Removal of Cu(II) from Aqueous Solution by Oil-Water Interfacial Emulsion Technique with Adsorbing Colloids

Abstract

Experimental investigations on the removal of Cu(II) from an aqueous solution were carried out by an interfacial emulsion technique with an adsorbing colloid (Al(OH)₃, FE(OH)₃), Cu(II) from the aqueous solution was segregated into a compact emulsion between water and a water-immiscible oil phase by an interfacial emulsion technique that uses the adsorptive power of the oil-water interface. Trimethylamine was effective as a surfactant for the removal of Cu(II), and the optimum pH for the removal of Cu(II) was found at 9.0 when using Fe(OH)₃ and at 10.0 when using Al(OH)₃ as an adsorbing colloid, respectively. The effects of pH, mixing time, initial surfactant concentration, initial Fe(III) concentration, and foreign ions (Na⁺, Ca²⁺, CI^?, NO₃ ^?, HPO₄ ^2?) on the removal efficiency were investigated. The adsorption and separation mechanisms for the removal of Cu(II) by the interfacial emulsion technique of adsorbing colloids were observed.     

Adsorption of Cu(II) and Cr(VI) onto Treated Shorea dasyphylla Bark: Isotherm,Kinetics, and Thermodynamic Studies

The efficacy of treated Shorea dasyphylla bark for Cu(II) and Cr(VI) adsorption was assessed in a batch adsorption system as a function of pH, agitation period, and initial metal concentration. The equilibrium nature of Cu(II) and Cr(VI) adsorption was described by the Freundlich, Langmuir, and Dubinin-Radushkevich isotherms. The maximum monolayer capacities of treated Shorea dasyphylla bark, estimated from the Langmuir equation were 184.66 and 42.72 mg/g for Cu(II) and Cr(VI), respectively. The experimental results were fitted using pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models; the pseudo-second order showed the best conformity to the kinetic data. Thermodynamic parameters such as enthalpy change (ΔH°), free energy change (ΔG°) and entropy change (ΔS°) were determined by applying the Van't Hoff equation. The adsorption of Cu(II) and Cr(VI) onto treated Shorea dasyphylla bark was found to be spontaneous and exothermic. The adsorption mechanism was confirmed by means of Fourier transform infrared (FTIR) and Energy dispersive X-ray (EDX) spectroscopy. The dimensionless constant separation factor (R _L), indicated that treated Shorea dasyphylla bark was favorable for Cu(II) and Cr(VI) adsorption.     

Modern hybrid sorbents – New ways of heavy metal removal from waters

The possibility of hybrid ion exchanger (HIX) application in the simultaneous removal of heavy metal ions such as Cr(VI), Cu(II) and Zn(II) as well as Cd(II) and Pb(II) was presented. The ion exchanger in question combines the unique properties of hydrated metal oxides with the mechanical and thermal stability of synthetic ion exchangers. The kinetics of the sorption process of Cr(VI), Cu(II) and Zn(II) as well as Cd(II) and Pb(II) in the presence of Cl⁻, NO₃⁻ and SO₄²⁻ as well as EDDS (ethylenediaminedisuccinic acid) was also analyzed. Additionally, the effect of initial concentration, phase contact time and pH was also studied. Taking into account the possibility of its application on a large scale, the parameters of the adsorption process were estimated based on the linear form of the Langmuir and Freundlich isotherms.     

An assessment of zinc oxide nanosheets as a selective adsorbent for cadmium

Zinc oxide nanosheet is assessed as a selective adsorbent for the detection and adsorption of cadmium using simple eco-friendly extraction method. Pure zinc oxide nanosheet powders were characterized using field emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The zinc oxide nanosheets were applied to different metal ions, including Cd(II), Cu(II), Hg(II), La(III), Mn(II), Pb(II), Pd(II), and Y(III). Zinc oxide nanosheets were found to be selective for cadmium among these metal ions when determined by inductively coupled plasma-optical emission spectrometry. Moreover, adsorption isotherm data provided that the adsorption process was mainly monolayer on zinc oxide nanosheets.     

