Removal of heavy metals and neutralisation of acid mine drainage with un-activated attapulgite

Unactivated attapulgite was characterised and utilised as an adsorbent for the removal of heavy metal and neutralisation of acid mine drainage (AMD) from a gold mine. Adsorption experiments were carried out by agitation of a fixed amount of attapulgite with a fixed volume of AMD in a thermostatic shaker for varying times. Attapulgite showed that it can neutralise acid mine drainage as the pH after 4 h was 7.11. The results showed that metal ion removal after 4 h was 100% for Cu(II) and Fe(II), 93% for Co(II), 95% for Ni(II) and 66% for Mn(II) using a 10% (w/v) attapulgite loading. The experimental data best fit the Langmuir Isotherm with maximum adsorption capacities for Cu(II), Co(II), Mn(II), Fe(II) and Ni(II) being 0.0053, 0.0044, 0.0019, 0.01, and 0.0053 mg/g, respectively. The adsorption process fitted well the pseudo first order kinetics for Co(II) and Cu(II) and pseudo second order for Ni(II), Mn(II) and Fe(II). Thermodynamic data show that Cu(II), Co(II), Fe(II) and Ni(II) adsorption was thermodynamically spontaneous whilst Mn(II) was not thermodynamically spontaneous. The process is endothermic for Cu(II), Co(II), Mn(II), and Ni(II) and exothermic for Fe(II). Spent attapulgite (attapulgite that has already been used to remove metals) could be reused twice without regeneration.     

Insights into the mode of action of the anti-Candida activity of 1,10-phenanthroline and its metal chelates

Metal complexes of malonie acid (metal = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I)) were prepared and only the Ag(I) complex inhibited the growth of Candida albicans. Malonate complexes incorporating the chelating 1,10-phenanthroline (1,10-phen) ligand showed a range of activities: good (Mn(II), Cu(II), Ag(I)); moderate (Zn(II)); poor (Co(II), Ni(II)). Metal-free 1,10-phen and Ag(CH(3)CO(2)) were also highly active. The metal-free non-chelating ligands 1,7- phenanthroline and 4,7-phenanthroline were inactive and the Cu(II), Mn(II) and Zn(II) complexs of 1,7-phen displayed only marginal activity. Whereas the Cu(II) malonate/1,10-phen complex induces significant cellular oxidative stress the Zn(II) analogue does not.     

Synthesis,Characterization, and Applications of a New Chelating Resin Containing 4-2-(Thiazolylazo) Resorcinol (TAR)

A new phenol–formaldehyde based chelating resin containing 4-(2-thiazolylazo) resorcinol (TAR) functional groups has been synthesized and characterized by Fourier transform infrared spectroscopy and elemental analysis. Its adsorption behavior for Cu(II), Pb(II), Ni(II), Co(II), Cd(II), and Mn(II) has been investigated by batch and column experiments. The chelating resin is highly selective for Cu(II) in the pH range 2 ～ 3, whereas alkali metal and alkaline earth metal ions such as Na(I), Mg(II), and Ca(II) are not adsorbed even at pH 6. Quantitative recovery of most metal ions studied in this work except Co(II) is achieved by elution with 2M HNO₃ at a flow rate of 0.2 mL min^?1. A similar trend is observed for distribution coefficient values. The quantitative separations achieved on a mini-column of chelating resin include Cd(II) – Cu(II), Mn(II) – Pb(II), Co(II) – Cu(II), Mn(II) – Ni(II), and Mn(II) – Co(II) – Cu(II). The recovery of copper(II) is quantitative (98.0–99.0%) from test solutions (10–50 mg/L) by 1 mol/L HNO₃-0.01 mol/L EDTA. The chelating resin is stable in acidic solutions below 2.5 M HNO₃ or HCl as well as in alkaline solution below pH 11. The adsorption behavior of the resin towards Cu(II) was found to follow Langmuir isotherm and second order rate.     

