Adsorption Process Of Cu Research Articles

Eco-friendly synthesis of magnetic zeolite A from red mud and coal gasification slag for the removal of Pb2+ and Cu2+

The issue of heavy metal pollutants has gained global attention, while the disposal of industrial wastes remains a critical environmental concern that requires urgent treatment. In this study, the successful synthesis of magnetic zeolite A (MZA) aimed at the Pb2+ and Cu2+ removal was accomplished by capitalizing on the synergetic interplay between the red mud (RM) and coal gasification slag (CGS) compositions. A reduction roasting reaction involving iron and carbon was innovatively integrated into the conventional alkali fusion-activation process of silicon-aluminum components. The physicochemical properties and preparation mechanism of MZA were characterized using various analytical techniques. Adsorption isotherms and kinetics were analyzed employing various well-known models, and the reusability of MZA was investigated. The result showed that hematite in RM was converted into magnetite and metallic iron during the alkali fusion-synchronous reduction roasting process, and the aluminosilicates from RM and CGS were transformed into zeolite A through a hydrothermal method. The Langmuir and pseudo-second order models well described the Pb2+ adsorption behavior, while the adsorption process of Cu2+ followed the Freundlich and Elovich models best. These results confirmed the successful synthesis of MZA with excellent adsorption performance and magnetic properties, thereby demonstrating the potential of RM and CGS in heavy metal removal through resource utilization.

Enhanced removal of antibiotics and heavy metals in aquatic systems using spent mushroom substrate-derived biochar integrated with Herbaspirillum huttiense.

A novel integrated removal strategy was developed to enhance the concurrent elimination of copper (Cu), zinc (Zn), oxytetracycline (OTC), and enrofloxacin (ENR) from the aqueous environments. The underlying adsorption mechanisms of spent mushroom substrate (SMSB) and the Herbaspirillum huttiense strain (HHS1), and their efficacy in removing Cu, Zn, OTC, and ENR was also examined. Results showed that the SMSB-HHS1 composite stabilized 29.86% of Cu and 49.75% of Zn and achieved removal rates of 97.95% for OTC and 59.35% for ENR through a combination of chemisorption and biodegradation. Zinc did not affect Cu adsorption, and ENR did not impact the adsorption of OTC on SMSB. However, the co-presence of OTC and ENR modified the adsorption behaviors of both Cu and Zn. Copper and Zn enhanced the adsorption of OTC and ENR by serving as bridging agents, facilitating the interaction between the contaminants and SMSB. Conversely, OTC and ENR inhibited the adsorption process of Cu by obstructing its interaction with the SMSB and occupying the oxygen-containing functional groups. The ‒OH (3415 cm-1) and C-O-C (1059 cm-1) functional groups were identified as the principal active sites to form hydrogen bonds and interact with Cu and Zn, leading to the formation of CuP4O11 and Zn4CO3(OH)6H2O. HHS1 also enhanced antibiotic removal through biodegradation, as evidenced by the decrease of ‒C‒O and increase of ‒C = O groups. This study underscores the innovative potential of the SMSB-HHS1 composite, offering a sustainable approach to addressing multifaceted pollution challenges in the aquatic environments.

MXene/polyaniline/sodium alginate composite gel: Adsorption and regeneration studies and application in Cu(II) and Hg(II) removal

