Pre-concentration efficiency of chelex-100 resin for heavy metals in seawater : Part 1. Effects of pH and Salts on the Distribution Ratios of Heavy Metals

The chelating characteristics of Chelex-100 resin were studied for selected heavy metals in seawater medium. The results of batch equilibrium and breakthrough experiments show that the metal-chelating efficiency of the resin is lower in seawater than in freshwater. These differences are caused by the complicated speciation of heavy metals in seawater medium and by the high concentrations of magnesium and calcium present which act as competitors to heavy metal ions. The optimal pH values for column operation are strongly affected by the salt matrix. Careful choice of experimental conditions is necessary to avoid losses of cadmium and manganese from seawater. For better performance, seawater samples should be adjusted to pH 6–7 before loading onto a Chelex-100 column.     

Functionalization of chitosan with 3,4-dihydroxybenzoic acid for the adsorption/collection of uranium in water samples and its determination by inductively coupled plasma-mass spectrometry

A chitosan resin derivatized with 3,4-dihydroxybenzoic acid moiety (CCTS-DHBA resin) was newly synthesized for the collection/concentration of trace uranium by using cross-linked chitosan (CCTS) as base material, and the adsorption behavior of uranium as well as 60 elements on the resin was examined by passing the sample solutions through a mini-column packed with the resin. After the elution of the collected elements on the resin with 1 M HNO₃, the eluates were measured by inductively coupled plasma-mass spectrometry (ICP-MS).The CCTS-DHBA resin can adsorb several metal cations and several oxoanionic elements at appropriate pH. Among these metal ions, uranium shows an excellent adsorption behavior on this resin. Uranium as UO₂²⁺ species can be adsorbed on the resin by chelating mechanism with adsorption capacity of 330 mg g⁻¹ resin. Through the column treatment, the complete removal of large amounts of alkali and alkaline earth matrices without any loss of adsorption efficiency over prolonged usage were achieved with this resin.The CCTS-DHBA resin was applied to the adsorption/collection of uranium in tap water, river water and seawater samples with satisfactory results. The validation of the proposed method was carried out by analyzing uranium in the standard reference materials of SLRS-4, CASS-4, and NASS-5 after passing through the CCTS-DHBA resin, and the results showed good agreement with the certified values.     

Functionalization of chitosan with 3-nitro-4-amino benzoic acid moiety and its application to the collection/concentration of molybdenum in environmental water samples

A chitosan resin functionalized with 3-nitro-4-amino benzoic acid moiety (CCTS-NABA resin) was newly synthesized for the collection/concentration of trace molybdenum by using cross-linked chitosan (CCTS) as base material. The carboxyl group of the moiety was chemically attached to amino group of cross-linked chitosan through amide bond formation. The adsorption behavior of molybdenum as well as other 60 elements on the resin was examined by passing the sample solutions through a mini-column packed with the resin. After the elution of the elements collected on the resin with 1 M HNO₃, the eluates were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) and atomic emission spectrometry (ICP-AES).

The CCTS-NABA resin can adsorb several metal ions, such as vanadium, gallium, arsenic, selenium, silver, bismuth, thorium, tungsten, tin, tellurium, copper, and molybdenum at appropriate pHs. Among these metal ions, only molybdenum could be adsorbed almost completely on the resin at acidic regions. An excellent selectivity toward molybdenum could be obtained at pH 3–4. The adsorption capacity of CCTS-NABA resin for Mo(VI) was 380 mg g⁻¹ resin. Through the column pretreatment, alkali and alkaline earth metals in river water and seawater samples were successfully removed.

The CCTS-NABA resin was applied to the adsorption/collection of molybdenum in river water and seawater samples. The concentrations of molybdenum in river water samples were found in the range of 0.84 and 0.95 ppb (ng g⁻¹), whereas molybdenum in seawater was about 9 ppb. The validation of the proposed method was carried out by determining molybdenum in the certified reference materials of SLRS-4, CASS-4, and NASS-5 after passing through the CCTS-NABA resin; the results showed good agreement with the certified values.     

