Desorption Of Copper Research Articles

Comparative Analysis of Hydrogel Adsorption/Desorption with and without Surfactants.

In this particular study, a hydrogel known as SAP-1 was synthesized through the grafting of acrylic acid-co-acrylamide onto pullulan, resulting in the creation of Pul-g-Poly (acrylic acid-co-acrylamide). Additionally, a sponge hydrogel named SAP-2 was prepared by incorporating the surfactant sodium dodecyl benzene sulfonate (SDBS) into the hydrogel through free radical solution polymerization. To gain further insight into the composition and properties of the hydrogels, various techniques, such as Fourier transform infrared spectroscopy, hydrogen nuclear magnetic resonance (1H NMR), atomic absorption spectroscopy, and field emission scanning electron microscopy (FE-SEM), were employed. Conversely, the absorption kinetics and the equilibrium capacities of the prepared hydrogels were investigated and analyzed. The outcomes of the investigation indicated that each of the synthesized hydrogels exhibited considerable efficacy as adsorbents for cadmium (II), copper (II), and nickel (II) ions. In particular, SAP-2 gel displayed a remarkable cadmium (II) ion absorption ability, with a rate of 190.72 mg/g. Following closely, SAP-1 gel demonstrated the ability to absorb cadmium (II) ions at a rate of 146.9 mg/g and copper (II) ions at a rate of 154 mg/g. Notably, SAP-2 hydrogel demonstrated the ability to repeat the adsorption-desorption cycles three times for cadmium (II) ions, resulting in absorption capacities of 190.72 mg/g, 100.43 mg/g, and 19.64 mg/g for the first, second, and third cycles, respectively. Thus, based on the abovementioned results, it can be concluded that all the synthesized hydrogels possess promising potential as suitable candidates for the adsorption and desorption of cadmium (II), copper (II), and nickel (II) ions.

An efficient method for recovery of organic phase from crud in solvent extraction unit of Sarcheshme copper complex in Iran by guar gum

One of the problems of all industries that use metal extraction with organic solvents is stable emulsions and finally the formation of crud. The formation of crud is usually accompanied by the loss of a significant amount of the causal solvent and thus increases the process costs. Therefore, the removal of crud and recovery of its organic phase is of particular importance. In this research, the applicability of polysaccharides such as guar gum, xanthane gum, Arabic gum and starch for recovery of organic phase from the crud formed in copper extraction/electrowining unit of Sarchashmeh copper complex (IRAN) was studied. The results showed that guar gum is an effective additive which let the organic phase to be recovered with up to 95% yield. To ensure that gum do not have a negative effect on the system and that the absorption and desorption of copper is done correctly, the extraction/stripping properties of the organic phase separated with guar gum is compared with the organic phase separated without additives. Surface tension analysis of the guar gum-recovered organic phase also confirmed the suitability of guar gum for recovery of organic phase from crud.

Study on Copper Desorption Behavior from Microplastic Particles in Different Media

Study on Copper Desorption Behavior from Microplastic Particles in Different Media

Sorption of Copper Ions from the Nitric Acid Solution of Electrolytic Refining of Silver with Using Chelating Resin Axionit BPA

The article considers a sorption method for extracting copper ions from a model nitric acid solution based on a solution of electrolytic refining of silver with using sorbents with bis-picolylamine functional groups: Dowex M-4195 and AXIONIT BPA. The possibility of extracting copper to residual concentrations in the solution of less than 10 mg/l is shown. The working capacity of both samples under batch conditions, as well as the dynamic exchange capacity and the full dynamic exchange capacity under dynamic сonditions (column test), are determined. The effect of the flow rate of the solution into the column on the kinetics of the sorption of copper ions on AXIONIT BPA is shown. The possibility of desorption of copper with a solution of 3 %, 5 % NH4OH was investigated, and a two-stage scheme of desorption of copper was tested: 5 % and 10 % with a solution of ammonium hydroxide

Depression, Anxiety, Quality of Life, and Coping Strategies in People Exposed to Periodic Floods of Capivara River in Imperatriz City – Maranhão State, Brazil

