in the adsorption of Au (III) and Ag(I). In addition, electrostatic interaction can be responsible for the adsorption of Au (III) by NH₂-ZIF-8. The regeneration experiments results show that the adsorption capacities of NH₂-ZIF-8 towards Au (III) and Ag(I) can maintain after three cycles. This work provides a reliable method to improve the adsorption kinetics for metal ions.     

水杨酸型螯合树脂对Fe(III)离子的螯合吸附行为

以5-氨基水杨酸(ASA)为胺化试剂, 使氯甲基化的交联聚苯乙烯(CMCPS)微球表面的苄氯基团发生亲核取代反应, 制得了水杨酸型螯合树脂ASA-CPS. 研究了该螯合树脂对金属离子的螯合吸附行为, 探讨了其吸附热力学与吸附机理, 考察了介质pH值对树脂螯合吸附性能的影响以及树脂对不同金属离子的螯合吸附能力. 实验结果表明, 水杨酸型螯合树脂ASA-CPS 对重金属离子具有强螯合吸附性能, 尤其对Fe3+离子表现出很强的螯合吸附能力, 常温下吸附容量可达21 g/100 g. 吸附过程属熵驱动的化学吸附过程, 升高温度, 吸附容量增高; 在可抑制金属离子水解的pH范围内, 介质的pH值越高, 螯合吸附能力越强; 对于性质不同的金属离子, ASA-CPS的吸附性能是有差别的, 吸附容量的顺序为Fe3+>Ni2+>Cu2+>Zn2+.