Preconcentration Of Cu Research Articles

Use of Fe3O4 Magnetic Nanoparticles Coated with Polythiophene for Simultaneous Preconcentration of Cu (II), Co (II), Cd (II), Ni (II) and Zn(II) Ions Prior to their Determination by MIS-FAAS

A multielement preconcentration procedure based Fe3O4 magnetic nanoparticles coated with polythiophene(Fe3O4@PTh MNPs) as a solid phase was reported for Cu(II), Co(II), Cd(II), Ni(II) and Zn(II) ions. Following the preconcentration, the ions were determined by microsample injection system-flame atomic absorption spectrometer (MIS-FAAS). The effect of sample pH, type and volume of eluent, sample volume, extraction time, amount of adsorbent and interfering ions were optimized. The analytes were preconcentrated from 75 to 150 mL of sample solutions buffered to pH 7. The eluent was 1 mL of 1 mol L-1 HNO3 solution. Under optimum conditions, the limits of detection for the analyte ions varied from 1 to 10 ?g L-1. The adsorption capacities of Fe3O4@PTh was in the range of 2.85 to 9.76 mg g-1. The method was validated by analysis of the certified reference materials. The relative errors and standard deviations were lower than 5%. The developed procedure was applied to various water, soil and some vegetable samples.

A polymer inclusion membrane for the simultaneous determination of Cu(II), Ni(II) and Cd(II) ions from natural waters

A novel polymer inclusion membrane (PIM), doped with pyridine-2-acetaldehyde benzoylhydrazone (2-APBH) as extractant, was synthesized and applied for the simultaneous extraction and preconcentration of Cu(II), Ni(II) and Cd(II) ions from natural waters of different salinities. Poly(vinyl chloride) (PVC) and tributyl phosphate (TBP) were used to prepare the polymeric membrane. The carrier-mediated extraction of Cu(II), Ni(II) and Cd(II) ions by PIM was based on the reaction of 2-APBH as a polydentate ligand, forming uncharged chelates at pH 8. After a back-extraction step from the membrane to an acid solution (0.3 mol L-1 nitric acid), these ions were quantitative determined by flame atomic absorption spectroscopy. The optimum values of different analytical variables were determined by using the modified simplex method. The results showed limits of detection of 0.33 µg L-1 for Cu(II), 0.75 µg L-1 for Ni(II) and 0.48 µg L-1 for Cd(II). The accuracy was successfully assessed by analyzing a certified reference river water (LGC 6019). The applicability of the proposed PIM on real samples was also demonstrated on estuarine and seawater samples, with high salinities.

Multi-walled carbon nanotubes functionalized with bathocuproinedisulfonic acid: analytical applications for the quantification of Cu(II).

This work reports the successful non-covalent functionalization of multi-walled carbon nanotubes (MWCNTs) with bathocuproinedisulfonic acid (BCS) and the analytical application of the resulting dispersion (MWCNTs-BCS) to develop an electrochemical sensor for Cu(II) quantification. The sensor was obtained by casting glassy carbon electrodes (GCEs) with MWCNTs-BCS. The sensing mechanism was based on the open circuit preconcentration of Cu(II) at the electrode surface by complexation of Cu(II) through the phenanthroline ring nitrogen of the BCS that supports the MWCNTs, the reduction of the preconcentrated Cu(II), and final differential pulse voltammetry-anodic stripping in 0.020M acetate buffer, pH5.00. The sensitivity of the sensor was (2.73 ± 0.08) μAμM-1, with a linear range between 5.0 × 10-7M and 6.0 × 10-6M, a detection limit of 0.15μM (9.5μgL-1), and reproducibility of 6.2% using the same dispersion and 7.1% using three different MWCNTs-BCS dispersions. The quantification of Cu(II) was highly selective even in the presence of As3+, Cr3+, Cd2+, Ni2+, Pb2+, Co2+, Zn2+, Fe2+, Hg2+, Rh, Ir, and Ru. The proposed sensor was successfully used for quantifying Cu(II) in tap water. Graphical abstract.