Investigation of Heavy Metal Ion Adsorption Characteristics of Poly(N,N Dimethylamino Ethylmethacrylate) Hydrogels

Abstract

In this study, Poly(N,N dimethyl‐amino ethylmethacrylate) (Poly(DMAEMA)) hydrogels with varying compositions were prepared in the form of rods by irradiating ternary mixtures of N,N‐dimethylamino ethylmethacrylate/ethyleneglycoldimethacrylate/water with gamma rays at ambient temperature. Swelling studies of poly (DMAEMA) hydrogels were performed at different pH values and maximum swelling values reached at pH 2. The adsorption characteristics of Pb(II), Cd(II), Ni(II), Zn(II), Cu(II), and Co(II) ions to poly(N,N dimethylamino ethylmethacrylate) hydrogels were investigated by a batch process. The order of affinity based on amount of metal ion uptake was found as follows: Cu(II)>Zn(II)?Co(II)>Pb(II) >> Ni(II)>Cd(II). In the adsorption studies of Cu(II), Zn(II), Co(II), Pb(II), Ni(II), and Cd(II) ions the Langmuir type adsorption isotherms were observed for all gel systems.     

Adsorption Behavior of Iminodiacetic Acid Type of Chelating Gel Prepared from Waste Paper

Abstract

Adsorption gel was prepared from waste recycled paper by immobilizing iminodiacetic acid (IDA) functional group by chemical modification. The gel exhibited good adsorption behavior for a number of metal ions viz. Cu(II), Pb(II), Fe(III), Ni(II), Cd(II), and Co(II) at acidic pH. The order of selectivity was found to be as follows: Cu(II)>Pb(II)>Fe(III)>Ni(II)～Cd(II)～Co(II). From the adsorption isotherms, the maximum adsorption capacity of the gel for both Cu(II) and Pb(II) was found to be 0.47 mol/kg whereas that for Cd(II) was 0.24 mol/kg. A continuous flow experiment for Cd(II) showed that the gel can be useful for pre‐concentration and complete removal of Cd(II) from aqueous solution.     

Sorption isotherms of metal ions onto an N-(2-sulfoethyl)chitosan-based material from single- and multi-component solutions

The scope of work is to study the mutual influence of metal ions during their sorption by sulfoethylated chitosan. The sorption isotherms of metal ions from single- and multi-component solutions are obtained. The sorption capacity of the sorbent towards Ag(I) and Cu(II) is revealed to be 1.63 and 1.41 mmol/g in single-, and 1.40 and 0.85 mmol/g in five-component solution. By comparing the affinity parameter and capacity of sulfoethylated chitosan towards ions in single- and multi-component solutions, it is concluded that Ag(I) and Cu(II) ions suppress the sorption of cobalt(II), nickel(II), zinc(II), cadmium(II), magnesium(II), calcium(II), strontium(II), barium(II), manganese(II) and lead(II).     

Synthesis,Composition, and Ion-Exchange Behavior of Thermally Stable Zr(IV) and Ti(IV) Arsenophosphates: Separation of Metal Ions

Abstract

Two new inorganic ion-exchange materials, Zr(IV) and Ti(IV) arsenophosphates, have been synthesized. They are reproducible in behavior and possess excellent thermal stability. Their tentative structures have been proposed based on pH titrations, thermogravimetry, chemical analysis, IR studies, and other ion-exchange properties. Distribution studies of some metal ions have also been made on the basis of which several useful binary separations have been achieved such as Fe(III) from VO(II), Cu(II), and Zn(II); Pb(II) from Cu(II), Hg(II), and Zn(II); Ti(IV) from UO₂(II) and Ce(IV); and Mg(II) from Sr(II) and Ba(II).     

Part 8. Preparation,characterization and metal complexing of poly[(2‐hydroxyethyl)‐DL‐aspartamide] in aqueous solution

Poly[(2‐hydroxyethyl)‐DL ‐aspartamide] was synthesized by polyreaction of aspartic acid and subsequent polymer‐analogous functionalization with ethanolamine. The water‐soluble polymer was characterized by FTIR, NMR, TGA and light‐scattering measurements. The metal complexing properties of the polymer were studied for Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Sr(II), Cd(II) and Pb(II) ions in aqueous solution using the liquid‐phase polymer‐based retention (LPR) method. According to the retention profiles of LPR, Cr(III), Fe(III), Cu(II) and Pb(II) showed a strong interaction with this polymer under these conditions, indicated by retention values of about 100 %. In contrast, Co(II), Ni(II), Zn(II), Sr(II) and Cd(II) exhibited retention values of only 50–60 % in dilute solution at pH 5. © 2000 Society of Chemical Industry     

Recovery and Concentration of Metal Ions. II Multimembrane Hybrid System

Abstract

The multimembrane hybrid system (MHS) has been developed and used for the transportation and separation of divalent metal ions from multicomponent solutions. The system consists of three membranes in series

ion-exchange membrane | liquid membrane | ion-exchange membrane

The experiments were performed with liquid membranes composed of di(2-ethylhexyl)phosphoric acid in kerosene and Nafion-120 perfluorosulfonic acid polymer membranes. The fluxes and separation characteristics have been determined for MHS separating a solution of Zn(II), Mn(II), Cu(II), and Ni(II) sulfates as the feed phase, and the strip phase containing sulfuric acid. The results of competitive permeation experiments have shown the selectivity order Zn(II) > Mn(II) > Cu(II) ? Co(II), Ni(II). High separation coefficients were found for Zn(II), Cu(II), and Mn(II) compared to Ni(II) and Co(II).     