Synthesis of novel chitosan resin derivatized with serine moiety for the column collection/concentration of uranium and the determination of uranium by ICP-MS

A chitosan resin derivatized with serine moiety (serine-type chitosan) was newly developed by using the cross-linked chitosan as a base material. The adsorption behavior of trace amounts of metal ions on the serine-type chitosan resin was systematically examined by packing it in a mini-column, passing a metal solution through it and measuring metal ions in the effluent by ICP-MS. The resin could adsorb a number of metal cations at pH from neutral to alkaline region, and several oxoanionic metals at acidic pH region by an anion exchange mechanism. Uranium and Cu could be adsorbed selectively at pH from acidic to alkaline region by a chelating mechanism; U could be adsorbed quantitatively even at pH 3–4. Uranium adsorbed on the resin was easily eluted with 1 M nitric acid: the preconcentration (5-, 10-, 50- and 100-fold) of U was possible. The column treatment method was used prior to the ICP-MS measurement of U in natural river, sea and tap waters; R.S.D. were 2.63, 1.13 and 1.37%, respectively. Uranium in tap water could be determined by 10-fold preconcentration: analytical result was 1.46±0.02 ppt. The resin also was applied to the recovery of U in sea water: the recovery tests for artificial and natural sea water were 97.1 and 93.0%, respectively.     

Synthesis and application of modified poly (styrene‐alt‐maleic anhydride) networks as a nano chelating resin for uptake of heavy metal ions

A chelating resin based on modified poly (styrene‐alt‐maleic anhydride) with 3‐aminobenzoic acid was synthesized. This modified resin was further reacted by 1,2‐diaminoethane or 1,3‐diaminopropane in the presence of ultrasonic irradiation to prepare tridimensional chelating resin for the removal of heavy metal ions from aqueous solutions. The adsorption behavior of Fe(II), Cu(II), Zn(II) and Pb(II) ions was investigated by synthesized chelating resins in various pH. Among the synthesized resins, CSMA‐AB1 and CSMA‐AB2 demonstrated a high affinity for the selected metal ions compared to SMA‐AB, and the order of removal percentage changes as follow: Fe(II) > Cu(II) > Zn(II) > Pb(II). The adsorption of all metal ions in acidic medium was moderate, and it was favored at the pH value of 6 and 7. Also, the prepared resins were examined for removal of metal ions from industrial wastewater and were shown to have a very efficient adsorption in the case of Cu(II), Fe(II) and Pb(II); however, the adsorption of Zn(II) was lower than others. The resin was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction analysis and thermogravimetric analysis/derivative thermogravimetry. Copyright © 2012 John Wiley & Sons, Ltd.     

SYNTHESES AND ADSORPTION PROPERTIES OF PHENOL-FORMALDEHYDE-TYPE CHELATING RESINS BEARING THE FUNCTIONAL GROUP OF TARTARIC ACID

Several kinds of novel chelating resins bearing the functional group of tartaric acid (TTA-FQ-12, TTA-FQ-23, and TTA-FQ-34) were synthesized by reacting epoxy maleic anhydride, which was prepared through the oxidization reaction of maleic anhydride by hydrogen peroxide, with phenol-formaldehyde resin containing polyamine (FQ resins series). The effects of such factors as reaction time, reaction temperature and pH value on the loading capacity of TTA in resins were investigated. The results showed that the optimum reaction conditions are as follows: time 9-12h; temperature 90-105℃;pH value 6-10. The loading capacities of TTA can reach 0.15, 0.14, and 0.11 mmol/g^-1 when the functional group of FQ resin was -OCH2CH2NHC2H4NH2, -O(CH2CH2NH)2C2H4NH2 and -O(CH2CH2NH)3C2H4NH2), respectively. The structures of resins were characterized by FTIR spectra. The primary study on the adsorption properties of the resins for metal ions showed that there are two kinds of adsorption mechanisms i.e. ion exchange and chelate in the adsorption process. TTA-FQ resins have much higher adsorption selectivity for Pb^2 and Zn^2 than for Cu^2 and Ni^2 . These resins can probably be used for separating Pb^2 or Zn^2 in the mixture of metal ions or for treating wastewater containing heavy metal ions.     

