基于原子转移自由基聚合制备新型螯合树脂及其吸附性能

以氯甲基化聚苯乙烯树脂(CMPS)为基质, 通过表面引发原子转移自由基聚合(SI-ATRP)反应将聚甲基丙烯酸缩水甘油酯(PGMA)接枝到树脂表面, 再与亚氨基二乙酸(IDA)反应, 制备了一种新型螯合树脂. 采用红外光谱、 元素分析及比表面积与微孔分析仪对其结构进行表征. 树脂表面甲基丙烯酸缩水甘油酯(GMA)接枝量和IDA含量及对Ni(Ⅱ), Cu(Ⅱ)和Pb(Ⅱ)的吸附容量均随聚合时间的延长而增大, 聚合时间为18 h时, 最大吸附容量分别为1.29, 1.19和0.83 mmol/g. 结果表明, SI-ATRP是制备高吸附容量及吸附容量可控的螯合树脂的可行方法.     

氧化石墨烯/富勒烯复合材料增敏多金属离子印迹电化学传感器

制备了一种对Pb(Ⅱ)、Cd(Ⅱ)和Cu(Ⅱ)等多金属离子具有灵敏、选择性响应的新型印迹传感器。 以甲基丙烯酸与乙二胺四乙酸分别为功能单体与配体,乙二醇二甲基丙烯酸酯为交联剂制备出多金属离子印迹聚合物。 采用滴涂法将离子印迹聚合物均匀地修饰至氧化石墨烯/富勒烯复合材料修饰碳电极表面,成功制备出灵敏的多金属离子印迹电化学传感器。 采取循环伏安法、交流阻抗和差分脉冲法等技术对印迹电化学传感器的性能进行表征,结果表明该多金属离子印迹电化学传感器具有良好的选择性。 在1.0×10^-9~5.0×10^-7 mol/L范围内,该多金属离子印迹电极的响应电流与金属离子浓度呈现良好的线性关系,对Pb(Ⅱ)、Cd(Ⅱ)和Cu(Ⅱ)金属离子的最低检测限分别为5.0×10^-10、5.0×10^-10和1.0×10^-10 mol/L。 该多金属离子印迹电化学传感器成功用于实际样品中微量Pb(Ⅱ)、Cd(Ⅱ)和Cu(Ⅱ)等金属离子的检测。     

螯合吸附材料PAO/SiO_2对重金属离子的螯合吸附行为

将丙烯腈接枝聚合在微米级硅胶微粒表面,经偕胺肟化转变,制得了接枝有聚偕胺肟(PAO)的复合型螯合吸附材料PAO/SiO2。本文重点考察了螯合吸附材料PAO/SiO2对几种重金属离子的螯合吸附行为,深入地研究了吸附机理。研究结果表明,偕胺肟基团与重金属离子之间的静电作用与配位螯合作用的协同,导致PAO/SiO2对重金属离子产生强的螯合吸附作用。在可抑制金属离子水解的pH范围内,介质的pH值越高,PAO/SiO2的螯合吸附能力越强;PAO/SiO2对性质不同的金属离子的吸附性能是有差别的,吸附容量的顺序为Cu2+Ni2+Pb2+Cd2+。     

硫代乙酰胺-聚苯乙烯树脂吸附剂制备及其对铅、镉、铜、镍、铁的萃取

以大孔聚苯乙烯苄胺树脂为载体通过Mannich反应制备了一种新型固相萃取吸附剂TAA-PS(硫代乙酰胺改性聚苯乙烯树脂)。利用FTIR和元素分析对其进行表征。研究了其对痕量金属离子的萃取性能,确定了对Pb2 、Cd2 、Cu2 、Ni2 和Fe3 等金属离子的最佳吸附条件。与其它吸附剂相比,本研究合成的固相萃取吸附剂具有高吸附容量和相当快的吸附速率。应用于自来水和湖水中痕量Pb2 、Cd2 、Cu2 、Ni2 和Fe3 的萃取富集,取得较好结果。     

一种螯合树脂的合成及对金属离子的吸附研究

采用表面引发原子转移自由基聚合(SI-ATRP)技术,以自制的单分散磁性聚合物微球(Fe3O4/PGMA/EDMA)为ATRP大分子引发剂,Cu Br/2,2'-联吡啶(Bpy)为催化剂,将乙烯基四唑聚合在磁性聚合物微球表面,制备了磁性螯合吸附树脂,用元素分析对其进行了表征,并测定了该树脂对几种金属离子的吸附性能,结果发现新型螯合树脂对贵金属离子吸附能力强,具有良好的应用前景,工业推广价值较高。     

