Polyethyleneimine supports for resins with retention properties for heavy metals. Part 3

Summary Resins with retention properties for copper(II) and uranium(VI)were synthesized by crosslinking of polyethyleneimine with 1,9-dibromononane and 1,10-dibromodecane, and subsequent alkylation with dimethylsulphate. The effect of the pH on the retention, elution assays in acid and basic medium, and maximun capacity of load were determined. Moreover, the thermal behaviour was studied.     

Linear polyethyleneimine supports for resins with retention properties for heavy metals. Part 2

Summary A linear polyethyleneimine obtained by cationic polymerization of 2-methyl-2-oxazoline was crosslinked with 1,4-dibromo-2-butene (IML-1). This resin subsequently was N-alkylated with dimethyl sulphate (IML-1M). With both resins were carried out analytical assays, such as: pH dependence for copper (II), uranium (VI), iron (II) and (III); maximum capacity of load for copper and uranium; elution assays. Moreover, the morphology by scanning electron microscopy and thermal stability were studied.     

Polyethyleneimine supports for resins with retention properties for heavy metals part I

Summary Resins with retention properties for copper (II), and uranium (VI) have been synthesized by crosslinking of polyethyleneimine with 1,4-dibromo-2-butene and subsequent alkylation with dimethyl sulphate. The influence of pH on the retention, maximum capacity of load and elution assays were determined.     

Polysulfones with chelating groups for heavy metals retention

The formation conditions of new quaternized polysulfones with chelating groups (methyl 3‐pyridyl ketone) (KQPSF) and the major factors influencing the retention process of copper ions were analyzed by attenuated total reflection Fourier transform infrared spectroscopy, atomic force microscopy, environmental scanning electron microscopy, and differential scanning calorimetry. The investigations showed that the percentage of copper ions retained by KQPSF increases by increasing both the time of immersion in a CuCl₂·2H₂O aqueous solution, and molarity, the maximum value being attained on immersion for 48 h, at a temperature of 60°C and a molarity of 1.5 M. It can be concluded that methyl 3‐pyridyl ketone might be used for obtaining complex polysulfone structures employed by multiple applications, including wastewater purification. POLYM. COMPOS.,, 2012. © 2012 Society of Plastics Engineers     

Functional copolymers with retention properties for heavy metal ions

Summary Poly (N-phenylmaleimide-co-2-methylaziridine); poly [p-methylphenyl-maleimide-co-1-(2-hydroxyethyl)aziridine]; poly [p-methoxyphenylmaleimide-co-1-(2-hydroxyethyl)aziridine] and poly [N-phenylmaleimide-co-1-(2-hydroxyethyl)aziridine] were synthesized by spontaneous coplymerization. All the resins were insoluble in water. It was found that the resins with 1-(2-hydroxyethyl)aziridine moiety showed the highest adsorption ability for uranium.     

Vinyl resins with retention properties for heavy metal ions

Summary Resins with carboxylic pendant groups were synthesized. The resins were characterized by elemental analyses and FT-IR spectroscopy, and the ability to bind copper (II) and uranium (VI) by batch method at different pH was studied. Uranium(VI) is adsorbed at pH 3 and pH 4 above 88%. The maximum capacity of load for uranium(VI) is higher than IRA-400, a commercial resin. Elution assays for Cu(II) and U(VI) from the loaded resins with sulfuric acid and sodium carbonate were also carried out.     

Branched poly(ethylene imine) support for resins with retention properties for heavy metal ions

A crosslinked poly(ethylene imine), using epichlorohydrin as crosslinker, was prepared and subsequently modified in order to obtain the corresponding N-methylated, N-carboxymethylated and N-phosphonomethylated derivatives. The sorption characteristics of these functionalized resins were studied by a batch equilibration technique, for uptake of Cu(II), Fe(II), Fe(III) and uranyl ions from aqueous solution. Resins with tertiary amine or ammonium groups show negligible sorption for Fe(II), Fe(III) and Cu(II) at pH 1, in contrast with high sorption for U(VI), which is readily eluted with sodium carbonate.     

改性玉米淀粉对重金属捕集性能的研究

研究了二硫代氨基甲酸改性玉米淀粉(DTCS)对单一重金属溶液中重金属离子的捕集作用,考察了影响其捕集作用的因素,包括重金属种类、pH、温度、混凝时间、无机离子的干扰等,确定了合适的应用条件.结果表明,在单一重金属离子浓度为1.0×10-3 mol/L的溶液中,DTCS对重金属离子捕集的选择性:Cu2 ＞Pb2 ＞Cd2 ＞Zn2 ＞Ni2 ,去除率分别为99.91%、99.88%、87.36%、85.17%、66.36%,且K 、Ca2 等无机离子对其去除效果影响不大.     

Resins containing amino and carboxylic acid groups. Synthesis,characterization, and metal ion retention properties

The crosslinked poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide], P(MAPDSA), and poly[3‐(methacryloylamino)propyl]dimethyl(3‐sulfopropyl)ammonium hydroxide‐co‐acrylic acid], P(MAPDSA‐co‐AA), were synthesized by radical polymerization. The resins were completely insoluble in water. Due to the lower metal ion retention of P(MAPDSA), the metal ions investigated under competitive and noncompetitive conditions for Cu(II), Cd(II), Hg(II), Zn(II), Pb(II), and Cr(III) ions by batch and column equilibrium procedures were carried out only for P(MAPDA‐co‐AA), particularly for Hg(II). The resin–Hg(II) ion equilibrium was achieved before 15 min. The resin showed a maximum retention capacity value for Hg(II) at pH 2 of 1.89 meq/g. The resin showed a high selectivity to Hg(II) ions. The recovery of the resin was investigated at 25°C with different concentrations of HNO₃ and HClO₄. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 525–530, 2005     

Sorption properties of modified peat with respect to petroleum and heavy metals

The group composition of high-moor peat modified by mechanical activation was studied, and the physicochemical characteristics of this peat were determined. It was found that the preliminary mechanical activation of peat, in particular, in the presence of iron oxyhydoxide improved its characteristics as a sorbent for petroleum and heavy metals.     