羧甲基壳聚糖/聚乙烯醇/甘油环氧树脂蛇笼型复合螯合膜的制备及对金属离子的吸附性能

以交联甘油环氧树脂交联的聚乙烯醇(PVA)为笼树脂，羧甲基壳聚糖(CCTS)为蛇树脂制备了具有蛇笼结构的复合螯合膜，研究了其对Cu^2 、Ni^2 、Pb^2 、Fe^3 、Zn^2 ，Hg”^2 、Cd^2 等金属离子的吸附性能，研究表明，该树脂对Cu^2 、Ni^2 、Pb^2 有较好的吸附性能，其中PVA是对Cu^2 的吸附的主要贡献者，而CCTS则是在对Ni^2 的吸附中起主要作用。该树脂可以用于含Cu^2 废水的处理。     

Synthesis of cross-linked chitosan modified with the glycine moiety for the collection/concentration of bismuth in aquatic samples for ICP-MS determination.

A chelating resin, cross-linked chitosan modified with the glycine moiety (glycine-type chitosan resin), was developed for the collection and concentration of bismuth in aquatic samples for ICP-MS measurements. The adsorption behavior of bismuth and 55 elements on glycine-type chitosan resin was systematically examined by passing a sample solution containing 56 elements through a mini-column packed with the resin (wet volume; 1 ml). After eluting the elements adsorbed on the resin with nitric acid, the eluates were measured by ICP-MS. The glycine-type chitosan resin could adsorb several cations by a chelating mechanism and several oxoanions by an anion-exchange mechanism. Especially, the resin could adsorb almost 100% Bi(III) over a wide pH region from pH 2 to 6. Bismuth could be strongly adsorbed at pH 3, and eluted quantitatively with 10 ml of 3 M nitric acid. A column pretreatment method with the glycine-type chitosan resin was used prior to removal of high concentrations of matrices in a seawater sample and the preconcentration of trace bismuth in river water samples for ICP-MS measurements. The column pretreatment method was also applied to the determination of bismuth in real samples by ICP-MS. The LOD of bismuth was 0.1 pg ml(-1) by 10-fold column preconcentration for ICP-MS measurements. The analytical results for bismuth in sea and river water samples by ICP-MS were 22.9 +/- 0.5 pg ml(-1) (RSD, 2.2%) and 2.08 +/- 0.05 pg ml(-1) (RSD, 2.4%), respectively.     

Synthesis of chitosan resin possessing a phenylarsonic acid moiety for collection/concentration of uranium and its determination by ICP-AES

A chitosan resin possessing a phenylarsonic acid moiety (phenylarsonic acid type chitosan resin) was developed for the collection and concentration of trace uranium prior to inductively coupled plasma (ICP) atomic emission spectrometry (AES) measurement. The adsorption behavior of 52 elements was systematically examined by packing it in a minicolumn and measuring the elements in the effluent by ICP mass spectrometry. The resin could adsorb several cationic species by a chelating mechanism, and several oxo acids, such as Ti(IV), V(V), Mo(VI), and W(VI), by an anion-exchange mechanism and/or a chelating mechanism. Especially, U(VI) could be adsorbed almost 100% over a wide pH region from pH 4 to 8. Uranium adsorbed was easily eluted with 1 M nitric acid (10 mL), and the 25-fold preconcentration of uranium was achieved by using a proposed column procedure, which could be applied to the determination of trace uranium in seawater by ICP-AES. The limit of detection was 0.1 ng mL⁻¹ for measurement by ICP-AES coupled with 25-fold column preconcentration.     

