Solid Phase Extraction and Preconcentration of Trace Heavy Metal Ions in Natural Water with 2,2′‐Dithiobisaniline Modified Amberlite XAD‐2

Abstract

A solid phase extraction and preconcentration methodology utilizing a new chelating resin is described for the separation of Cd, Ni, Co, Cu, and Zn. The chelating resin matrix was prepared by covalently linking 2,2′‐dithiobisaniline synthesized from 2‐aminothiophenol with the benzene ring of polystyrene‐divinylbenzene resin Amberlite XAD‐2 through a –N?N– group. Its adsorption and preconcentration behavior for Cd, Ni, Co, Cu, and Zn in aqueous solution was studied using batch and column procedures in detail. The newly designed resin quantitatively adsorbs Cd, Ni, Co, Cu, and Zn above pH 5.0. Subsequent elution with 2 M HCl readily strips the sorbed metal ions from the resin. The sorption capacity is 360, 230, 170, 200, and 150 mol g^?1 for Cd, Ni, Co, Cu, and Zn, respectively. Their preconcentration factors are 80–200. The time for 80% sorption was less than 10 min for all five metal ions. The effects of electrolytes on the preconcentration were also investigated with the recoveries >95%. The procedure was validated by analysis of a standard reference river sediment material (GBW 08301 China). The developed method was successively utilized for the determination of Cd, Ni, Co, Cu, and Zn in tap water and river water by flame atomic absorption spectrometry (FAAS) after column SPE and preconcentration. The 3σ detection limits for these metal ions were found to be 0.10, 0.34, 0.42, 0.16, and 0.52 g L^?1, respectively. The relative standard deviation was <10% for the determination of 10 g each of Cd, Ni, Co, Cu, and Zn in a 100 mL water sample.     

Exploring Lower Limits of Plant Elemental Defense by Cobalt, Copper, Nickel, and Zinc

Elemental defense is a relatively newly recognized phenomenon in which plants use elements present in their tissue to reduce damage by herbivores or pathogens. In the present study, neonates of the generalist herbivore, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), were fed artificial diets amended with varying concentrations of Co, Cu, Ni, and Zn that are hyperaccumulated by plants to determine minimum lethal concentrations (MLC) and minimum sublethal concentrations (MSC) for each metal. MLC values (dry mass) for Co (45 μg/g), Ni (230 μg/g), and Zn (280 μg/g) were below published minimum hyperaccumulator levels. MSC levels (dry mass) for Co (15 μg/g), Ni (140 μg/g), and Zn (200 μg/g) were at concentrations lower than published minimum accumulator levels. Furthermore, both MLC and MSC values for Zn were within normal tissue concentrations. These results indicate that elemental defense for Co, Ni, and Zn may be effective at concentrations lower than hyperaccumulator levels and so may be more widespread than previously believed.     

废弃钒钛系选择性催化还原催化剂重金属浸出特性

为探讨废弃选择性催化还原（SCR）催钒钛系催化剂中重金属的浸出毒性及其浸出特性,收集了山东某电厂的废弃SCR催化剂进行实验。采用固体废弃物毒性浸出方法硫酸/硝酸法（HJ/T299-2007）进行废弃SCR催化剂毒性浸出实验,同时开展了不同溶液pH、不同浸出时间和不同液固比（L/S）下废弃SCR催化剂中重金属浸出特性的实验研究。结果表明：废弃钒钛系SCR催化剂有一定的重金属浸出毒性,其中V和Zn的浸出浓度偏高,分别为13.8mg/L和2.1mg/L;pH对重金属的浸出影响显著,强酸对Cr、Ni、Cu和Zn的浸出有促进作用,V在强酸强碱环境下（pH<3或pH>11）容易释放;V、Cr、Ni和Cu主要在浸出过程的前2h内释放,18h时释放率都已高达96%以上,18h后这4种重金属浸出基本完成,而Zn在浸出18h后仍有6%释放,浸出周期相对较长;室温下加大液固比对废弃催化剂中V的浸出仅起稀释作用;Cr、Ni、Cu和Zn的溶出在液固比（L/S）<30时受溶解度的影响,L/S>30时被稀释。     

