Copper Ions Removal from Wastewater by Electrocoagulation Using Cement-based Cathode Plates

The present work uses PEO solution to well disperse carbon fiber and identifies percolation thresholds of carbon fiber and carbon black which are used as conductive fillers.The resultant cathode plates have an average compressive strength of 27.3 MPa and flexural strength of 29.09 MPa,which demonstrate excellent mechanical properties.The Cu^(2+)removal efficiency was measured at different current densities in EC process with cement-based cathode plate,while the voltage changes were recorded.The results showed that the cement-based cathode plate operated stably and achieved 99.7%removal of 1 L of simulated wastewater with a Cu^(2+)concentration of 200 ppm at a current density of 8 m A/cm^(2)for 1 h.Characterization of floc and tested cathode plates,SEM and EDS analyses,and repeatability testing of the tested plates demonstrate the reusability of the plates,proving that cement-based plates can effectively replace metal cathode plates,reduce the cost of EC and improve the applicability of EC devices.

Adsorption and activation of copper ions on chalcopyrite surfaces:A new viewpoint of self-activation

The adsorption behaviors of copper ions on chalcopyrite surfaces were investigated based on zeta potential measurements, X-ray photoelectron spectroscopy, copper ion adsorption experiments, first-principles calculations, and Hallimond tube cell flotation experiments. The results show that copper ions activate the chalcopyrite as a result of the interactions between copper ions and sulfur on the chalcopyrite surface. This adsorption increases the flotation rate under certain conditions, and this is beneficial for the flotation of chalcopyrite. The copper ions in the flotation pulp are mainly derived from surface oxidation dissolution and the release of fluid inclusions, and these effects enable chalcopyrite to be activated.

Influence of copper ions and calcium ions on adsorption of CMC on chlorite

The effects of copper ions and calcium ions on the depression of chlorite using CMC（carboxymethyl cellulose） as a depressant were studied through flotation tests,adsorption measurements,ζ potential tests and co-precipitation experiments.The results show that the electrostatic repulsion between the CMC molecules and the chlorite surfaces hinders the approach of the CMC to the chlorite while the presence of copper ions and calcium ions enhances the adsorption density of CMC.The action mechanisms of these two types of ions are different.Calcium ions can not adsorb onto the mineral surfaces,but they can interact with the CMC molecules,thus reducing the charge of the CMC and enhancing adsorption density.Copper ions can adsorb onto the mineral surfaces,which facilitates the CMC adsorption through acid/base interaction.The enhanced adsorption density is also attributed to the decreased electrostatic repulsion between the CMC and mineral surfaces as copper ions reduce the surface charge of both the mineral surfaces and the CMC molecules.

Adsorption behavior and mechanism of copper ions in the sulfidization flotation of malachite

Malachite is one of the main minerals used for the industrial enrichment and recovery of copper oxide resources, and copper ions are unavoidable metal ions in the flotation pulp. The microflotation, contact angle, and adsorption experiments indicated that pretreatment with an appropriate concentration of copper ions could improve the malachite recovery, and the addition of excess copper ions reduced the hydrophobicity of the malachite surface. The results of zeta potential tests indicated that sodium sulfide and butyl xanthate were also adsorbed on the surface of malachite pretreated with copper ions. X-ray photoelectron spectroscopy(XPS) results indicated that —Cu—O and —Cu—OH bonds were formed on the surface of the samples. After pretreatment with an appropriate concentration of copper ions, the number of —OH groups on the mineral surface decreased, whereas the number of Cu—S groups on the mineral surface increased, which was conducive to the sulfidization of malachite. After adding a high concentration of copper ions, the —OH groups on the mineral surface increased, whereas the number of Cu—S groups decreased, which had an adverse effect on the sulfidization flotation of malachite. Time-of-flight secondary ion mass spectrometry showed that pretreatment with copper ions resulted in a thicker sulfidization layer on the mineral surface.