Synthesis, characterization, and properties of an efficient and selective adsorbent to mercury (II)

The synthesis of a water-insoluble adsorbent resin was carried out by radical polymerization of [2-(methacryloyloxy)ethyl] trimethyl ammonium chloride by using ammonium peroxydisulfate as initiator and N,N′-methylene-bis-acrylamide (MBA) as crosslinking reagent. The adsorbent was characterized by elemental analyses, and FT-IR spectroscopy. The thermal stability was studied in the presence of Hg(II). The ability to bind Hg(II), Cd(II), Zn(II), Pb(II), Cu(II), Cr(III), and U(VI) as well as the maximum adsorption capacity, and elution of the Hg(II) from the loaded resin was studied. At pH 2 the adsorbent retained 95% of Hg(II) from an aqueous solution containing 1 g/L in Hg(II). The retention of other metal ions was lower than 15%. Sorption selectivity from the binary mixtures Hg(II)-Cd(II), Hg(II)-Zn(II), Hg(II)-Pb(II), and Hg(II)-Cr(III) was studied at the optimum sorption pH value. Received: 20 April 1997/Revised: 24 July 1997/Accepted: 6 August 1997     

Synthesis and characterization of poly(acrylaminophosphonic-carboxyl-hydrazide) chelating fibre

The poly(acrylaminophosphonic-carboxyl-hydrazide) chelating ion exchange fibre was prepared by the amination and phosphorization reaction of the hydrazine-modified polyacrylonitrile fibre. The structure of the chelating fibre and the same fibre saturated by Cu(II) and Ag(I) ions was investigated by IR spectrometer in detail. In addition, the crystalline and surface characteristics of the chelating fibre were determined by X-ray diffraction and SEM. The higher binding capacities of the fibrous sorbent for Cu(II), Pb(II), Zn(II), Co(II), Ni(II), Hg(II), Cd(II), Mn(II), Cr(III) and Ag(I) and the effect of pH value on adsorption of the chelating fibre for Cu(II) and Hg(II) ions were examined.     

Mono- and multi-component biosorption of lead(II), cadmium(II), copper(II) and nickel(II) ions onto coco-peat biomass

The potential of using coco-peat biomass (CPB) has been assessed for the removal of Pb(II), Cd(II), Cu(II) and Ni(II) ions from single and quaternary solutions. According to Langmuir isotherm, the maximum biosorption capacity of CPB was 0.484, 0.151, 0.383 and 0.181 mmol/g for Pb(II), Cd(II), Cu(II) and Ni(II) ions, respectively. Scanning electron microscopy along with energy-dispersive X-ray spectroscopy and Fourier-transform IR spectroscopy confirmed changes in the biosorbent functionality after metal sorption. Through quaternary isotherm experiments, 16.1%, 48.2%, 32.3% and 46.5% decrease in experimental uptakes were observed for Pb(II), Cd(II), Cu(II) and Ni(II), respectively, in the presence of other metal ions.     

Kinetic and Equilibrium Modeling of Pb(II) and Co(II) Sorption onto Rose Waste Biomass

Abstract

An attempt was made to assess the biosorption potential of rose waste biomass for the removal of Pb(II) and Co(II) ions from synthetic effluents. Biosorption of heavy metal ions (>90%) reached equilibrium in 30 min. Maximum removal of Pb(II) and Co(II) occurred at pH 5 and 6 respectively. The biosorbent dose for efficient uptake of Pb(II) and Co(II) was 0.5 g/L for both metals. The biosorbent size affected the Pb(II) and Co(II) biosorption rate and capacity. Rose waste biomass was found effective for Pb(II) and Co(II) removal from synthetic effluents in the concentration range 10–640 mg/L. Equilibrium sorption studies showed that the extent of Pb(II) and Co(II) uptake by the rose waste biomass was better described by the Langmuir isotherm in comparison to the Freundlich model. The uptake capacities of the two metal ions were 156 and 27.15 mg/g for Pb(II) and Co(II) respectively.     