Removal of Cu(II) and Zn(II) Using Lignocellulosic Fiber Derived from Citrus reticulata (Kinnow) Waste Biomass

Abstract

The biosorption of Cu(II) and Zn(II) using dried untreated and pretreated Citrus reticulata waste biomass were evaluated. The Cu(II) and Zn(II) sorption were found to be dependent on the solution pH, the biosorbent dose, the biosorbent particle size, the shaking speed, the temperature, the initial metal ions (800 mg/L), and the contact time. Twenty-eight physical and chemical pretreatments of Citrus reticulata waste biomass were evaluated for the sorption of Cu(II) and Zn(II) from aqueous solutions. The results indicated that biomass pretreated with sulphuric acid and EDTA had maximum Cu(II) and Zn(II) uptake capacity of 87.14 mg/g and 86.4 mg/g respectively. Moreover, the Langmuir isotherm model fitted well than the Freundlich model with R ² > 0.95 for both metal ions. The sorption of Cu(II) and Zn(II) occurred rapidly in the first 120 min and the equilibrium was reached in 240 min. FTIR and SEM studies were also carried out to investigate functional groups present in the biomass and the surface morphological changes of biomass.     

Extraction of cadmium from solutions containing various heavy metal ions by Amberlite LA-2

In present study, selective extraction of cadmium from acidic leach solutions, containing various heavy metal ions, by emulsion liquid membrane (ELM) is studied. For this reason, the zinc plant copper cake was leached with sulfuric acid and main acidic leach solution containing Zn(II), Cu(II), Fe(II), Cd(II), Co(II) and Ni(II) ions was obtained. After Zn(II), Cu(II), Fe(II) and Cd(II) ions in the acidic leach solution were separated, the important parameters influencing the extent of cadmium extraction were investigated and optimum conditions were determined. Cadmium extraction was influenced by number of parameters like initial metal ion concentration, mixing speed, phase ratio, extractant concentration, surfactant concentration, the stripping solution type and concentration, and the feed solution acid concentration. The optimum values of parameter above mentioned were used and cadmium in the acidic leach solution containing 650 mg Cd/L, 365 mg Co/L, 535 mg Ni/L, and 1260 mg Zn/L was almost completely extracted within 10 min. The results showed that it is possible to extract 99% of cadmium after 10 min contact time by using ELM from aqueous solutions, containing Fe(II), Al(III), Cu(II), Zn(II), Pb(II), Co(II) and Ni(II) ions, at the optimum operating conditions.     

Selective extraction,separation and recovery of Cu(II) in presence of Zn(II) and Ni(II) from leach liquor of waste printed circuit board using microcapsules coated with Cyanex 272

The study was conducted to optimize the selective extraction and recovery of Cu(II) in the presence of Zn(II) and Ni(II) from the leach liquor of waste printed circuit boards (PCBs). The extraction experiments were carried out according to 2⁴ factorial design of experiment to optimize the extraction factors. The design was analyzed using MINITAB to determine the main effects and interactions of the chosen extraction factors. The factors chosen were: extraction pH, amount of Cyanex 272 in dispersed phase during MC-Xs preparation, amount of MC-Xs and temperature. The pH, amount of MC-Xs and temperature were found to be statistically significant. The optimized experimental conditions for the Cu(II) extraction in presence of Zn(II) and Ni(II) were extraction pH 6.0, amount of Cyanex 272 in dispersed phase 3 g, amount of MC-Xs 2.5 g and Temperature 45 °C. Factorial design of experiment was also carried out to determine the Cu(II) stripping factors from the loaded MC-Xs using H₂SO₄ solution. The liquid-liquid extraction Cu(II) was conducted with the prime aim to evaluate the nature of Cu(II) complex extracted by Cyanex 272. Results showed that the extraction species is [Cu(HA₂)(Ac)·2HA]. Finally, a complete process for the separation and recovery of Cu(II), Zn(II) and Ni(II) from the leach liquor of waste PCBs was conducted based on the optimized experimental condition and effect of pH on extraction.     