Copper Ions Stimulate the Proliferation of Hepatic Stellate Cells via Oxygen Stress in vitro

This study examined the effect of copper ions on the proliferation of hepatic stellate cells （HSCs） and the role of oxidative stress in this process in order to gain insight into the mechanism of he- patic fibrosis in Wilson＇s disease. LX-2 cells, a cell line of human HSCs, were cultured in vitro and treated with different agents including copper sulfate, N-acetyl cysteine （NAC） and buthionine sulfoxi- mine （BSO） for different time. The proliferation of LX-2 cells was measured by non-radioactive cell proliferation assay. Real-time PCR and Westem blotting were used to detect the mRNA and protein ex- pression of platelet-derived growth factor receptor 13 subunit （PDGFI3R）, ELISA to determine the level of glutathione （GSH） and oxidized glutathione （GSSG）, dichlorofluorescein assay to measure the level of reactive oxygen species （ROS）, and lipid hydroperoxide assay to quantify the level of lipid peroxide （LPO）. The results showed that copper sulfate over a certain concentration range could promote the pro- liferation of LX-2 cells in a time- and dose-dependent manner. The effect was most manifest when LX-2 cells were treated with copper sulfate at a concentration of 100 ~tmol/L for 24 h. Additionally, copper sulfate could dose-dependently increase the levels of ROS and LPO, and decrease the ratio of GSH/GSSG in LX-2 cells. The copper-induced increase in mRNA and protein expression of PDGF^R was significantly inhibited in LX-2 cells pre-treated with NAC, a precursor of GSH, and this phenome- non could be reversed by the intervention of BSO, an inhibitor of NAC. It was concluded that copper ions may directly stimulate the proliferation of HSCs via oxidative stress. Anti-oxidative stress therapies may help suppress the copper-induced activation and proliferation of HSCs.

Synthesis of Poly(acrylic acid)-Grafted Carboxymethyl Cellulose for Efficient Removal of Copper Ions

Biocompatible and high content grafted carboxymethyl cellulose-g-poly(acrylic acid)powder was successfully synthesized in an aqueous system,and used as adsorbents for the removal of Cu(II)in aqueous solution.The copolymer was characterized by FT-IR and SEM techniques.Graft copolymerization introduced a large number of carboxyl groups in the polymer and caused the micro-surface of the material to be porous.The fundamental adsorption behaviors of the material were studied.The adsorption kinetics was well fitted with pseudo-second order equation,while the adsorption isotherm preferred to be described the Langmuir equation.The maximum adsorption capacity obtained from the Langmuir model was 154.32 mg/g,indicating that the adsorption capacity of carboxymethyl cellulose was improved remarkably after grafting poly(acrylic acid).Moreover,Fourier transform infrared spectroscopy(FT-IR)has been used to investigate the adsorption mechanisms at molecular levels,which revealed that carboxyl groups are facile to form bidentate carboxylates with metal ions.Thus,this environment friendly copolymer will be a promising candidate for application in removal of heavy metal ions.

Synthesis of platy potassium magnesium titanate and its application in removal of copper ions from aqueous solution

Platy potassium magnesium titanate (K0.8Mg0.4Ti1.6O4, KMTO) was synthesized by a flux method. The potential application of KMTO in removing copper ions from water pollutants was investigated. The crystal phases of specimens were identified by XRD. The morphology and structural information were characterized by SEM and TEM. The adsorption behavior under different conditions was investigated, including different pH values and different initial copper ion concentrations. The results show that the maximum adsorption capacity of Cu(II) ions is 290.697 mg/g, and almost 99.9% of Cu(II) ions can be removed, which is much higher than that of other sorbents reported. The kinetics of KMTO for the adsorption of Cu(II)ions was studied and the best fit can be obtained by the pseudo-second-order model. Adsorption isothermal data can be well interpreted by the Freundlich equation (R2=0.991). In conclusion, this study highlights that KMTO is a potential material for the efficient removal of heavy metal ions in polluted water. It also opens up a new opportunity for the applications of platy KMTO.

Recovery of Copper Ions from Wastewater by Hollow Fiber Supported Emulsion Liquid Membrane

Recovery of copper ions from wastewater using a hollow fiber supported emulsion liquid membrane (HFSELM) was studied with LIX984N as carrier, kerosene as diluents, and sulfuric acid solution as stripping phase. Effects of compositions of feed and emulsion liquid phase, flow rates on both sides of membrane, and hollow fiber module parameters were investigated. The stability of the emulsion liquid phase without surfactant and the effect of buffer in the feed phase on the extraction rate were also evaluated. It is found that the stability of the emulsion phase without surfactant is poor. Higher flow velocity gives shorter residence time for the emulsion liquid phase on the tube side, reducing the effect of particle coalescence on the separation process. The extraction rate increases with the increase of feed phase pH, carrier concentration, hydrogen ion concentration in the stripping phase, and ef- fective hollow fiber area. The phase ratio in the emulsion liquid phase has a negative effect on extraction rate. The flow rates on both sides have little influence on the extraction performance of the HFSELM, while buffer addition in the feed solution improves the extraction efficiency.

