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.

An IR Study on Adsorption of CO and NO on Copper Ion-exchanged Zeolite Beta

Thee adsorption of CO and NO on copper ion-exchanged zeolite Beta was investigated using IR method.It was found that the thermalvacuum pretreatment procedure could result in the reduction of Cu2+ions in zeolite Beta.The adsorption of CO on Cu+sites in zeolite Beta closely follows Langmuir isotherm.Another Cu+species may form during the reaction between water and CO.The catalytic decomposition of NO on the zeolite was observed at room temperature,indicating that the decomposition reaction may occur between two coordinated NO ligands of the same dinitrosyhc complex.Furthermore,the appearance of two series of NO adsorption bands reveals that copper ions existing at different cation sites may have different effect on the adsorption and decomposition of NO molecules.

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

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+).

Highly Efficient Adsorption of Copper Ions by a PVP-Reduced Graphene Oxide Based On a New Adsorptions Mechanism

Polyvinylpyrrolidone-reduced graphene oxide was prepared by modified hummers method and was used as adsorbent for removing Cu ions from wastewater. The effects of contact time and ions concentration on adsorption capacity were examined. The maximum adsorption capacity of 1689 mg/g was observed at an initial p H value of 3.5 after agitating for 10 min. It was demonstrated that polyvinylpyrrolidone-reduced graphene oxide had a huge adsorption capacity for Cu ions, which was 10 times higher than maximal value reported in previous works. The adsorption mechanism was also discussed by density functional theory. It demonstrates that Cu ions are attracted to surface of reduced graphene oxide by C atoms in reduced graphene oxide modified by polyvinylpyrrolidone through physisorption processes, which may be responsible for the higher adsorption capacity. Our results suggest that polyvinylpyrrolidone-reduced graphene oxide is an effective adsorbent for removing Cu ions in wastewater. It also provides a new way to improve the adsorption capacity of reduced graphene oxide for dealing with the heavy metal ion in wastewater.

Comparative Study of Adsorption of Copper Ion onto Locally Developed and Commercial Chitosan

Chitosan synthesized locally with a degree of deacetylation 71% and chitosan with a degree of deacetylation 68% from Sigma Aldrich were used to investigate adsorption of Cu2+ ion in aqueous solution. The results obtained from equilibrium isotherm adsorption studies of Cu2+ ion were an-alyzed in five adsorption models namely: Langmuir, Freundlich, Temkin, Elovich and Dubin- Ra-dushkevich. The isotherms equation was indicated to be well fitted to Langmuir, Freundlich, Temkin and Elovich under the concentration range studied. The kinetic parameters were evaluated utilizing the pseudo-first-order and pseudo-second-order equations, and the adsorption kinetics followed the mechanism of the pseudo-second-order equation for all systems studied, evidencing chemical sorption as the rate-limiting step of adsorption mechanism and not involving a mass transfer in solution. The FTIR studies revealed that the greater sorption of heavy metal was attributed to the large number of primary amine groups available on the surfaces of the chitosan and the abundant carboxyl groups on chitosan.

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.

Double open mouse-like terpyridine parts based amphiphilic ionic molecules displaying strengthened chemical adsorption for anticorrosion of copper in sulfuric acid solution

In this study,the benign target double terpyridine parts based amphiphilic ionic molecules(AIMs 1,2)and the reference single terpyridine segment included AIMs(AIMs 3,4)were synthesized through a multi-step method,and the molecular structures were fully characterized.The excellent anticorrosion of the target AIMs for copper surface in H_(2)SO_(4) solution was demonstrated by the electrochemistry analysis,which was more superior over those of the reference AIMs.The standard adsorption free energy changes of the target AIMs calculated by the adsorption isotherms were lower than -40 kJ·mol^(-1),suggesting an intensified chemical adsorption on metal surface.The molecular modeling and molecular dynamic computation of the studied AIMs were performed,demonstrating that the target AIMs exhibited lower highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps and greater adsorption energies than the reference ones.The chemical adsorption of the AIMs on metal surface was revealed by various spectroscopic methods including scanning electron microscopy,atomic force microscopy,Fourier transform infrared spectroscopy,attenuated total reflection infrared spectroscopy,Raman and X-ray diffraction.

