Amount Of Metal Ions Research Articles

Copper and Nickel Removal from Aqueous Solutions Using New Chelating Poly[Acrylamide/N‐vinyl pyrrolidone/3‐(2‐hydroxyethyl carbamoyl)acrylic acid] Hydrogels

New poly[Acrylamide/N‐vinyl pyrrolidone/3‐(2‐hydroxyethyl carbamoyl)acrylic acid], poly [AAm/NVP/HECA], chelating hydrogels with different composition of HECA monomer have been prepared via free radical solution polymerization using N,N‐methylene bisacrylamide as a crosslinker. The hydrogels obtained were loaded with metal ions and characterized by FT‐IR spectroscopy, Scanning Electron Microscope (SEM) and Thermogravimatric analysis (TGA). The removal of Cu2+ and Ni2+ from aqueous solutions by the hydrogel was examined by a batch equilibrium method. The influence of treatment time, pH, initial concentration of the metal ions and HECA content in the feed compositions on the amount of adsorbed metal ions was studied. Swelling of the hydrogel was also carried out in distilled water and metal ion solutions. The removal of the metal ions followed the following order: Ni2+>Cu2+. The amount of metal ions removed increased with increasing HECA content in the feed composition, treatment time, pH of the medium and initial concentration of metal ions. The desorption of metal ions were carried out using 1 N HCl and 0.5 N H2SO4. The poly[AAm/NVP/HECA] hydrogels could be used many times without significantly decreasing their adsorption capacity.

Sorption of Some Heavy Metal Ions by Chitosan and Chemically Modified Chitosan

Chitosan was produced by deacetylation ofchitin with sodium hydroxide at a temperature of 117 °C (Randal et al, 1979). In this study, chitosan was prepared from African giant land snail (Archachatina marginata), and acrylamide was grafted onto the chitosan to produce chitosan grafted acrylamide (cga). The two varieties (chitosan and cga) were separately used as adsorbents for the removal of some heavy metal ions (Pb 2 ', Cd 2 ', and Ni 2+ ) from aqueous systems. The amount of metal ions (Pb 2 ', Cd 2 ', and Ni 2+ ) adsorbed onto chitosan at optimum temperature (45 °C) ranged from 43.88-60.60 %, 27.50-58.60% and 41.30-58.90%, respectively. That adsorbed onto cga ranged from 49.40-65.56%, 56.50-97.90% and 29.60-64.80%, respectively. Results revealed that cga sorption capacity was approximately twice as high as chitosan.

Porous macrobeads composed of metal oxide nanocrystallites and with percolated porosity

In this work, we report a method of preparing porous metal oxide macrobeads using a cation-exchange resin with sulfonic acid groups as templates and aqueous solutions of metal salts as precursors. The metal–resin complexes formed on the pore surface of resins were firstly transformed into metal hydroxide precipitates in the pores after a treatment of ammonia, and then the metal oxide macrobeads were produced by calcination. In our experiment, Fe2O3, Al2O3 and TiO2 macrobeads were prepared from FeCl2, Al(NO3)3 and Ti(SO4)2. Our findings show that the loading content of metal ions plays a key role in the preparation of metal oxide macrobeads with conformability and integrity. If metal ions in the precursors have higher valence, the amount of metal ions that can be loaded to the resins is fewer. Therefore, repeating the ion-loading and ammonia-precipitation cycle is necessary to increase the loading content of metal species. Complete macrobeads can be obtained from one cycle for Fe2O3, two cycles for Al2O3 and three cycles for TiO2. The as-synthesized metal oxides are spherical in shape, over 200 µm in size, have relatively high surface area, contain both mesopores and macropores and are crystalline. These properties make them potentially useful as catalysts, catalyst supports, absorbents and separation materials, especially for fixed-bed reactors or chromatography columns.