Biosorption effects of copper ions on Candida utilis under negative pressure cavitation

Under the optimal condition of copper ions adsorption on yeast,we found some different effects among static adsorption, shaking adsorption and negative pressure cavitation adsorption, and the methods of yeast with different pretreatments also affect adsorption of copper ions. At the same time, the change of intercellular pH before and after adsorption of copper with BCECF was studied. The copper distribution was located by using PhenGreen （dipotassium salt and diacetate）, and the surface of yeast was observed by an atomic force microscope. The results showed that negative pressure cavitation can improve bioadsorption capacity of copper ions on yeast. However, the yeasts＇ pretreatment has a higher effect on bioadsorption. It indicates that heavy metal bioadsorption on yeast has much relation with its cellular molecule basis. With the adsorping, the intercellular pH of yeast increased gradually and changed from acidity to alkalescence. These results may suggest that negative pressure cavitation can compel heavy metals to transfer from the cell surface into inside cell and make the surface of yeast coarse.

Effects of copper ions on dissolution mechanism of marmatite

The dissolution mechanism of marmatite in the presence of Cu^(2+)was intensively studied by experiments and density functional theory(DFT) calculations. Leaching experiments showed that Cu^(2+)accelerated marmatite dissolution at high temperatures(above 55 ℃), but the trend was reversed at low temperatures(below 45 ℃), which may be because the reaction mechanism between Cu^(2+)and marmatite changed from surface adsorption to bulk substitution with increasing temperature. The substitution reaction caused more zinc atoms in the marmatite crystal lattice to be released and enhanced the electrochemical reactivity, while the adsorption of copper ions at low temperatures would passivate marmatite, thus inhibiting the reaction process. DFT calculations showed that the energy of the substitution reaction was more negative than that of the adsorption reaction at high temperatures, which further verified the proposed mechanism.

Extended adsorption transport models for permeation of copper ions through nanocomposite chitosan/polyvinyl alcohol thin affinity membranes

Transport of copper ions through nanocomposite chitosan/polyvinyl alcohol thin adsorptive membranes has been mathematically investigated in the current study. Unsteady-state diffusive transport model was coupled with the Freundlich isotherm to predict the concentration of the ions in dialysis permeation operation. Pristine model was not successful in predicting the experimental data based upon its low coefficients of determination（0.1

Effect of copper ions implantation on the corrosion behavior of ZIRLO alloy in 1 mol/L H_2SO_4

In order to study the effect of copper ion implantation on the aqueous corrosion behavior of ZIRLO alloy, specimens were implanted with copper ions with fluences ranging from 1×10^16 to 1×10^ ions/cm^2, using a metal vapor vacuum arc source （MEVVA） at an extraction voltage of 40 kV, The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy （XPS） and Auger electron spectroscopy （AES）, respectively. Glancing angle X-ray diffraction （GAXRD） was employed to examine the phase transformation due to the copper ion implantation. The potcntiodynamic polarization technique was used to evaluate the aqueous corrosion resistance of implanted ZIRLO alloy in a 1 mol/L H2SO4 solution. It was found that a significant improvement was achieved in the aqueous corrosion resistance of ZIRLO alloy implanted with copper ions when the fluence is 5×10^16 ions/cm^2. When the fluence is 1×10^16 or 1×10^17 ions/cm^2, the corrosion resistance of implanted sanaples was bad. Finally, the mechanism of the corrosion behavior of copper-implanted ZIRLO alloy was discussed.