The imperative to efficiently remove heavy metals from water has heightened the demand for adsorbents capable of co-adsorbing heavy metals and offering robust reusability. A novel composite adsorbent (PANI@SA-SNM) was synthesized with amine/sulfur-modified MXene, in-situ polymerized polyaniline (PANI) and sodium alginate (SA). Cu(II) and Hg(II) were used as model pollutants to test the adsorption capacity and stability of the adsorbent. Results showed that this adsorbent illustrated remarkable stability and adaptability across a pH range of 3 to 7 due to the proton transfer effect in PANI. The pseudo-second-order kinetic and Langmuir model were suitable for describing the physical and chemical adsorption process of Cu(II) and Hg(II). Thermodynamic analysis confirmed the adsorption process to be spontaneous and endothermic. The maximum adsorption capacity calculated by the Langmuir model was 255.81 mg g−1 for Cu(II) and 352.76 mg g−1 for Hg(II) (C0 = 50 ∼ 1000 mg L−1, pH = 4, Dos = 0.02 g/50 mL and T = 303.15 K), outperforming most of the reported adsorbents. In the study of binary systems, we found that the adsorbent exhibited effective co-adsorption capacity, and the differential competitive relationship between two ions was regulated by complex factors. Detailed characterizations revealed the adsorption mechanism, which involved physical adsorption, electrostatic attraction, ion exchange, complexation, and redox reaction. Moreover, the adsorbent maintained high desorption and adsorption efficiency for both ions over eight cycles thanks to strong protonation, Ca2+’s chelation and PANI’s reversibility. This research not only provides a new method for improving gel reusability, but also offers insights for ions co-adsorption study.

Adsorption of Metal Ions from Single and Binary Aqueous Systems on Bio-Nanocomposite, Alginate-Clay.

The aim of this work is to characterize and evaluate the retention of Cu2+ and Ni2+ from single and binary systems by alginate-Moroccan clay bio-composite with the utilization of calcium chloride as a cross-linking agent, using the ionotropic gelation method. The bio-nanocomposite was characterized by using a variety of techniques (SEM, EDX, XRD, and pHPZC). The efficiency of the adsorbent was investigated under different experimental conditions by varying parameters such as pH, initial concentration, and contact time. To demonstrate the adsorption kinetics, various kinetic models were tried and assessed, including pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Elovich models. The research results show that the adsorption process of Cu2+ and Ni2+ metal ions follows a pseudo-second-order kinetic model, and the corresponding rate constants were identified. To evaluate the parameters related to the adsorption process in both single and binary systems, different mathematical models of isotherms, such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich, were investigated. The correlation coefficients obtained showed that the most suitable isotherm for describing this adsorption process is the Langmuir model. The process is considered to be physical and endothermic, as suggested by the positive values of ΔH° and ΔS°, indicating increased randomness at the solid/liquid interface during Cu2+ and Ni2+ adsorption. Furthermore, the spontaneity of the process is confirmed by the negative values of ∆G°. The bio-nanocomposite beads demonstrated a maximum adsorption capacity of 370.37 mg/g for Ni2+ and 454.54 mg/g for Cu2+ in the single system. In the binary system, the maximum adsorption capacities were observed to be 357.14 mg/g for Ni2+ and 370.37 mg/g for Cu2+. There is significant evidence for the use of alginate-Moroccan clay bio-nanocomposite as a cost-effective alternative adsorbent for the efficient removal of metal ions in single and binary systems.

Preparation of MgAl-LDHs loaded with blast furnace slag and its removal of Cu(II) and methylene blue from aqueous solution

ABSTRACT Blast furnace slag (BFS) is a kind of waste produced in industrial production, as well as a valuable secondary resource. In this paper, layered double hydroxides composites (BFS/LDHs) were prepared by aqueous polymerization, with industrial waste BFS as modifier and magnesium nitrate, aluminium nitrate, and urea as raw materials. BFS/LDHs have been characterized by using scanning electron microscopy (SEM), fourier infrared spectrometer (FT IR), x-ray diffraction (XRD), and the specific surface area analyser (BET). The adsorption of BFS/LDHs on Cu (II) and methylene blue (MB) was investigated by batch experiments. The results showed that the adsorption capacity of BFS/LDHs to Cu (II) is stronger than that of MB. What’s more, the solid concentration effect was found in the process of sorption kinetics and sorption isotherms. The sorption kinetics curves of Cu (II) and MB on BFS/LDHs were well fitted by the quasi-second-order kinetics under different adsorbent concentrations. Langmuir and Freundlich sorption isotherm models were used to analyse the adsorption. It showed that the adsorption conforms to Langmuir and Freundlich’s adsorption isotherm models. The BFS/LDHs composites have good recycling availability in this adsorption process of Cu (II) and MB, the removal capacity of which was reduced by 16.1% and 3.8% after being recycled for six times, respectively. More importantly, BFS/LDHs composites are not only expected to become a sewage treatment agent, but also to solve the problem of industrial waste treatment, which is a win–win strategy.

