Synthesis,characterization, and antimicrobial studies of newly developed metal‐chelated epoxy resins

A series of novel metal‐chelated epoxy resins have been synthesized by the condensation of epichlorohydrin (1‐chloro‐2, 3 epoxy propane) with bisphenolic metal chelates in alkaline medium. The bisphenolic chelates were initially prepared by the reaction of 3‐formyl‐4, 4′‐dihydroxy diphenyl methane and diamine (ethylenediamine/o‐phenylenediamine) in 1:2 molar ratio and then with Cu(II), Ni(II), and Co(II) acetate. The metal‐chelated epoxy resins were characterized by various instrumental techniques, such as elemental analysis, DSC and TGA, electronic, FTIR, ¹H‐NMR, and ¹³C‐NMR spectra. The physicochemical properties, viz., epoxide equivalent weight (eq/100 g), hydroxyl value (eq/100 g), refractive index, specific gravity, and specific viscosity were measured by standard procedures. The antimicrobial activities of these chelated resins were screened against Escherichia coli, Staphylococcus aureus, Bacillius subtilis (bacteria), and Candida albicans, Mucor species (yeast) by using agar well diffusion method. All the polymeric chelates show promising antimicrobial activities. Among these polymeric chelates (ERPD)‐Cu(II) shows better antimicrobial activities, which can be attributed to higher stability constant of Cu(II) chelate than others. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1347–1355, 2006     

Kinetic and equilibrium modeling of liquid‐phase adsorption of lead and lead chelates on activated carbons

The sawdust (SD) waste generated in the timber industry was converted to a low‐cost activated carbon (SDAC) using a simpler and cheaper activation process, single‐step steam pyrolysis activation. The possibility of utilizing SDAC for the removal of lead (Pb(II)) in the absence of ligands and nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA) chelated Pb(II) complexes from the liquid phase was examined and the results were compared with those for commercial activated carbon (CAC). SDAC shows a high adsorption capacity for Pb(II) and Pb(II) chelates compared with CAC. The extent of adsorption of Pb(II) and Pb(II) chelates on activated carbons was found to be a function of solution pH and species distribution of Pb(II) and Pb(II) chelates. The optimum pH range for the removal of Pb(II) in the absence of ligands by SDAC was 6.5–8.0, whereas its maximum removal by CAC was observed at pH 6.5. In the presence of ligands, the extent of Pb(II) adsorption was enhanced in the pH range 2.0–5.0 and was reduced significantly in the pH range 6.0–8.0. The maximum uptake of Pb(II) chelates for both carbons was observed at pH 5.0. Kinetic models such as pseudo‐first‐order, pseudo‐second‐order and pore diffusion were tested to investigate the adsorption mechanism. Batch kinetic studies showed that the adsorption of Pb(II) from aqueous solutions with and without ligands could be best described by a psuedo‐first‐order model for both carbons. The effect of pH on the adsorption isotherms of Pb(II) and Pb(II) chelates was also investigated. The applicability of the Langmuir and Freundlich isotherms, established for various initial concentrations of the adsorbate and for different pH values, was tested at 30 °C. Copyright © 2003 Society of Chemical Industry     

选择性螯合滴定法测定铋

用ＭＳＡ为释放剂，选择性螯合滴定法测定镀层和镀液中铋。用ＥＤＴＡ螯合Ｂｉ＾３＋和其他阳离子，然后加入ＭＳＡ分解Ｂｉ－ＥＤＴＡ螯合物，释放出的ＥＤＴＡ用锌标准溶液返滴定。实验结果表明，各种阳离子都不干扰。该方法已成功地用于测定锡铋铈合金镀层和镀液中的含量。     

Polychelatogene zur Anreicherung und Abtrennung von Metallionen in homogener Phase mit Hilfe der Membranfiltration