Conductivity of nonaqueous solutions of aromatic polymers containing ionizable side groups

The concentration dependence of the equivalent conductivity has been measured for dilute DMAc solutions of K, Na, and Li salts of aromatic polymers with ionizable side groups [poly(diphenylenesulfophthalide) and poly(arylene ether ketone) with side COOH groups]. A correlation between the concentration dependences of the equivalent conductivity and reduced viscosity shows that the first parameter initially sharply decreases with an increase in concentration and then achieves a limiting value at a rather low concentration and that precisely in this concentration range the polyelectrolyte effect manifests itself in the concentration versus reduced viscosity curve. With an increasing amount of metal ions incorporated into the polymer, the equivalent conductivity grows. It was demonstrated that the type of counterion affects the reduced viscosity and equivalent conductivity of salt solutions. This effect depends on the structure of the polymer backbone: for poly(arylene ether ketone) salts, the reduced viscosity and the equivalent conductivity increase in the sequence Li → Na → K, while for poly(diphenylenesulfophthalide) salts, the reduced viscosity increases in the reverse order and the equivalent conductivity remains almost invariable. The limiting values of the equivalent conductivity and the degree of association of polyelectrolytes have been estimated in terms of the Arrhenius-Ostwald theory. It has been shown that, in the case of poly(diphenylenesulfophthalide) salts, the equivalent conductivity and the degree of association are higher than those for poly(arylene ether ketone) salts with side COOH groups. This finding is indicative of a stronger binding of counterions by poly(arylene ether ketone).

Sorption and desorption of Cd, Co, Cu, Ni and Zn from carbonated Portland cement

A material with potential for use as a sorbent has been prepared by carbonating damp Portland cement in a 100%CO2 atmosphere at a pressure of 3 bars. Analysis by XRD showed the main crystalline phase present, after eight 1 h cycles of carbonation, to be calcite. A series of batch sorption experiments involving single metal solutions of Cd, Co, Cu, Ni, Zn, at concentrations varying from 200 to 1000 mg L−1, were carried out employing the carbonated media. The solid residues obtained, were then used to examine the desorption of metals over a 24 h timescale. The zeta potential and conductivity of suspensions prepared from the residues were also recorded. The results showed the sorbent could remove significant quantities of metal ions from solution, and up to 176 mg g−1 was recorded for Cd. The desorption experiments showed metal release rates <1% by mass of metal adsorbed. Electrophoretic analysis gave different values for zeta potential and conductivity for each sorbent–metal system, indicating that sorption might take place via different mechanisms including inner- and outersphere complexation.

Preconcentration and Determination of Lead, Cadmium and Nickel from Water Samples Using a Polyethylene Glycol Dye Immobilized on Poly(hydroxyethylmethacrylate) Microspheres

A simple and sensitive preconcentration analysis-atomic absorption spectrometric procedure is described for the determination of lead, cadmium and nickel. The method is based upon on-line preconcentration of metal ions on a minicolumn of Cibacron Blue F3-GA immobilized on poly(hydroxyethylmethacrylate), poly(HEMA). The enrichment factors obtained were 42 for lead, 52 for cadmium and 63 for nickel (sample volume 10 mL and sample flow rate 5 mL/min). The relative standard deviations (n = 10), in 10 mL sample solutions containing 100 microg/L Pb(2+), 10 microg/L Cd(2+) and 100 microg/L Ni(2+) were 8.9, 3.7 and 3.5%, respectively. The limits of detection (blank + 3s) (n = 10), were found to be 12.01 microg/L for Pb(2+), 1.34 microg/L for Cd(2+) and 28.73 microg/L for Ni(2+). The accuracy of the system was checked with certified and tap water samples spiked with known amounts of metal ions. No significant difference was found between the achieved results and the certified values.