Trace contaminant removal is of contemporary concern in drinking water and wastewater treatment, given increasing evidence of potential toxicity of various heavy metals and metalloids in water at parts per billion (ppb) concentration levels. Currently, only high-pressure reverse osmosis can reliably remove trace concentration contaminants from water but with high energy cost. Thus, the search is on for techniques and methods able to remove trace concentration contaminants with a lower energy footprint. Adsorption, a low energy technique for water and wastewater treatment is one possibility, which when coupled with the use of low-cost biomass as adsorbent, would further improve process efficiency. This synopsis describes work done on examining the use of local marine seaweed, Sargassum sp. for removing copper at low (4 to 20 ppm, parts per million) and trace concentration (< 1000 ppb), with and without ammonium ion interference at different solution pH. Specifically, to reduce organic leaching and improve mechanical stability, formaldehyde crosslinking was used and was effective in enhancing stability of seaweed between pH 3 and 9. But, residual organic leaching of ~ 4 ppm meant that modified seaweed was not suitable for drinking water treatment. Batch kinetic and equilibrium studies revealed that up to a threshold ammonium concentration of 50 ppm [NH4+-N], there was good sorption of copper on formaldehyde crosslinked seaweed (treated seaweed), with residual copper concentration of 0.5 ppm. Residual copper concentration increased with increase in ammonium concentration (up to 2500 ppm [NH4+-N]); thereby, highlighting a competitive binding effect for treated seaweed’s surface functional groups. Attempts to remove trace concentration copper highlighted feasibility of the approach. However, significant residual equilibrium concentration of copper remained in the solution. More importantly, thermodynamic considerations point to the existence of a finite residual equilibrium concentration for copper in water; thereby, making adsorption not feasible as a method for completely removing trace concentration copper. Additionally, surface concentration of copper at the adsorbent might, in some cases, be higher than the bulk solution; thus, leading to desorption of copper from the seaweed surface back to the solution. Collectively, adsorption is not capable of completely removing a contaminant such as is the case for reverse osmosis where the non-porous membrane serves as barrier separating treated water from raw influent.

Desorption of zinc, copper and lead ions from loaded flax fibres

ABSTRACT Biosorption is an efficient and cost-effective method for heavy metals’ remediation. However, saturated biosorbents may pose a serious problem for the environment. Flax fibres have shown very good adsorption capacities to remove zinc, copper and lead ions from contaminated aqueous solutions. In this study, adsorption–desorption cycles were conducted with loaded flax fibres in batch mode to recover heavy metals using four types of solutions: hydrochloric acid solution, nitric acid solution, sodium hydroxide solution and ultrapure water. Desorption kinetic studies, conducted with loaded flax fibres, showed very fast desorption of zinc, copper and lead when using nitric and hydrochloric acids with a selectivity sequence of Zn (totally desorbed) > Cu (94%) > Pb (80–73%). Desorption kinetic was slower with the use of sodium hydroxide and showed much lower desorption rates of Zn (62%) > Pb (12%) > Cu (7%). Desorption of zinc and copper from previously loaded fibres from binary metal ion system in lead solution was also investigated. Different concentrations ranging from 0.04 to 0.20 mmol/L were tested. The obtained results demonstrated a significant release in the order Zn (18–90%) > Cu (2–42%), while lead was still efficiently adsorbed. Retention efficiencies of zinc and copper and adsorption efficiency of lead resulted in the same adsorption efficiencies of the three metal ions onto flax fibres in the ternary metal ion system.

Cu-Doped TiNxOy Thin Film Resistors DC/RF Performance and Reliability

We fabricated Cu-doped TiNxOy thin film resistors by using atomic layer deposition, optical lithography, dry etching, Ti/Cu/Ti/Au e-beam evaporation and lift-off processes. The results of the measurements of the resistance temperature dependence, non-linearity, S-parameters at 0.01–26 GHz and details of the breakdown mechanism under high-voltage stress are reported. The devices’ sheet resistance is 220 ± 8 Ω/□ (480 ± 20 µΩ*cm); intrinsic resistance temperature coefficient (TCR) is ~400 ppm/°C in the T-range of 10–300 K; and S-parameters versus frequency are flat up to 2 GHz with maximum variation of 10% at 26 GHz. The resistors can sustain power and current densities up to ~5 kW*cm−2 and ~2 MA*cm−2, above which they switch to high-resistance state with the sheet resistance equal to ~200 kΩ/□ (~0.4 Ω*cm) caused by nitrogen and copper desorption from TiNxOy film. The Cu/Ti/TiNxOy contact is prone to ageing due to gradual titanium oxidation while the TiNxOy resistor body is stable. The resistors have strong potential for applications in high-frequency integrated and hybrid circuits that require small-footprint, medium-range resistors of 0.05–10 kΩ, with small TCR and high-power handling capability.