Modelling and Optimisation of Copper Adsorption in Solution by the Response Surface Method

Copper is considered a heavy metal that can be toxic at certain concentrations and its presence in water is a potential threat to public health. These heavy metals also contribute to a remarkable degradation of the environment, hence the need for effective treatment methods to remove them. In this study, a mixture of titaniferous sand and calcium silicate was used as adsorbent material to eliminate copper in solution. The calcium silicate was synthesised from fluosilicic acid, which is a by-product of phosphoric acid manufacture. The titaniferous sand is a residue from a mining industry. Both adsorbents were characterised by infrared spectroscopy and X-ray fluorescence to determine their compositions and physicochemical properties. The response surfaces, through the Box-Behnken model, were used to model and optimise various adsorption parameters, namely initial copper concentration (A: 60 - 200 mg/L), adsorbent dose (B: 0.1 - 0.6 g) and pH (C: 4 - 10). The copper removal efficiency (98.92%), after statistical analysis, was obtained under the following optimal conditions: an adsorbent dose of 0.55 g, an initial copper concentration of 197.25 mg/L and a pH of 9.85. The study of the effects of the operating parameters showed that they had a positive effect on the copper removal efficiency.

Kinetics and equilibrium adsorption of copper(Ⅱ) and nickel(Ⅱ) ions from aqueous solution using sawdust xanthate modified with ethanediamine

Sawdust xanthate modified with ethanediamine was used for the removal of Cu（Ⅱ） and Ni（Ⅱ） from aqueous solution. The influence of various operating parameters such temperature and adsorbent dosage on the adsorption isotherms of modified sawdust was investigated. Thermodynamic parameters, namely Gibbs free energy （△GΘ）, enthalpy （△HΘ） and entropy （△SΘ） of Cu（Ⅱ） and Ni（Ⅱ） adsorption process were calculated, showing that the adsorption is a spontaneous and exothermic process. The modified extended Langmuir equation approaches provide excellent prediction of the binary adsorption. In single and binary systems, the overall adsorption data were best described by the pseudo-second order kinetic model, then the calculated values of activation energy of Cu（Ⅱ） and Ni（Ⅱ） adsorption process were 59.12 and 55.92 kJ/mol respectively. The results show that the affinity of each metal ion onto the modified sawdust surface is influenced by the presence of the other one.

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.

Synthesis of novel silica-supported chelating resin containing tert-butyl 2-picolyamino-N-acetate and its properties for selective adsorption of copper from simulated nickel electrolyte

A novel silica-supported tert-butyl 2-picolyamino-N-acetate chelating resin (Si-AMPY-1) was successfully synthesized and characterized by elemental analysis, FT-IR, SEM and 13 C CP/MAS NMR. The adsorption behaviors of the Si-AMPY-1 resin for Cu(Ⅱ) and Ni(Ⅱ) were studied with batch and column methods. The batch experiments indicated that the Si-AMPY-1 resin adsorbed Ni(Ⅱ) mainly via physisorption, while adsorbed Cu(II) via chemisorption. The column dynamic breakthrough curves revealed thatthe Si-AMPY-1 resin can efficiently separate Cu(Ⅱ) from the simulated nickel electrolyte before the breakthrough point. Moreover, the concentration of Cu(Ⅱ) in the column effluent was decreased to be less than 3 mg/L within the first 43 BV (bed volumes), and the mass ratio of Cu/Ni was 21:1 in the saturated resin, which completely satisfied the industrial requirements of the nickel electrorefining process. Therefore, it was concluded that the Si-AMPY-1 resin can be a promising candidate for the deep removal of Cu(Ⅱ) from the nickel electrolyte.

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.

