Desorption Of Copper Research Articles

Copper desorption kinetics in wheat (Triticum aestivum L.) rhizosphere in some sewage sludge amended soils

Rhizosphere has different chemical and biological properties from bulk soils. Information about copper (Cu) desorption characteristics in the rhizosphere soils is limited. The objectives of this study were to determine Cu desorption characteristics and the correlation of its parameters with Cu extracted by DTPA-TEA, AB-DTPA and Mehlich 3 in bulk and rhizosphere amended soils with sewage sludge (10 g of sewage sludge was added to 1 kg soil) under greenhouse conditions in a rhizobox. The kinetics of Cu desorption in the rhizosphere and bulk was determined by successive extraction with DTPA-TEA in a period of 1 to 504 h at 25 ± 1 °C. The results showed that Cu extracted using several chemical extractants in the rhizosphere were significantly (P < 0.05) lower than in the bulk amended soils. In addition, Cu extracted using successive extraction in the rhizosphere were significantly (P < 0.01) lower than in the bulk soils. The best model for describing extraction data for the bulk and rhizosphere soils was the parabolic diffusion equation. Desorption kinetics of Cu conformed fairly well to first order and power function models. The results indicated that Cu diffusion rate in the wheat rhizosphere soils lower than in the bulk soils. Cu desorption rate in parabolic diffusion ranged from 0.326 to 0.580 mg kg−1 h−1/2 in the bulk soils, while it ranged from 0.282 to 0.490 mg kg−1 h−1/2 in the rhizosphere soils. Significant correlation (P < 0.05) between determine R values of parabolic diffusion and Cu desorption during 504 h with extracted Cu using DTPA-TEA, AB-DTPA and Mehlich 3 were found in the bulk and the rhizosphere soils. The results of this research revealed that Cu desorption characteristics in the wheat rhizosphere soils are quite different from bulk soils amended with sewage sludge.

Adsorption and desorption of copper(II) ions onto garden grass

The garden grass (GG) was firstly used to remove copper(II) from water as bioadsorbent. From the results of characterisation, the GG had the merits of high specific surface area, significant adsorption sites and functional groups. Copper-adsorption significantly depends on the initial copper concentrations, contact time, pH, adsorbent doses, particle sizes and temperature. The positive values of ΔG° indicates that the adsorption of copper onto garden grass is non-spontaneous and values lies within the ranges of 4.452–13.660kJ/mol for supporting physical adsorption. 0.1N H2SO4 was found as suitable eluent, which could be used 5 cycles of adsorption–desorption. The data from adsorption and desorption equilibrium were well fitted by the Langmuir, SIPS and Redlich–Peterson isotherm models. The maximum adsorption and desorption capacities were 58.34 and 319.03mg/g, respectively, for 1g dose. Adsorption and desorption kinetics could be described by the Pseudo-first-order model.

Competitive adsorption and desorption of copper and lead in some soil of North China

The competitive adsorption and desorption of Pb(II) and Cu(II) ions in the soil of three sites in North China were investigated using single and binary metal solutions with 0.01 mol·L−1 CaCl2 as background electrolyte. The desorption isotherms of Pb(II) and Cu(II) were similar to the adsorption isotherms, which can be fitted well by Freundlich equation (R2>0.96). The soil in the three sites had greater sorption capacities for Pb(II) than Cu (II), which was affected strongly by the soil characteristics. In the binary metal solution containing 1:1 molar ratio of Pb(II) and Cu(II), the total amount of Pb(II) and Cu(II) adsorption was affected by the simultaneous presence of the two metal ions, indicating the existence of adsorption competition between the two metal ions. Fourier transform infrared (FT-IR) spectroscopy was used to investigate the interaction between soil and metal ions, and the results revealed that the carboxyl and hydroxyl groups in the soil were the main binding sites of metal ions.