A ‘three in one’ complexing agent enables copper desorption from polluted soil, its removal from groundwater and its detection

High groundwater concentrations of heavy metals such as copper are toxic to humans. Attenuated total reflectance – Fourier transform infrared spectroscopy (ATR-FTIR) demonstrated that the environmentally benign surfactant sodium lauryl lactylate (SLL) formed bidentate complexes with copper ions. CuSO4 increased the surface tension and the compressional rigidity of SLL films at air-water interfaces, providing additional evidence of SLL-Cu interactions. Here, we harness for the first time the formation of Cu-SLL complexes to achieve the three following objectives. First, SLL enabled the facile detection of copper in water samples, by enhancing the color of copper solutions (10−3 M copper concentrations could be detected with the naked eye). Second, SLL promoted the desorption of copper from model polluted soils. Therefore, SLL can be useful for surfactant flushing applications, in which surfactants are used to enhance the remediation of polluted aquifers through pump and treat. Third, SLL enhanced the treatment of water polluted with copper ions. Specifically, SLL favored the partitioning of Cu2+ into canola oil, purifying water. Therefore, canola oil could be used as liquid sorbent for the treatment of groundwater in SLL-enhanced pump and treat, in which polluted groundwater would be pumped and then treated at the surface. The safety of the proposed treatment can be improved by injecting fluids obtained with the biopolymer sodium alginate (Na-alginate) around the treated area. Na-alginate fluids (at 0.5 wt%) had low viscoelastic moduli before contact with Cu2+ (facilitating their injection) and gelled when intercepting Cu2+ ions (to allow their confinement inside the boundaries of the treated area).

Adsorption and desorption of zinc and copper in acid mine drainage onto synthesized zeolite from coal fly ash

Synthetic zeolite is considered a more effective adsorbent due to its high purity and high removal efficiency. On the other hand, acid mine drainage contains various metal ions, such as zinc, copper, iron, and manganese which are toxic for the ecosystem in a certain concentration. One of the solutions to remove these metal ions is through adsorption. Therefore, the study of adsorption and desorption of zinc and copper onto synthetic zeolite was conducted. The synthetic zeolite was synthesized from coal fly ash and the acid mine drainage was prepared artificially. The adsorption experiment was carried out using a batch system. NaCl, H2SO4, and HNO3 were used as desorption agent. The adsorption studies revealed that the removal efficiency of both Zn2+ and Cu2+ onto the studied adsorbent decrease with the increase of adsorbate concentration. While the adsorption selectivity for multi-system synthetic AMD solution by the studied adsorbent were found to the order of Fe2+> Cu2+> Zn2+> Mn2+.After being reused three times, the synthetic zeolite shows a decrease in for Zn2+ and Cu2+ adsorption efficiency of about 10%. Furthermore, the desorption study shows the ineffective use of NaCl, H2SO4, and HNO3 as desorption agents in this study.

Metabolomic and secretomic approach to the resistance features of the fungus Aspergillus niger IOC 4687 to copper stress.

Metabolomic and secretomic analyses of Aspergillus niger IOC 4687 indicated the features of resistance of this strain to copper stress. To investigate the metabolites produced under oxidative stress conditions, gas chromatography-mass spectrometry analysis was performed. The secretome principal component analysis results showed that mannitol could be the main metabolite responsible for conferring resistance to the fungus, and gluconic acid is the possible cause of copper desorption because of its chelating ability. The meta-analysis of the metabolome of A. niger IOC 4687 indicated that a low concentration of sorbitol and ribonolactone during growth may be an indicator of oxidative stress.