Décontamination à l'échelle pilote de sédiments pollués en métaux toxiques par lixiviation chimique et biologique

Pilot studies were carried out to evaluate different options for metal‐polluted (Cd, Cr, Cu, Ni, Pb and Zn) sediment decontamination. Chemical and biological leaching tests were done in a 350‐L capacity stirredtank reactor. The use of short acidic sediment washing steps (pH 2.0–3.0) was not an efficient approach for metal removal. The addition of an oxidant agent during the first washing step resulted in a large increase of removal yields for Pb (53–76%), Cd (54–92%) and Zn (69–93%). However, other metals were not well leached from sediments: Cr (6–30%), Cu (0–34%) and Ni (1–16%). The bioleaching treatment, with or without chemical washing steps, allows very good removal yields for Cd (82–100%), Cu (44–70%) and Zn (80–87%). On the other hand, this method was not efficient to remove other metals like Cr (6–16%), Ni (12–21%) and Pb (14–33%). The metals solubilized by chemical and/or biological leaching techniques can be efficiently removed from solution by precipitation using lime.     

Aqueous sulphur dioxide leaching of Cu,Ni, Co,Zn and Fe from smelter slag in absence of oxygen

Smelter slag and sulphur dioxide are waste products of non‐ferrous pyrometallurgical processes. Dissolution behaviour of Co, Cu, Fe, Ni and Zn from smelter slag in aqueous sulphur dioxide was studied. Experiments were carried out in batch mode, under near ambient conditions. Under the conditions studied, 81% Co, 60% Fe, 35% Ni and 68% Zn extraction were achieved within 3 h, while Cu behaved very differently. The initial dissolution of Cu was rapid, but subsequent precipitation lowered its overall extraction. The precipitation of Cu was more temperature sensitive than its dissolution. At 65°C all the dissolved Cu was precipitated in 2.5 h. The successive precipitation was explained based on the solution chemistry of the Cu‐Fe‐S(IV) system. Dissolution kinetics of the other metals were evaluated using the shrinking core model. Diffusion through the product/ash layer appeared to be the rate controlling step. SEM‐EDS analysis was used to characterize the slag and to confirm the existence of a product/ash layer after leaching.     

Effects of O2 on aqueous SO2 leaching of Co,Cu and Ni from discard smelter slag

In the leaching of non‐ferrous smelter slag with a dissolved gas mixture of SO₂ and O₂, the behaviour of Co, Cu, Ni, Zn and Fe was studied in a 1‐L batch reactor. The parameters investigated include P_SO2, P_O2, temperature, particle size and pH. Co, Zn and Fe behaved similarly while Ni and Cu displayed distinguishable characters. The addition of O₂ prevented the precipitation of Cu after dissolution, and increased acidity of the leaching solution. The increase in acid strength resulted in an increase in the extraction of Co, Zn and Fe. The effect of acidity on Cu and Ni extraction was however much weaker. The combination of SO₂ and O₂ was found to be a more effective oxidant of Fe(II) to Fe(III) than O₂ alone. Simultaneous extraction of valuable metals and removal of Fe could be achieved by leaching at pH of 3 to 4. Maximum selectivities obtained for Co, Ni and Cu over Fe were 300, 2000 and 4000, respectively.     

