Recovery Of Copper Ions Research Articles

Carboxyl and polyamine groups functionalized polyacrylonitrile fibers for efficient recovery of copper ions from solution.

Heavy metals (e.g., Cu) in wastewater are attractive resources for diverse applications, and adsorption is a promising route to recovery of heavy metals from wastewater. However, high-performance adsorbents with high adsorption capacity, speed, and stability remain challenging. Herein, chelating fibers were prepared by chemically grafting amine and carboxyl groups onto the polyacrylonitrile fiber surface and used in the wastewater's adsorption of Cu2+. The adsorption behavior of Cu2+ on the fibers was systematically investigated, and the post-adsorption fibers were comprehensively characterized to uncover the adsorption mechanism. The results show that chelated fiber has a 136.3mg/g maximum capacity for Cu2+ adsorption at pH = 5, and the whole adsorption process could reach equilibrium in about 60min. The adsorption process corresponds to the quasi-secondary kinetic and Langmuir models. The results of adsorption, FTIR, and XPS tests indicate that the synergistic coordination of -COOH and -NH2 plays a leading role in the rapid capture of Cu2+. In addition, introducing hydrophilic groups facilitates the rapid contact and interaction of the fibers with Cu2+ in the solution. After being used five times, the fiber's adsorption capacity remains at over 90% of its original level.

Competitive recovery of copper ions using ethyl acetoacetate modified chitosan/organo-functionalized alginate hydrogel beads: kinetics and isothermal sorption studies

Surface functionalization of chitosan using some chelating ligands not only improves sorption capacity but also induces selectivity into the biopolymer. The current study is based on the facile synthesis of ethyl acetoacetate modified chitosan and surface-functionalized alginate composite beads (EAA-MCSA). Chemical modification of sodium alginate was carried out to graft amino thiocarbamate moiety (-OCSNHNH2) to entrench selectivity and specificity across the linear chains of preliminary polysaccharide. Biosorbent (EAA-MCSA) was thoroughly characterized by FT-IR and SEM analysis and employed in the form of composite hydrogel beads for competitive Cu(II) recovery. Newly grafted aminothiocarbamate (-OCSNHNH2) and 1,3-dicarbonyl moieties (-COCH2CO-) are supposed to act as potential chelating sites for enhanced Cu(II) sorption. Kinetic data could be well depicted using pseudo-second order rate law (R2 = 0.99, qexp≈qe,th = 85.25 mg/g, k2 = 0.45–1.17 ×10−2 g/mg.min−1) and sorption data was found in close agreement with Langmuir adsorption isotherm (R2 = 0.99, qm= 390.21 mg/g at 298 K and pH = 6.0, KL= 0.44–0.49 ×10−2 L/mg). The ΔG° values (−20.75, −21.10, −21.30 and −21.50 kJ/mol) and positive ΔH° (−7.63 kJ/mol) designated the sorption process as spontaneous and exothermic, respectively. Hence, EAA-MCSA could be a better sorbent for adsorptive remediation of Cu(II) from dilute effluents.

Improving Membrane Filtration for Copper Speciation: Optimal Salt Pretreatments of Polyethersulfone Membranes to Prevent Analyte Retention.

Membrane filtration has been increasingly used to separate dissolved metal ions from dispersed particles, commonly using ultrafiltration membranes, for example, polyethersulfone (PES) membranes with a molecular weight cut-off of 3 kDa. The disadvantage of this technique is an undesired retention of ions, resulting from Coulomb interactions with sulfonic acid groups of the membrane. Therefore, such a membrane acts similar to a cation exchanger column. We solved this drawback by a pretreatment of the PES membrane by other cations. Using CuSO4 as a model compound, we compared the effectiveness of five cations using their salt solutions (Ca2+, Mg2+, Fe2+, Ag+, Ba2+) as pretreatment agents and identified the most effective pretreatment component for a high recovery of copper ions. After membrane filtration without pretreatment, only 52 ± 10%, 64 ± 5%, 75 ± 8%, and 89 ± 7% of nominal Cu concentrations were obtained using initial concentrations of 0.2, 0.5, 1.0, and 4.0 mg L-1, respectively. The efficiency of the investigated cations increased in the order Fe < Ag < Mg < Ca < Ba. Furthermore, we analyzed the most efficient concentration of the pretreatment agent. The best performance was achieved using 0.1 mol L-1 CaCl2 which increased copper recovery to slightly below 100%, even at the lowest tested Cu concentration (recovery 93 ± 10% at 0.2 mg L-1). In the environmentally relevant Cu concentration range of 0.2 mg L-1, 0.1 mol L-1 BaCl2 was identified as the most efficient pretreatment (103 ± 11%).