Dual-functional pyrene implemented mesoporous silicon material used for the detection and adsorption of metal ions

A fluorescent active organic–inorganic hybrid material Py N-SBA-15 was synthesized by implementing pyrene derivatives into mesoporous SBA-15 silica.Py N-SBA-15 had detection and removal functionalities toward Al^(3+),Cu^(2+),and Hg^(2+).On the one hand,Py N-SBA-15 was used as a fluorescence sensor and displayed high sensitivity toward Al^(3+),Cu^(2+),and Hg^(2+)cations (limit of detection:8.0×10^(-7),1.1×10^(-7),and 2.9×10^(-6)mol·L^(–1),respectively) among various analytes with“turn-off”response.On the other hand,the adsorption studies for these toxic analytes (Cu^(2+),Hg^(2+),and Al^(3+)) showed that the ion removal capacity could reach up to 45,581,and 85 mg·g^(-1),respectively.Moreover,the Langmuir isotherm models were better fitted with the adsorption data,indicating that the adsorption was mono-layer adsorption.Kinetic analysis revealed that the adsorption process was well described by the pseudo-second-order kinetic model for Cu^(2+)and Hg^(2+)and pseudo-first-order kinetic model for Al^(3+).The prepared silica material could be reused in four recycles without significantly decreasing its adsorption capacity.Therefore,the Py N-SBA-15 material can serve as a promising candidate for the simultaneous rapid detection and efficient adsorption of metal ions.

Fluoride Ion Adsorption Effect and Adsorption Mechanism of Self-Supported Adsorbent Materials Based on Desulfurization Gypsum-Aluminate Cement

The adsorption method has the advantages of low cost,high efficiency,and environmental friendliness in treating fluorinated wastewater,and the adsorbent material is the key.This study combines the inherent anion-exchange adsorption properties of layered double hydroxides(LDHs).Self-supported porous adsorbent materials loaded with AFm and AFt were prepared from a composite cementitious system consisting of calcium aluminate cement(CAC)and flue gas desulfurization gypsum(FGDG)by chemical foaming technique.The mineral composition of the adsorbent material was characterized by X-ray diffraction(XRD)and Scanning electron microscopy(SEM).Through the static adsorption experiment,the adsorption effect of the mineral composition of the adsorbent on fluoride ions was deeply analyzed,and the adsorption mechanism was revealed.XRD and SEM showed that the main hydration phases of the composite cementitious system consisting of CAC and FGDG are AFm,AFt,AH_(3),and CaSO_(4)·2H_(2)O.FGDG accelerates the hydration process of CAC and inhibits the transformation of AFt to AFm.The AFt content increased,and the AFm content decreased or even disappeared as the amount of FGDG increased.Static adsorption experiment results showed that AFm and AFt in adsorbent materials could significantly enhance the adsorption of fluoride ions.The adsorption of F^(−)in aqueous solution by PAG tends more towards monolayer adsorption with a theoretical maximum capacity of 108.70 mg/g and is similar to the measured value of 112.77 mg/g.

Correlation Evaluation of Ion Adsorption-Based Rare Earth Leaching Performance Based on Zeta Potential Drop Leaching

Rare earth elements are indispensable raw materials for advanced aero-engines, special optical materials, and high-performance electronic products. With the development of the social economy, the global demand for rare earth resources is increasing, and rare earths have become a key metal for the development of new industries and frontier technologies that are highly valued both at home and abroad. Ion-adsorbed rare earth ores are an important source of rare earths, so the efficient green leaching of ion-adsorbed rare earths is important. Researchers found that the selection of an efficient green leaching agent for ion-adsorbed rare earths is based on the zeta potential of tailing clay minerals in addition to leaching efficiency, and both zeta potential and leaching ion concentration are related to mineral acidity and alkalinity, and the pH of tailing water suspension is a direct indicator of environmental water quality requirements. Therefore, the efficiency of the leaching process is closely integrated with the environmental evaluation, and the characteristics and correlation of the changes in zeta potential, pH, conductivity and pollutant concentration of the pulp of clay mineral content during the leaching process of ore leaching and tailings aqueous electrolyte solution leaching are studied by evaluating the leaching system, and a set of correlation leaching efficiency and environmental impact evaluation method is established based on the results of the above analysis, which is of scientific development of ion adsorption rare earth resources. It has important theoretical significance and practical application value.