Macromolecular chelating agents have been synthesized and investigated for the complexation with various metals in homogeneous phasing using membrane filtration. Quite a number of water-soluble basis polymers such as poly(vinylamine), poly(acrylic acid), poly(ethyleneimine), and copolymers, and their derivatives are listed and discussed in respect to their application for the chelation of transition metals. The polymers had molecular masses between 20000 and 200000 daltons. The application of membrane filtration rendered it possible to separate excess metallic ions from the polymer chelate in a continuous or discontinuous process. Studies on the metal-binding capacity of the polymer ligand exhibited the possiblity of preparation of macromolecular chelating agents which are selective for different metals. There after, the introduction of chelating groups such as iminodiacetic acid, thiourea, pyridine-2-aldimine, and others, improved significantly the selectivity for the metals copper, nickel, palladium, mercury, iron, gold, and platinum. For the regeneration of the polymer ligands electrolysis and protolysis can be used. The macromolecular chelates remained water-soluble independent of the chelated metal and the polymeric chelating agent. According to these studies, certain metals can be removed selectively from waste water or other diluted solutions in homogeneous phase by the application of polymeric chelating agents.     

Metal‐chelated polyamide hollow fibers for human serum albumin separation

We modified microporous polyamide hollow fibers by acid hydrolysis to amplify the reactive groups and subsequent binding of Cibacron Blue F3GA. Then, we loaded the Cibacron Blue F3GA‐attached hollow fibers with different metal ions (Cu²⁺, Ni²⁺, and Co²⁺) to form the metal chelates. We characterized the hollow fibers by scanning electron microscopy. The effect of pH and initial concentration of human serum albumin (HSA) on the adsorption of HSA to the metal‐chelated hollow fibers were examined in a batch system. Dye‐ and metal‐chelated hollow fibers had a higher HSA adsorption capacity and showed less nonspecific protein adsorption. The nonspecific adsorption of HSA onto the polyamide hollow fibers was 6.0 mg/g. Cibacron Blue F3GA immobilization onto the hollow fibers increased HSA adsorption up to 147 mg/g. Metal‐chelated hollow fibers showed further increases in the adsorption capacity. The maximum adsorption capacities of Co²⁺‐, Cu²⁺‐, and Ni²⁺‐chelated hollow fibers were 195, 226, and 289 mg/g, respectively. The recognition range of metal ions for HSA from human serum followed the order: Ni(II) > Cu(II) > Co(II). A higher HSA adsorption was observed from human serum (324 mg/g). A significant amount of the adsorbed HSA (up to 99%) was eluted for 1 h in the elution medium containing 1.0M sodium thiocyanide (NaSCN) at pH 8.0 and 25 mM ethylenediaminetetraacetic acid at pH 4.9. Repeated adsorption–desorption processes showed that these metal‐chelated polyamide hollow fibers were suitable for HSA adsorption. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3346–3354, 2002     

The Adsorption and Desorption Characteristics of EDTA-Chelated Copper Ion by Activated Carbon

Abstract

This paper addresses the effect of EDTA, a strong agent, on the removal of copper ion from solutions using activated carbon adsorption. Experimental studies indicate the presence of EDTA significantly altered the adsorption behavior of copper on the activated carbon due to the formation of copper chelate species in the solution. The adsorption isotherms and kinetics were found to be strong functions of solution pH and the ratio of copper ion and EDTA concentrations. Adsorption of EDTA-Cu chelates was found to be more favorable than those of free copper ion and unbound EDTA species in the solution. Experimental results indicated that the desorption of chelated copper ion from activated carbon by NaOH and HClO⁴ solutions was influenced by the initial adsorption conditions. A significantly higher quantity of copper ion was recovered with HClO⁴ than with NaOH. Combining the adsorption and desorption data of copper and EDTA, and an understanding of the species distribution of copper in the presence of EDTA, the behavior of the adsorption of EDTA-chelated copper on the activated carbon was described. The predominant adsorbed copper species was the chelated form, CuEDTA^2-, which can be adsorbed on activated carbon surfaces with either the Cu end or the EDTA end bonding directly to the surface.     