高容量咪唑型螯合树脂的制备及其对Cd(Ⅱ)和Zn(Ⅱ)的吸附性能

以氯甲基化交联聚苯乙烯树脂(CMCPS)为载体和大分子引发剂,1-乙烯基咪唑(VIM)为单体,溴化亚铜/2,2'-联吡啶为催化剂体系,采用表面引发原子转移自由基聚合技术(SI-ATRP),将1-乙烯基咪唑接枝到CMCPS树脂表面,制得新型咪唑型螯合树脂(VIM-CMCPS),并采用X射线光电子能谱、元素分析和扫描电镜对其进行表征。考察了该螯合树脂对Cd2+和Zn2+的吸附性能、动力学和热力学参数。该螯合树脂表面VIM接枝密度达1.008 mg/m2。结果表明,该树脂对Cd2+和Zn2+的吸附量随溶液初始浓度和温度的升高而增加,当p H值分别为3.6和2.4时,对Cd2+和Zn2+的吸附效果最佳,树脂的静态饱和吸附容量分别为653.1 mg/g和793.3 mg/g,Langmuir和Freundlich方程均呈现良好的拟合度。热力学平衡方程计算得ΔG0,ΔH=24.47 k J/mol,ΔS0,表明该吸附过程是自发、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。     

螯合树脂S930对Cu(Ⅱ)、Pb(Ⅱ)、Cd(Ⅱ)的吸附性能与作用机理研究

通过静态吸附和动态吸附研究系统分析了螯合树脂S930对单组分与双组分体系中Cu(Ⅱ)、Pb(Ⅱ)、Cd(Ⅱ)的吸附行为,经结构表征(FT-IR、XPS)与软硬酸碱理论(HASB)深入探讨了3种金属离子在S930树脂上的作用机理。结果表明,树脂吸附金属离子的最佳pH值为5.0左右,且对Cu(Ⅱ)、Pb(Ⅱ)的吸附过程符合Langmuir方程,而对Cd(Ⅱ)的吸附过程符合Freundlich方程。吸附过程在6h左右达到平衡,且符合Lagergren二级吸附动力学模型,表明化学作用是吸附速率决定步骤。Cu(Ⅱ)、Pb(Ⅱ)的动态吸附过程符合Thomas模型。FT-IR、XPS及HASB同时证明树脂对Cu(Ⅱ)、Pb(Ⅱ)的作用包括离子交换与配位作用,而对Cd(Ⅱ)的作用以离子交换为主,是树脂对Cd(Ⅱ)吸附选择性较差的主要原因。     

后交联胺化聚苯乙烯树脂对铜离子的吸附选择性研究

以三乙烯四胺化交联聚苯乙烯(PS-NH2)为原料,以环氧氯丙烷(ECH)为交联剂,合成了后交联胺化聚苯乙烯树脂Ps-NH2-ECH.研究了PS-NH2和PS-NH2-ECH在静态条件下对重金属离子Cu2 、Ni2 、Zn2 、Cd2 、Pb2 的吸附选择性,以及PS-NH2-ECH在动态条件下对Cu2 、Ni2 的吸附选择性.结果表明,PS-NH2-ECH对Cu2 的吸附选择性较Ps-NH2有显著提高.     

接枝壳聚糖对铅、镉吸附行为研究及应用

在碱性条件下,用环氧氯丙烷交联制备水不溶性交联壳聚糖(CCTS),将丙烯腈单体接枝到CCTS分子骨架上制得接枝壳聚糖(CTCA)。研究了CTCA对水中Pb2 、Cd2 的吸附富集行为和洗脱行为,用原子吸收光谱法测定。结果表明,溶液的pH值为6.0时,Pb2 、Cd2 的吸附率达94%和95%,吸附容量分别达到56.6 mg/g、47.0 mg/g。用1 mol/L HCl洗脱,Pb2 、Cd2 的解吸率均可达97%。方法的检出限为:Pb2 ,0.065μg/L;Cd2 ,0.024μg/L。对10 mg/L的Pb2 、Cd2 溶液进行分离富集和测定,其相对标准偏差为3.4%和5.2%。方法已用于天然水中Pb2 、Cd2 的分离富集和测定,其回收率:Pb2 ,94%~101.9%;Cd2 ,95.6%~108%。     