Analysis of metal ions in crude oil by reversed-phase high performance liquid chromatography using short column

In this study a rapid, simultaneous analysis of V, Ni, Fe and Cu in crude oil was achieved by high performance liquid chromatography using 10 cm length reversed-phase C18 column. Since the amount of metal ions is at a very low level, in this work, solvent extraction of metals by a ligand such as 8-hydroxyquinoline from acidic media was investigated with some modification to previous procedures. Average extraction recoveries were 99, 85, 94 and 96 for V, Ni, Fe and Cu, respectively. The proposed method was successfully applied to the crude oil which was obtained from Koshk area in southern Iran. Fast analysis of metal ion in reversed-phase short column was achieved with methanol/water (55/45, v/v) and the detection limits measured as three times the background noise were obtained. Also it was shown that if small amount of 8-hydroxyquinoline was added to the mobile phase, the peak height and the peak symmetry were improved. A typical chromatogram for the separation of the 8-hydroxyquinoline complexes of V (V), Ni (II), Fe (III) and Cu (II) in crude oil was obtained in less than 4 min.

Seashells: Detoxifying Agents for Metal-Contaminated Waters

Effective treatments of industrial waste streams and toxic spills containing heavy metals depend on the rapid removal of high concentrations of metal ions. Here we describe such a method using minimally-processed waste mollusk and crustacean exoskeletons. The process of metal extraction and immobilization was studied using atomic absorption, SEM/EDAX, and x-ray diffraction to investigate both solution and mineral phases. Compared to calcium carbonates of geologic origin, biomineralized shell materials exhibit extremely rapid sequestration of metal ions: a 10,000 mg L−1 Pb solution for example, can be reduced to less than about 0.5 mg L−1 in five minutes using comminuted shell of clam (M. mercenaria), while at higher initial concentrations, both clam and oyster (C. virginica) shell can extract almost twice their weight of Pb. The uptake mechanism involves the exchange of Ca for Pb in the inorganic fraction of the shell structure. Results highlight the importance of both surface area and the presence of the organic matrix of biominerals in determining the rate and quantity of metal ions abstracted, and the uniquely coherent residues produced in the process.

Preconcentration of Some Trace Metal Ions from Drinking and Tap Water Samples by Sorption on Amberlite XAD‐4 after Complexation with Di‐2‐Pyridyl Ketone Thiosemicarbazone

A method was established for enrichment of trace levels of Co(II), Ni(II), Fe(II), and Cu(II) ions in aqueous solutions. These metals were quantitatively retained on an Amberlite XAD‐4 column, after complexation with di‐2‐pyridyl ketone thiosemicarbazone (DPKT). After elution with 1 M HNO3 in acetone, concentration of metals were measured by atomic absorption spectrometry. The effect of major cations of drinking and tap water samples on the sorption of metal ions also were investigated. The amount of the analyte metal ions determined after preconcentration was basically in agreement with the added amount. The developed method was used for the determination of trace amounts of metal ions in drinking and tap water samples with good results, such as relative standart deviations below 2% (N=6) and recoveries greater than >95%.

Quantification of Trace Elements in Protein Bands Using Synchrotron Radiation X-ray Fluorescence after Electrophoretic Separation

Abstract A procedure was proposed for quantification of Fe, Cu and Zn in protein bands using synchrotron radiation X-ray fluorescence (SRXRF) after isoelectric focusing (IEF). Calibration standards were prepared by adding certain amounts of metal ions and free-metal proteins to electrophoresis gel. The calibration curves were obtained in the range of 0–8 μmg/g metals, and linear relationship was observed between dosage of metals and fluorescent intensity ( R 2 > 0.99). The detection limits were 2.43, 1.12, and 0.96 μmg/g for Fe, Cu and Zn, respectively, by the proposed method. Recoveries of 90.4% and 115.7% for Fe and Zn, respectively, were obtained when applying the procedure to quantification of the trace elements in protein bands of human hemoglobin separated with IEF. The combined techniques of SRXRF and IEF have advantages of quantifying trace elements in proteins and identifying proteins simultaneously. It can be employed for speciation analysis of trace elements in biological samples.