Adsorption of Cr(VI) on Cross‐Linked Chitosan Beads

Abstract

A possibility of Cr(VI) removal by the adsorption method is discussed in the paper. An adsorbent were hydrogel chitosan beads are produced by the phase inversion method (by changing pH). The possibility of removing Cr(VI) ions by both pure chitosan hydrogel and its chelate compounds (chitosan cross‐linked with Cu(II) and Ag(I) ions) was investigated. The adsorption proceeded from the solutions of potassium dichromate and ammonium dichromate (NH₄)₂Cr₂O₇ and K₂Cr₂O₇. The process rates and adsorption isotherms were determined and described by relevant equations. The process rate was described by the pseudo‐ and second‐order equations, and adsorption equilibria by the Langmuir equations. A slight advantageous change in adsorption properties of chitosan beads was revealed after cross‐linking (for chromium concentration up to 10 g/dm³). A maximum adsorption was 1.1 g_Cr/g chitosan. Results of the studies show that chitosan hydrogel proves useful in the removal of Cr(VI) ions, additionally, cross‐linking with Cu(II) and Ag(I) ions has an advantageous effect in the case of low‐concentrated solutions.     

Detection of trivalent-iron based on low-dimensional semiconductor metal oxide nanostructures for environmental remediation by ICP-OES technique

A large-scale synthesis of undoped low-dimensional semiconductor metal oxide nanostructures (ZnO nanoparticles, NPs) by simple wet-chemical method was performed using reducing agents at low temperature. The NPs were characterized in terms of their morphological, structural, and optical properties, and efficiently applied for the metal ions uptake. The detailed structural, compositional, and optical characterizations of the NPs were evaluated by powder X-ray diffraction pattern (XRD), Fourier-transform infra-red spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Electron dispersion spectroscopy (EDS), and UV–vis. spectroscopy, respectively which confirmed that the obtained NPs are well-crystalline undoped ZnO and possessed good optical properties. The ZnO NSs morphology was investigated by FESEM, which confirmed that the calcined materials were spherical shape in nano-level and growth in huge-quantity. The analytical efficiency of newly synthesized ZnO NPs was also investigated for a selective separation of trivalent iron [Fe(III)] prior to its determination by inductively coupled plasma-optical emission spectrometry (ICP-OES). The selectivity of ZnO NPs towards different metal ions, including Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Ni(II), Zn(II), and Zr(IV), was studied. Data obtained from the selectivity study suggested that that ZnO NPs phase was the most selective towards Fe(III). The static uptake capacity of Fe(III) was found to be ~79.80 mg g⁻¹. Moreover, adsorption isotherm data also provided that the adsorption process was mainly monolayer on a homogeneous adsorbent surface.     

Removal of Cu(II), Fe(III), and Cr(III) from Aqueous Solution by Aniline Grafted Silica Gel

Abstract

The aniline moiety was covalently grafted onto silica gel surface. The modified silica gel with aniline groups (SiAn) was used for removal of Cu(II), Fe(III), and Cr(III) ions from aqueous solution and industrial effluents using a batch adsorption procedure. The maximum adsorption of the transition metal ions took place at pH 4.5. The adsorption kinetics for all the adsorbates fitted better the pseudo second‐order kinetic model, obtaining the following adsorption rate constants (k₂): 1.233 · 10^?2, 1.902 · 10^?2, and 8.320 · 10^?3 g · mg^?1 min^?1 for Cr(III), Cu(II), and Fe(III), respectively. The adsorption of these transition metal ions were fitted to Langmuir, Freundlich, Sips, and Redlich‐Peterson isotherm models; however, the best isotherm model fitting which presented a lower difference of the q (amount adsorbed per gram of adsorbent) calculated by the model from the experimentally measured, was achieved by using the Sips model for all adsorbates chosen. The SiAn adsorbent was also employed for the removal of the transition metal ions Cr(III) (95%), Cu(II) (95%), and Fe(III) (94%) from industrial effluents, using the batch adsorption procedure.     

Surface selectivity competition of newly synthesized polyarylidene(keto amine) polymers toward different metal ions