Improved Copper Ion Recovery Efficiency through Surface Modification of Membranes in the Electrodialysis/Solvent Extraction Process

Improved Copper Ion Recovery Efficiency through Surface Modification of Membranes in the Electrodialysis/Solvent Extraction Process

Optimization of a rotating cylinder electrode electrochemical reactor for metal recovery: An innovative approach and method combining CFD and response surface methodology

The optimization of electrochemical reactors for metal recovery using hydrodynamic and mass transfer models with CFD is addressed. The performance of a rotating cylinder electrode (RCE) electrochemical reactor is considered. The optimization procedure has two stages.The first comprises developing a validated 3D model of metal electrodeposition at different hydrodynamic regimes. The hydrodynamics are described by the Reynolds-averaged Navier‒Stokes (RANS) equations using the standard k-ε turbulence models. The diffusion-convection equation with turbulent mixing and concentration wall function was used for the transport of electroactive species. The model was validated with experimental data obtained in a batch reactor with two different diameters of the RCE. Additionally, the model was validated in the continuous mode of operation as a part of the proposed methodology for one case of the hydrodynamic conditions for each reactor geometry.The second stage presents a methodology for optimizing the operation of an RCE reactor using the abovementioned validated models. The optimization process was carried out using response surface methodology (RSM), where three objective functions were analyzed: the fractional conversion of the reactant, the specific energy consumption, and the current efficiency. The effectiveness of the proposed method was proven by the copper ion recovery in a continuous RCE reactor under optimized conditions.

A clean process for selective recovery of copper from industrial wastewater by extraction-precipitation with p-tert-octyl phenoxy acetic acid

A novel method for the selective removal and recovery of copper ion from copper-containing wastewater by extraction-precipitation with p-tert-octyl phenoxy acetic acid as a precipitant is presented. The morphology, thermal stability and solubility of POAA were synthesized and characterized. Then the application of POAA to precipitate copper from simulated copper-containing wastewater was studied. The effects of some factors (i.e., time, pH, temperature, dosage of precipitant) on copper precipitation efficiency (P%) and water solubility of POAA were discussed. The extraction-precipitation mechanism of POAA and Cu2+ was investigated by slope analysis combined with SEM, EDS, XPS and IR spectra. The concentration and purity of copper from industrial wastewater increased from 100.2 mg/L to 27,916 mg/L and 13.71%–93.01% respectively, treating by the proposed extraction-precipitation. Moreover, POAA revealed good stability in the recycling processes. Extraction-precipitation strategy is simple, efficient and sustainable, which can effectively reduce the volume of sludge in the process of wastewater treatment and produce copper concentrated solution with industrial value, which has revealed application potential for the clean production of copper smelting enterprises.

Innovative method for encapsulating highly pigmented biomass from Aspergillus nidulans mutant for copper ions removal and recovery.

Biosorption has been considered a promising technology for the treatment of industrial effluents containing heavy metals. However, the development of a cost-effective technique for biomass immobilization is essential for successful application of biosorption in industrial processes. In this study, a new method of reversible encapsulation of the highly pigmented biomass from Aspergillus nidulans mutant using semipermeable cellulose membrane was developed and the efficiency of the encapsulated biosorbent in the removal and recovery of copper ions was evaluated. Data analysis showed that the pseudo-second-order model better described copper adsorption by encapsulated biosorbent and a good correlation (r2 > 0.96) to the Langmuir isotherm was obtained. The maximum biosorption capacities for the encapsulated biosorbents were higher (333.5 and 116.1 mg g-1 for EB10 and EB30, respectively) than that for free biomass (92.0 mg g-1). SEM-EDXS and FT-IR analysis revealed that several functional groups on fungal biomass were involved in copper adsorption through ion-exchange mechanism. Sorption/desorption experiments showed that the metal recovery efficiency by encapsulated biosorbent remained constant at approximately 70% during five biosorption/desorption cycles. Therefore, this study demonstrated that the new encapsulation method of the fungal biomass using a semipermeable cellulose membrane is efficient for heavy metal ion removal and recovery from aqueous solutions in multiple adsorption-desorption cycles. In addition, this reversible encapsulation method has great potential for application in the treatment of heavy metal contaminated industrial effluents due to its low cost, the possibility of recovering adsorbed ions and the reuse of biosorbent in consecutive biosorption/desorption cycles with high efficiency of metal removal and recovery.