Effect of contamination sources on the rate of zinc, copper and nickel release from various soil ecosystems

Background and objectiveSoil is a substantive component in biosphere habitually endangered to superfluity contaminants particularly potential toxic elements (PTEs). The source of soil contaminants is very critical in controlling both their release and expected hazards in the different soil ecosystems. This study aims to investigate the effect of low-quality irrigation water (LQW) on the extent of soil pollution through desorption of zinc (Zn), nickel (Ni) and copper (Cu) from different polluted soils, collected from LQW irrigated farms for more than 40–80 years at Giza and Kafr-Elsheikh Governorates, Egypt.ResultsModels incorporated modified Freundlich (MFE), Elovich, first order and parabolic diffusion (PDE) showed significant results in describing the kinetic data under Egyptian conditions. Results entailed that according to the coefficient of determination (R2) and standard error, all used models well described the desorption of Cu, Ni and Zn, the most prevalent contaminants in the trailed soil ecosystems; for example, the R2 values were higher than 0.96** for zinc desorption using MFE model. As far as the PTEs levels are considered, the highest contaminant desorption rates were recorded at Kafr-Elsheikh site, followed by Kombora, and the lowest ones were in Abo Rawash soil ecosystem. The succession of more than one model to describe the kinetic perspective confirmed that the different mechanisms take place in PTEs sorption, distribution and subsequently release from different soil ecosystems.ConclusionsThe numerical values indicated that the soil ecosystems contaminated with industrial effluents were higher than those irrigated with sewage effluents regardless of the type of land use. More attention should be paid to low-quality water application in agriculture irrigation and its environmental risks.

Determination of Pb (II), Cu (II), Co (II), Mn (II), and Fe (III) by electrothermal atomization atomic absorption spectrometry after preconcentration with nanofibers

The results of sorption preconcentration of some heavy metal (HM) ions with their subsequent determination in natural and drinking water by electrothermal atomization atomic absorption spectrometry (ETAAS) are presented. The sorption and desorption (0.01 – 1 M HNO3) of lead, copper, iron, cobalt and manganese ions from aqueous media on nanofiber samples obtained from polyacrylonitrile (PAN) with subsequent directed modification by 1.25 M NaOH solution upon heating (70°C) (PAN*) are studied and optimized. Nanofibers were obtained by capillary-free electroforming from solutions of PAN in dimethylformamide. This method is advantageous for the simplicity of equipment, high energy efficiency of nanofiber production, versatility and flexibility in controlling process parameters and allows production of nanomaterials with desired properties. The values of the extraction degree (95.8 – 99.5%) and selectivity coefficients for competing pairs of metal ions are calculated: вPb/Cu = 1.2; вPb/Co = 2.8; вPb/Mn = 3.2;вCu/Co = 1.7; вCu/Mn = 3.7; вCo/Mn = 2.5. A comparative analysis of the sorption activity of the obtained nanofibers revealed that the character of lead, copper, cobalt and manganese ion sorption by nanofibers is non-selective at pH 6 – 8 and selective for iron (III) ions at pH  3. A technique of sorption-atomic absorption determination of the aforementioned metal ions in real objects with preliminary nanofiber concentration at the level of tenths and hundredths of MPC is proposed. Non-woven materials based on modified PAN are used as effective extractants of nanogram quantities of HM ions. The detection limits for heavy metal ions are 40 – 80 ng/dm3.

Influence of agro-industrial wastes on the sorption, desorption, and distribution of copper in soils polluted by mine tailings

The objective of this work was to modify minimally two agro-industrial wastes, to evaluate their effectiveness for the retention of copper in soils contaminated by mining tailings, as well as to evaluate the changes in the chemical forms of the metal in the soil and thus also evaluate the attenuation of copper desorption in a short period after a mine tailing spill on the soil. The solid wastes of olive mill and grape stalks of the wine-making process were modified minimally, through washing processes and partial alkalization, to obtain substrates with greater capacity for copper sorption. Two agricultural soils near a tailing impoundment were studied: a sandy loam soil with pH close to neutral and high total and available copper content and a clay soil with low copper content, slightly acid pH, and high clay content. Both soils were treated with mine tailings from the same site to simulate an involuntary spill of mining waste. The contaminated soils were treated with the organic amendments to study the sorption, desorption, and distribution of Cu in a period of 30 days. The application of simple procedures such as alkalinization or washing of the agro-industrial wastes improved the Cu sorption capacity and facilitated the application of these materials to the soil. The application of mine tailings to the soils decreased the Cu sorption and the affinity of the substrate for the metal. This adverse effect was ameliorated by the incorporation of minimally treated olive mill wastes and grape stalks, increasing the sorption by a range of 15 to 75% compared to untreated soils. In substrates with sandy loam soil, both amendments decrease the soluble fraction of Cu, an effect that was not observed in clay soil. In parallel, both amendments increased the fraction of metal bound to the oxidizable fraction, an effect that was greater for grape stalks. The organic amendments used in this study were effective to reduce the initial contamination by copper after a spill of mine tailing wastes containing this metal. In this sense, both amendments applied to sandy loam soil increased the organic matter content and the Cu sorption capacity, effects that are maintained for at least 30 days. In clay soil, these effects were observed only for grape stalks, probably due to its greater metal sorbent capacity compared to the olive oil waste.