Study on the adsorption performance of Cu2+ in wastewater by red mud

The treatment of copper-nickel wastewater has consistently posed a challenging problem in the field of environmental protection. In this experimental study, the adsorbent used was prepared from Bayer's method-derived red mud (RM). The adsorption characteristics of RM adsorbent on Cu2+ in copper-nickel wastewater, as well as the impact of Ni2+ on the removal effectcy of Cu2+, were investigated. The adsorption performance of Cu2+ in copper-nickel wastewater by adsorbent dosage, adsorption time and pH were investigated, and the adsorption mechanism was discussed. The adsorption process conformed to the pseudo-second-order kinetic model (R2 =0.986) and the Langmuir model (R2 =0.989), indicating that it was a monolayer chemical adsorption process. The raw materials were characterized using various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray fluorescence (XRF). The results indicated that the adsorption process of Cu2+ and Ni2+ on RM was primarily influenced by surface chemical groups such as O-H, C-O-C, Si-C, and Si-O, among others. The adsorption rate of Cu2+ by RM could achieve 100% when the concentration of Cu2+ solution was 100 mg/L, with an optimal dosage of adsorbent at 0.20 mg/L and the best adsorption effect observed after 240 min. The adsorption of Cu2+ and Ni2+ by RM exhibits unidirectional competitive adsorption behavior. Furthermore,in competitive adsorption experiments, RM exhibits good selectivity towards Cu2+, with Ni2+ exhibiting minimal inhibitory effect on Cu2+ when the two elements coexist. Therefore, this paper offers potential research value for the large-scale application of RM in copper-nickel wastewater treatment processes.

Radiation synthesis and chemical modifications of p(AAm-co-AAc) hydrogel for improving their adsorptive removal of metal ions from polluted water

The research focuses on utilizing gamma irradiation to synthesize polyacrylic acid-co-polyacrylamide p(AAm-co-AAc) hydrogels. The effect of synthetic parameters on physicochemical features of p(AAm-co-AAc) hydrogls were examined, including acrylic acid (AAc): acrylamide (AAm) weight ratios, monomer concentration, and gamma irradiation dosage (kGy). At the optimum synthetic conditions (30 kGy and 75% AAc), different chemical modifications are explored to incorporate sulfonate, hydroxyl, carboxyl, cysteine, thiol, and amine functional groups within the bare hydrogel (Cpd 0) structure. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses confirmed the success development of functionalized hydrogels (namely Cpd 1 to 6) with three-dimensional porous structures. These modified hydrogels include Cpd 1, a sulfonated hydrogel through a sulfonation reaction; Cpd 2, modified via NaOH hydrolysis; Cpd 3, modified using thionyl chloride; Cpd 4, incorporating cysteine modification through reaction with cysteine; Cpd 5, with 4-(Dimethylamino) benzaldehyde; and Cpd 6, modified with 3,4-Dimethylbenzoic acid.The effect of hydrogel composition and surface functionalities on the swelling capacity and interactions with scale-forming/heavy metal ions (e.g., Ba2+, Sr2+, and Cu2+) was investigated in saline water solution (NaCl = 1000 mg/L). Batch adsorption studies reveal that all modified hydrogels exhibited higher removal efficiency for the three metal ions than unmodified p(AAm-co-AAc) hydrogel, validating the key role of surface functionalities in tailoring hydrogel affinity for metal ions adsorption. Amongst these, NaOH-treated hydrogel (Cpd 2) outperformed all other modified ones in the removal of Cu2+, Ba2+, and Sr2+ ions, with maximum capacities of 13.67, 36.4, and 27.31 mg/g, respectively. Based on adsorption isotherm and kinetic modeling, the adsorption process of the three metal ions onto all modified hydrogels better obeyed Freundlich isotherm and pseudo-first-order kinetic models. Thermodynamic studies also indicated that the adsorption behavior of Sr2+ ions can exhibit both exothermic and endothermic characteristics, depending on the nature of hydrogel surface chemistry. Conversely, the adsorption process of Cu2+ and Ba2+ ions onto all modified hydrogels is endothermic, suggesting favorable chemical adsorption mechanisms. These findings reveal that the specific adsorption performance of hydrogel is dependent on the type of modification and the targeted heavy metal ions. Based on the nature of hydrogel surface functionality, surface modifications can change the charge density, hydrophilicity, and overall chemical environment of the hydrogel, offering a versatile approach to optimize the adsorption affinity/selectivity of hydrogel's in removing scale-forming/heavy metals from water solutions.