In Vitro Study of Elements in Herbal Remedies

Decreased glucose tolerance is a first sign of diabetes mellitus and therefore rigorous control must be taken in carbohydrate and lipid metabolisms. Herbal remedies (lyophilized extracts of Myrtilli folium and Phaseoli fructus sine seminibus (L1), Myrtilli folium, Phaseoli fructus sine seminibus, and Salviae folium (L2) are traditionally used in mid-European folk medicine and in common adjuvant therapy for the prevention of complications in type 2 diabetes. Significant iron (355.7 +/- 13.8 mg/kg) and zinc (84.73 +/- 1.83 mg/kg) concentration was found in L1 and chromium (3.82 +/- 2.71 mg/kg) in L2. Ion concentrations in teas made from L1 and L2 are relatively low because the quantities of metal ions in teas do not cover the daily need, although the teas are good sources for some elements. According to the Recommended Daily Allowances, the tea of L1 is a good source for iron and manganese, whereas for chromium, the tea of L2 is better. For evaluating the element bioavailability, an in vitro dialysis system was applied to determine the element transfer from tea of the lyophilized sample to the plasma (buffer pH=7.4). Measurements showed that the elements transferred between 6.90% (iron from tea of L2) and 90.05% (chromium from tea of L2) through the membrane from teas to the plasma. Metal ions in teas of herbal remedies might contribute to the favorable therapeutic effect of preventing complications, because they might transfer through the membranes in relatively high percentages.

Historical iron gall ink containing documents — Properties affecting their condition

Iron gall ink, also referred to as iron gallotannate ink, is one of the most important inks in the history of western civilisation, and was in widespread use from the middle ages until the 20th century. Unfortunately, iron ions and acids present in these inks induce enhanced degradation of paper, thus severely damaging numerous historical artefacts. Yet, when examining documents, it is frequently observed that not all materials containing iron gall ink are suffering from ink corrosion. While some are completely destroyed, others may be in excellent condition even centuries after their creation. In order to establish the main properties of materials, common to severely degraded documents, the effects of the type and quantity of metal ions in the ink, as determined by in-air PIXE method, pH of the ink on paper, grammage of paper, its absorptivity and the width of ink lines were evaluated against the extent of corrosion. Using multiple linear regression analysis, a correlation has been obtained between the width of the applied ink lines, pH, grammage of paper and the extent of ink corrosion. Based on these factors, which can be acquired non-destructively from most historical documents, it is therefore possible to predict the stability of historical iron gall ink containing paper.

Investigation of Metal Ion Removal Selectivity Properties of the Modified Polyacrylamide Hydrogels Prepared by Transamidation and Hofmann Reactions

Modified crosslinked polyacrylamides having different functional groups prepared by transamidation reaction in aqueous and non‐aqueous medium and by Hofmann reaction were used as chelating agents for removal of Cu(II), Cd(II) and Pb(II) ions from aqueous solutions at different pH values. Under non‐competitive conditions, polymers adsorbed different amounts of metal ions, depending on their functional groups and swelling abilities. The metal ion adsorption capacities of polymers changed between 0.11–1.71 mmol/g polymer. Under competitive conditions, while the polymers having mainly secondary amine groups were highly selective for Cu(II) ions (99.4%), those having mainly secondary amide and carboxylate groups have shown high selectivity towards Pb(II) ions (99.5%). The selectivity towards Cu(II) ion decreased and Pb(II) ion selectivity increased by the decrease of the pH of the solutions. The high initial adsorption rate (<10 min) suggests that the adsorption occurs mainly on the polymer surface. A regeneration procedure by treatment with dilute HCl solution showed that the modified polymers could be used several times without loss of their adsorption capacities.

Medicinal Plant TEAS Recommended as nutritional source for element supplementation

Herbal teas may be effective in adjuvant therapy for the prevention of complications of diabetes mellitus II. Agrimoniae herba, Betulae folium, Bursae pastoris herba, Foenigraeci semen, Galegae herba, Maydis stigma, Taraxaci radix, Phaseoli fructus sine seminibus, Urticae folium, and their teas were analysed by ICP-OES for element content. Concentration of the elements of crude drug samples obtained are in good agreement with the average concentrations of plants, although some significantly high concentration has been found for manganese (893 mg kg-1), zinc (275 mg kg-1) and iron (492 mg kg-1) in Betulae folium, for copper (41.2 mg kg-1) in Galegae herba, for iron (2692 mg kg-1) in Taraxaci radix, for calcium (41210 mg kg-1) and magnesium (6275 mg kg-1) in Urticae folium. The common characteristic feature of crude drugs is the relatively high concentration of chromium (0.8-16.3 mg kg-1). Ion concentrations of teas are relatively low. The quantities of metal ions do not cover the daily needs, nevertheless,...