高容量亚胺基二乙酸型螯合树脂的制备及吸附性能

以甲基丙烯酸缩水甘油酯(GMA)为单体, 氯甲基化的交联聚苯乙烯树脂(CMCPS)为大分子引发剂, CuBr/2,2'-联吡啶(Bpy)为催化剂, 采用表面引发原子转移自由基聚合(SI-ATRP)技术, 使甲基丙烯酸缩水甘油酯聚合在CMCPS树脂表面, 制得了环氧化聚合物. 将该聚合物与亚胺基二乙酸(IDA)反应, 制备了高容量亚胺基二乙酸型螯合树脂(IDA-PGMA-CMCPS), 用元素分析对其进行了表征. 考察了螯合树脂对Cu²⁺的吸附性能及动力学和热力学参数. 该螯合树脂表面IDA接枝密度达8.15 mg/m². 研究结果表明, 树脂对Cu²⁺的吸附量随离子浓度和温度的升高而增加, 当pH值为2.2时, 对Cu²⁺离子的吸附效果最佳. 树脂的静态饱和吸附容量为1339.66 mg/g, Langmuir和Freundlich方程均呈现良好的拟合度. 通过热力学平衡方程计算ΔG<0, ΔH=270.60 kJ/mol, ΔS>0, 表明该吸附过程是自发、 吸热、 熵增加的过程. 动力学研究结果表明, 准二级动力学方程能较好拟合动力学实验结果, 该过程符合准二级动力学模型.     

CMC-Na/DETA-B62型蛇笼树脂对金属离子的吸附性能

本文研究了自合成的蛇笼型螯合树脂-二乙烯三胺交联甘油环氧树脂/羰甲基纤维素体系对Cd^2 ,Pb^2 ,Fe^2 的吸附量，吸附动力学，等温吸附过程等静态吸附性能，同时研究了pH值等因素对吸附性能的影响。实验结果表明，该树脂对Cd^2 具有较强的吸附选择性，能在Cd^2 ,Pb^2 ,Fe^2 3种离子共存时选择吸附Cd^2 ，其选择性系数分别为Kcd^2 /pb^2 =3.77,Kcd^2 /Fe^2 =9.61。该树脂对上述3种离子的吸附量可分别达4.00,1.06,0.42mmol/g。该类树脂可用于含重金属离子污水的处理和金属离子的分离等方面。     

巯基树脂对重金属离子的吸附性能

研究了自合成的巯基树脂对重金属离子Pb^2 、Cu^2 、Cd^2 ．Ni^2 、Co^2 的吸附容量、吸附动力学、等温吸附过程等静态吸附性能，同时研究了影响吸附的因素和吸附机理．结果表明，该树脂对软酸型重金属离子吸附容量高．pH=5．0-5．7，低温有利于吸附，树脂对各重金属离子等温吸附在实验浓度范围内均符合Langmuir和Freundnch方程．吸附机理研究表明，巯基与重金属离子发生了离子交换和配位反应，化学吸附起支配作用。     

A new chelating sorbent for metal ion extraction under high saline conditions

A new chelating polymeric sorbent was developed by functionalizing Amberlite XAD-16 with 1,3-dimethyl-3-aminopropan-1-ol via a simple condensation mechanism. The newly developed chelating matrix offered a high resin capacity and faster sorption kinetics for the metal ions such as Mn(II), Pb(II), Ni(II), Co(II), Cu(II), Cd(II) and Zn(II). Various physio-chemical parameters like pH-effect, kinetics, eluant volume and flow rate, sample breakthrough volume, matrix interference effect on the metal ion sorption have been studied. The optimum pH range for the sorption of the above mentioned metal ions were 6.0–7.5, 6.0–7.0, 8.0–8.5, 7.0–7.5, 6.5–7.5, 7.5–8.5 and 6.5–7.0, respectively. The resin capacities for Mn(II), Pb(II), Ni(II), Co(II), Cu(II), Cd(II) and Zn(II) were found to be 0.62, 0.23, 0.55, 0.27, 0.46, 0.21 and 0.25 mmol g⁻¹ of the resin, respectively. The lower limit of detection was 10 ng ml⁻¹ for Cd(II), 40 ng ml⁻¹ for Mn(II) and Zn(II), 32 ng ml⁻¹ for Ni(II), 25 ng ml⁻¹ for Cu(II) and Co(II) and 20 ng ml⁻¹ for Pb(II). A high preconcentration value of 300 in the case of Mn(II), Co(II), Ni(II), Cu(II),Cd(II) and a value of 500 and 250 for Pb(II) and Zn(II), respectively, were achieved. A recovery of >98% was obtained for all the metal ions with 4 M HCl as eluting agent except in the case of Cu(II) where in 6 M HCl was necessary. The chelating polymer showed low sorption behavior to alkali and alkaline earth metals and also to various inorganic anionic species present in saline matrix. The method was applied for metal ion determination from water samples like seawater, well water and tap water and also from green leafy vegetable, from certified multivitamin tablets and steel samples.     