Development of physico-chemical speciation procedures to investigate the toxicity of copper,lead, cadmium and zinc towards aquatic biota

A range of model compounds was studied to test the effect of complexing agents on the adsorption of copper, lead, cadmium and zinc by Chelex-100 resin, oxine porous glass, thiol porous glass and thiol resin, from seawater and distilled water. The thiol materials, while showing behaviour similar to Chelex-100 resin and oxine porous glass for zinc, cadmium and lead, retained copper much more strongly. Methods for measuring lipid-soluble metal complexes in waters were also studied. Bio-Rad SM2 resin was the most suitable extractant, although a citrate buffer of pH 5.7 was needed to prevent the co-adsorption of free metal ions. Seawater and various fresh waters were analyzed for trace metal speciation by using Chelex-100 resin, thiol resin and anodic stripping voltammetry to determine labile metal. Bio-Rad SM2 resin and hexane—butanol extraction were used for the estimation of lipid-soluble metal. The polluted water samples had higher fractions of labile and organic-soluble metal, but it was concluded that some of the waters contained unidentified ligands which caused speciation behaviour different from that of the synthetic solutions with model ligands. The factors involved in the choice of speciation procedures for the measurement of the toxic fraction of a metal in a water sample are discussed in detail.     

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.     

Synthesis and efficiency of a spherical macroporous epoxy-polyamide chelating resin for preconcentrating and separating trace noble metal ions

The determination of noble metals in various materials usually requires their preconcentration and separation from other elements. In spite of the improvements in analytical instrumentation and the development of new analytical techniques such as ICP-MS, which are capable of detecting metal ions at ppt levels, the interference caused by the sample matrix still exists and is perhaps the most serious problem, making a pre-determination enrichment step necessary. Thus, the search for efficient preconcentration and separation methods is essential. A series of chelating resins that can selectively adsorb noble metal ions from aqueous solutions have been described. Functional groups, such as salicylaldoxime and thiosemicarbazide have been incorporated in cross-linked polymers or porous silica gel. These resins have very high selectivity for one or several types of noble metal ion. However, desorption of noble metals from these resins is usually difficult. Hence, the development of an adsorbent from which noble metals can be easily desorbed is needed. In this paper, a new spherical macroporous epoxy-polyamide chelating resin that met this requirement was synthesized by one step reaction. The synthesis of the resin was safe, rapid and more simple and economical than many report adsorbents. Meanwhile, the resin showed more advantages: better acid and alkali resistance; higher adsorption capacity and lower preconcentration concentrations. A resin column procedure combined with inductively coupled plasma atomic emission spectrometry (ICP-AES) for the determination of trace Rh(III), Ru(III) and Ir(IV) in real samples was established.     

Direct evidence for two interaction modes in adsorption of divalent metal ions to iminodiacetate-type chelating resins.

The adsorption curves of divalent metal ions (M2+) to an iminodiacetate(IDA)-type chelating resin (-L2-) under the condition of metal ions in excess against IDA groups clearly indicated the difference in contribution between two species. Copper and nickel are adsorbed only as [(-L)M(II)], while cadmium and calcium are adsorbed as [(-L)M(II)] and [(-LH)2M(II)]. Addition of salts may enhance the deprotonation of IDA groups, interfere with the adsorption as [(-LH)2M(II)], and yield remarkable changes in adsorption curves, depending on the metal ions.     

ADSORPTION SELECTIVITY FOR Cu^2＋,Ni^2＋,Co^2＋IONS USING CROSSLINKING CHITOSAN RESINS IMPRINTED BY METAL IONS

Metal ion-imprintedly crosslinked chitosan resin 1 and resin 2 were prepared by the use of Cu^2+ and Ni^2+ as template ions and glutaraldehyde as crosslinking agent,respectively,Through investigation on the adsorption capacties and binding constants for Cu^2+,Ni^2+ and Co^2+ ions on chitosan resins,resin 1 and resin 2 exhibit the adsorption selectivity for the mixture solution of 1L1 Cu^2+ and Ni^2+ ions.The adsorption selectivity of metal ion-imprinted resins for their template ions in much higher than that of uncrosslinked chitosan resin.     