On the fate of heavy metals in municipal solid waste combustion Part I: devolatilisation of heavy metals on the grate

The aim of this study has been to investigate the chemistry and volatility of the heavy metals As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn on the grate of a MSW fired furnace, using equilibrium calculations. Focus has been on the influence of varying MSW composition and operational parameters such as air/fuel ratio and temperature. Equilibrium distributions at 950–1600 K, under reducing and oxidising conditions on the grate, showed that Cd, Hg and Pb are fully volatilised. However, Cr is found to be stable in solid phase, in the entire temperature range. The volatile behaviour of Cd, Cr, Hg and Pb show no significant influence, while As, Cu, Ni and Zn are strongly influenced by one or more of the parameters; temperature, fuel/air and chlorine/metal ratios.     

Epoxy Resins from 1980 to Date. Part 1

Epoxy resins are essentially prepolymers that contain on an average two or more epoxide groups per molecule. The object of the present review article is to give up-to-date information regarding the reactions of these resins with various curing agents leading to crosslinked or thermoset resins with excellent strength, toughness, and chemical resistance. The end-use consumption of epoxy resins covers a broad range of applications such as adhesives, bonding, construction materials (flooring, paving, and aggregates), composites, laminates, coating, molding, and textile finishing. Recently these resins have penetrated into the aero- and spacecraft industry. It is expected that anybody engaged in industry or academic research will find enough material in this review to start work, and need not search the literature before 1990.     

生物滞留技术净化径流中重金属研究进展

综述了国内外雨水径流中重金属污染现状,分析了重金属在径流中以及生物滞留介质中的赋存形态。简要介绍了生物滞留技术中几种常见的设施,并阐述了生物滞留设施构造及滞留介质类型对净化重金属效果的重要影响。指出了在长期运行条件下,存在重金属从生物滞留设施中渗出的风险,未来可以针对这方面开展研究。     

Interaction of heavy metals with chitin and chitosan. III. Chromium

The interaction of the natural marine polymer chitin and its deacetylated derivative chitosan with chromium has been investigated. The uptake of chromium from aqueous solution was determined from changes in concentration as measured by atomic absorption spectroscopy. The uptake of Cr(III) on chitosan was significantly greater than that on chitin. The smaller the size fraction of the chitin/chitosan, the greater the uptake of Cr(III). The Cr(III) uptake increased with increasing solution pH. Minimal desorption of chromium was observed on washing previously chromium-equilibrated chitosan with distilled water. The uptake of Cr(III) by chitosan was enhanced in the presence of phosphate, whereas the converse was not observed. Minimal uptake of Cr(VI) as dichromate by chitin and chitosan was measured. Cr-containing nodules were noted in the SEM/EDAX analysis for Cr(III)-equilibrated chitosan. Cr-containing clusters were detected for Cr(III)- plus phosphate-equilibrated chitosan. XPS results supported the conclusions drawn from the isotherm studies.     

Complexes of poly(2-N,N-dimethylaminoethyl) methacrylate with heavy metals I. Preparation and properties

The present paper studies the synthesis of complexes of poly(2-N,N-dimethylaminoethyl) methacrylate with aqueous solutions of of salts of FeSO₄.2H₂O; CoCl₂.6H₂O; CuCl₂.2H₂O; VOSO₄.5H₂O; Na₂MoO₄.2H₂O and Na₂WO₄.2H₂O. The introduction of metal ions depends on the content of crosslinking agent and was in the range from 1.18 to 59.63 mg metal ion/g polymer carrier. The study of polymer complexes by IR and Moesbauer spectroscopy, as well as EPR, provides possibilities to suggest the probable co-ordination structure of the compounds.     

Adsorption properties of modified peat toward organic compounds and heavy metals

The adsorption properties of peat modified by mechanical activation in the presence of iron oxide hydroxide were studied. Based on the results of the determination of adsorption activity and microcalorimetric studies, it was established that physical absorption processes predominate on the interaction of the modified peat sorbents with a model organic substance and the aqueous solutions of metal salts. It was demonstrated that new types of sorbents with high sorption properties can be obtained based on peat mechanically activated in the presence of water treatment wastes     

Electrokinetic remediation of soils contaminated with heavy metals

This paper describes the results obtained from an electrokinetic treatment of a real soil polluted by lead acetate. Powdered soil samples were pressed with a consolidometer till 100 kPa to obtain cylindrical specimens with the same characteristics as a subsoil. Tests were carried out in a Perspex electrochemical cell where soil specimens were introduced with a hollow punch. A low intensity direct current was applied in order to remove contaminants, due to electrophoresis and electroosmosis phenomena. The water flow, conductivity, apparent electroosmotic coefficient, as well as other characteristic parameters, were measured throughout the test. The water content and degree of pore saturation were estimated at the beginning and end of the test. The soil slab was divided into four slices and the Pb concentration profile determined. The main factor governing the extraction of contaminant was found to be the pH in the acidic range. Indeed, under these conditions high removal efficiencies could be reached. These results could lead to the design of a new electrochemical treatment cell equipped with a cationic membrane to expand the region of favourable pH within the soil.