Adsorptive accumulation of Cd(II), Co(II), Cu(II), Pb(II), and Ni(II) from water on montmorillonite: influence of acid activation

The present work investigates the influence of acid activation of montmorillonite on adsorption of Cd(II), Co(II), Cu(II), Ni(II), and Pb(II) from aqueous medium and comparison of the adsorption capacities with those on parent montmorillonite. The clay-metal interactions were studied under different conditions of pH, concentration of metal ions, amount of clay, interaction time, and temperature. The interactions were dependent on pH and the uptake was controlled by the amount of clay and the initial concentration of the metal ions. The adsorption capacity of acid-activated montmorillonite increases for all the metal ions. The interactions were adsorptive in nature and relatively fast and the rate processes more akin to the second-order kinetics. The adsorption data fitted both Langmuir and Freundlich isotherms, indicating that strong forces were responsible for the interactions at energetically nonuniform sites. The Langmuir monolayer capacity of the acid-activated montmorillonite is more than that of the parent montmorillonite (Cd(II): 32.7 and 33.2 mg/g; Co(II): 28.6 and 29.7 mg/g; Cu(II): 31.8 and 32.3 mg/g; Pb(II): 33.0 and 34.0 mg/g; and Ni(II): 28.4 and 29.5 mg/g for montmorillonite and acid-activated montmorillonite, respectively). The thermodynamics of the rate processes showed the adsorption of Co(II), Pb(II), and Ni(II) to be exothermic, accompanied by decreases in entropy and Gibbs free energy, while the adsorption of Cd(II) and Cu(II) was endothermic, with an increase in entropy and an appreciable decrease in Gibbs free energy. The results have established the potential use for montmorillonite and its acid-activated form as adsorbents for Cd(II), Co(II), Cu(II), Ni(II), and Pb(II) ions from aqueous media.     

Novel Chelating Resin for Solid-Phase Extraction of Metals in Certified Reference Materials and Waters

A new chelating resin, poly(diacetonitrile methacrylamide-co-divinylbenzene-co-vinylimidazole), was synthesized and characterized by infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and elemental analysis. The novel resin was used for the first time as a chelating adsorbent for the preconcentration of Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn from various samples by flame atomic absorption spectrometry. The adsorption capacities of the resin were 29.3, 31.6, 29.3, 27.3, 35.5, 31.7, 39.8, and 32.3?mg?g^?1 for Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn, respectively. The detection limits of the metal ions were from 0.42 to 3.21?µg?L^?1. A preconcentration factor of 30 for all metal ions was obtained. The precision of the method as the relative standard deviation was less than or equal to 2.6%. The described method was validated with certified reference materials and fortified real samples. The method was used for the determination of the analytes in well water and wastewater.     

Pyrocatechol Violet immobilized Amberlite XAD-2: synthesis and metal-ion uptake properties suitable for analytical applications

Amberlite XAD-2 has been functionalized by coupling it, through the ---N=N--- group, with Pyrocatechol Violet (PV), and the resulting resin has been characterized by elemental analysis, thermogravimetric analysis (TGA) and IR spectra. The resin has been used for preconcentrating Zn(II), Cd(II), Pb(II) and Ni(II) ions prior to their determination by flame atomic absorption spectrometry. The optimum pH values for quantitative sorption are 5, 5–7, 4, and 3 for Zn, Cd, Pb and Ni, respectively. The four metals can be desorbed (recovery ˜98%) with 4 M HNO₃; also, 4 M HCl is equally suitable except for Zn. The sorption capacity of the resin is 1410, 1270, 620 and 1360 μg g⁻¹ resin for Zn, Cd, Ni and Pb, respectively. The effect of F⁻, Cl⁻, NO₃⁻, SO₄²⁻ and PO₄³⁻ on the sorption of these four metal ions has been investigated. They are tolerable in the range 0.01–0.20 M, for Pb. In the sorption of Zn(II) and Ni(II), the tolerance limits of all these ions are upto 0.01 M, whereas for Cd(II), F⁻, NO₃⁻, and PO₄³⁻ have been found to be tolerable upto 0.50, 0.10 and 0.10 M, respectively. The preconcentration factors are 60, 50, 23 and 18 for Zn, Cd, Pb and Ni, respectively. Simultaneous collection and determination of the four metals are possible. Cations commonly present in drinking water do not affect the sorption of either metal ion if present at a concentration level similar to that of water. The method has been applied to determine Zn, Ni and Pb content of well-water samples (RSD ≤9%).     