Some Semiconductor Properties of Carboxymethyl Cellulose-Copper Complexes

Metal chelates of three grades of carboxymethyl cellulose (CMC) (LI-L3) with Cu(II) ions, either originating from CuCl₂ or CuSO₄, were prepared and characterized by elemental analysis, infrared spectra, and electrical conductivity studies. The results showed that the degree of substitution of CMCs and the origin of the Cu(II) ion have a profound effect on the amount of metal included in the polymer complexes and the structure and the electrical conductivity of the prepared complexes. CMC acts as a uninegatively charged bidentate ligand when it is chelated with Cu(II) of CuCl₂ via the carboxymethyl group and exhibits the formula Cu(L)₂, whereas it acts as a binegatively charged bitentate ligand when it is chelated with CuSO₄ via the carboxymethyl and secondary hydroxyl groups and exhibits the formula CuL.2H₂O. The investigation revealed that the electrical conductivity depends on the temperature and has two maximum peaks. The values of the activation energy for the conductivity of CMC and their complexes indicated that the samples changed from a low-semiconductor to a high-semiconductor property with heating. It is found that CMC-Cu(II) complexes formed from CuSO₄ exhibit a high-semiconductor property compared to complexes derived from CuCl₂.     

Mass transfer and kinetic behaviour of chelated cadmium solutions

The effect of the chelating agents nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA) on the electrodeposition of cadmium from solutions was studied. Experimental results show that the presence of a chelating agent severely inhibits cadmium reduction. The mass transfer and kinetic behaviour of cadmium ions in chelated solutions (NTA and EDTA) were investigated. The observed overall diffusion coefficients of the chelated cadmium solutions, using the simple Levich equation, were found to be a function of the solution pH and the chelating agent. The relevant kinetic properties, such as the reaction order, αz, k_f⁰ and the equilibrium potential, were measured for cadmium ions in the chelated solutions. The diffusion coefficients of the more stable chelated cadmium species were found to be less than those of the less stable chelated cadmium species, thus causing more interference in the diffusion step.     

Effect of organic chelates on the performance of hybrid sol–gel coated AA 2024-T3 aluminium alloys

Sol–gels are organic–inorganic polymers formed by hydrolysis/condensation reactions of alkoxide precursors, primarily silanes, which have found applications as electronic, optical and protective coatings. These coatings possess important characteristics such as chemical stability, physical strength and scratch resistance. Further performance improvement is achieved through the incorporation of zirconium and titanium based nanoparticles, also formed through the sol–gel process. However due to the inherent difference in the reactivity of the precursors, the hydrolysis of each precursor must be carried out separately before being combined for final condensation. Zirconium precursors are commonly chelated using acetic acids, prior to hydrolysis, to lower the hydrolysis rate.In this body of work various ligands such as organic acids, acetyl acetone (AcAc) and 2,2′-bipyridine (Bipy) were used to control the zirconium hydrolysis reaction and form nanoparticles within the silane sol matrix.Nanoparticle modified coatings formed from the silane sol on AA 2024-T3 aluminium were characterised spectroscopically, electrochemically and calorimetrically to evaluate the potential effect of the different chelates on the final film properties while neutral salt spray tests were performed to study their anti-corrosion performance. Results indicate that the acid ligand modified coatings provided the best performance followed by AcAc, while Bipy was the poorest. In all cases the zirconium nanoparticle improved the protective properties of the sol–gel coating.     