Changes in the sorption, desorption, distribution, and availability of copper, induced by application of sewage sludge on Chilean soils contaminated by mine tailings

The effect of mine tailings and sewage sludge was evaluated on sorption, desorption, availability and distribution of copper in two soils, one high (sandy soil) and one low in copper (clay soil). In both soils contaminated by mine tailings the copper sorption capacity and the affinity of the substrate for the metal decreased substantially compared to the uncontaminated soils, however, the sorption remained always high in the clay soil substrates. In the substrates with sandy soil, the high Cu content and lower clay content were determining factors in the lower magnitude of the sorption. Similarly, metal desorption was closely related to these two parameters, and it was higher in clay soil with lower pH. In general, the application of sewage sludge favored the sorption of Cu in soils contaminated and uncontaminated with mine tailings, and in all cases desorption decreased, an effect that remained for at least 30 days. Simple extraction of Cu with CaCl2 and diethylenetriaminepentaacetic acid gave contradictory results, so a careful choice of the procedure is required, depending on the level of metal in the soil and on the acting principle of the extracting agent. In that relation, more complete information on the changes in the metal forms was obtained by application of the sequential extraction procedure proposed by the European Community Bureau of Reference.

Polydopamine Nanoparticles as a New and Highly Selective Biosorbent for the Removal of Copper (II) Ions from Aqueous Solutions

The adsorption and desorption of copper (II) ions from aqueous solutions were investigated using polydopamine (PD) nanoparticles. The nanoscale PD nanoparticles with mean diameter of 75 nm as adsorbent were synthesized from alkaline solution of dopamine and confirmed using scanning electron microscopy and X-ray diffraction analysis. The effects of pH (2–6), adsorbent dosage (0.2–0.8 g L−1), temperature (298–323 K), initial concentration (20–100 mg L−1), foreign ions (Zn2+, Ni2+, Cd2+, Fe2+, and Ag+), and contact time (0–360 min) on adsorption of copper ions were investigated through batch experiments. The isotherm adsorption data were well described by the Langmuir isotherm model. The maximum uptake capacity of Cu2+ ions onto PD nanoparticles was found to 34.4 mg/g. The kinetic data were fitted well to pseudo-second-order model. Moreover, the thermodynamic parameters of the adsorption (the Gibbs free energy, entropy, and enthalpy) were studied.

Application of Cu fertilizer on Cu recovery and desorption kinetics in two calcareous soils

Desorption of copper (Cu) is an important factor in determining Cu availability in calcareous soils. The aims of this investigation was to study the influences of application of Cu fertilizer on copper desorption and recovery of two calcareous soils of Iran and determine the best models for description of the kinetics of Cu release in these soils. For this purpose, copper sulfate (CuSO4·5H2O) fertilizer at the levels of 0, 3, 5 and 10 mg of Cu per kg of soil was mixed with soils. The soils were incubated at 25 ± 1 °C and near field capacity for 90 days in the greenhouse. For Cu desorption studies, samples were extracted with 0.01 M EDTA at pH 7.0 with shaker for periods of 5–2,880 min. Results showed that in each of the two soils, the amount of cumulative recovery and desorption of Cu from fertilized samples increased with the increase in the level of Cu fertilizer. Two-constant-rates and simple Elovich were the best equations for description of Cu desorption from soils. Release rate constants of these equations in the fertilized soils were greater than in unfertilized soils.

Adsorption and desorption of copper and zinc in tropical peat soils of Sarawak, Malaysia

Tropical peat soils are inherently deficient in micronutrients particularly copper (Cu) and zinc (Zn). In addition, limited information is available on the adsorption and desorption of these micronutrients in these soils, which are important factors governing nutrient concentration in the soil solution and nutrient availability to plants. A study was carried out to quantify adsorption and desorption of Cu and Zn in three untreated and limed tropical peat soils of Sarawak, Malaysia. Copper and Zn adsorption increased gradually with increasing levels of added Cu and Zn in both control and limed soils. The adsorption of Cu and Zn in limed soils increased by 50 and 67 fold, respectively, relative to control soils. The Freundlich constant (KF) values for Cu in both control and limed peat soils were higher than for Zn indicating that Cu is more strongly adsorbed to the soil solid phase than Zn. The KF values for Cu and Zn in this study were higher than those reported for other soil types. The percentage of adsorbed Cu and Zn susceptible to desorption into 5mM DTPA was higher than that desorbed by 10mM Ca(NO3)2 in all soils. A higher percentage of Cu than that of Zn was desorbed by DTPA because Cu has a higher critical stability constant with DTPA. Liming is necessary to increase the pH of peat soils but it also inevitably decreases the solubility and hence the bioavailability of Cu and Zn. This study provides evidence on the importance of adsorption and desorption data for estimating nutrient availability for plant uptake in tropical peat soils.