Polyacrylonitrile and Hybrid SBA-15: A Robust Composite Material for Use as Copper (II) Adsorbent in Flow Conditions

Novel processes for treating industrial wastewater containing metals are needed nowadays in order to meet environmentally safe water treatment standards. Attention has been paid to innovative adsorbents that permit to trap and subsequently desorb ions, permitting their selective recovery. In this work, we design a robust porous exchange matrix able to adsorb Cu (II) (often found in industrial wastewater), that meets the following requirements: (a) to perform copper desorption with a minimum condition modification, (b) to preconcentrate already desorbed ions, (c) to be reusable, and (d) to be able to work in flow condition. A hybrid mesoporous material matrix (HMM) composed of a hybrid mesoporous filler embedded into a highly accessible polymer was chosen as adsorbent. The mesoporous filler is mesoporous silica (SBA-15) chemically modified through post-grafting with amino groups. The composite material was prepared by combining the adsorbent material and polyacrylonitrile (PAN). The system could be easily processed in columns of fixed bed in order to perform copper adsorption–desorption. Under these conditions, a Cu (II) loading of 1.2 × 10−3 mol per gram of adsorbent material was obtained. Copper desorption was performed in HCl 0.1 M, achieving a final concentration at least 5 times higher than the initial one. The material was reused 10 times without losing its adsorption capacity, demonstrating its potentiality for water treatment.

Cu(II) adsorption on 2-thiouracil-modified Luffa cylindrica biochar fibres from artificial and real samples, and competition reactions with U(VI)

The adsorption of Cu(II) ions by biochar fibres prior and after modification with 2-thiouracil on real and artificial samples has been studied by batch-type adsorption experiments, FTIR and XPS spectroscopy and competition reactions using U(VI) ions as competitor cations. The experimental data of the artificial samples clearly show that the modified material presents extraordinary higher affinity for Cu(II) ions even in the acidic pH range, the spectroscopic data indicate the formation of inner-sphere complexes and the competition reactions significantly higher selectivity of the 2-thiouracil modified biochar fibres for Cu(II). The 2-thiouracil-modified biochar fibres have been successfully applied to acid mine drainage (AMD) samples regarding the selective separation of Cu(II) ions from “real” samples. Regarding the desorption of copper from the biochar surface, although 100% copper recovery was achieved by eluting the metal ion using 1 M HNO3, the deterioration of the modified biochar fibers due to extensive 2-thiouracil release from the biochar surface limits the applicability of the present adsorbent in routine and large-scale applications.

Performances and behavior of a water-soluble and pH-sensitive polycarboxybetaine used for metal ion recovery

Zwiterionic functional groups give polycarboxybetaines a great ability to chelate copper and their use for metal ions recovery was suggested in previous studies. The use of a water-soluble and pH-sensitive polymer (polycarboxy-ethyl-3-aminocrotonate - PCEAC) was investigated for the removal of copper from aqueous solution. The equilibrium adsorption level was determined as a function of temperature, pH and initial adsorbate concentration. The good fit to the Langmuir model offered various information about copper uptake mechanisms. The maximal adsorption capacities were found to reach 253 ± 11 mg of copper per g of PCEAC at pH = 6. The thermodynamic parameters such as free energy, enthalpy and entropy changes for the adsorption of copper were computed to predict the nature of adsorption process. The removal of copper was varying from 2% to 97% depending on pH and initial copper concentration. A particular behavior of PCEAC at pH = 4 is discussed and explained by viscosity measurements as a particular conformation of the polymer. The effect of cadmium on copper adsorption was also tested. Some co-adsorption phenomena were observed at low cadmium concentrations ([Cd]/[Cu]≤1), while copper desorption in favor of cadmium adsorption were quantified at higher cadmium concentrations ([Cd]/[Cu]>1).