PECULIARITIES OF METALIZATION OF PULLED POLYETHYLENE

The results of experimental studies of the peculiarities of metallization of granular polyethylene are presented. The influence of concentration factors on the metallization process of zinc-activated polyethylene granules of brand Liten PL-10 was investigated. It is established that by changing the concentration of copper sulfate and sodium hydroxide, as well as the degree of loading of polymeric raw materials, it is possible to effectively regulate the amount of recovered copper on granules of polyethylene, and therefore the thickness of the metal layer formed on them. The use of the method of preliminary processing of activated polyethylene granules in a solution of copper sulfate can significantly reduce the induction period and increase the rate of recovery of copper ions.

Structurally designed porous polymer monoliths as probe-anchoring templates as benign and fast responsive solid-state optical sensors for the sensing and recovery of copper ions

In this study, we report on the superior ion-capturing and sensing competence of a new breed of aqua-compatible solid-state ion-sensor using a structurally organized polymer monolith, for the ocular sensing of trace levels of divalent copper ions. The polymer monolithic template exhibits a single block framework with a uniform structural pattern and porous network that serves as an efficient host for the homogeneous probe anchoring, to constitute a renewable solid-state optical sensor. Here, a series of solid-state colorimetric Cu(II) sensors has been designed using three indigenously synthesized chelating probes (molecules) namely, 4-butyl-N-(2-(2,4-dinitrophenyl)hydrazine-1-carbonothioyl)benzamide (BNHCB), 2-(thiophen-2-ylmethylene)hydrazinen-1-carbothioamide (TMHCA), and 4-butylphenyl(diazenyl)-2-mercaptopyrimidine-4,6-diol (BDMPD). The polymer monoliths are characterized using various surface and structural analysis techniques such as HR-SEM, HR-TEM, XPS, XRD, FT-IR, EDAX, and BET surface area analysis. The fabricated solid-state sensors exhibit excellent selectivity and sensitivity for copper ions with unique color transitions that are reliable even at ultra-trace (ppb) levels. The impact of diverse sensing parameters such as solution pH, probe concentration, sensor quantity, target ion concentration, temperature, response kinetics, and matrix tolerances have been optimized. The fabricated sensor materials proffer maximum sensing efficiency in neutral pH conditions, with a limit of detection (LD) and quantification (LQ) values of 0.56 and 1.87 μg l−1, 0.30 and 1.0 μg l−1, and 0.12 and 0.42 μg l−1, for BNHCB-, BDMPD-, and TMHCA-anchored polymer sensors, respectively. The proposed reusable solid-state colorimetric sensors are environmentally benign, cost-effective and data reproducible, with superior analytical performance.

Recovery of Copper Ions from Industrial Wastewater by Electrodeposition

Recovery of Copper Ions from Industrial Wastewater by Electrodeposition

Experimental results and optimization via the design of experiment (DOE) of the copper ion recovery from aqueous solutions using emulsion liquid membrane (ELM) method

Experimental results and optimization via the design of experiment (DOE) of the copper ion recovery from aqueous solutions using emulsion liquid membrane (ELM) method

Potential-responsive ions-selectively capture effect for efficient removal of copper ions from wastewater

A concept of target ions removal from wastewater by using a potential-responsive film with ions-selectively capture effect was proposed. A poly(2,2′-dithiodianiline) (poly(DTDA)) film with three-dimensional (3D) porous structure was fabricated based on this concept to remove copper ions from wastewater. By modulating the applied potential on the film, disulfide/dithiolate (-S-S−/−S- −S-) of poly(DTDA) acted as the claw to selectively capture and release the copper ions. The mechanism of the potential-responsive ions-selectively capture effect on the capture/release process was analyzed by using X-ray photoelectron spectra (XPS), Raman spectra and density functional theory (DFT) calculations. Furthermore, the poly(DTDA) film exhibited high selectivity to copper ions in two kinds of real industrial wastewater and maintained excellent release efficiency of copper ions. Finally, the capture capacity retention and release efficiency remained more than 0.8 and 90% after 10 consecutive cycles, respectively. Such a poly(DTDA) film could be a potential material for the removal and recovery of copper ions from wastewater in industrial processes and the proposed concept is expected to be also applied for the removal of other target ions by developing special materials.