Sorption Behavior of Dowex PSR-2 and Dowex PSR-3 Resins of Different Structures for Metal(II) Removal

The sorption behavior of palladium(II) (Pd(II)) onto strongly basic anion exchange Dowex resins was studied depending on the concentration of hydrochloric acid (0.1–6.0 M HCl–100 mg Pd(II)/L), concentration of hydrochloric and nitric(V) acids (0.1–0.9 M HCl–0.9–0.1 M HNO₃–100 mg Pd(II)/L), and the time of contact of the solution with the anion exchange resin in the batch mode. Similar research was carried out also for the base metal ions such as cobalt(II) (Co(II)), copper(II) (Cu(II)), nickel(II) (Ni(II)), and zinc(II) (Zn(II)). The sorption process was also examined depending on the initial Pd(II) concentration, agitation rate, bead size distribution, and temperature. Pd(II) sorption was also checked in the column mode. The equilibrium and kinetic characteristics of the sorption of Pd(II) with the Dowex PSR-2 and Dowex PSR-3 anion exchange resins were determined. The possibilities of Pd(II) elution and reuse using the batch method was exploited. Pd(II) and Zn(II) sorption on the Dowex resins is time and concentration of acids dependent. Evaluating the determination coefficients, the kinetic studies showed that the pseudo-second-order equation and the Langmuir model described the data more appropriately than others. The maximum sorption capacity was 165.15 mg Pd(II)/g for Dowex PSR-2 and 184.39 mg Pd(II)/g for Dowex PSR-3. Dowex resins give quantitative Pd(II) removal from diluted acidic solutions.     

Adsorption properties of poly(acrylaminophosphonic-carboxyl-hydrazide)type chelating fiber for heavy metal ions

In this article, the adsorption properties of poly(acrylaminophosphonic-carboxyl-hydrazide) chelating fibers for Cu(II), Cd(II), Co(II), Mn(II), Pb(II), Zn(II), Ni(II), and Cr(III) are investigated by a batch technique. Based on the research results of binding capacity, adsorption isotherm, effect of pH value on sorption, and adsorption kinetics experiments, it is shown that the poly(acrylaminophosphonic-carboxyl-hydrazide) chelating fibers have higher binding capacities and good adsorption kinetic properties for heavy metal ions. The sorption of the metal ions on the chelating fibers is strongly dependent on the equilibrium pH value of the solution. The adsorption isotherms of Cu(II) and Cd(II) on the chelating fiber exhibit a Langmuir-type equation. The adsorbed Cu(II), Cd(II), Zn(II), and Pb(II) could be eluted by diluted nitric acid. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 7–14, 1998     

Sorption of heavy metal ions from aqueous solutions in the presence of EDTA on monodisperse anion exchangers

Conventional precipitation methods of industrial sewage and wastewater purification are not very effective and are insufficient in many cases. This implies the necessity of searching new, effective methods exploiting cheap, accessible and ecologically safe ion exchangers and sorbents. The paper presents the studies on removal of heavy metal ions — Cu(II), Zn(II), Co(II), Ni(II) and Fe(III) — from aqueous solutions in the presence of EDTA carried out on commercially available, strongly basic monodisperse anion exchangers with the polystyrene skeleton gel, Lewatit MonoPlus M 500; and the macroporous, Lewatit MonoPlus MP 500, which are more widely applied in water purification processes. The research results indicate a high affinity of the Lewatit MonoPlus M 500 and Lewatit MonoPlus MP 500 anion exchangers in the chloride form for copper(II), nickel(II), cobalt(II) and zinc(II) complexes with EDTA. The affinity series for the heavy metal complexes in the 0.001 M M(II)/(III)–0.001 M EDTA and 0.001 M M(II)/(III)–0.001M EDTA–0.001 M–0.002 M NaOH systems were found for the Lewatit MonoPlus M 500 anion exchanger in the chloride form to be as follows: Cu(II) > Ni(II) > Co(II) > Zn(II) Fe(III). In the case of the Lewatit MonoPlus MP 500 anion exchanger in the chloride form there was found the following affinity series: Cu(II) > Co(II) > Ni(II) > Zn(II) Fe(III). These anion exchangers can be applied in the removal of copper(II) complexes from waters and wastewaters.     

