Removal Of Cu Research Articles

Graphitic C3N4 incorporated chitosan-poly(vinyl alcohol) blend nanocomposites for the removal of Cu(II) and Cr(VI) ions from aqueous solutions

Graphitic C3N4 incorporated chitosan-poly(vinyl alcohol) blend nanocomposites for the removal of Cu(II) and Cr(VI) ions from aqueous solutions

Ultra-thin proton conducting carrier layers for scalable integration of atomically thin 2D materials with proton exchange polymers for next-generation PEMs.

Scalable approaches for synthesis and integration of proton selective atomically thin 2D materials with proton conducting polymers can enable next-generation proton exchange membranes (PEMs) with minimal crossover of reactants or undesired species while maintaining adequately high proton conductance for practical applications. Here, we systematically investigate facile and scalable approaches to interface monolayer graphene synthesized via scalable chemical vapor deposition (CVD) on Cu foil with the most widely used proton exchange polymer Nafion 211 (N211, ∼25 μm thick film) via (i) spin-coating a ∼700 nm thin Nafion carrier layer to transfer graphene (spin + scoop), (ii) casting a Nafion film and cold pressing (cold press), and (iii) hot pressing (hot press) while minimizing micron-scale defects to <0.3% area. Interfacing CVD graphene on Cu with N211 via cold press or hot press and subsequent removal of Cu via etching results in ∼50% lower areal proton conductance compared to membranes fabricated via the spin + scoop method. Notably, the areal proton conductance can be recovered by soaking the hot and cold press membranes in 0.1 M HCl, without significant damage to graphene. We rationalize our finding by the significantly smaller reservoir for cation uptake from Cu etching for the ∼700 nm thin carrier Nafion layer used for spin + scoop transfer compared to the ∼25 μm thick N211 film for hot and cold pressing. Finally, we demonstrate performance in H2 fuel cells with power densities of ∼0.23 W cm-2 and up to ∼41-54% reduction in H2 crossover for the N211|G|N211 sandwich membranes compared to the control N211|N211 indicating potential for our approach in enabling advanced PEMs for fuel cells, redox-flow batteries, isotope separations and beyond.

Removal of Cu2+ from AMD by goethite modified biochar combined with sodium alginate: characterization, performance and mechanisms

Efficient and environmentally friendly removal of Cu2+ from wastewater was the focus of recent research. However, the acid mine drainage (AMD) produced during the mining process, characterized by low pH...

Application of the Biomass of Leaves of Diospyros kaki L.f. (Ebenaceae) in the Removal of Metal Ions from Aqueous Media

Using straightforward and cost-effective methods, persimmon leaves were converted into high-quality powder. This powder was applied as an adsorbent for the removal of Cu(II) and Cd(II) from aqueous solutions. Scanning electron microscopy (SEM) revealed the presence of particles with non-homogeneous sizes and rough textures. The biosorbent exhibited a specific surface area of approximately 0.44 ± 0.015 m2 g−1. Elemental analysis and energy-dispersive X-ray spectroscopy (EDX) confirmed the presence of elements such as sulfur, phosphorus, nitrogen, and oxygen. The results of 13C nuclear magnetic resonance (13C-NMR), obtained using the cross-polarization technique, show the presence of groups containing sulfur and oxygen. Infrared spectroscopy (FTIR) indicated the existence of amine and hydroxyl groups. The material was used in the solid-phase extraction of Cu(II) and Cd(II) in batch experiments, and its adsorption capacity was evaluated as a function of time, pH, and analyte concentration. The fraction with a diameter between 63 and 106 μm was selected for the adsorption tests. Kinetic equilibrium was reached within 5 min, and the experimental data were fitted to the pseudo-second-order kinetic model. The optimum pH for the adsorption of both metal species was approximately 5.0. The adsorption isotherms were adjusted using the modified Langmuir equation, and the maximum amount of metal species extracted from the solution was determined to be 0.213 mmol g−1 for Cu(II) and 0.215 mmol g−1 for Cd(II), with high linear correlation coefficients for both metals. Persimmon leaves are typically abundant during the growing season, and because they are seasonal, the Diospyros kaki L.f. tree undergoes the natural process of leaf abscission, ensuring the availability of leaves for application.