Removal of Copper from Water by Adsorption onto Banana Peel as Bioadsorbent

Banana peel, a fruit waste were used to produce bioadsorbent through environment friendly process. It were cut, washed, dried, grounded into powder and used for copper removal. Copper adsorption onto banana peel was depended upon the controlling parameters such as particle size, doses, pH, contact time, agitation speed and temperature. Slightly acidic water (pH = 6) was found to be suitable for copper removal. Equilibrium data were well fitted (R 2 = 0.998) with the Langmuir and Freundlich isotherms. The monolayer adsorption capacity was 27.78 mg/g. The calculated RL and 'n' values has proved the favorability of copper adsorption onto banana peel. Copper adsorption was followed the second order kinetic properly rather than other models. The equilibrium adsorption capacity was 1.439, 8.849, 18.182, 31.250 and 71.429 mg/g when initial copper concentrations were 10, 50, 100, 200, and 400 mg/l respectively. Solvent 0.1N Sulphuric acid showed higher desorption of copper (94%) and adsorption-desorption process can be continued till seven cycles efficiently.

Removal of Cu2+ from Aqueous Solutions by Adsorption on Chemically Modified Cellulosic Supports

Low-cost materials containing carboxyl groups have been synthesized by grafting succinic anhydride onto sawdust and cotton fibers. These materials were used after activation with NaHCO3 for the removal of Cu2+ from water. Removal of copper was carried out at different concentrations in a discontinuous reactor and in a continuous adsorption column. The adsorption of Cu2+ obeys to the Langmuir isotherm law and the values determined for the separation factor show that the system adsorbent/adsorbed substance is favorable to the adsorption process. Copper desorption and adsorbent regeneration can be achieved with diluted acid.

Influence of soil properties on heavy metal sequestration by biochar amendment: 2. Copper desorption isotherms

Contaminant desorption constrains the long-term effectiveness of remediation technologies, and is strongly influenced by dynamic non-equilibrium states of environmental and biological media. Information is currently lacking in the influence of biochar and activated carbon amendments on desorption of heavy metal contaminants from soil components. In this study, copper sorption–desorption isotherms were obtained for clay-rich, alkaline San Joaquin soil with significant heavy metal sorption capacity, and eroded, acidic Norfolk sandy loam soil having low capacity to retain copper. Acidic pecan shell-derived activated carbon and basic broiler litter biochar were employed in desorption experiments designed to address both leaching by rainfall and toxicity characteristics. For desorption in synthetic rain water, broiler litter biochar amendment diminished sorption–desorption hysteresis. In acetate buffer (pH 4.9), significant copper leaching was observed, unless acidic activated carbon (pH pzc = 3.07) was present. Trends observed in soluble phosphorus and zinc concentrations for sorption and desorption equilibria suggested acid dissolution of particulate phases that can result in a concurrent release of copper and other sorbed elements. In contrast, sulfur and potassium became depleted as a result of supernatant replacements only when amended carbon (broiler litter biochar) or soil (San Joaquin) contained appreciable amounts. A positive correlation was observed between the equilibrium aluminum concentration and initial copper concentration in soils amended with acidic activated carbon but not basic biochar, suggesting the importance of cation exchange mechanism, while dissolution of aluminum oxides cannot be ruled out.