A new series of polyarylidene(keto amine)s (PAKAs) 3_a?3_e based on thiophene moieties in polymer main chains were synthesized with the solution polycondensation technique. The polymers were synthesized by the reaction of the new monomer 1,1′‐(1E,1′E)‐(2‐oxocyclohexane‐1,3‐diylidene)bis(methanylylidene)bis(thiophene‐5,2‐diyl)bis(2‐chloroethanone) ( 2 ) with different diamines. The new monomer was first synthesized under the normal conditions of the Friedel–Crafts reaction. The results obtained from both elemental and spectral analyses were consistent with the chemical structure of the new monomers and the polymers. Moreover, the identification of the polymers was carried out with different characterization techniques. The analytical competition of the newly synthesized PAKA polymers as selected examples ( 3_d and 3_e ) was also evaluated for a selective extraction of metal ions, including Cd(II), Co(II), Cu(II), Cr(III), Fe(III), Ni(II), and Zn(II), before their determination by inductively coupled plasma–optical emission spectrometry. The results of the selectivity study demonstrated that the 3_d and 3_e polymers was the most selective toward Co(II) and Fe(III), respectively. However, the adsorption capacity of 3_d for Co(II) was improved by 10.10% in comparison to that of 3_e for Fe(III) after only 1 h of contact time. Moreover, the adsorption isotherm data also showed that the adsorption process was mainly monolayer on the homogeneous adsorbent surfaces of both polymers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40873.     

Simutaneous Removal of Heavy Metal Ions from Wastewater by Foam Separation Techniques

Abstract

The objective of the present work is to extend the application of adsorbing colloid flotation techniques to remove mixtures of metal ions. The systems studied are: 1) Co(II) and Cr(VI); 2) Co(II), Ni(II), and Cr(VI); 3) Cr(VI), Cu(II), and Zn(II); 4) Cr(VI), Cu(II), Zn(II), and Ni(II); 5) Cd(II), Pd(II), and Cu(II). Ferric hydroxide and aluminum hydroxide were used as the coprecipitant, and sodium lauryl sulfate was used as the collector and frother. The ionic strength of the solution was adjusted with NaNO₃ or Na₂SO₄. It was found that all the heavy metals can be removed effectively by a single step foam flotation treatment.     

Direct Synthesis of Diethyl Carbonate from CO2 and CH3CH2OH Over Cu–Ni/AC Catalyst

Cu?CNi/AC (Active carbon) catalysts were synthesized and characterized by temperature programmed reduction, X-ray diffraction, Scanning electron microscopy, chemical analysis, and N₂ adsorption. Their activities (in terms of TOF) in the direct synthesis of diethyl carbonate from CO₂ and CH₃CH₂OH were also evaluated. The presence of a Cu?CNi alloy phase may explain the significant increase in activity of bimetallic catalysts compared with monometallic samples.     

Polyethylenimine-modified sugarcane bagasse cellulose as an effective adsorbent for removing Cu(II) from aqueous solution

Polyethylenimine-modified sugarcane bagasse cellulose (SBCMP), as a new adsorbent, was synthesized by the reaction of polyethylenimine (PEI) with sugarcane bagasse cellulose and glutaraldehyde. The adsorption of Cu(II) by SBCMP was pH-dependent, and the higher removal efficiency of Cu(II) appeared in the range of pH 3.0–6.0. The adsorption isothermal data fitted well with the Langmuir model, and the maximum adsorption capacity of SBCMP was up to 107.5 mg/g. The adsorption kinetics was best described by the pseudo-second-order kinetic. The adsorption of Cu(II) by SBCMP was unfavorable at high temperatures, and thermodynamic analyses implied that the adsorption of Cu(II) by SBCMP was an exothermic reaction. Fourier transform infrared spectroscopy (FT-IR) combined with X-ray photoelectron spectroscopy (XPS) revealed that Cu(II) adsorption on SBCMP mainly controlled by the nitrogen atoms of  NH group in PEI. The results of regeneration cycles showed that SBCMP was suitable for reuse in the adsorption of Cu(II) from aqueous solution. These experimental results suggested that SBCMP is expected to be a new biomass adsorbent with high efficiency in removing Cu(II) from wastewater.     

Development of PU‐TZnO solid‐phase extractor for selective detection of mercury in complex matrices

In this study, a new effective solid‐phase extractor (PU‐TZnO 3) was developed for a selective extraction and determination of mercury using inductively coupled plasma optical emission spectrometry. The selectivity of PUA (PU‐TZnO 0.5, PU‐TZnO 1, PU‐TZnO 3, or PU‐TZnO 5) was investigated toward several metal ions, including Au(III), Cd(II), Co(II), Cu(II), Hg(II), Pb(II), Pd(II), and Zn(II). Based on selectivity and pH studies, Hg(II) was the most quantitatively adsorbed on PU‐TZNO 3 phase at pH 2, indicating that PU‐TZnO 3 is more selective for Hg(II) as compared to other metal ions. Based on the adsorption isotherm analysis, the maximum adsorption capacity of PU‐TZnO 3 phase for Hg(II) was found to be 99.68 mg g⁻¹, following the Langmuir adsorption isotherm model. Further kinetic models suggested pseudo second‐order kinetic model for adsorption of Hg(II) on the PU‐TZnO 3. In addition, results of thermodynamic investigation demonstrated that a general spontaneous process is favorable for adsorption mechanism of Hg(II) on PU‐TZnO 3. POLYM. COMPOS., 38:2106–2112, 2017. © 2015 Society of Plastics Engineers     