Solvent Impregnated Resins containing Quinizarin: Preparation and Application to Batch‐mode Separation of Cd(II), Cu(II), Ni(II), and Zn(II) in Aqueous Media Prior to the Determination by Flame Atomic Absorption Spectrometry

Abstract

Preparation of a high stable solvent impregnated resins (SIR) containing 1,4‐dihydroxyanthraquinone (quinizarin, QNZ) was proposed using Amberlite XAD‐16 beads. The SIR was applied for the separation of Cd(II), Cu(II), Ni(II), and Zn(II) in aqueous media prior to the determination by flame atomic absorption spectrometry (FAAS). The optimum conditions for batch mode extraction of the above metal ions were investigated and it was found that the sorption of these metal ions from a 1000‐ml aliquots of the solution on 1.5 g of the SIR can be carried out quantitatively at pH of 9.5 and an ionic strength of 0.01 mol dm^?3. The sorbed metal ions were subsequently eluted with 10 ml 2 mol dm^?3 HCl and the eluent was subjected to FAAS. Beer's law was obeyed in the range of 9×10^?9 ?1×10^?7 mol dm^?3 for Cd(II) and Zn(II), and 9×10^?8 ?1×10^?6 mol dm^?3 for Cu(II) and Ni(II) contents. Significant interference was not observed due to the various ions, which could be found in natural water samples. The practical applicability of the method was confirmed using a synthetic certificated reference material (CRM) and spiked natural water samples.     

Removal Characteristics of Cd(II), Cu(II), Pb(II), and Zn(II) by Natural Mongolian Zeolite through Batch and Column Experiments

The removal characteristics of Cd(II), Cu(II), Pb(II), and Zn(II) from model aqueous solutions by 5 natural Mongolian zeolites were investigated. The adsorption of metals on zeolites reached a plateau value within 6 h. The adsorption kinetic data were fitted with adsorption kinetic models. The equilibrium adsorption capacity of the zeolites was measured and fitted using Langmuir and Freundlich isotherm models. The order of adsorption capacity of zeolite was Pb(II) > Zn(II) > Cu(II) > Cd(II). The maximum adsorption capacity of natural zeolite depends on its cation exchange capacity and pH. The leaching properties of metals were simulated using four leaching solutions. The results show that natural zeolite can be used as an adsorbent for metal ions from aqueous solutions or as a stabilizer for metal-contaminated soils.     

Separation of Copper and Zinc by Solvent Extraction During Reprocessing of Flotation Tailings

Results from the solvent extraction of copper and zinc from pregnant solutions after bioleaching of re-floated tailings from the Kipushi concentrator in DR of Congo are presented. LIX984N has been used as extractant for copper, while D2EHPA as such for zinc, following prior removal of the ferric iron via precipitation. The McCabe-Thiele diagrams constructed for Cu and Zn extraction have theoretically suggested the need for two stages for copper and one for zinc. Stripping these metals to the aqueous phase by sulphuric acid has yielded rich electrolytes with 48.5 g/L copper and 85.5 g/L zinc. Thus, copper and zinc could be further recovered from the stripped solutions by electrolysis.     

Extraction and Concentration of Isoflavones from Soybean (Glycine max)

The extraction and concentration of isoflavones from defatted soy flour (DSF) is attempted by leaching, membrane process and liquid-liquid extraction. The optimized extraction conditions by response surface methodology (RSM) resulted in an isoflavone content of 3.2 mg/g of DSF. The extracted isoflavones are processed by ultrafiltration for preliminary purification resulting in 3.0 mg/g of DSF, and then concentrated by liquid-liquid extraction with diethyl ether (4.8 mg/g DSF). The final isoflavone content is 69 mg/g of dried extract with an overall recovery of 57.5%. The optimization of extraction conditions resulted in an about 2.5 fold enhancement of isoflavones and concentration step enriched the isoflavones by about 8.5 fold compared to initial extract.     

Experimental study on functional graphene oxide containing many primary amino groups fast-adsorbing heavy metal ions and adsorption mechanism

Highly oxygenated graphene oxide was synthesized. Ethylenediamino graphene oxide (EDAGO) with many amino and hydroxyl groups was prepared for adsorbing heavy metal ions in wastewater. The maximum adsorption capacities of EDAGO for Pb(II), Cu(II), Ni(II), Zn(II) and Co(II) were 740.7, 97.0, 84.1, 70.8 and 68.2 mg/g, respectively, when pH values were 5.0, 4.0, 5.0, 5.0 and 5.0, respectively. Removal efficiencies of EDAGO for Pb(II), Cu(II) and Zn(II) were 99.2%, 95.8% and 93.9%, respectively; moreover, the adsorbent can be reused and exhibits very high removal efficiencies.     