Amberlite XAD-2 functionalized with o-aminophenol: synthesis and applications as extractant for copper(II), cobalt(II), cadmium(II), nickel(II), zinc(II) and lead(II)

A stable chelating resin matrix was synthesized by covalently linking o-aminophenol (o-AP) with the benzene ring of the polystyrene–divinylbenzene resin, Amberlite XAD-2, through a –N=N– group. Elemental analyses, thermogravimetric analysis (TGA) and infrared spectra have characterized the resulting chelating resin. It has been used to preconcentrate Cu²⁺, Cd²⁺, Co²⁺, Ni²⁺, Zn²⁺ and Pb²⁺, prior to their determination by flame atomic absorption spectrometry. The optimum pH values for quantitative sorption of Cu, Cd, Co, Ni, Zn and Pb are 6.2–7.4, 5.6–7.2, 5.6–9.0, 6.0–9.0, 5.7–7.0 and 5.0–6.0, respectively. These metals are desorbed (recovery 91–98%) with 4 mol dm⁻³ HNO₃. The sorption capacity of the resin is 3.37, 3.42, 3.29, 3.24, 2.94 and 3.32 mg of metal g⁻¹ of resin, respectively, for Cu, Cd, Co, Ni, Zn and Pb. The effect of NaF, NaCl, NaNO₃, Na₂SO₄, and Na₃PO₄ on the sorption of these metal ions has been investigated. These electrolytes are tolerable up to 0.01 mol dm⁻³ in case of all the metal ions, except Cl⁻ which is tolerable even up to 0.1 mol dm⁻³ for Zn and 1.0 mol dm⁻³ for Pb. The preconcentration factor for Cu, Cd, Co, Ni, Zn and Pb are 50, 50, 100, 65, 40 and 40 (concentration level 10–25 μg dm⁻³) respectively. Simultaneous enrichment of the six metals is possible. The method has been applied to determine Cu, Cd, Co, Ni, Zn and Pb content in well water samples (RSD≤8%).     

Poly(vinylbenzyl Pyridinium Salts) as Novel Sorbents for Hazardous Metals Ions Removal

Novel efficient complexing resins—poly(vinylbenzyl pyridinium salts) fabricated through poly(vinylbenzyl halogene-co-divinylbenzene) quaternization of N-decyloxy-1-(pyridin-3-yl)ethaneimine and N-decyloxy-1-(pyridin-4-yl)ethaneimine—were tested as adsorbents of Pb(II), Cd(II), Cu(II), Zn(II), and Ni(II) from aqueous solutions. The structure of these materials was established by ¹³C CP-MAS NMR, X-ray photoelectron spectroscopy, elemental analysis, and Fourier transform infrared spectroscopy, as well as thermogravimetric and differential thermal analyses. The textural properties were determined using scanning electron microscopy and low-temperature N₂ sorption. Based on the conducted sorption studies, it was shown that the uptake behavior of the metal ions towards novel resins depended on the type of functionalities, contact time, pH, metal concentrations, and the resin dosage. The Langmuir model was investigated to be the best one for fitting isothermal adsorption equilibrium data, and the corresponding adsorption capacities were predicted to be 296.4, 201.8, 83.8, 38.1, and 39.3 mg/g for Pb(II), Zn(II), Cd(II), Cu(II), and Ni(II), respectively. These results confirmed that owing to the presence of the functional pyridinium groups, the resins demonstrated proficient metal ion removal capacities. Furthermore, VBBr-D4EI could be successfully used for the selective uptake of Pb(II) from wastewater. It was also shown that the novel resins can be regenerated without significant loss of their sorption capacity.