Silica Gel‐Immobilized 5‐aminoisophthalohydrazide: A novel sorbent for solid phase extraction of Cu, Zn and Pb from natural water samples

A novel silica sorbent, silica gel‐immobilized 5‐aminoisophthalohydrazide (SiO2‐APH), was prepared by the condensation of 3‐chloropropyl‐functionalized silica gel with 5‐aminoisophthalohydrazide (APH) derived from dimethyl 5‐aminoisophthalate as a starting material and used for separation and preconcentration of Cu, Zn, and Pb metals in water samples using Flame Atomic Absorption Spectrometry (FAAS). The characterization of the new sorbent was carried out by Elemental Analysis, Thermogravimetric Analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR). Important analytical parameters including as pH, amount of sorbent, type and amount of eluting solvent, sample volume, vortex and ultrasonic bath time, matrix ions that effect the developed SiO2‐APH‐solid phase extraction (SPE) method were investigated and optimum parameters were detected. Recoveries of examined metals were obtained as 98% for Cu and Pb and 101% for Zn. The relative standard deviation (RSD, n = 8) of Cu, Zn and Pb metals were 3.2, 2.8 and 1.6%, respectively. Limit of detections (LODs) (n = 10) were found as 2.7 μg L−1 for Cu, 7.4 μg L−1 for Zn and 3.5 μg L−1 for Pb μg L−1. The accuracy of the new method was assessed by analyzing of TMDA‐51.4 and TMDA‐70.2 certified reference materials. The results obtained for metals were in a good agreement with certified values. Addition/recovery test was applied to the real well, river, dam and stream water samples to check the accuracy of the method. The results showed that the developed SiO2‐APH‐SPE method can be effectively used as an alternative method for determination of Cu, Zn, and Pb metals in water samples.

Selective solid phase extraction and pre-concentration of Cu(II) ions from aqueous solution using Cu(II)-ion imprinted polymeric beads

A new Cu(II)-ion imprinted polymeric (IIP) beads (∼ 450 μm) were prepared by suspension polymerization of methyl methacrylate (monomer) and ethylene glycol dimethacrylate (crosslinker) in the presence of Cu(II)-picolinic acid (functional ligand) binary complex wherein Cu(II) ion is used as an imprint ion. The imprinted Cu(II) ions were removed from the polymeric matrix using 1 M HCl, thereby creating the cavities for the selective adsorption of Cu(II) ions. For the comparison purpose, control polymeric (CP) beads were similarly prepared without the use of Cu(II) ions. The prepared IIP beads were characterized using different analytical techniques such as scanning electron microscopy, energy dispersive X-ray spectroscopy, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, surface area and pore size distribution. The optimum solution pH was determined to be 5.0 and equilibrium was achieved within 60 min. Nature of eluent, eluent concentration and sample volume were also studied. The synthesized IIP exhibited high selectivity coefficients for the Cu(II)/Ni(II), Cu(II)/Co(II) and Cu(II)/Zn(II) are 26.8, 34.0 and 57.7, respectively. The IIP beads can be used up to seven adsorption/desorption cycles with the recovery not less than 97 %. The detection limit corresponding to three times the standard deviation of the blank was found to be 0.3 μg mL−1.

Simultaneous Spectrometric Determination of Cu(II), Co(II), and Ni(II) in Pharmaceutical and Environmental Samples with XAD-4/DMMDTC Solid-Phase Extraction System.

A method for the preconcentration of Cu(II), Co(II), and Ni(II) based on their complex formation with the potassium salt of 2.6-dimethyl-morpholinedithiocarbamate (DMMDTC) and the Amberlite XAD-4 resin as a solid support in a column was suggested. Cu(II), Co(II), and Ni(II) were detected by using the suggested spectrophotometric method in Triton X-100 media. The analytes were adsorbed as DMMDTC complexes on Amberlite XAD-4 column at the pH range of 4-6 and eluted with 0.5 M HNO3 in acetone. The best possible enrichment factors for trace metal ions were achieved by optimizing the experimental conditions including reagent amount, eluent type, sample and eluent flow rates, sample volume, and the effects of matrix ions. The detection limits of Cu(II), Co(II), and Ni(II) were found to be 11.2, 26.1, and 1.37 μg L-1, respectively. The accuracy of the proposed method was confirmed by determining the analytes in two Certified Reference Materials (TMDA-70.2 Ontario Lake Water and BCR-715 Waste Water) with the recoveries of more than 90%. The proposed method was successfully applied to the environmental and pharmaceutical samples.