An acylhydrazone-linked covalent organic framework for removal of Cu(II) from aqueous solution and its applications in catalysis

An acylhydrazone-linked covalent organic framework (TH-MT–COF–OH) was synthesized using 2,5-dihydroxyterephthalic hydrazide and 2,4,6-tris(4-methoxybenzaldehyde)-1,3,5-triazine as building blocks. The obtained TH-MT–COF–OH exhibited excellent adsorption capacity for Cu(II) from aqueous solution, with maximum removal efficiency of 99.2 % at pH = 7. The theoretical maximum adsorption capacity (Qm) reached 137.17 mg/g based on Langmuir model. Moreover, the adsorption kinetics simulated results consistent with the pseudo-second-order model, suggesting the adsorption mechanism of Cu(II) by TH-MT–COF–OH was mainly governed by chemisorption. Interestingly, after adsorbing Cu(II), the spent adsorbent Cu@TH-MT–COF–OH could be used as a reusable catalyst for organic synthesis, such as Ullmann-type cross-coupling reactions. These results further demonstrated the strong interaction between copper ions and adsorbents leading to the stable adsorption against the erosion of organics. What's more, the pristine TH-MT–COF–OH also presented high catalytic activity in Knoevenagel condensation reactions. In addition, the TH-MT–COF–OH and Cu@TH-MT–COF–OH were recyclable and could be reused.

A strategy for deep removal of Cu from Ni anolyte based on the ion-exchange method

The sulfide precipitation method has been one of the major strategies used for the removal of Cu from the Ni anolyte. However, the high cost and short shelf-life of the Cu removal agents have consistently posed problems in the practical industrial use of the Ni anolyte purification process. In the present study, a new method for removing Cu from Ni anolyte based on ion exchange is proposed to address the drawbacks of the current sulfide precipitation method. Through isothermal adsorption curve analysis, thermodynamic studies, kinetic studies and cross-sectional SEM-EDS analyses, it was found that the selectivity difference of D850 resin to Cu2+ and Ni2+ is dependent on iminodiacetic acid forming a triple bond with Cu2+ while forming a double bond with Ni2+ in the removal of Cu from a Ni anolyte. The resin dynamic adsorption experiments showed that the fixed-bed ion exchange process is quite similar to the cascade solvent extraction process. The investigations into resin regeneration found that the desorption of Cu2+ and Ni2+ was adequately completed for static desorption when the desorbent concentration was than more 1 mol/L for 60 min. The experiments on D850 resin desorption showed that the desorption equilibrium time, desorbent concentration, and desorption temperature were key factors affecting the desorption of Cu2+ and Ni2+. The dynamic desorption process revealed that a high concentration of hydrochloric acid and a high flow rate could accelerate the desorption process, concentrating the outflow peak and facilitating the collection of Cu2+ and Ni2+. This Cu removal method based on resin ion exchange utilizes the different characteristics of iminodiacetic acid adsorbing Cu and Ni to achieve efficient Cu removal from the Ni anolyte and its recycling. This method is superior to the current method due to its high selectivity, fast adsorption, high desorption rate, and high Cu–Ni ratio of the desorption solution.

Camellia oleifera shell–reduced graphene oxide for adsorption of copper(II)

Copper pollution in aquatic environments poses a significant health challenge due to its non-biodegradable nature. This study introduces a novel and environmentally friendly approach to preparing Camellia oleifera shell extract reduced graphene oxide (COS-rGO) for the effective removal of Cu(II) from aqueous solutions. By using a 0.5 g/L dosage of COS-rGO at a pH of 5.1 and a temperature of 20 °C, an 85.8 % removal efficiency (18.7 mg/g) of Cu(II) was achieved at an initial concentration of 10 mg/L. Various characterization techniques, including Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), were employed to examine the synthesized COS-rGO. Additionally, thermodynamic and kinetic studies were conducted to investigate the mechanism of Cu(II) adsorption on COS-rGO. The results demonstrate that the adsorption of Cu(II) on COS-rGO follows pseudo-second-order kinetics, representing a spontaneous exothermic reaction. Our findings further support that the removal of Cu(II) by COS-rGO is driven by chemical adsorption in accordance with the rate-controlled process based on the Langmuir adsorption model. Overall, this study presents the green synthesis of COS-rGO as a promising technique for producing a cost-effective adsorbent from waste materials, which can be utilized for the mitigation of heavy metals in water.