聚丙烯腈基螯合纤维的研究进展

回顾了聚丙烯腈基螯合纤维近年的研究进展,介绍了聚丙烯腈基螯合纤维的制备方法,螯合机理以及其应用情况,并对今后聚丙烯腈基螯合纤维的发展进行了展望。认为开发具有消臭、抗菌等多功能纤维,制备纳米金属/聚丙烯腈基复合纤维,将会被更多关注,前景乐观。     

Facile access to enantiomerically pure bis(sulfoxide) chelates of late transition metals

Herein contains a report detailing the synthesis and characterization of six, chiral, late-transition metal complexes all chelated using R_S,R_S-bis(p-tolylsulfinyl)ethane, R_S,R_S-BTSE. All complexes revealed S-ligation to the metal with an expected contraction of the sulfinyl-oxygen bond length when compared to free sulfoxide. The presented data serve to illustrate three attractive, yet unexplored, aspects of the bis(sulfoxide) bidentate ligand: (i) bidentate sulfoxide ligands, when chelated to a metal, give rise to complexes that are pseudo-C₂ symmetric in terms of both sterics and electronics, (ii) the sulfoxides, unlike typical N-, P-, and O-based ligands, present the coordination sphere with a significant amount of steric and electronic mismatch, and (iii) the data support the fact that sulfoxides are moderate σ-donors and good-to-excellent π-acceptors – an aspect that should afford such metal chelates with a wide degree of reactivity. Finally, X-ray crystallographic experiments, coupled with an extensive CCDC search, provide an opportunity to establish the following ligand-ranking scheme for bidentate ligands spanned by an ethylene bridge, R₂N–<RS(O)–<RS–<R₂P–, based on the trans influence of chloride salts of Pt(II).     

Chelation of chitosan derivatives with zinc ions. II. Association complexes of Zn2+ onto O,N‐carboxymethyl chitosan

The chelation of zinc ions onto O,N‐carboxymethyl chitosan (ONCMCh) was characterized using a Fourier transform infrared (FTIR) spectrophotometer and a scanning electron microscope (SEM). From the FTIR spectra, little change in the absorption intensities and frequencies at 3300–3600 cm⁻¹ of Zn²⁺ ONCMCh chelated specimens suggested that  OH and  NH₂ groups were not participating in the chelation reaction. The absence of absorption bands at 1755–1700 cm⁻¹ suggested that the carboxyl group CO was not ionized, and the ionized CO bands were observed at 1400–1600 cm⁻¹ for chelated specimens. Thus, the chelation sites took place at the carboxyl group rather than at the  OH and NH₂ groups. It also confirmed that water‐insoluble chelates, which were formed through the Zn O and Zn N bonds, presented a tetrahedral structure. The water‐soluble complexes where zinc ions connected with oxygen of CO and water molecules were only due to electron attraction. Formation of different microstructures on the surfaces, as revealed by SEM, provided evidence to distinguish different chelating mechanisms between water‐soluble and water‐insoluble complexes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1476–1485, 2001     

有机中微肥的生产及其应用前景

我国中低产田面积占总耕地面积70%以上,其中大部分存在有机质和中微量元素缺乏和肥料利用率低的问题。为防止中微量元素施入土壤后被固定而失效,提出利用废弃资源,生产有机中微肥(如氨基酸、木质素磺酸、腐植酸中微肥等),其生产成本比EDTA螯合中微肥低,并简要介绍了各种有机中微肥的生产工艺过程。只要做到测土施肥,有针对性加入有机中微肥,即可达到提高作物产量、品质,提高肥料利用率,提高土壤肥力的良好效果。     

Synthesis of monodisperse nonporous crosslinked poly(glycidyl methacrylate) particles with metal affinity ligands for protein adsorption