Runoff behaviour of metallic materials used for roofs and facades - a 5-year field exposure study in Switzerland

Different metallic materials, which are in use for building roofs and facades, were exposed to open atmosphere in Dübendorf (Switzerland). The following materials were investigated: copper and zinc with different surface treatment, tinned copper, galvanized steel, aluminium, stainless steel, tinned stainless steel, titanium, and lead. The runoff during rain periods were collected and chemically analysed. It could be shown that copper, zinc and lead release “measurable” amounts of metallic ions and only a small fraction of “particulate” matter. From aluminium, stainless steel and titanium the release was smaller than the detection limit (< 0.01 mg L−1) of the analysis method used. The runoff data will be compared with the corrosion data. The corrosion rate decreases in the course of time whereas the runoff rate shows relatively a constant behaviour.

Selectivity of cyclam modified poly( p-chloromethyl styrene-ethyleneglycol dimethacrylate) microbeads for Cu(II), Ni(II), Co(II) and Zn(II)

Poly( p-chloromethyl styrene-ethyleneglycol dimethacrylate) polymeric microbeads, poly( p-CMS-EGDMA), with an average size of 186 μm were synthesized by the suspension polymerization of p-chloromethyl styrene conducted in an aqueous medium. 1,4,8,11-Tetraazacyclotetradecane (cyclam) was reacted with polymer active group under the nitrogen atmosphere for 18 h at 65 °C. Fourier transform infrared spectrometer (FT-IR) and elemental analyzer were used to characterize the plain and cyclam modified microbeads. The affinity of the cyclam modified poly( p-CMS-EGDMA) microbeads for some metal ions was examined. The adsorption/desorption behaviour of the modified microbeads from aqueous solution containing different amount of metal ions (0.05–20 mM) at different pH values (2.0–7.0) was studied. The uptake of metal ions onto the modified poly( p-CMS-EGDMA) microbeads from solution containing a single metal ions were found to be 232.1, 119.2, 132.1, and 116.8 mg g −1 polymer for Cu(II), Zn(II), Ni(II), and Co(II), respectively. More than 95% of the adsorbed metal ions were desorbed for 48 h in desorption medium containing 3 M HNO 3. Poly( p-CMS-EGDMA) co-polymeric microbeads containing cyclam ligand were found to be suitable for repeated use without noticeable loss of adsorption capacity. The selectivity of metal ions was found in the order of Cu(II) ≫ Ni(II) > Zn(II) > Co(II). The recovery of different metal ions in the competitive medium is really high for Cu(II), Co(II), Ni(II), and Zn(II) besides the other metal ions namely Cr(III), Pb(II), Cd(II), and Mn(II) at pH 5.0 and also pH 2.0.

FS02.1 The role of metallurgy in allergic contact dermatitis to metals

The critical factor in determining if an alloy may induce metal sensitisation or elicit allergic contact dermatitis is the release rate of soluble metal ions of allergenic metals at the skin surface. Metals or alloys in direct and prolonged contact with body fluids may result in electrochemical reactions (commonly called corrosion) that release metal ions. Induction or elicitation of metal allergy results if a sufficient amount of metal ions are released and absorbed through the skin where they react with the human immune system. The virtual insolubility of most metals and alloys in aqueous media (including body fluids) limits the bioavailability of metal ions. Several factors influence the rate of corrosion: metal or alloy metallurgical structure, surface films, surface finish, geometry, process history, and composition; body fluid composition, amount, pH, electrolytic properties, dissolved oxygen and other gas content; and the service environment (e.g. temperature, flow rate, etc). A review of recently published studies on metal allergy from a metallurgical perspective provides information that helps explain why certain metals and alloys cause allergic reactions and others (e.g. most stainless steels) do not. This information is useful in predicting what alloys will cause allergic reactions under varying conditions. In order to predict allergic reactions and responses to metals and alloys, metallurgical aspects of ion release should be taken into account. This presentation will increase understanding and interpretation of results of clinical or other scientific studies (e.g. studies in vitro) of reactions and responses to metals and alloys by providing a metallurgical perspective.