CHARACTERIZATION AND EVALUATION OF LEVEXTREL EXTRACTION CHROMATOGRAPHIC RESINS FOR TRACE METAL SEPARATION SCHEMES IN AUTOMATIC WATER QUALITY CONTROL SYSTEMS.

ABSTRACT

This paper presents the results of the selective removal of Zn(II) from Cu(II), Cd(II), Ni(II) and Pb(II) using ‘Extraction Chromatographic Resins’ Lewatit TP80T84, which contains dK2,4,4-trimethylpentyl)pbosphinic acid as active component. The extraction and selectivity patterns of the resin were obtained from the metal distribution coefficients as a fiinction of pH. Experimental data of Pb(II), Ni(II) and other natural water occurring metal ions, such as Ca(II), were analyzed graphically and numerically in order to describe the metal extraction reactions. Analysis of the results showed that the extraction of these metal ions can be explained assuming the formation of metal complexes in the resin phase with a general composition ML2(_{q 3}HL)q, where q takes different values depending on the metal studied. Finally the efficiency of the resin in the selective removal of Zn(II) from the toxic heavy metal group Cu(T±), Cd(II), Ni(II) and Pb(II) were evaluated.of divalent metal ions (Zn(II), Cu(II), Cd(n), Ni(II), Pb(n)). Concerning the extraction selectivity of Lewatit TP80784 resins versus Zn(II), Cu(II)( Cd(n), Ca(n), Pb(n) and Ni(II), no differences have been found in comparison with the selectivity of this extractant in organic solvents (36). The results of the numerical treatment indicate that the extraction of Pb(n) and Ni(II) can be explained by assuming the formation of PbL₂(HL₂ and NiL₂(HL)₂. However, the extraction of Ca(II) can be explained assuming the formation of two species CaL₂ and Ca(NO₃)L|The analysis of the separation factors indicates that Lewatit TP80784 allows a quantitative separation of Zn(II) from Cd(II), Ni(II) and Pb(II) with ApHso greater that 2 and quasi-quantitative separations (90-95%) from Cu(II)|The results obtained in the extraction of Zn(IT), Cu(H), Cd(II), Ni(II), and Pb(n) from water samples in column experiments are very satisfactory, and the sytem will be used on-line in a multicomponent spectrophotometric method for the monitoring of low levels of toxic metal ions in surface waters.     

SYNERGIC EXTRACTION OF AMMONIACAL Ni

The synergic extraction of Ni from ammoniacal sulfate solution by mixtures of LIX 64N and Kelex 100 was studied using slope analysis, continuous variation, and mathematical modeling. This extractant pair was discovered as part of a study to find extractants that perform ?at the higher pH level needed for leaching Cu, Ni, and Co, and thus eliminate ammonia stripping/recharging steps in current processes. Ni was more efficiently extracted at higher pH with the LIX 64N/Kelex mixture than with either extractant alone. A model is proposed based on four different stoichiometrics, each contributing to the overall reaction. Those four Ni/LIX 64N/ Kelex species are 1/2/0, 1/0/3, 1/1/1, and 1/2/1. Ammonia is coextracted, but can be selectively scrubbed with 2 g/L H₂S0₄ Ni can be selectively stripped from the Ni- and Cu-loaded extractants with 10 g/L H₂S0₄ then Cu is stripped with 150 g/L H₂S0₄ A continuous process was simulated with a batchwise circuit, which showed no loss of extraction efficiency in 10 cycles.     