Synthesis of sulphonic acid functionalized magnetic mesoporous silica for Cu(II) and Co(II) adsorption

Sulphonic acid functionalized core-shell magnetic mesoporous silica nanoparticles have been synthesized and used for preconcentration and enrichment of Cu(II) and Co(II). Mercapto groups were introduced via co-condensation which were then oxidized by H2O2 to incorporate the sulphonic acid functionality on the silica shell. The higher surface area of the sorbent and magnetic core simplified the extraction process. The adsorption of Cu(II) and Co(II) was achieved in less than 30 min at pH 7. The data showed that the adsorption mechanism followed pseudo-second order rate. The experimental data fits well in Langmuir, Freundlich and Temkin adsorption models. The maximum adsorption capacities for Cu(II) and Co(II) were 132 mg/g and 99.1 mg/g respectively. The newly synthesized material was successfully employed to develop an efficient preconcentarion method prior to the analysis of Cu(II) and Co(II) by graphite furnace atomic absorption spectrometer (GFAAS). The factors affecting the analysis were optimized and interferences from co-existing ions were also investigated. The detection limits for Cu(II) and Co(II) were 20 ng/L and 27 ng/L respectively. The results indicate that the new sorbent can be used for efficient preconcentration of Cu(II) and Co(II) from complex environmental samples.

Solid-phase extraction of copper as 1-(2-pyridylazo)-2-naphthol (PAN) chelates on Coprinus atramentaria

ABSTRACT A solid-phase extraction method for separation-preconcentration of copper as 1-(2-pyridylazo)-2-naphthol (PAN) on Coprinus atramentaria has been presented. The copper concentration was determined by micro-sampling flame atomic absorption spectrometry (FAAS). It could be discussed that the developed method has low LOD in addition to high preconcentration factor. By considering the over advantages of recommended method, we can suggest the use of its to preconcentration of Cu(II) by routinly. The various analytical factors affecting the efficiency of extraction were optimised. Copper(II)-PAN chelate was quantitatively recovered at pH 6.0 on Coprinus atramentaria and eluted with 2 M HNO3. The limit of detection, limit of quantification, inter-day and intra-day precision values of copper were 0.7 μg L−1, 2.33 µg L−1, 5.31% and 5.15%, respectively. The pre-concentration factor was 70. The method was confirmed by applying the method to certified reference materials and addition–recovery tests prior to application to the determination of copper ions in various samples recovery results. The solid-phase extraction with FAAS is a successful method for the determination of copper in different samples.

A new hybrid sorbent 2,2’-pyridil functionalized SBA-15 (Pyl-SBA-15) synthesis and its applications in solid phase extraction of Cu(II) from water samples

A mesoporous hybrid material, 2,2’-Pyridil-SBA-15 (Pyl-SBA-15) was synthesized by anchoring 2,2’-Pyridil onto the surface of SBA-15. The application of Pyl-SBA-15 as a sorbent in separation and preconcentration of Cu(II) ions in water samples was studied. Effect of different parameters like pH, volume of eluent, sample flow rate and interfering ions was investigated. The preconcentration capacity value of the prepared material under optimized conditions for Cu(II) was 0.88 ± 0.01 mmol g−1. The Cu(II) ions collected onto the sorbent were eluted out with 6 mL of 1 M HNO3 and determined by atomic absorption spectroscopy (AAS). The enrichment factor and detection limit of Cu(II) were found to be 66.6 and 0.38 μg L-1 respectively.