Copper Release Behavior in Two Calcareous Soils Amended with Three Organic Materials

Understanding time-dependent copper (Cu) desorption behavior is critical for improving the prediction of Cu availability in soils. This study was conducted to evaluate the influence of municipal waste compost, sheep manure, and wheat straw on desorption characteristics of Cu and to evaluate the suitability of different kinetic models to describe the Cu release pattern in two calcareous soils. Diethylenetriaminepentaacetic acid (DTPA) and ethylenediaminetetraacetic acid (EDTA) were employed to extract Cu from soils. Best-fitted kinetic models including Elovich, simple Elovich, two-constant rate, and parabolic diffusion were selected based on their low standard error and high coefficient of determination. Extractable copper significantly decreased with increasing rates of sheep manure and wheat straw but increased with increasing rates of municipal waste compost amendment. Results revealed that copper was more readily desorbed from clay soil compared to silt loam soil. The copper desorption patterns were almost similar for both extractants; however, EDTA extracted more Cu from soils.

Effects of poultry manure and pistachio compost on the kinetics of copper desorption from two calcareous soils

Land disposal of organic waste materials may alter the heavy metal status of the soil by affecting metal solubility or dissociation kinetics. The aim of this investigation was to study the influences of two organic matters (poultry manure and pistachio compost) on copper desorption of two calcareous soils of Iran and determine the best models for description of the kinetics of Cu release in this soils. Organic matters were added to soils at the rate of 300 g kg−1, and samples were incubated at 24–25°C and near field capacity for 90 days. For Cu desorption studies, samples were extracted with 0.01 M EDTA at pH 7.0 with shaker for periods of 5 to 2,880 min. Results showed that during the reaction periods from 5 to 2,800 min, desorption of Cu from two soils increased with time. In the all of samples, copper release was rapid at first and then became slower until equilibrium was approached. In the two soils, desorption of Cu, which increased in poultry manure and decreased in pistachio compost treatments than the control soil, and two-constant rate and simple Elovich were the best equations for description of Cu desorption from soils.

Electroreduction of nitrate ions on Pt(1 1 1) electrodes modified by copper adatoms

Kinetics and mechanism of nitrate ion reduction on Pt(1 1 1) and Cu-modified Pt(1 1 1) electrodes have been studied by means of cyclic voltammetry, potentiostatic current transient technique and in situ FTIRS in solutions of perchloric and sulphuric acids to elucidate the role of the background anion. Modification of platinum surface with copper adatoms or small amount of 3D-Cu crystallites was performed using potential cycling between 0.05 and 0.3 V in solutions with low concentration of copper ions, this allowed us to vary coverage θ Cu smoothly. Following desorption of copper during the potential sweep from 0.3 to 1.0 V allowed us to estimate actual coverage of Pt surface with Cu adatoms. Another manner of the modification was also applied: copper was electrochemically deposited at several constant potentials in solutions containing 10 −5 or 10 −4 M Cu 2+ and 5 mM NaNO 3 with registration of current transients of copper deposition and nitrate reduction. It has been found that nitrate reduction at the Pt(1 1 1) surface modified by copper adatoms in sulphuric acid solutions is hindered as compared to pure platinum due to induced sulphate adsorption at E < 0.3 V. Sulphate blocks the adsorption sites on the platinum surface and/or islands of epitaxial Cu(1 × 1) monolayer thus hindering the adsorption of nitrate anions and their reduction. The extent of inhibition weakly depends on the copper adatom coverage. Deposition of a small amount of bulk copper does not affect noticeably the rate of nitrate reduction. Nitrate reduction on copper-modified Pt(1 1 1) electrodes in perchloric acid solutions occurs much faster as compared to pure platinum. The steady-state currents are higher by 4 and 2 orders of magnitude at the potentials of 0.12 and 0.3 V, respectively. The catalytic effect of copper adatoms is largely caused by the facilitation of nitrate adsorption on the platinum surface near Cu ad and/or on the islands of the Cu(1 × 1) monolayer (induced nitrate adsorption). Hydrogen adatoms block the adsorption sites on platinum for NO 3 − anion adsorption and inhibit reactions of nitrate reduction even at moderate surface coverage. The products of nitrate reduction in sulphuric and perchloric acids are essentially the same (NO and ammonia) irrespective of the presence or absence of Cu on the platinum surface.