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.

Removal of Cu2+ from Aqueous Solution by Cement-Based Absorbent Incorporating Fly Ash

Removal of Cu2+ from Aqueous Solution by Cement-Based Absorbent Incorporating Fly Ash

Multifunctional phthalocyanine NIR sensor for fluorescent and colorimetric dual-imaging and removal of intracellular and environmental Cu2+

Cu2+ sensing and removal are of great significance for environment protection and human health. Herein, multifunctional Cu2+ sensor system for both detection and removal of intracellular and environmental Cu2+ based on trans/cis interconversion of silicon phthalocyanine (SiPc) was developed. This phthalocyanine based Cu2+ sensor shows remarkably dual-mode NIR fluorescence and colorimetric responses for recognition of Cu2+, resulting in insoluble chelate for Cu2+ removal as well as the extremely high anti-interference in the presence of various anions and cations. The binding mechanism and stoichiometry ratio were systematically revealed. Intracellular fluorescence imaging in MCF-7 cells demonstrated that Cu2+ could be efficiently detected in living cells and form insoluble chelate for clearance. As the result, this novel phthalocyanine based multifunctional sensor can be used for dual-mode NIR fluorescence/colorimetric detection and removal of Cu2+ in either complicated environment or biological systems.

The investigation of the binding ability between sodium dodecyl sulfate and Cu (II) in urban stormwater runoff

The simultaneous presence of heavy metals and surfactants in runoff induces complexation and ecological harm during migration. However, interactions between these pollutants are often overlooked in past studies. Thus, investigating heavy metal-surfactant complexes in runoff is imperative. In this work, Cu (II) and sodium dodecyl sulfate (SDS) were selected to investigate the interaction between heavy metals and surfactants due to the higher detected frequency in runoff. Through 1H NMR and FTIR observation of hydrogen atom nuclear displacement and functional group displacement of SDS, the change of SDS and Cu (II) complexation was obtained, and then the complexation form of Cu (II) and SDS was verified. The results showed that solution pH values and ionic strength had significant effects on the complexation of Cu (II). When the pH values increase from 3.0 to 6.0, the complexation efficiency of SDS with Cu (II) increased by 12.12% at low concentration of SDS, which may be attributed to the excessive protonation in the aqueous solution at acidic condition. The increase of ionic strength would inhibit the complexation reaction efficiency by 19.57% and finally reached the platform with concentration of NaNO3 was 0.10 mmol/L, which was mainly due to the competitive relationship between Na (I) and Cu (II). As a general filtering material in stormwater treatment measures, natural zeolite could affect the interaction between SDS and Cu (II) greatly. After the addition of SDS, the content of free Cu (II) in the zeolite-SDS-Cu (II) three-phase mixed system was significantly reduced, indicating that SDS had a positive effect on the removal of Cu (II) from runoff. This study is of great significance for investigating the migration and transformation mechanism of SDS and Cu (II) in the future and studying the control technology of storm runoff pollution.

Rice husk-based cellulose nanocrystal/poly(vinyl alcohol) composite film for the removal of Cu (II) cation from aqueous solution

Abstract In this study, a nanocomposite film comprising poly(vinyl alcohol) (PVA) and rice husk-derived cellulose nanocrystals (CNC) was introduced as a novel sorbent for removing copper (II) cations. First, CNC was isolated from neat rice husk, and then these particles with many ratios compared to PVA (2, 4, 6, and 10 wt.%) were added to the PVA solution to render the nanocomposite films. The obtained films were evaluated using scanning electron microscopy, Fourier-transform infrared spectroscopy, and water uptake tests. The optimal condition for the sorbent preparation was 10 wt.% of CNCs to PVA. The maximum ion adsorption percentage of the PVA/CNC 10 % film reached 55 % after 3 h exposure to 70 ppm Cu (II) ion solution at 25 °C. This research suggested a facile and feasible fabrication method of a nanocomposite film, considered a potential sorbent for the adsorption of copper (II) ions.