In-situ Cu(II) enrichment and recovery from low-strength copper-laden wastewater using a novel electrically enhanced microbial copper recovery cell (MCRC)

An innovative electrically enhanced microbial copper recovery cell (MCRC) was proposed in this study to achieve fast and efficient in-situ enrichment and recovery of copper (Cu) ions from low-strength copper-laden water. The unique design of the system enabled in-situ copper recovery without altering the properties of wastewater or introducing other undesired substances. The copper ions could be efficiently enriched and removed, and this process was greatly enhanced by the application of additional voltage. The MCRC obtained a maximum current density of 1.62 ± 0.01 A m−2, and exhibited outstanding copper removal efficiency of 95.4% with an initial copper concentration of 5 mg L–1 at an applied voltage of 0.8 V, as well as the copper removal rate significantly increased by 196%. Furthermore, it was found out that the removal efficiency maintained >93% when the initial copper concentration increased 4 times to 20 mg L–1, while the removal rate increased 380%, which indicated the high potential of the MCRC system for practical applications. The deposited copper at the cathode could promote the electrochemical catalytic activity, as which favored the electron transfer reaction and lessened the internal resistance by 91%. This MCRC system provided a potential and efficient treatment strategy to improve the enrichment and recovery of copper ions for low-strength copper-laden wastewater.

Simultaneous recovery of copper(II) from two different feed solutions based on a three-compartment module with selective polymer inclusion membranes

A novel strategy for a three-compartment module with selective polymer inclusion membranes (PIMs) was proposed for the simultaneous recovery of copper ions from two different feed solutions using 2-hydroxy-5-nonyl-benzaldoxime (M5640) as the carrier. The effects of the membrane composition and the concentration of sulfuric acid in the stripping solution on the transport of Cu(II) were evaluated. The simultaneous transport of Cu(II) through the PIMs was further performed from both copper–nickel–cobalt and copper–zinc solutions in a three-compartment module. The results showed that Cu(II) could be selectively transported into the stripping solution, whereas Ni(II), Co(II), and Zn(II) were left in the respective raffinates. Moreover, FT-IR, XPS and small-angle X-ray scattering (SAXS) analyses of the PIMs were performed to disclose the selective transport mechanism of Cu(II). To further verify the feasibility of the innovative application, the continuous enrichment transport and membrane stability were tested and compared with the performance of other liquid membrane systems. Owing to its high efficiency, selectivity, and good membrane stability, the three-compartment module can be potentially used for the removal and recovery of target metal ions from various leachates and industrial raffinates.

Decomplexation of Cu(II)-EDTA over oxygen-doped g-C3N4: An available resource towards environmental sustainability

Photocatlytic decomplexation provides an effective way to tackle the problem of heavy metal contamination. By far, the exploration of more efficient photocatalysts with low environmental risk is still an important but challenging issue. In this study, the feasibility of using metal-free carbon nitride as environmental-friendly catalysts for photocatalytic decomplexation was demonstrated, using Cu(II)-EDTA as a model contaminant. A facile oxygen doping strategy could significantly enhance the interfacial separation of photogenerated holes, which was determined to be the most effective reactive species for decomplexation reactions. Compared to pristine g-C3N4, oxygen doped sample exhibited 2.5-fold enhanced photoactivity. The hypothesis of using decomplexation solution as sustainable resource for fabricating copper modified photocatalysts was further investigated. The in-situ formation of Cu or Cu2O resulted in the significantly improved activity for hydrogen evolution over recycled photocatalysts. According to the component analysis, chemical reduction strategy was beneficial for the sufficient recovery of copper ions, while the photoreduction method led to the most efficient utilization of copper metals. This study not only presents a promising method for the treatment of heavy metal-contaminated water, but also provides a sustainable way to utilize decomplexation solution as valuable resource for clean energy production.

Surface functionalized carbon microspheres for the recovery of copper ion from refinery wastewater

Micro-sized carbon spheres (CNS) were synthesized by hydrothermal process from glucose solution at 443.15 K and two different reaction times. The synthesized CNS samples were surface functionalized with hydroxyl (-OH) functional groups using NaOH treatment, and were tested in batch adsorption to remove heavy metal ion (Cu2+) from aqueous solutions. Experimental results revealed that CNS contains mostly amorphous carbon. NaOH functionalized CNS had significantly higher adsorption capacity of copper ∼170×10−3 Kg Cu2+/Kg-CNS as compared to the untreated CNS. The adsorption isotherms were well fitted by the Langmuir isotherm equation. The surface morphology of the native and functionalized CNS samples was characterized by a number of techniques and based on which the adsorption of copper ion was discussed.