Adsorption-desorption properties of bazalt tuff and catalytic activity of acido complexes of palladium(II) and copper(II) in the reaction of carbon(II) oxide oxidation with oxygen

Desorption of palladium(II) and copper(II) from the K2PdCl4-Cu(NO3)2-KBr/H-BT-6 catalysts, in which bazalt tuff from various deposits subjected to acid modification is used as carrier, was studied.

Comparisons of Various Chemical Extracts as Quantity Factors to Determine Metal-Buffering Capacity of Soils

Applicability of various chemical extracts was investigated as quantity (Q) factors to determine cadmium (Cd), zinc (Zn), and copper (Cu) desorption quantity–intensity (Q/I) relationships in soils. The metal extracts were sums of sequential metal fractions (except the residual fraction) using Tessier's (TSE) and Community Bureau of Reference (BCR) procedures and various single chemical extracts: 1.0 M potassium nitrate (KNO3), 1.0 M magnesium nitrate [Mg(NO3)2], 1.0 M magnesium chloride (MgCl2), and 0.11 M acetic acid (CH3COOH) solutions. Water-extractable metal was applied as a fixed intensity (I) factor. The TSE or BCR metal fractions were significantly correlated with diethylenetriaminepentaacetic acid (DTPA)–extractable metals, and all the metal desorption Q/I curves were linearly fitted. However, most of metal BC values estimated by using the single chemical extracts were very low and did not have consistent trends for target metals. Only 0.11 M CH3COOH-extractable metals might be reliable. Therefore, TSE and BCR metal fractions can be applicable to replace DTPA-extractable metals, and 0.11 M CH3COOH-extractable metals might also be useful.

Investigation of adsorption and ultrasound assisted desorption of lead (II) and copper (II) on local bentonite: A modelling study

This paper assesses the potential of the natural bentonite for the adsorption and ultrasonic desorption of toxic heavy metal cations (i.e., Pb(II) and Cu(II)). Adsorption and desorption processes have been modelled with the aid of a factorial design-approach. The ability of untreated bentonite to remove Pb(II) and Cu(II) from aqueous and acidic solutions at different pH values has been studied for different metal concentrations by varying the amount of adsorbent, temperature, stirring speed and contact time. The same factors, except stirring speed and metal concentration, were applied in desorption study. Ultrasound power was used for desorption instead of stirring speed. A flame atomic absorption spectrometer was used for measuring the Pb(II) and Cu(II) concentration before and after both experimental studies. The results show that the highest adsorption for both Pb and Cu were obtained in excess of 99 % and the highest desorption for Pb and Cu obtained were 28.71% and 66.61% respectively. It is believed that the models obtained for adsorption and desorption may provide a background for detailed mechanisms searches, pilot and industrial scale applications.

Copper Biosorption by Biomass of Marine Alga: Study of Equilibrium and Kinetics in Batch System and Adsorption/Desorption Cycles in Fixed Bed Column

Copper biosorption onto chemically modified biomass of marine alga Sargassum filipendula was investigated in a batch reactor and a fixed bed column. Experiments were carried out in the batch reactor to obtain kinetic and equilibrium data and to assess the copper desorption efficiency of different eluent solutions. The pseudo-first-order, pseudo-second-order, and Langmuir kinetic models were used to correlate kinetic data. The experimental data fitted well to the pseudo first order and Langmuir kinetic models. Langmuir and Freundlich models were applied to describe the equilibrium data obtained at a fixed temperature of 30°C and at pH values of 3.0, 4.0, 5.0, and 6.0. The maximum capacities of copper biosorption onto the algal biomass were 1.43, 1.59, 2.40, and 2.36 mequiv./g at pH 3.0, 4.0, 5.0, and 6.0, respectively. The efficiencies of two eluent solutions (calcium chloride and hydrochloric acid) for copper removal from the biomass were evaluated at different concentrations (0.1, 0.2, 0.5, and 1.0 mol/L). The efficiencies of the calcium chloride solutions varied from 1% to 14%, while efficiencies varying from 95% to 99% were obtained when hydrochloric acid solutions were applied. Three adsorption/desorption cycles were carried out in a fixed bed column using 0.1 mol/L hydrochloric acid as eluent solution. The results showed that an increase in the number of cycles led to a reduction in the adsorption capacity of the alga. The desorbed copper fraction presented no significant variation, remaining around 63% in the three adsorption/desorption cycles.