Monodisperse nonporous crosslinked poly(glycidyl methacrylate) (PGMA) particles with immobilized metal affinity ligands were prepared for selective recovery of proteins. The PGMA particles, with an average size of 2.2 µm, were prepared by a simple dispersion polymerization of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA). The particles were characterized by scanning electron microscopy (SEM) and Fourier‐transform infrared spectroscopy (FTIR). The epoxy groups of the particles were modified with the metal chelating agent iminodiacetic acid (IDA), which forms metal–IDA chelates at the active sites. After charging with copper ions, the particles were used to recover a model protein, bovine hemoglobin (BHb), in a batchwise manner. The particles had the adsorption capacity of 218.7 mg g⁻¹ with little nonspecific adsorption. The adsorption behavior could be described with the Langmuir equation. The effect of pH on the adsorption was also studied. Regeneration of the metal‐chelated particles was easily performed with 50 mmol L⁻¹ ethylenediaminetetraacetic acid (EDTA), followed by washing with water and reloading with Cu²⁺. The particles could be very useful as an affinity separation adsorbent. Copyright © 2005 Society of Chemical Industry     

Adsorption of copper(II) and EDTA‐chelated copper(II) onto granular activated carbons

Waste streams generated by electroless copper plating in the printed circuit boards manufacturing industry often contain copper complexed by strong chelating agents such as EDTA. The consequence of metal complexation by chelating agents is that alternative treatment to chemical precipitation is often necessary to achieve the low metal concentrations required by increasingly stringent environmental regulations. This paper examines the feasibility of using activated carbon to remove EDTA‐chelated copper(II) species as well as free copper(II) ions from aqueous solution. The adsorption characteristics of copper(II) and EDTA‐chelated copper(II) on two granular activated carbons prepared from coal and coconut shell were evaluated. Adsorption equilibrium data of copper(II) on the two carbons corresponded well to the Langmuir model. The coconut shell‐based carbon exhibited a greater adsorption capacity for copper(II) than the coal‐based carbon under similar experimental conditions. Solution pH had a considerable influence on copper(II) adsorption by the two carbons. Low adsorption levels of copper(II) at pH 3 and high adsorption levels in the pH range of 4–6 were observed. However, a reverse adsorption trend was observed when the chelating agent EDTA was added to the copper(II) solution. Adsorption of EDTA‐chelated copper(II) by the two carbons was higher at pH 3 than at pH 6. The contrasting adsorption behaviour of copper(II) ions and EDTA‐chelated copper(II) species can be readily explained in terms of electrostatic interaction in that solution pH influences the surface charge of the carbons as well as the charge property of copper(II) ions and EDTA‐chelated copper(II) species. © 2000 Society of Chemical Industry     

Study on EDTA‐chelated copper adsorption by granular activated carbon

Equilibrium and kinetic experiments on uptake of single‐species copper, EDTA, and EDTA‐chelated copper by an H‐type granular activated carbon under various factors, such as pH, ionic strength and EDTA concentration were carried out in this study. Adsorption of copper ions was increased with an increase in solution pH when the solution contained single‐species or EDTA‐chelated copper ions. The solution pH increased significantly from its lower initial value, which resulted from the adsorption of hydrogen ions by the carbon. The efficiency for the single‐species metal ion removal was increased from 5 to 95% when the solution pH was increased from 2 to 7.5. EDTA‐chelated metal ion removal, however, was increased from 7 to 97% as the pH was increased from 1.5 to 7.5. EDTA adsorption percentages increased when the solution pH was increased and the initial concentration was decreased. Slightly higher EDTA‐chelated copper removal was observed when the ionic strength was higher and the ratio of EDTA to copper concentrations was 1:1. Kinetic experiments demonstrated that the copper adsorption occurred rapidly in the first hour. No further change in the removal was observed after 3 and 6 h for single‐species or EDTA‐chelated, respectively. The EDTA‐chelated copper adsorption kinetics was enhanced with an increase in EDTA concentration and a decrease in ionic strength. © 2000 Society of Chemical Industry     