Rapid oxidation of black phosphorus induced by copper ions via promoting oxygen bonding and phosphate desorption

Black phosphorus(BP)has garnered significant interest in the field of biomedicine because of its exceptional degradability.The oxidation product of BP phosphate has been utilized in numerous studies for the purpose of repairing bone defects and inducing apoptosis and autophagy in cancer cells.Nevertheless,this process has drawbacks in terms of low yield and a slow rate of phosphate production.In this study,we found that the oxidation rate of BP was increased 120-fold and the yield proportion of phosphate BP product was increased from 30%to 85%with the presence of less than 0.1%copper ions(Cu^(2+))in the reaction system.The enhancement was attributed to the fact that the presence of Cu^(2+)promoted the bonding of oxygen on the BP surface and then the desorption of phosphate molecules from the BP surface.This study offers a novel perspective on the process of BP oxidation and introduces innovative concepts for the development of biological drug delivery systems capable of rapid decomposition.

Functional decoration on a regenerable bifunctional porous covalent organic framework probe for rapid detection and adsorption of copper ions

Developing fluorescence porous probe for detecting and eliminating Cu^(2+) contamination in water or biosystem is an essential research project that has attracted considerable attention.However,improving the fluorescence detecting efficiency while enhancing the adsorption capacity of the porous probe is of great challenge.Herein,a bifunctional two-dimensional imine-based porous covalent organic framework(TTP-COF)probe was designed and synthesized from 1,3,5-tris(4-aminophenyl)benzene(TAPB)and 2,4,6-Triformylphloroglucinol(TP)ligand.TTP-COF displayed rapid detection of Cu^(2+)(limit of detection(LOD)=10 nmol·L^(−1) while achieving a high adsorption capacity of 214 mg·g^(−1)(pH=6)at room temperature with high reusability(>5 cycles).The key roles and contributions of highπ-conjugate and delocalized electrons in TABP and functional–OH groups in TP were proved.More importantly,the fluorescence quenching mechanism of TTP-COF was studied by density functional theory theoretical calculations,revealing the crucial role of intramolecular hydrogen bonds among C=N and–OH groups and the blocking of the excited state intramolecular proton transfer process in detecting process of Cu^(2+).

Copper ions-me diate d dynamic re dox-responsive microgels synergize with silicone for efficient and sustainable antibacterial properties

The antifouling of marine facilities placed below the waterline is a key constraint to the development of the marine economy.Currently,commercial Cu_(2)O-based antifouling coatings still have defects such as agglomeration,oxidation,short duration and high dosage.For this reason,we developed for the first time a triple antifouling system consisting of Cu_(2)O@poly(NIPAM-co-DAm)(Cu_(2)O@PND)dynamic redox micro-gels triggered by copper ions and polydimethylsiloxane(PDMS).The catechol groups of PND nanogels can chelate Cu^(2+)and reduce it in situ to obtain Cu_(2)O@PND microgels,which guarantees the stable release of Cu^(+).Furthermore,Cu_(2)O remains stable and free from oxidation because of the electron transfer between PND and Cu^(2+).Finally,superior antifouling performance was achieved by combining the stable Cu^(+)re-leased from Cu_(2)O,in situ conversion of PND to hydrogel,and its oxidation to produce active substances and H_(2)O_(2),and PDMS coating with low surface energy.

A Bright Nitrogen-doped-Carbon-Dots based Fluorescent Biosensor for Selective Detection of Copper Ions

In this work,a novel fluorescent biosensor has been constructed for rapid detection of Cu(Ⅱ)via the interaction between the fluorophore groups on the surface of nitrogen-doped-carbon-dots(N-CDs)and·OH produced from the catalytic reaction between Cu(Ⅱ)and cysteine(Cys).Specifically,Cu(Ⅱ)can catalyze the oxidation of Cys to form cystine(Cys–Cys)and hydrogen peroxide(H_(2)O_(2)),and Cu(Ⅱ)can also catalyze the decomposition of H_(2)O_(2)to produce hydroxyl radicals(·OH)by the Fenton-like reaction.·OH can oxidize and destroy the surface structure of N-CDs,resulting in the fluorescence quenching of the N-CDs.Under the optimal experimental conditions,the linear range of Cu(Ⅱ)is determined to be 0.05–25μmol L_(-1,),and the limit of detection is 23 nmol L^(-1)with the limit of quantitation of 77 nmol L^(-1).Besides,some characterizations are provided to verify the proposed principle.The method has been successfully applied for the detection of Cu(Ⅱ)in human serum and environmental water with high sensitivity and higher selectivity.