A Potential Criterion to Evaluate Copper Adsorption in Wood Cell Wall

A geometrical definition, fractal dimension, was introduced in this study to evaluate copper adsorption in wood treated with copper-containing preservatives. It is based on the assumption that some copper would compete the hydroxyl groups in wood cell wall with water molecules, and therefore influence the fractal dimension of internal wood surfaces revealed by the moisture adsorption in wood. Southern yellow pine (Pinus spp.) specimens were treated with different concentrations of copper ethanolamine (Cu-EA) solution to obtain different copper retention levels. Then the adsorption isotherms of untreated and Cu-EA treated specimens were determined at 4, 15, 30, and 40 ℃ to provide the source data for fractal dimension calculation. The results showed that, at all temperatures, the fractal dimension of the internal wood surfaces had a decreasing trend with increasing copper retention. That is, the internal spaces in wood become 搕hinner?due to the copper adsorption on some hydroxyl groups in wood cell wall. The correlation between the fractal dimension and adsorbed copper ions makes it possible to evaluate the copper adsorption in wood cell wall.

Adsorption Properties and Cost of Dicarboxylic Nanocellulose on Copper Ions for Wastewater Treatment

The accumulation of Cu^(2+)in water is a potential threat to human health and environment.Dicarboxylic nano-cellulose(DNC)with rich carboxyl groups was prepared through the NaIO_(4)–NaClO_(2) sequential oxidation meth-od to efficiently remove copper ions,and the Cu 2+adsorption properties and cost were studied.The maximum adsorption capacity reached 184.2 mg/g at pH 6 and an adsorbent dose of 5 g/L.Theoretically,the maximum adsorption capacities of monocarboxylic nanocellulose(MNC),DNC,and tricarboxylic nanocellulose(TNC)with carboxyl groups as the main adsorption sites were calculated to be 228.7,261.3,and 148.1 mg/g,respectively.The Cu^(2+)adsorption costs of MNC,DNC,and TNC were calculated and compared with those of powdered activated carbon(PAC).The Cu^(2+)adsorption capacity of DNC is higher than that of PAC,and the adsorption cost is close to or lower than that of PAC,demonstrating that the DNC prepared by sequential oxidation of NaIO_(4)–NaClO_(2) has competitive adsorption capacity and cost in the treatment of wastewater containing Cu^(2+).

Studies on Adsorption Behavior and Mechanism of Copper(Ⅱ) onto Amino Methylene Phosphonic Acid Resin

The adsorption behavior and the mechanism of a novel chelate resin, amino methylene phosphonic acid resin(APAR) for Cu(Ⅱ) were investigated. Cu(Ⅱ) was quantitatively adsorbed by APAR in the medium of pH=4 09. The statically saturated adsorption capacity is 181 mg/(g resin). Cu(Ⅱ) adsorbed on APAR can be eluted by 1 0-3 0 mol/L HCl. The rate constant is k 298 =5 58×10 -5 s -1 . The adsorption of Cu(Ⅱ) on APAR follows the Freundlich isotherm. The Δ H of the adsorption is 3 91 kJ/mol. The apparent activation energy is E a=21 4 kJ/mol. The coordination molar ratio of APAR to Cu(Ⅱ) is 1/1. It is shown that the nitrogen and the oxygen atoms in the functional group of APAR coordinate to Cu(Ⅱ).

Copper Adsorption on Olivine

Copper adsorption on olivine supplied by the A/S Olivine Production Plant at Aheim in western Norway was studied. The factors were evaluated which affect the uptake of copper. It is shown that the equilibrium pH of aqueous solution has the greatest influence on copper adsorption thanks to the competitive adsorption between proton and copper ions, and the adsorption of copper to olivine increases rapidly with pH increasing from 4 to 6. Moreover, initial copper concentration and olivine dose possess significant effect on copper adsorption, for the adsorption rate of copper increases with olivine dose increasing or initial copper concentration decreasing at the same pH. In addition, the ionic strength effect on the adsorption was also investigated, but it owns little effect on the adsorption process of copper due to the formation of inner sphere adsorption of copper on olivine. The experimental data show that olivine has a high acid buffer capacity and is an effective adsorbent for copper.