The preparation and properties of chelates of transition metal ions with the homopolymer and copolymers of p-vinylbenzoylacetone

p-Vinylbenzoylacetone (VBA) was prepared by the condensation of p-vinylacetophenone and ethyl acetate. This monomer was homopolymerized and copolymerized with acrylamide or maleic anhydride to produce polymers which would chelate substantial amounts of transition metal ions such as Cu²⁺, Ni²⁺, Co²⁺, Eu³⁺, and VO²⁺. In the case of the Cu²⁺ and Ni²⁺ chelates, about 80–90% of the metal ion could be eluted by dilute mineral acids. The resulting eluted products apparently have a somewhat porous structure because they are capable of rechelating these ions from water solution, even though the solid homopolymer which had not been chelated and eluted is too hydrophobic to chelate very much metal ion from water solution. The eluted Cu²⁺ chelate readily reaccepted Cu²⁺ ions from water solution and discriminated against Ni²⁺ almost completely. However, the eluted Ni²⁺ chelate would reaccept both Cu²⁺ and Ni²⁺ ions, but exhibited a strong preference for Cu²⁺ ions in competitive batch experiments. The VO²⁺ chelate was an effective heterogeneous phase catalyst for the epoxidation of allyl alcohols such as geraniol with tert-butylhyroperoxide. The chelate was stable under these oxidative conditions and could be recovered unchanged and reused.     

提高深色羊绒摩擦牢度的研讨

深色羊绒摩擦牢度与纤维本身所合“杂质”有关，染色前，用合有替合剂和表面活性剂的水溶液进行前处理，用媒介染料染羊毛时添加分散替合剂，用Lanasol活性染料染羊毛时添加由异丁醇、苄醇、脂肪叔胺聚氧乙烯改组成的匀染剂可以提高摩擦牢度。探讨了染料的化学结构、染料的纯度、染料的提升力、染色后处理与干、湿摩擦牢度的关系。     

Dimedone and phenylazo dimedone chelates of europium as emitters in polymers

Transparent polymers when incorporated with strongly fluorescent europium chelates were found to be responding to excitation with UV radiation. In this work, two novel europium chelates have been synthesized using the β‐diketones dimedone and phenylazo dimedone along with 1,10‐phenanthroline. These chelates were characterized by elemental analyses, magnetic susceptibility measurements, UV, IR, and ESI mass spectral techniques. The chelates synthesized with metal : β‐diketone : 1,10‐phenanthroline ratio 1 : 3 : 1 were incorporated into polymer matrices. Four polymers, polyethylene vinyl acetate or acetate (EVA), polystyrene (PS), poly methyl methacryalate (PMMA), and polyethylene glycol (PEG) were used for the studies. All these, except the liquid oligomer PEG were cast into thin films. PEG was used as such for the studies. The photoluminescence spectra of the plain polymers were found to be having peaks very close to the absorption peaks of the polymers doped with europium chelate. This observation can be used in optical devices. Thermal analyses like TG/DTG/DTA of the polymer films were conducted to ascertain the thermal stability of the material. The SEM analyses of the films indicated a smooth surface with uniform distribution of the doped chelate. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Cathodic Tb(III) chelate electrochemiluminescence at oxide-covered magnesium and n-ZnO:Al/MgO composite electrodes

Some of the luminescent aromatic Tb(III) chelates can be excited at oxide-covered magnesium and n-ZnO:Al/MgO composite electrodes by cathodic pulse polarization in aqueous solution. This is based on the cathodic injection of hot electrons into the aqueous electrolyte solution and successive redox reactions in one-electron steps resulting in the excited states of the chelates. Due to the relatively long luminescence lifetime of multidentate Tb(III) chelates, these chelates can be very sensitively detected by time-resolved electrochemiluminescence (TR-ECL) measurements using the present working electrodes. Thus, metal or highly doped semiconductor electrodes coated by a thin MgO film lend themselves as nontransparent or in some cases, even optically transparent working electrodes for generation of free radicals and cathodic ECL in aqueous solution. The results suggest that also other even more efficient optically transparent composite tunnel emission electrodes than the present n-ZnO:Al/MgO electrodes could be constructed by coating n-ZnO:Al glass electrodes with other wide band gap insulating oxides.