Zur Reaktionsweise von Cellulose mit Alkalimetallen in flüssigem Ammoniak; reaktionskinetische Untersuchungen und eigenschaften von 2,3,6-Tri-O-lithiumcellulose

Structural data of ammonia swollen cellulose were obtained by kinetic investigations of the reaction of lithium, sodium and potassium with cotton fibers in liquid ammonia. The alkali metals reacted in a relatively rapid initial reaction with the accessible hydroxyl groups on the surface of structural units in the cellulose. The accessibility data found corresponded to those obtained by deuterium exchange in D₂O. While K/NH₃ did not react further with the ordered NH₃-cellulose a slow attack was found by Na/NH₃ with a constant rate. Faster was the reaction with Li/NH₃ (first order in cellulose). Thereby, characteristic differences were found between the used cellulose of differently ordered structures (cellulose I, II, III). This was traced back to the formation of different NH₃- cellulose-adducts. 2,3,6-Tri-O-lithiumcellulose was obtained from cotton cellulose without chain degradation. The lithium cellulosate was characterized by infrared spectroscopy, thermoanalytic investigations and by X-ray diffractions. Following measurements showed that cellulose reacted with Li/NH3 by a sheet lattice reaction.     

Hydrogenation of CO2 to dimethyl ether on La-, Ce-modified Cu-Fe/HZSM-5 catalysts

Cu–Fe–La/HZSM-5 and Cu–Fe–Ce/HZSM-5 bifunctional catalysts were prepared and applied for the direct synthesis of dimethyl ether (DME) from CO₂ and H₂. The catalysts were characterized by X-ray diffraction (XRD), N₂ adsorption–desorption, H₂-temperature programmed reduction (H₂-TPR), and X-ray photoelectron spectroscopy (XPS). The results showed that La and Ce significantly decreased the outer-shell electron density of Cu and improved the reduction ability of the Cu–Fe catalyst in comparison to the Cu–Fe–Zr catalyst, which may increase the selectivity for DME. The Cu–Fe–Ce catalyst had a greater specific surface area than the Cu–Fe–La catalyst. This promoted CuO dispersion and decreased CuO crystallite size, which increased both the DME selectivity and the CO₂ conversion. The catalysts were stable for 15 h.     

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.     

Metal cation removal by P(VC-r-AA) copolymer ultrafiltration membranes

A series of amphiphilic copolymers containing poly(vinyl chloride-r-acrylic acid) (P(VC-r-AA) ) was synthesized and used to prepare membranes via a nonsolvent induced phase separation method. The prepared membranes were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and water contact angle and zeta potential measurements. The copolymer P(VC-r-AA) chains did not dissolved in a coagulation bath, indicating that the AA segments were completely retained within the membrane. Enriching degree of AA segments in surface layer was 2 for copolymer membrane. In addition, the introduction of AA segments made the membrane electronegative and hydrophilic so that the membrane was sensitive to the solution pH. The fouling resistance, adsorption of Cu(II), Cr(III) and Ce(IV) ions and the desorption properties of the membranes were also determined. The copolymer membranes exhibited good antifouling performance with a fouling reversibility of 92%. The membranes also had good adsorption capacities for Cu(II), Cr(III) and Ce(IV) ions. The optimal pH for Cu(II) adsorption was 6 and the copolymer membrane has potential applications for low concentration Cu(II) removal.