PEI-modified chitosan/activated carbon composites for Cu(II) removal from simulated pyrophosphate plating rinsing wastewater

It is a challenging task to remove heavy metal ions efficiently from the wastewater containing high concentrations of complexants. In this work, a novel PEI-modified chitosan/activated carbon composite adsorbent (PCA) was prepared and applied to the removal of Cu(II) from pyrophosphate plating rinsing wastewater. The main species of Cu(II) in the pyrophosphate wastewater was [Cu(HP2O7)2]4− or [Cu(P2O7)2]6−, which were denoted as [Cu(II)-PP] anions. The maximum adsorption capacity of PCA for Cu(II) reached 1.41 mmol g−1 under the condition of pH = 8 and molar ratio of pyrophosphate to Cu(II) = 4:1. The adsorption kinetic behavior of Cu(II) on PCA followed the Elovich model best and PCA attained adsorption equilibrium within 36 h. The thermodynamic studies showed that the adsorption process of Cu(II) by PCA was endothermic and spontaneous. The PCA fixed bed column was used to remove Cu(II) from simulated pyrophosphate plating rinsing wastewater. After three consecutive adsorption-desorption cycles, the adsorption performance, hydraulic conductivity, and mechanical stability of PCA column did not decrease. The FTIR and XPS analysis results indicated that [Cu(II)-PP] anions can be adsorbed on PCA by electrostatic attraction with protonated amine groups or coordination with the amine groups of PCA via ligand substitution.

Production of imprinted polystyrene resins for copper ions removal from wastewater

Imprinted resins have attracted much attention for their high contaminant removal and reuse performance. Chloroacetylated polystyrene resins, polyethyleneimine, epichlorohydrin, and Cu(II) were used as support, functional monomer, cross-linker and template, respectively. The ion-imprinted resins (PS-PEI@SIP) and non-imprinted resins (PS-PEI@NIP) were prepared by the combination of amination reactions and surface ion-imprinting technique. The adsorption processes of Cu(II) with PS-PEI@SIP and PS-PEI@NIP followed pseudo-second-order kinetics. The langmuir isothermal adsorption model was consistent with the adsorption curve, indicating that Cu(II) were uniformly adsorbed on the PS-PEI@SIP surface. Thermodynamic experiments showed that the adsorption of Cu(II) by PS-PEI@SIP was a spontaneous process, and high temperature was favorable for adsorption. In addition, the selectivity of PS-PEI@SIP to Cu(II) was confirmed by multi-component competitive adsorption experiments. When Cu(II) mixed with Ni(II), Zn(II) and Cd(II), the selection coefficients of PS-PEI@SIP for Cu(II) were 31.98, 37.19 and 64.27. The results showed that PS-PEI@SIP had high adsorption capacity and good selectivity for Cu(II) ions in mixed ionic solution, and the adsorption capacity was 89.4 mg·g–1. The simulation wastewater dynamic adsorption experiment showed that the PS-PEI@SIP adsorption column could treat 52.8 BV Cu(II) concentration (C＜7.5 mg·g–1), when the influent Cu(II) concentration was 150 mg∙L−1. When 1 mol∙L−1 HCl solution was used for dynamic desorption of PS-PEI@SIP, the desorption rate was more than 92%, indicated that PS-PEI@SIP had good regeneration performance. These results provided basic information for the production of imprinted adsorbent resins.