New modified carbon based solid phase extraction sorbent prepared from wild cherry stone as natural raw material for the pre-concentration and determination of trace amounts of copper in food samples

A new activated carbon (AC) adsorbent was prepared from cherry stone of native wild cherry shrub of Kurdistan as raw material. The AC was modified by acidic and microwave modification methods and applied as dispersive solid phase extraction (dSPE) sorbent. Hydrochloric (15% w/w) and nitric (32.5% w/w) acids were used to oxidize the porous surface of AC and to change its surface chemistry. Acidic functional groups on acidic modified AC (AM-AC) sample were seen in related FT-IR spectrum. Also, microwave radiation led to significant changes in porous structure of modified sample especially increasing its surface area from 120.07 m2 g−1 to 160.2 m2 g−1, based on results of BET experiments. SEM images showed porous structure in prepared sorbent. In the next step, the acidic and microwave modified AC (AMM-AC) was used in dSPE process at ng mL−1 concentration levels for extraction and pre-concentration of Cu (II) prior to flame atomic absorption spectrometric determination. Various parameters affecting the process were evaluated. The optimum sorbent amount, extraction time, pH and extraction temperature were found to be 15 mg, 15 min, 7 and 30 °C, respectively. In the concentration range from 0.8 to180 ng mL−1, the calibration curve was linear with correlation coefficient (r) of 0.9983. The enrichment factor 100 was obtained. The relative standard deviation was 3.87% (for n = 7), the limit of detection was 0.31 ng mL−1, and relative recoveries in food samples were in the range of 95.7–103.6%.

Green nanosilica@folic Acid (VB9) nanocomposite for engineered adsorptive water remediation of bivalent lead, cadmium and copper

Folic acid (VB9) was used as an eco-friendly sequestering chemical compound to modify and develop a novel nanocomposite via surface immobilization and chemical bonding with nanosilica (Nano-SiO2) in the chloride form to generate Nano-SiO2@VB9. The synthesized materials were investigated and characterized by several means of SEM, HR-TEM, TGA, FT-IR, XRD and surface area determination. The tendency of Nano-SiO2@VB9 nanocomposite to extract and remove bivalent lead, cadmium and copper ions was studied and optimized under various variables including pH of contact medium, nanocomposite dose, contact time, effect of metal ion concentration and interfering cations-anions. The highest determined capacity values were 562.1, 973.8 and 152.1 mg g−1 for Cd(II), Pb(ІІ) and Cu(II), respectively. The optimum contact time for sorption of metal ions was identified as 25 min, while 10.0 mg of Nano-SiO2@VB9 nanocomposite was the optimum dosage to establish the maximum capacity values. The adsorbed ions were arranged in a multilayer surface and the equilibrium up-take of metal ions by Nano-SiO2@VB9 nanocomposite was favorably characterized by the Freundlich adsorption isotherm model. The potential applications of Nano-SiO2@VB9 for removal and preconcentration of Cu(II), Pb(II) and Cd(II) from real water samples using multistage microcolumn were also studied to confirm excellent percentage extraction values 94–100%, 100% and 57–81%, respectively.

4-クロロカテコールで化学修飾したシリカゲルによる銅(II)の予備濃縮

4-クロロカテコールで化学修飾したシリカゲルによる銅(II)の予備濃縮

Fabrication, characterization and theoretical investigation of novel Fe3O4@egg-shell membrane as a green nanosorbent for simultaneous preconcentration of Cu (II) and Tl (I) prior to ETAAS determination

Eggshell membrane modified by Fe3O4 magnetite were prepared and used as an adsorbent for simultaneous extraction and preconcentration of copper and thallium ions via magnetic solid phase extraction (MSPE) method. After adsorption, these ions were desorbed with hydrochloric acid followed with specific determination by electrothermal atomic absorption (ETAAS). The prepared Surface modification of eggshell membrane with doped Fe3O4 magnetite nanoparticles was investigated with field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM) and X-ray diffraction (XRD) spectrometry was used to characterize the adsorbent. The MSPE requirement was optimized. The detection limits of 0.96 and 0.17 ng/L were obtained for copper and thallium, respectively. The linear range was 0.020–0.420 ng/mL for copper and 0.005–0.065 ng/mL for thallium. The relative standard deviations of the method for eight replicate determination of 0.100 and 0.015 ng/mL of Cu (II) and Tl (I) were ±2.62% and ±4.51%, sequentially. The technique was employed for the determination of target ions in different environmental samples with high recoveries. For understanding the interaction between Fe3O4 and CaCO3, the adsorption structures and energies of a CaCO3 on the Fe3O4 (111) surface have been computed at the level of density functional theory.