Separation and recovery of copper from waste printed circuit boards leach solution using solvent extraction with Acorga M5640 as extractant

Waste printed circuit boards (WPCBs) have received extensive attention in recent years because of its harmfulness and resource. In this work, two-step leaching process was carried out by using steel pickling waste liquor (SPWL) as the leaching agent. The leaching solution contains a variety of metals, especially iron, which will have an effect on the recovery of copper. Acorga M5640 (M5640) extractant with a kerosene diluent was used to recover copper from WPCBs leach solution, and the separation factor is adopted to analyze the effects of these metal ions. The effect of different parameters such as pH of aqueous phase, phase ratio (O/A), M5640 concentration, contact time as well as the concentration of H₂SO₄ as stripping reagent were investigated. Over 90.0% copper was extracted with pH 1.1, phase ratio (O/A) 1/1, M5640 concentration 16%, contact time 3 min at room temperature. For the stripping process, the 60 s contact time and 2.5 mol/L H₂SO₄ concentration are suitable with 90.0% stripping percentage of copper. Copper extraction isotherm accords with Langmuir isotherm equation and the results show that iron is the most influential metal ion for copper extraction, which will reduce the theoretical saturation of the extractant. The extractant M5640 has excellent reuse performance and can be recycled more than 10 times, which demonstrated M5640 has the industrial application value in the extraction of copper from WPCBs leach solution.     

Selective Transport of Cu(II) across a Polymer Inclusion Membrane with 1-Alkylimidazole from Nitrate Solutions

The selective transport of copper(II), zinc(II), cobalt(II), and nickel(II) ions from nitrate solutions across polymer inclusion membranes (PIMs), which consist of cellulose triacetate as polymeric support, o-nitrophenyl pentyl ether as plasticizer, and 1-alkylimidazole (alkyl from hexyl- to decyl) as ion carrier was reported. PIM was characterized by using atomic force microscopy (AFM) technique. The results show that Cu(II) can be separated very effectively from other transition metal cations as Zn(II), Co(II), and Ni(II) (at a concentration of 10^?3 mol/dm³ each). Alkyl substituents at position 1 of the imidazole ring have been found to affect the hydrophobic properties and initial flux of the transported metal ions. The efficiency of separation of metal ions by 1-alkylimidazole followed the sequence: Cu(II) > Zn(II) > Co(II) > Ni(II). The highest selectivity coefficient for Cu(II) was found with 1-hexylimidazole and its 1 mol/dm³ solution in PIM. Separation of the ions was more effective for the nitrates(V) than for chlorides.     

Recovery of copper from a surface altered chalcopyrite contained ball mill spillage through bio-hydrometallurgical route

Bioleaching studies for chalcopyrite contained ball mill spillages are very scarce in the literature. We developed a process flow sheet for the recovery of copper metal from surface activated (600 °C, 15 min) ball mill spillage through bio-hydrometallurgical processing route. Bioleaching of the activated sample using a mixed meso-acidophilic bacterial consortium predominantly A. ferrooxidans strains was found to be effective at a lixiviant flow rate of 1.5 L/h, enabling a maximum 72.36% copper recovery in 20 days. Mineralogical as well as morphological changes over the sample surface were seen to trigger the bioleaching efficiency of meso-acidophiles, thereby contributing towards an enhanced copper recovery from the ball mill spillage. The bio-leach liquor containing 1.84 g/L Cu was purified through solvent extraction using LIX 84I in kerosene prior to the recovery of copper metal by electrowinning. Purity of the copper produced through this process was 99.99%.     

Synthesis of sulfur nanoparticles-loaded alumina as a low-cost sorbent for the preconcentration of nickel from real samples

This study reports a simple method for the synthesis of α-sulfur-nanoparticles-loaded alumina as a reliable kind of sorbents in solid-phase extraction (SPE) methods for the preconcentration and determination of trace levels of Ni(II) from real samples. The most important advantage of this technique is not using the ligand as a complexing agent and hence the disadvantages of other SPE methods have been avoided. The calibration graph was linear over the range of 0.66–100 µg/L and the relative standard deviation (RSD) of 1.98% at 50 µg/L was obtained. The limit of detection (LOD) and preconcentration factor (PF) were obtained as 0.22 µg/L and 250, respectively. The maximum adsorption capacity of the adsorbent was found to be 18 mg/g for Ni(II).