The adsorption properties of steel slag-based porous geopolymer for Cu2+ removal

Blocky geopolymer was employed as a cost-effective and efficient adsorbent for the removal of Cu2+, and 72 wt% of steel slag was used as the raw material. This study focuses on the adsorption process and mechanism of copper ions by steel slag-based porous geopolymer (SPG). A series of adsorption experiments show that the adsorption of Cu2+ depends on the oxygen-containing functional groups and silica-containing functional groups of SPG. And a large number of blue flocs containing CuSiO3, Cu2(OH)2CO3, and Cu(OH)2 are attached to the surface of the adsorbent. Furthermore, it is considered that electrostatic attraction, ion exchange and chemical precipitation are the main adsorption mechanism. Based on adsorption isotherm and kinetics analysis, the adsorption process of Cu2+ conforms to the Freundlich isotherm model and the pseudo-first-order kinetic model. Therefore, multi-layer chemical and physical adsorption coexists, and physical adsorption controls the adsorption rate and adsorption potential. This study provides a fundamental basis for the removal of Cu2+ from aqueous environments by porous geopolymers with a bulk structure.

Preparation of a Series of Highly Efficient Porous Adsorbent PGMA-N Molecules and Its Application in the Co-Removal of Cu(II) and Sulfamethoxazole from Water.

This paper presents a highly efficient porous adsorbent PGMA-N prepared through a series of amination reactions between polyglycidyl methacrylate (PGMA) and different polyamines. The obtained polymeric porous materials were characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), specific surface area test (BET), and elemental analysis (EA). Thereinto, the PGMA-EDA porous adsorbent exhibited excellent ability to synergistically remove Cu(II) ions and sulfamethoxazole from aqueous solutions. Moreover, we studied the effects of pH, contact time, temperature, and initial concentration of pollutants on the adsorption performance of the adsorbent. The experimental results showed that the adsorption process of Cu(II) followed the pseudo-second-order kinetic model and Langmuir isotherm. The maximum adsorption capacity of PGMA-EDA for Cu(II) ions was 0.794 mmol/g. These results indicate that PGMA-EDA porous adsorbent has great potential for application in treating wastewater coexisting with heavy metals and antibiotics.

Co-adsorption and competitive adsorption of sulfamethoxazole by carboxyl-rich functionalized corn stalk cellulose in the presence of heavy metals

Diethylenetriamine pentaacetic acid (DTPA) functionalized modified corn stalk cellulose (DCS) was successfully prepared and applied to the adsorption of sulfamethoxazole (SMZ) wastewater in the presence of copper (Cu). Compared with the raw corn stalk cellulose (RCS), DCS has the characteristics of more hydrophilic groups, larger contact space and lower steric hindrance. The adsorption amount for Cu and SMZ in binary system were 4.41 mg/g and 29.7 mg/g, respectively. Additionally, DCS has good pH buffering capability, resistance to potentially interfering ions (NaCl and HA) and great regeneration performance after 5 cycles. More importantly, the experimental results demonstrated competitive adsorption and complexation synergy occurred between Cu, SMZ and DCS. Cu inhibited the adsorption of SMZ while SMZ promoted the adsorption of Cu, which was attributed to the fact that SMZ provided additional adsorption sites or complexation reduced the surface charge of Cu. Based on this situation, density functional theory (DFT) calculations were carried out for the further explanation of adsorption mechanism. The molecular electrostatic potential maps showed that DCS possessed more SMZ adsorption sites than Cu, and the adsorbed Cu or SMZ on DCS would provide additional adsorption sites. The equilibrium configurations and binding energy indicated that the competitive adsorption, bridge effect adsorption and co-adsorption would occur simultaneously. The total electron density and differential charge confirmed that SMZ was more likely to overlap electron clouds and transfer electrons with DCS, while the adsorption process of Cu was conformed the complexation adsorption dynamic equilibrium. This paper provided a new perspective on the co-adsorption and competitive adsorption processes by multisystem experiments and abundant DFT calculations and indicated the good adsorption performance of DCS on SMZ in the presence of Cu.