ADSORPTION SELECTIVITY FOR Cu~(2 ),Ni~(2 ),Co~(2 )IONS USING CROSSLINKING CHITOSAN RESINS IMPRINTED BY METAL IONS

1introductionChitosan,adeacetylatedderivativeofchitin,isnatUralpolysaccharideswithfreeaminogroups.Itcanactasanexcellentadsorbenttoadsorbnotonlyvariousorganiccompoundsincludingpolychlorinatedbiphenyls,proteinsandnucleicacids,butalsometalions[1~sl.ChitosanhasbeenwidelyemployedasaneffectivecoagulatingagentinactivatedsludgeplantSandfoodprocessingfactories,andalsoinpreparation,concentTationandpurificationofmetalionsinhydrometallurgy.Chitosanbehavesasanaturalchelatingpolymer.Chitosanundergoeschela…     

Adsorption behavior of uranium(VI) and other ionic species on cross-linked chitosan resins modified with chelating moieties

Cross-linked chitosan resins with catechol (catechol-type chitosan, type 1 and type 2), iminodiacetic acid (IDA-type chitosan), iminodimetylphosphonic acid (IDP-type chitosan), phenylarsonic acid (phenylarsonic acid-type chitosan), or serine (serine-type chitosan) were prepared for the collection and concentration of uranium(VI). The adsorption behavior of U(VI) and other ionic species, such as metal ions and oxo-acid ions, on the cross-linked chitosan (base material) and chitosan resins modified with chelating moieties was examined using a column procedure. Especially, the catechol-type chitosan (type 2) adsorbed U(VI) at pH 2-7, and selectively collected U(VI) at acidic pH regions by forming a stable chelate with hydroxyl groups of catechol moiety introduced to the chitosan. Also, the adsorption properties of cationic and anionic species present in aquatic media were elucidated. The adsorption ability for U(VI) was in the order: catechol-type chitosan (type 2) > serine-type chitosan > phenylarsonic acid-type chitosan > the others. The catechol-type chitosan (type 2) was useful for the collection and concentration of uranium(VI).     

A comparison of preconcentration reagents for flow injection analysis flame atomic spectrometry

A small range of new commercially available chelating resins are compared with a resin prepared in-house in terms of their applicability for on-line preconcentration and matrix separation. The flow injection manifold was designed for rapid matrix separation and the resins were tested for the determination of Cull, ZnII, CdII, MnII and NiII. The resin based on controlled pore glass was found to be better for this rapid procedure because it did not require conditioning, although the polymer based resins had better capacities. The commercially available controlled pore glass based iminodiacetate (IDA) resin had a comparable performance to the in-house controlled pore glass 8-hydroxyquinoline (CPG-8-HQ) resin. The IDA resin had a much higher capacity than the 8-HQ, however as with all IDA based resins, some retention of Call was observed. The sample throughput was 12 h⁻¹.     

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+.     

基于壳聚糖及其衍生物的金属离子吸附剂的研究进展

综述了近年来以壳聚糖和壳聚糖衍生物为原料的金属离子吸附剂的研究进展．重点介绍了壳聚糖及其衍生物的交联和功能化反应，以及交联后的树脂对多种金属离子的吸附情况．常用的交联剂包括戊二醛、甲醛及环氧氟丙烷，(聚)乙二醇双缩水甘油醚等，壳聚糖树脂的功能化主要包括向其中引入冠醚、羧甲基等功能团，其中羧甲基化是最常用最有效的方法．另外，还介绍了金属离子模板壳聚糖树脂以及基于壳聚糖衍生物的蛇笼树脂的合成。     

Selective metal sorption on cross-linked poly(vinylpyridine) resins

The sorption behaviour of several metal ions on five kinds of poly(4- or 2-vinylpyridine) resins, cross-linked with divinylbenzene, and with different surface properties, are examined. All the resins proposed sorb some metal ions effectively in a similar manner by anion-exchange, while the sorption of metal ions by complex formation with the pyridine moiety is strongly affected by the surface properties of the resins. A macroreticular poly(4-vinylpyridine) resin shows high affinity for copper and nickel ions in acetate buffer. Sodium chloride and/or methanol added to the working solutions influence the sorption capacities for metal ions. This resin was applied to the separation of copper/cobalt and nickel/cobalt and the concentration of copper from sea-water by a column operation.