Effect of sorption conditions on the state of copper(II) ions in the phase of AN-31 ion exchange resin, according to data from ESR and UV–vis diffuse reflectance spectroscopy

It is found that the sorption recovery of copper ions from water solutions in the phase of AN-31 low basicity anion exchanger has a mixed character. It is established via diffuse reflectance spectroscopy that ions are stabilized through complexation with the participation of the functional groups of the sorbent with the formation of structures [Cu(NR3)2(OH)2(H2O)2], [Cu(NR3)3(OH)(H2O)2], and as a result of the physical adsorption of oxide dimers and planar-squared copper clusters. It is shown that increasing the ionic strength of a solution by introducing sodium chloride into the system greatly improves the capacity of the sorbent and leads to the uniform distribution of copper ions in the resin matrix. The similarity between the ESR spectrum parameters of copper-containing samples of the ion exchanger, obtained in a wider range of pH, is determined via ESR and testifies to the homogeneity of the stabilization positions of Cu2+ ions. The crystalline field of tetragonal-elongated octahedron is typical of all Cu2+ ions. All of the complexes have Cu(NO3)2 coordination nodes with the covalent bonding of Cu2+ ions and the amine groups of the sorbent.

Removal of copper ions from aqueous solution by the sodium salt of the maleic acid-allylpropionate-styrene terpolymer.

The sodium salt of the maleic acid-allylpropionate-styrene terpolymer was used for recovery of copper ions from aqueous solution. Effects of contact time, sorbent weight and initial Cu2+ ion concentrations on removal efficiency were tested. The maximum experimental sorption capacity of the sorbent for copper ions is 0.71 g g-1. The sorption isotherm of copper ions onto a prepared polymer sorbent has been studied and the equilibrium data were analyzed using Langmuir and Freundlich isotherm models. The adsorption isotherm data showed that copper ions adsorption on the sorbent was better fitted to the Langmuir isotherm model. The Lagergren pseudo-first- and pseudo-second-order kinetic models were applied to examine the kinetics of the copper ions sorption by the synthesized sorbent. The kinetic data are best described by the pseudo-second-order model. The calculated value of the maximum sorption capacity by the pseudo-second-order equation (0.62 g g-1) corresponds well with its experimentally found value (0.71 g g-1). Considering the obtained kinetic data, and the Fourier transform infrared spectroscopy (FT-IR) and UV-vis spectra of the sorbent after the sorption, it is possible to come to the conclusion that during the sorption process Cu2+ ions enter a complex with the carboxylic groups of the maleic acid units of the sorbent.

Copper Ion Recovery from Mine Water by Ion Flotation

Solutions containing copper ions are produced at copper mines due to its dissolution from ores and dumps. It is important to recover these ions to prevent this toxic element from entering the environment and because it could be economical. We investigated the use of ion flotation for extracting Cu ions from diluted mine water from the Veshnaveh Mine in Qom, Iran. Experiments were conducted using floatation cells at pH 6, 9, and 12 with diluted solutions containing 10 mg L−1 of Cu. Sodium dodecyl sulfate and hexadecyl trimethyl ammonium bromide (HTAB) were used as collectors and methyl isobutyl carbinol (MIBC) and ethanol were used as frothers. The best result was achieved by maximizing Cu ion recovery and minimizing water recovery at pH 12, using 100 mg L−1 of HTAB and 0.1 % (v/v) of MIBC. Copper and water recovery were 79 and 24 %, respectively.

Determination of Cu(II) in water and food samples by Na+-cloisite nanoclay as a new adsorbent: Equilibrium, kinetic and thermodynamic studies

Na+-MMT (sodium montmorillonite) or Na+-cloisite nanoclay as a new adsorbent was employed for the sorption of Cu(II) ions from water and food samples in batch system. Copper ion determination was carried out by applying the solid phase extraction (SPE) method followed by atomic absorption spectroscopy (AAS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The effects of varying parameters such as initial concentration of metal ions, volume of the standard solutions, eluent and buffer solutions characteristics, amount of adsorbent, contact time, and temperature on the adsorption process, also, the role of desorption and centrifugation time on the desorption step were explored. The effect of the interfering ions on the recovery of copper ions was also examined. This optimized method was applied to a variety of real water and food samples. The adsorption data was correlated with Freundlich, Langmuir, Dubinin–Radushkevich (D–R), and Temkin isotherms. The kinetic data were described with pseudo-first-order, pseudo-second-order and double-exponential models. The adsorption process follows a pseudo-second-order reaction scheme. Calculation of ΔG0, ΔH0 and ΔS0 showed that the nature of Cu(II) ion sorption onto Na+-cloisite nanoclay was exothermic and was favored at lower temperature.