Citrus fruit residues as alternative precursors to developing H2O and CO2 activated carbons and its application for Cu(II) adsorption.

Due to its toxicity, the presence of Cu(II) ions released in aquatic environments presents a serious threat to the environment and human health. In search of sustainable and low-cost alternatives, there are citrus fruit residues, which are generated in large quantities by the juice industries and can be used to produce activated carbons. Therefore, the physical route was investigated for producing activated carbons to reuse citrus wastes. In this work, eight activated carbons were developed, varying the precursor (orange peel-OP, mandarine peel-MP, rangpur lime peel-RLP, and sweet lime peel-SLP) and the activating agent (CO2 and H2O) to remove Cu(II) ions of the aqueous medium. Results revealed promising activated carbons with a micro-mesoporous structure, a specific surface area of around 400 m2g-1, and a pore volume of around 0.25 cm3g-1. In addition, Cu (II) adsorption was favored at pH 5.5. The kinetic study showed that the equilibrium was reached within 60min removing about 80% of Cu(II) ions. The Sips model was the most suitable for the equilibrium data, providing maximum adsorption capacities (qmS) values of 69.69, 70.27, 88.04, 67.83mgg-1 for activated carbons (AC-CO2) from OP, MP, RLP, and SLP, respectively. The thermodynamic behavior showed that the adsorption process of Cu(II) ions was spontaneous, favorable, and endothermic. It was suggested that the mechanism was controlled by surface complexation and Cu2+-π interaction. Desorption was possible with an HCl solution (0.5mol L-1). From the results obtained in this work, it is possible to infer that citrus residues could be successfully converted into efficient adsorbents to remove Cu(II) ions from aqueous solutions.

Facile production of highly active rice straw bioadsorbent to remove Cu in wastewater

A bioadsorbent with a high specific surface area and high content of oxygen-containing functional groups was prepared from silica depleted rice straw ash (SDRSA). The starting material was a by-product of rice straw after alkoxysilane extraction. The maximum adsorption capacity of SDRSA for copper ions was 26.7 mg/g, which was higher than previously reported biomass adsorbents. The effects of adsorbent dose, pH, contact time, and other conditions on the adsorption performance of SDRSA on Cu2+ were investigated. The adsorption process of Cu2+ on SDRSA was well fitted by the Langmuir isotherm model and the pseudo-second-order kinetic model. The physicochemical properties and adsorption mechanism of SDRSA were investigated by specific surface area testing (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Boehm titration methods. Electrostatic interaction, complexation, ion exchange, and precipitation are the possible Cu2+ removal mechanisms. The preparation method requires only simple washing and drying, and the alcohol can be distilled and recycled. Thus, SDRSA is very low cost and convenient to prepare in large quantities. This work presents a novel approach to optimize adsorbent production to mitigate heavy metal pollution.

Artificial neural network (ANN) modeling for simultaneous removal of a binary mixture of Pb(II) and Cu(II) by cobalt hydroxide nano‐flakes

AbstractA three‐layer artificial neural network (ANN) model was developed to predict the efficiency of Cu(II) and Pb(II) ion removal from aqueous solution by cobalt hydroxide nano‐flakes. It is based on experimental sets obtained from a D‐optimal design. The input variables to the neural network were as follows: the initial concentration of Pb(II) and Cu (II) ions (mg L−1), initial pH, and sorbent mass (g). The configuration of the backpropagation neural network for both Cu(II) and Pb (II) ions was a tangent sigmoid transfer function (tansig) at the hidden layer, linear transfer function (purelin) at the output layer, and Levenberg–Marquardt training algorithm (LMA). ANN‐predicted results were very close to the experimental results with a coefficient of determination (R2) of 0.9970 and mean square error (MSE) 0.000376. Analysis based on the ANN model indicated that sorbent mass appeared to be the most influential factor in the adsorption process of Cu(II) and Pb(II). Characterization of the cobalt hydroxide nano‐flakes and possible metal ions‐adsorbent interactions were confirmed by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), and scanning electron microscopy (SEM).