Removal of copper from aqueous solution using iron-containing adsorbents derived from methane fermentation sludge

Iron-containing adsorbents prepared from methane fermentation sludge (MFS) were characterized by N 2 adsorption, XRD, SEM, EDX, pH determination and elemental analysis. The experiments for copper removal from aqueous solution using the MFS-derived adsorbents were performed, and the effects of iron content, forms of the iron (hydr)oxides, surface basicity and pH of the aqueous solution on copper removal were elucidated respectively. The desorption studies were also performed and the mechanism of Cu(II) adsorption was proposed. The results indicated that the adsorbent obtained at 700 °C for 1 h in a steam atmosphere possessed the highest capability for Cu(II) adsorption. The high copper removal ability of the MFS-derived materials is attributed to their intermediate surface area, strong surface basicity and the presence of iron (hydr)oxides on their surface. The Cu(II) adsorption onto the composite adsorbents is via ion-exchange with H, Ca and K ions, surface precipitation and binding with active sites on the surface of iron (hydr)oxides at various pH values. The desorption of copper in deionized water is quite low. The irreversibility of copper adsorption on the iron-containing adsorbents is attributed to the formation of strong bonds between Cu(II) and the iron (hydr)oxides. The adsorbent can be applied to remove copper from water or soil by fixation onto the surface.

Removal of copper from nickel anode electrolyte through ion exchange

An novel method for removal of copper from nickel anodic electrolyte through ion exchange was studied after cupric deoxidization. Orthogonal design experiments show the optimum conditions of deoxidizing cupric into Cu + in the nickel electrolyte are the reductive agent dosage is 4.5 times as the theoretic dosage and reaction time is 0.5 h at 40 °C and pH 2.0. Ion exchange experiments show that the breakthrough capacity( Y) decreases with the increase of the linear flow rate( X): Y=1.559–0.194 X+ 0.006 7 X 2. Breakthrough capacity increases with the increase of the ratio of height to radius(RRH). The higher the initial copper concentration, the less the breakthrough capacity(BC). SO 4 2í and nickel concentration have no obvious change during the process of sorption, so it is not necessary to worry about the loss of nickel during the sorption process. Desorption experiments show that copper desorption from the resin is made perfectly with NaCl solution added with 4% (volume fraction) H 2O 2 (30%) and more than 100 g/L CuCl 2 solution is achieved.

Sugar-beet pulp pectin gels as biosorbent for heavy metals: Preparation and determination of biosorption and desorption characteristics

The present work reports the feasibility of using sugar-beet pectin gels for the removal of heavy metals from aqueous solutions. Sugar-beet pectin hydro- and xerogels were tested in the batch biosorption and desorption of cadmium, lead and copper. Pectins were successfully extracted and demethylated from the sugar-beet pulp, an agricultural residue, and gelled in the presence of CaCl 2 . The stability of the hydro- and xerogel pectin beads made them suitable for biosorption of heavy metals in different conditions. Biosorption data were fitted to the pseudo-second order kinetic model and the Langmuir isotherm model, obtaining the corresponding parameters. Treated and untreated beads were characterized using FTIR and SEM to determine possible binding mechanisms. The main mechanisms involved were ion exchange with calcium of gel structure and chelation or complexation with carboxyl groups. After biosorption, calcium in the gels was substituted by metal cations reorganizing the structure of the gel matrix in a way that was visible using scanning electron microscopy. HNO 3 0.1 M was the best eluant for the reutilization of the gels and recovered all the adsorbed metal unlike HCl and H 2 SO 4 . Sugar-beet pectins could be used as an efficient biosorbent for the treatment and recovery of Cu, Pb and Cd from wastewater.