Adsorptive properties of mesoporous silica modified with Lewis base molecule and its application in the preconcentration of Cu(II), Co(II), and Cd(II) from aqueous media

Adsorptive properties of mesoporous silica modified with Lewis base molecule and its application in the preconcentration of Cu(II), Co(II), and Cd(II) from aqueous media

Development of a Novel and Simple Electroanalytical Procedure for the Determination of Copper in Biofuel Employing a Sensor Based on Vulcan Functionalized with Carbazone

A novel and simple electroanalytical method for the determination of Cu2+ in biodiesel samples by stripping voltammetric analysis was developed. The method employs a carbon paste electrode (CPE) modified with Vulcan carbon, previouly functionalized with carbazone (CBZ). The CPE/Vulcan-CBZ sensor promoted a significant increase in the analytical signal obtained from copper as compared to unmodified CPE, and the CPE modified with Vulcan carbon (CPE/ Vulcan). Vulcan-CBZ, Vulcan and CBZ materials were characterized by Fourier transform infrared spectroscopy (FTIR) technique. The electrochemical behavior of the sensor was evaluated using cyclic voltammetry (CV) and square-wave anodic stripping voltammetric (SWASV) techniques. The CPE/Vulcan-CBZ modified electrode showed excellent response and was able to detect Cu2+ at nanomolar levels. The electrochemical method is based on preconcentration of Cu2+ ions on the CPE/Vulcan-CBZ at 0.35 V vs. Ag/AgCl(sat) in 0.2 mol L-1 ammonium sulfate solution ((NH4)2SO4), pH 3.5, during 120 s, followed by subsequent chemical stripping. The analytical signal showed a linear response for Cu2+ concentrations in the range from 6 to 190 nmol L-1 (r = 0.998), with a detection limit of 1.2 nmol L-1. The sensor was successfully applied for the determination of Cu2+ in biodiesel and the average recovery varied between 97.0 and 102.8% for the soybean biodiesel samples and between 109.6 and 111.0% for the babassu biodiesel samples showing a good accuracy for the proposed method.

Determination of Ultra Trace Copper in Water Samples by Differential Pulse Polarography after Solid Phase Extraction

A high selective and sensitive anodic stripping differential pulse polarographic method for determination of ultra-trace amounts of Cu 2+ ion in water samples is proposed. The method is based on the separation and preconcentration of Cu 2+ on an octadecyl bonded silica (ODBS) membrane disk modified by a recently synthesized triazene ligand, ([1-(ortoacyl benzene)3-(3,4-dichlorobenzene)triazene]). Various parameters such as, pH of aqueous solution (7-8), flow rates (10 mL min -1 ), the amount of ligand (6.0 mg) and the type of stripping solvent (0.1M nitric acid) have optimized. The breakthrough volume was greater than 500 mL with an enrichment factor of more than 100 and 3.88µg L -1 detection limit. The capacity of the modified disks is 220µg of copper per 6mg of the ligand. The effects of various cationic interferences on the percent recovery of copper ion were studied. The method was successfully applied to the determination of copper ion in different samples. DOI: http://dx.doi.org/10.17807/orbital.v9i5.1093

Selective Preconcentration of Trace Amounts of Cu(II) With Surface‐Imprinted Multiwalled Carbon Nanotubes

In this study, a new sorbent is synthesized using surface imprinting technique. Cu(II)‐imprinted multiwalled carbon nanotube sorbent (Cu(II)‐IMWCNT) is used as the solid phase in the solid‐phase extraction method. After the preconcentration procedure, Cu(II) ions are determined by high‐resolution continuum source atomic absorption spectrometry. A total of 0.1 mol L−1 ethylenediaminetetraacetic acid (EDTA) is used to remove Cu(II) ions from the sorbent surface. The optimum experimental conditions for effective preconcentration of Cu(II), parameters such as pH, eluent type and concentration, flow rate, sample volume, sorbent capacity, and selectivity are investigated. The synthesized solid phase is characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The maximum adsorption capacities of Cu(II)‐IMWCNT and non‐imprinted solid phases are 270.3 and 14.3 mg g−1 at pH 5, respectively. Under optimum experimental conditions for Cu(II) ions, the limit of detection is 0.07 μg L−1 and preconcentration factor is 40. In addition, it is determined to be reusable without significant decrease in recovery values up to 100 adsorption–desorption cycles. Cu(II)‐IMWCNT have a high stability. To check the accuracy of the developed method, certified reference materials, and water samples are analyzed with satisfactory analytical results.