Removal of metal ions in aqueous solutions by organic polymers: use of a polydiphenylamine resin

Adsorption of Ni(II), Cu(II), Zn(II), Pb(II) and Cd(II) ions on a polydiphenylamine resin prepared at a strongly oxidizing controlled potential of 3.2 V (vs. ECS) was studied in aqueous solutions. The optimum sorption conditions were determined. The optimum pH for the removal of metal ions was between 4 and 6 for Ni(II), 6 for Cu(II) and Pb(II) and 5 for Zn(II) and Cd(II). The total sorption capacity of the resin was 57.3 mg g⁻¹ for Ni(II), 23 mg g⁻¹ for Cu(II), 36.9 mg g⁻¹ for Zn(II), 19 mg g⁻¹ for Pb(II) and 24.5 mg g⁻¹ for Cd(II). The sorption capacity was compared with other conventional chelating polymers. The sorption kinetics was fairly rapid, as apparent from the loading half time (t_1/2) values, indicating a better accessibility of the chelating sites. The study of the selectivity of the metal ions in the binary solutions shows that the resin presents a higher affinity for the ions of nickel (II).     

Purification of Unrefined Nickel(II) Sulfate Solution by a Continuous Countercurrent Multistage Extraction with bis(2-Ethylhexyl)phosphinic Acid

Separation of cobalt(II) and nickel(II) using bis(2-ethylhexyl)phosphinic acid as an extractant has been investigated by a liquid–liquid and a continuous countercurrent extraction. For comparison, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester has also been used, and the results are discussed in terms of cobalt–nickel selectivity. Based on the results, a highly selective procedure using 20% bis(2-ethylhexyl)phosphinic acid in heptane has been proposed to separate zinc(II), copper(II), manganese(II), cadmium(II), magnesium(II) and cobalt(II) from nickel(II). The separation method has been successfully applied to purification of unrefined nickel(II) sulfate solutions. © 1997 SCI.     

Cationic Mobility Via Cation-Exchange Mechanism on Poly(8-Hydroxyquinoline) Matrix

The insertion of Al(III) cation into a poly(8-Hydroxyquinoline) (PHQ) instead of some metal ions such as Co(II), Ni(II), Zn(II) or Fe(III) ions via cation-exchange mechanism has been studied by several techniques. The presence of Al(III) and the absence of Co(II) cations has been proved by elemental analysis of the polymer chelates product. Molecular mechanics (MM+) calculations showed that the potential energy (PE, kJ mol⁻¹) of the optimum molecular geometric structure (OMG) of the PHQ–Al(III) matrix is about seventy-six (76.185) greater than the PE of the PHQ–Co(II) complex. The TGA thermograms show that the PHQ–Al(III) matrix is thermally unstable than the PHQ–Co(II) complex under the same conditions. These observations indicate that the PHQ–Al(III) is expanded coil-like form. So, the thermal decomposition of PHQ–Al(III) complex is easy than the compacted coil-likes form of PHQ–Co(II) complex. The incorporation of Al(III) ion via cation-exchange properties have been investigated by spectrophotometric technique. The decrease of the absorbance at about ~370 nm of PHQ–Co(II) complex associated with increasing concentration of Al(III) revealed the replacement of that metal ion by Al(III) into PHQ chain. The cation-exchange constant (K _ex) of the divalent ions [Ni(II), Co(II), Cr(II), Zn(II), Mn(II), Mg(II) and Cu(II)] from PHQ–M(II) by the additions of Al(III) according to the following series: Ni(II) > Co(II) > Cr(II) > Cu(II) > Zn(II) > Mn(II) > Mg(II).     

Divinylbenzene-crosslinked polyacrylamide-supported dithiocarbamates as metal complexing agents

Summary Dithiocarbamate (DTC) functions were incorporated into divinylbenzene-crosslinked (2–20 mole %) polyacrylamides by a two-step polymer-analogous reaction. The complexations of these resins with DTC functions in different structural environments were investigated towards Co(II), Ni(II), Cu(II), Zn(II) and Hg(II) by batch equilibration technique. The metal ion intake decreased with the extent of the DVB content in the order Hg(II)>>Cu(II)>Zn(II)>Ni(II)>Co(II). The time-course on complexation, swelling behaviours of the uncomplexed and complexed resins, recyclability, IR and thermogravimetric characterisation of the complexes were carried out. The swelling of the resins decreased on complexation with metal ions and the thermal stability increased.