Preparation of sludge–cyanobacteria composite carbon for synergistically enhanced co-removal of Cu(II) and Cr(VI)

Traditional sludge disposal is currently restricted by the risk of secondary pollution. Sludge carbon material has gained widespread attention because of its low cost and environmentally sustainable properties. However, owing to the high ash content and low–energy density of sludge, sludge pyrolysis alone has certain limitations, and the performance of carbon materials needs to be improved. Herein, a sludge–cyanobacteria composite carbon (SCC) was easily synthesized, and the adsorption process of Cu(II) and Cr(VI) by SCC was examined. SCC-700-2-50% exhibited a high SBET (1047.54 m2/g) and developed pore structure rich in functional groups (such as –NH, –OH, and C–O). The combination of pore structure and functional groups improved the adsorption performance of SCC. The adsorption processes exhibited a synergistic effect in a binary system: the qm of Cu(II) and Cr(VI) were 386 mg/g and 341 mg/g, respectively, and the selectivity of Cu(II) adsorption by SCC was greater than Cr(VI). The adsorption process, examined by SEM-EDS, FTIR, and XPS analysis, indicated that Cu(II) as a cationic interface strengthens Cr(VI) adsorption through electrostatic interaction, and the anion Cr(VI) created a valid electrostatic shield against the electrostatic repulsion between H+ and Cu(II), facilitating Cu(II) adsorption. SCC had great reusability: Cu(II) and Cr(VI) adsorption capacity were 90% and 84%, of the initial adsorption capacity, respectively, after six cycles. This study demonstrates the prospect of SCC as a valid adsorbent for multiple heavy metal contaminations removal.

Multicomponent adsorption of heavy metals onto biogenic hydroxyapatite: Surface functional groups and inorganic mineral facilitating stable adsorption of Pb(Ⅱ).

Due to the coexistence of various heavy metals in the contaminated environment, it is essential to comprehensively study the multicomponent adsorption of heavy metals in order to tackle these combined pollutants. Herein, the adsorption processes of Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) by biogenic hydroxyapatite (BHAp) were investigated in single and multicomponent systems. The maximum adsorption capacity for Pb(Ⅱ), Cu(Ⅱ) and Cd(Ⅱ) by BHAp in single system reached 311.16, 82.05 and 92.54mgg-1, respectively, while adsorption capacity for Cu(Ⅱ) and Cd(Ⅱ) in multicomponent system decreased more obviously than that of Pb(Ⅱ). Furthermore, the stability of Cu(Ⅱ) and Cd(Ⅱ) adsorbed on BHAp was indeed influenced in multicomponent system. By means of the characterization analysis, it was found that ion exchange was more instrumental in the adsorption processes of Cu(Ⅱ) and Cd(Ⅱ) in single system than in multicomponent system. Significantly, it was observed that the proportion of generally stable Pb(II) adsorbed on BHAp exceeded 95% in both single and multicomponent systems. This result might be due to the in-site growth of stable crystals of PbxCa10-x(PO4)6(OH)2, which was synergistically induced by surface functional groups and inorganic mineral of BHAp, and was unaffected by the coexistence of Cu(Ⅱ) and Cd(Ⅱ).