Tuning plasmon absorption of unmodified silver nanoplates for sensitive and selective detection of copper ions by introduction of ascorbate

Silver nanoplates as novel optical sensors for Cu^2＋ detection have been demonstrated.Silver nanoplates are synthesized via previous H_2O_2-NaBH_4 cyclic oxidation-reduction reactions.With introduction of ascorbate as mild reductants,Cu^2＋ ions are reduced into Cu~＋ and the Cu^＋ is further reduced to Cu,which is deposited on the surface of the silver nanoplates.The deposition of the Cu on the surface of the silver nanoplates allows a significant red-shift of their plasmon absorption.Therefore,trace Cu^2＋ can be detected.The shift of the plasmon absorption wavelength of silver nanoplates is proportional to the Cu^2＋concentration over a range of 40-340 μmol L^（-1） with a limit of detection of 9.0 μmol L^（-1）.Moreover,such silver nanoplate-based optical sensors provide good selectivity for Cu^2＋ detection,and most other metal ions do not disturb its detection.Moreover,the practicality of the proposed sensor was tested.This Cu^2＋assay is advantageous in its simplicity,selectivity,and cost-effectiveness.

Application of magnetic particles modified with amino groups to adsorb copper ions in aqueous solution

A magnetic adsorbent can be easily recovered from treated water by magnetic force, without requiring further downstream treatment. In this research, amine-functionalized silica magnetite has been synthesized using N-[3-（trimethoxysilyl）propyl]-ethylenediamine （TPED） as a surface modification agent. The synthesized magnetic amine adsorbents were used to adsorb copper ions in an aqueous solution in a batch system, and the maximum adsorption was found to occur at pH 5.5± 0. 1. The adsorption equilibrium data fitted the Langmuir isotherm equation reasonably well, with a maximum adsorption capacity of 10.41 mg/g. A pseudo second-order model could best describe the adsorption kinetics, and the derived activation energy was 26.92 kJ/mol. The optimum condition to desorb Cu2＋ from NH2/SiO2/Fe304 was provided by a solution with 0.1 mol/L HNO3.

Free cupric ions in contaminated agricultural soils around a copper mine in eastern Nanjing City, China

To determine the environmental free metal ion activity was a recent hot issue. A method to measure low-level free cupric ion activity in soil solution extracted with 0.01 mol/L KNO3 was developed by using cupric ion-selective electrode （ISE） and calibrating with Cu-buffer solution. Three copper buffers including iminodiacetic acid （IDA）, ethylenediamine （EN）, and glycine （Gly） were compared for calibrating the Cu-ISE curves in the range of free cupric ions （pCu^2＋） 7-13. The Cu-EN buffer showed the best electrode response and thus was applied as the calibration buffer. The pCu^2＋ of 39 contaminated agricultural soils around a copper mine was measured, ranging from 5.03 to 9.20. Most Cu in the soil solutions was found to be complexed with dissolved soil organic matters, averaging 98.1%. The proportion of free Cu^2＋ ions in the soil solutions decreased with the increasing of solution pH. Soluble Cu and free Cu^2＋ ions concentrations were analyzed by multiple linear regressions to evaluate the effects of soil properties on metal levels and speciation. The results showed that soil solution pH was the most significant factor influencing pCu^2＋ （with R^2 value of 0.76）, while not important for the soluble Cu concentration.

Interaction mechanism of Cu^(2+),Fe^(3+) ions and extracellular polymeric substances during bioleaching chalcopyrite by Acidithiobacillus ferrooxidans ATCC2370

The extracellular polymeric substances（EPS） of Acidithiobacillus ferrooxidans ATCC 23270,and iron and copper enclosed in EPS were extracted by ultrasonication and centrifugation methods to determine the interaction mechanism of Cu2＋,Fe3＋ and EPS during bioleaching chalcopyrite.Generally,Cu2＋ ions can stimulate bacteria to produce more EPS than Fe3＋ ions.The mass ratio of Fe3＋/Cu2＋ enclosed in EPS decreased gradually from about 4：1 to about 2：1 when the concentration of Cu2＋ ions increased from 0.01 to 0.04 mol/L.The amount of iron and copper bound together by EPS in ferrous-free 9K medium containing 1% chalcopyrite was about 2 times of that in 9K medium containing 0.04 mol/L Cu2＋ ions.It was inferred that the EPS with jarosites on the surface of chalcopyrite gradually acted as a weak diffusion barrier for Cu2＋,Fe3＋ ions transference during bioleaching chalcopyrite.