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Effect of oxides on the adhesion of Cu films deposited onto stainless steel by electron shower and thermal evaporation methods

When Cu films were deposited by thermal evaporation onto stainless steel substrates at 30°C, the oxygen gas in the vacuum chamber (1.5 x 10^-3 Torr) caused the adhesion of Cu films to increase from 3 to 5 MPa. Moreover, it increased further from 13 to 16 MPa when deposited at 300°C. The Cu film was not peeled off when deposited by the electron shower method and the epoxy resin failed (20 MPa), and this was independent of the addition of oxygen gas. As the chemical shift of Cu 2_p3/2 was observed at the interface between the Cu film and the substrate when oxygen gas was added, it is concluded that the adhesion is mainly determined by the chemical bonding, such as CuO and Cu₂O. The depth profile of Cu 2_p3/2 measured by X-ray photoelectron spectroscopy (XPS) using Ar etching showed apparent thermal diffusion of Cu into the substrate. But the Ar etching rate was decreased by Cu oxides at the interface. The amount of oxides depended on the substrate temperature and the deposition method for Cu film. Therefore, the depth profile of Cu measured by XPS did not represent the thermal diffusion of Cu into the substrate correctly. When the etching rate was modified, the diffusion of Cu was almost the same for different samples deposited at the same temperature, and the effect of the thermal diffusion on the adhesion was small. The adhesion on hydrated [Cr(OH)₃.0.4H₂O] and hydroxide [Cr(OH)₃] surfaces was lower than that on the oxide (Cr₂O₃) surface. In other words, the pretreatment of the substrates was very important to the adhesion.     

Highly selective oxidation of alcohols catalyzed by Cu(II)-Schiff base-SBA-15 with hydrogen peroxide in water

An efficient catalyst for selective oxidation of alcohols was prepared by grafting the Cu(II) Schiff base complex onto the channels of mesoporous silica material SBA-15. The characterizations illustrated that the functionalized SBA-15 maintained the primary hexagonally ordered mesoporous structure, and the Cu(II) Schiff base complexes were bonded inside the mesoporous channels of SBA-15. The selective oxidation of benzyl alcohol was carried out in water phase with hydrogen peroxide. The C₆H₅CH₂OH conversion could reach 98.5 % with 100 % of the selectivity to C₆H₅CHO under the optimum conditions. The catalyst could also react well on the selective oxidation of other primary alcohols.     

Environmental water remediation using covalently functionalized zerovalent iron nanocomposites with 2-pyridinecarboxaldehyde via 3-aminopropyltrimethoxysilane and ethylenediamine

The adsorption technology involving nano zerovalent iron (NZVI) has been widely employed to remediate polluted water based on a number of economic aspects. However, this technology is facing a high challenge in the removal process of pollutants due to hydrolysis and stability characteristics of zerovalent iron. Therefore, this study is aimed to demonstrate a method for encapsulation and functionalization of NZVI nanoparticles with 3-aminopropyltrimethoxysilane (NH₂) and 2-pyridinecarboxaldehyde (PY), respectively to produce the target nanocomposite (NZVI-NH₂-PY). Zerovalent iron nanoparticles are also aimed to functionalize with ethylenediamine (ED) and 2-pyridine carboxaldehyde to produce NZVI-ED-PY nanocomposite. The TEM images showed that the sizes of NZVI-NH₂-PY and NZVI-ED-PY nanocomposites are in the range 3.33–4.35 and 5.42–10.36 nm, respectively. More characterization evidences were concluded by thermal gravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The two novel magnetic nanocomposites have been used for removal of Co(II), Zn(II), Pb(II), Cd(II), Hg(II), Cu(II) beside radioactive isotopes (⁶⁵Zn and ⁶⁰Co) from water. NZVI-NH₂-PY nanocomposite was more selective toward Hg(II), Pb(II) and Cd(II), while NZVI-ED-PY was more selective toward Z(II), Co(II) and Co(II). Different kinetic models were applied and the investigated metal ions were characterized to undergo the pseudo-second order using both NZVI-NH₂-PY and NZVI-ED-PY nanocomposites.     

Heavy metals removal from solution by polyaniline/palygorskite composite

Batch adsorption experiments were carried out to remove heavy metal ions such as Cu (II), Ni (II), Cd (II), and Cr (VI) from single‐metal solutions using a polyaniline/palygorskite (PP) composite. Different parameters affecting the adsorption capacity such as contact time and pH of the solution have been investigated. The structural characteristics of the PP composite were studied in this work. Atomic absorption spectroscopy was used for the measurement of heavy metal contents, and the adsorption capacity (q_e) calculated were 114 mg Cu (II) g^?1, 84 mg Ni (II) g^?1, 56 mg Cd (II) g^?1, and 198 mg Cr (VI) g^?1 under optimal conditions. The removal of the metal ions from solutions was assigned to chelation, ionic exchange, and electrostatic attraction. Data from this study proved that the novel organic/inorganic composite presents great potential in the recovery and elimination of noble or heavy metal ions from industrial wastewater. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.