Investigation of Chromium(III)-Picolinate Adsorption on Some Soil Types

In the experiment adsorption characteristics of different soil types (humic sand, meadow soil, leached chernozem and meadow solonec) was examined on the basis of adsorption isotherms for Cr(III)-picolinate. The Langmuir equation was used to describe the isotherms by which the amounts of metal ions actually and maximally adsorbed by the soils were determined concerning the given complex. A comparison was made among the organically bound Cr(III)-picolinate, an inorganic Cr(III) compound and a Cr(VI) form examined in a previous study. Based on the adsorption isotherms, adsorption capacity of the Cr(III)-picolinate was found 20 times smaller on sandy soil and 50 times smaller on the chernozem comparing to that of the inorganic Cr(III)-chloride, thus, the bio-availability of the chromium for the plants is 20 and 50 times higher in case of the given soil types. For the well-known toxic Cr(VI)-form, the adsorption was 2 times higher in case of sandy soil and 5 times higher for chernozem than in case of the organic Cr(III)-complex compound.

Preconcentration and Speciation of Chromium(III) in Waters by Using 5-Palmitoyl-8-Hydroxyquinoline Immobilized on a Nonpolar Adsorbent

A method for the quantitative separation and preconcentration of trace amount Cr(III) in real samples has been developed. It is based on the sorption of Cr(III) ions onto a column of Amberlite XAD-2 resin functionalized with 5-palmitoyl-8-hydroxyquin oline reagent. The resin was used for speciation and preconcentration of chromium because this functionalized resin is selective for Cr(III) ions. The effect of pH, flow-rate, sorption capacity, reusability and effect of various metal cations and salt anions on the sorption on to the resin were investigated. The sorption is quantitative in the pH range of 4.5–7.0, and Cr(III) ion was desorbed by using hydrochloric acid. The amount of metal ion in the eluate was determined by a flame atomic absorption spectrometer. Total chromium was obtained by an efficient reduction of Cr(VI) to Cr(III) by hydroxylamine. The procedure has been applied to the determination and speciation of chromium in lake water, and in the chromium-plating baths.

Chelate extraction of transition metal ions by ethylene diamine diacetic acid with n-substituted octadecyl groups

An organic-soluble chelating agent, N,N′-di-n-octadecyl ethylenediamine-N,N′-diacetic acid (DOED) has been synthesized in two steps by (i) condensation of dibromoethane with 1-amino octadecane (octadecylamine) and (ii) subsequent reaction with sodium chloro acetate in alcohol–water mixture. The chelating agent in 2-ethylhexanol-cyclohexanol (1:1) solutions shows extremely high chelating ability for Ni(II), Co(II), Cu(II), Fe(III), Cr(III), and Cd(II) ions in neutral aqueous solutions. Extractions take place by the formation of (1:1) ligand-to-metal complexes, and extraction coefficients are in the range 0.74–0.99. The ligand can be regenerated almost quantitatively by washing its complexes with 1 M HCl and 0.2 M NaOH solutions successively. In each extraction step, the organic solution exhibits a clear-cut phase separation and does not need salting out. The chelating agent can be regenerated and recycled more than 24 times, without losing its extracting ability, due to nonhydrolyzability of linkages in its structure. Experiments indicate that in high metal concentrations (more than 1 M), the solvent mixture itself is able to extract appreciable amounts of metal ions (33–53%). The solubility in organic solvents, induced by long aliphatic chains, seems to be general and the method presented offers possibility of large scale chelate extraction of metal ions of relatively low concentrations.