Assessing Copper Adsorption, Internalization, and Desorption Following Algaecide Application to Control Lyngbya wollei from Lake Gaston, NC/VA, USA

Application of copper-based algaecide formulations is commonly conducted to control nuisance cyanobacterial blooms. Most field application scenarios have a rapid decline in external aqueous copper concentrations. Copper partitioned to algae can remain bound in external state, transition into the cell, or desorb back into solution. Understanding short-term fate of applied copper-based algaecides is critical in risk assessment for non-target species as well as achieving desired efficacy of target nuisance algae. This research assessed the ability of copper from different algaecide formulations to partition to Lyngbya wollei and the subsequent internalization and desorption of copper following cessation of the aqueous exposure. Following a 6-h exposure, there were no significant differences in total partitioned copper between copper sulfate and an ethanolamine chelated copper formulation (Captain® XTR). Four days after cessation of the aqueous copper exposure, all chelated copper and copper sulfate (except 2 mg Cu/L) exposures had significantly decreased adsorbed copper to L. wollei. However, chelated copper had significantly more internalized copper (P < 0.05) at the 0.5, 1, and 2 mg Cu/L treatments compared with the 6-h measurements and higher internalized copper than copper sulfate at the 2 and 4 mg Cu/L treatments. Average desorbed copper was lower in most chelated copper treatments compared with copper sulfate, although no statistically significant differences were measured between formulations. This information will allow water resource managers to select the most efficient algaecide formulation for desired algal control, with a better understanding of depuration potential, offsite movement, and risks to non-target organisms.

Methane adsorption and methanol desorption of copper modified boron silicate.

Boron silicate (BS) with a chabazite framework structure was synthesised using a direct route and rigorously characterized before it was ion-exchanged with copper to form Cu-BS. Employing in situ infrared spectroscopy, we show that Cu-BS is capable of oxidising methane to methoxy species and methanol interacts with the boron sites without deprotonation.

Binary Component Sorption of Cadmium, and Copper Ions onto Yangtze River Sediments with Different Particle Sizes

Sorption is a crucial process that influences immobilization and migration of heavy metals in an aqueous environment. Sediments represent one of the ultimate sinks for heavy metals discharged into water body. Moreover, the particle size of sediments plays an extremely important role in the immobilization of heavy metals. In this study, the sorption and desorption of cadmium (Cd) and copper (Cu) onto sediments with different particle sizes were investigated to predict the rate and capacity of sorption, to understand their environmental behaviors in an aqueous environment. Batch sorption and kinetic experiments were conducted to obtain the retained amount and rate of Cd and Cu in a binary system. Experimental data were simulated using sorption models to ascertain the sorption capacity and the kinetic rate. Results of European Communities Bureau of Reference (BCR) sequential extraction showed the highest concentration of Cd (0.344 mg kg−1), and its distribution varied with sediment particle size and site. Furthermore, most of Cu (approximately 57% to 84%) existed as a residual fraction. The sorption of Cu onto six sediments followed a pseudo-first order reaction, whereas that of Cd followed a pseudo-second order reaction. Additionally, the competitive Langmuir model fitted the batch sorption experimental data extremely well. The highest sorption capacities of Cd and Cu reach 0.641 mmol kg−1 and 62.3 mmol kg−1, respectively, on the smallest submerged sediment particles. The amounts of Cu and Cd desorbed (mmol kg−1) increased linearly with the initial concentration increasing. Thus, sediment texture is an important factor that influences the sorption of heavy metal onto sediments.

Dynamics of the sorption of copper(II) and silver(I) by materials based on sulfoethylchitosan with various degrees of crosslinking

Optimum conditions of the dynamic concentration of copper(II) and silver(I) ions simultaneously present in a solution with N-(2-sulfoethyl)chitosan with a degree of modification equal to 0.5 and different degrees of crosslinking by glutaraldehyde are determined. The values of coefficients of selectivity K Ag/Cu are determined under dynamic conditions. It is shown that the selectivity of the sorption of silver(I) increases (compared to copper(II)) as the degree of crosslinking of sorbents based on N-(2-sulfoethyl)chitosan is raised. Mathematical treatment of the obtained dynamic curves is performed according to the Thomas, Adams–Bohart, and Yoon and Nelson models. As a result, the values of dynamic capacity of sorbents, the rate constant of the reaction, and the release time of 50% of the sorbate are determined. The quantitative desorption of copper and silver from the surface of sorbents is achieved by using 1 mol/dm3 solution of nitric acid.