Magnetic Graphene Oxide as an Efficient Adsorbent for the Separation and Preconcentration of Cu(II), Pb(II), and Cd(II) from Environmental Samples

The separation and preconcentration of copper(II), lead(II), and cadmium(II) ions on magnetic graphene oxide (MGO) by solid-phase extraction was carried out. Quantitative recovery was obtained by adsorption of analytes on MGO at pH 6 and elution of 3 M HNO3 in 10% acetone. To optimize the presented method, the effects of various parameters-including pH, eluent conditions, and vortex time-were examined. Matrix effects were also investigated. Mean recoveries of the analytes were between 95 and 105%. The proposed method was validated by applying it to certified reference materials. Addition and recovery tests were also performed. The method was applied to verify the analyte content of several water and food samples.

Preconcentration and trace determination of copper (II) in Thai food recipes using Fe3O4@Chi-GQDs nanocomposites as a new magnetic adsorbent.

This study describes the preparation, characterization, and application of a new magnetic chitosan-graphene quantum dots (Fe3O4@Chi-GQDs) nanocomposite as an adsorbent for the preconcentration of Cu(II) in Thai food recipes or the so-called "Som Tam" (green papaya salad) prior to determination by inductively coupled plasma-optical emission spectrometry. The spectroscopic and magnetic properties along with the morphology and thermal property were analyzed using FTIR, EDX, XRD, TGA, VSM, and TEM. Preconcentration optimizations including pH, dosage of adsorbent, adsorption-desorption time, concentration and volume of elution solvent, sample volume and enrichment factor, and reusing time were investigated. Good linearity was obtained ranging from 0.05 to 1500µgL-1 with correlation coefficient of 0.999. Limit of detection was 0.015µgL-1. Relative recoveries of 85.4-107.5% were satisfactorily obtained. This Fe3O4@Chi-GQDs has high potential to be used as preconcentration method and can be reused 7times with high extraction efficiency.

A high activity adsorbent of chemically modified Cucurbita moschata (a novel adsorbent) for the removal of Cu(II) and Ni(II) from aqueous solution: Synthesis, characterization and metal removal efficiency

Abstract Remarkable adsorption potential towards Cu(II) and Ni(II) ions from wastewater under competitive sorption conditions was shown by alkali treated Cucurbita moschata biomass (ATCMB). The improvement in the adsorption properties of Cucurbita moschata biomass on treatment was because of the increase in the acidic functional groups on the surface of the adsorbent due to the chemical reaction taking place between sodium carbonate and lignocellulosic material. The alkali treatment of the adsorbent is simple and less time consuming as compare to other methods like physical activation such as the steam pyrolysis, etc. The influence of independent parameters, viz contact time, initial metal ion concentration, pH and adsorbent dosage on the process was investigated. The equilibrium equations were extensively investigated and found to be efficiently represented by Langmuir, Freundlich and Temkin isotherm models at different temperatures. Kinetic studies showed better applicability of second order kinetic model. The thermodynamic parameters (ΔH⁰ and ΔG⁰) suggest that adsorption of Cu(II) and Ni(II) ions was endothermic and spontaneous. The practical efficiency of ATCMB was demonstrated by removing Cu(II) and Ni(II) from single and binary-metal systems by column process. The breakthrough capacities of Cu(II) and Ni(II) ions in single metal system were higher than in binary-metal system. The desorption studies of Cu(II) and Ni(II) ions with 0.1 M HCl were conducted by column process. Therefore, these methods were further used for the extraction and pre-concentration of Cu(II) and Ni(II) ions from solutions of these metal ions prepared in DDW and in tap water for their determination using Atomic absorption spectrometry. Hence the highly efficient alkali treated Cucurbita moschata biomass showed rapid uptake of Cu(II) and Ni(II) indicating that it could be an excellent alternative for the removal of heavy metals by sorption process.