Synthesis, modification, and adsorption properties of Yb‐MOF: Kinetic and thermodynamic studies

In this paper, a novel Yb metal–organic frameworks {[Yb(L)(DMA)(H2O)]·(3H2O)}n(Yb‐MOF, H3Lis 4‐(N,N′‐bis(4‐carboxylbenzyl)amino)benzenesulfonic acid) was synthesized by solvothermal reaction. ModifiedYb‐MOFwas prepared by the potassium permanganate method for removing the Cu(II) and As(V) from simulated wastewater. The optimal pH value of modifiedYb‐MOFfor Cu(II) and As(V) adsorption was 5, and the optimal dosage of adsorbent was 0.04 mg/10 ml by static adsorption test. Four isothermal adsorption models (Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich models) were fitted and analyzed. The adsorption processes of Cu(II) and As(V) were consistent with Freundlich, Langmuir, and Temkin models. The highest Cu(II) and As(V) adsorption capacity are 59.418 and 81.169 mg/g, respectively. The adsorption kinetic model and thermodynamic analysis of the modifiedYb‐MOFfor Cu(II) and As(V) were studied. The results showed revealed that the pseudo‐second‐order kinetic had a higher correlation association with the Cu(II) and As(V) adsorption process, indicating that chemisorption was dominant in both processes. At 298 and 308 K, the Cu(II) and As(V) adsorption by modifiedYb‐MOFis spontaneous.

Competence kinetic and thermodynamic studies between natural bio-adsorbent green microalgae and synthetic adsorbent magnetic nanoparticles for copper(II) ion in water

ABSTRACT. The present work investigated the kinetic and thermodynamic study of adsorbents to remove copper ions from aqueous solutions and compared the efficiency between the natural microalgae bio-adsorbent chlorella species (sp.) and synthetic magnetic nanoparticles. All materials synthesized and characterized by Fourier transform infrared (FT-IR), scanning electron microscope (SEM), energy dispersive X-ray (EDX). The highest Cu+2 ion adsorption for the copper solution at 100 mg/L was 57.2%, while at pH 8 it was 59.7%. The more efficient adsorbent for Cu+2 acquired by chlorella was 0.24 mg/g. The second-order kinetic model is fitted, the activation energy (Ea) for the three adsorbents; Chlorella, Fe3O4, (Fe3O4 coated with SiO2) were 95.24, 40.69, 20.39 kJ/mol, respectively indicating the adsorption process is slower than the magnetic nanoparticles. Enthalpy activation changes (ΔH#) were endothermic and showed that the adsorption of the Cu+2 on the chlorella was chemisorption and on the magnetic nanoparticles was physisorption. Entropy change of activation (ΔS#), and activation Gibbs free energy change (ΔG#) showed that adsorption process of Cu+2 on the three adsorbents was feasible and spontaneous in temperature range 293-313 K. The novelty of this work is to determine the type and efficiency of adsorption of algae and nanoparticles.
 
 KEY WORDS: Adsorption, Kinetic models, Thermodynamic studies, Chlorella species, Magnetic nanoparticle, Efficiency percent
 Bull. Chem. Soc. Ethiop. 2023, 37(1), 183-196. 
 DOI: https://dx.doi.org/10.4314/bcse.v37i1.15

Removal of Copper(II) from Aqueous Environment Using Silk Sericin-Derived Carbon.

Sericin is a by-product of the silk industry. Its recycling contributes to environmental protection and the sustainable development of the cocoon silk industry. In this paper, on the basis of realizing sericin enrichment in solution, the Cu(II) adsorption capacities of sericin-derived carbon (SC), prepared at different pyrolysis temperatures, were studied. SC was characterized using scanning electron microscopy (SEM) and the zeta potential. The effects of the initial concentration of Cu(II), pH, adsorption temperature, and contact time on the adsorption process were evaluated, followed by an investigation of the mechanism of Cu(II) adsorption by SC. The results showed that SC has a porous structure that provides sites for Cu(II) adsorption. The maximum adsorption capacity of Cu(II) onto SC1050, 17.97 mg/g, was obtained at an adsorption temperature of 35 °C and a pH of 5.5. In addition, the pseudo-second-order kinetic model and Langmuir isotherm model correctly described the adsorption process of Cu(II) onto SC1050. Therefore, SC can act as a potential adsorbent for removing Cu(II) from water. This study helps promote the effective use of cocoon silk resources.