Composite adsorbents of aminated chitosan @ZIF-8 MOF for simultaneous efficient removal of Cu(II) and Congo Red: Batch experiments and DFT calculations

In this study, we employed a straightforward in-situ synthesis strategy to fabricate multi-site adsorption functional composites known as aminated chitosan@ZIF-8 (AmCs@ZIF-8) for the efficient removal of Cu(II) and Congo red. The AmCs@ZIF-8 adsorbed Cu(II) at pH 5 and Congo red at pH 3 with excellent removal efficiency values of 94 % and 100 % respectively. The maximum adsorption capacity for Cu(II) and Congo red are obtained as 785 mg g−1 and 1156 mg g−1, respectively. Interestingly, AmCs@ZIF-8 composites exhibited an excellent removal efficiency (>80 %) after reusing them for four sequential cycles. Analysis of the adsorption isotherm and kinetic data indicated that chemisorption primarily governed the adsorption of Cu(II) and Congo red by AmCs@ZIF-8. Furthermore, we elucidated the adsorption energy of Cu(II) and Congo red on the AmCs@ZIF-8 composite through density functional theory. Specifically, the adsorption energy values for Cu(II) with AmCs and ZIF-8 were −20.907 and −57.809 kcal·mol−1, and −26.514 and −16.242 kcal·mol−1 for Congo red, respectively. The efficient adsorption mechanism of Cu(II) and Congo red on the AmCs@ZIF-8 composite can be attributed to the synergistic effects of chelation, electrostatic attraction, ion exchange, and hydrogen bonding through the analysis of experimental characterization and theoretical calculation. Therefore, AmCs@ZIF-8 composites elevate the adsorption capacity of Cu(II) and Congo red in a single-component system and exhibit high removal efficiency (>90 %) in the context of the Cu(II)-Congo red binary system.

An efficient multi-functional ternary reusable nanocomposite based on chitosan@TiO2@Ag NP immobilized on cellulosic fiber as a support substrate for wastewater treatment

To effectively remove heavy metals, organic contaminants, and pathogenic bacteria from wastewater, an efficient multi-functional ternary nanocomposite based on chitosan (CS), titanium dioxide (TiO2 NP), and silver nanoparticles (Ag NP) was prepared. Different tools were used to confirm the successful synthesis of the CS/TiO2 NP/Ag NP nanocomposite. Then, the CS/TiO2 NP/Ag NPnanocomposite was immobilized on the cellulosic fiber as a support substrate for its easy removal and reuse. On a lab scale, CS/TiO2 NP/Ag NP nanocomposite@cellulosic fiber was used to remove Cu (II) ions, methyl orange (MO), and methylene blue (MB), as well as inhibit microbes.The results demonstrate that the greatest removal of Cu (II) ions was 95 % at a concentration of 50 mg/L, pH 5, a temperature of 25 °C, an agitation speed of 200 rpm with 1 g adsorbent dose, and a contact time of 150 min. The pseudo-second-order model explained the batch adsorption kinetics well, while the Langmuir model explained the adsorption isotherm well with an adsorption capacity of 7.71 mg/g. Adsorption thermodynamic parameters revealed that adsorption is a spontaneous, exothermic, increased randomness, and non-specific chemisorption approach.The photodegradation of MO and MB by CS/TiO2 NP/Ag NP nanocomposite@cellulosic fiber was investigated. The results reveal that at pH 3, the MO dye showed the highest photodegradation percentage (90 %), while the MB dye displayed the highest photodegradation percentage (94 %) at pH 11, after an irradiation time of 120 min under visible light. The rate constants for MO and MB were 0.01218 and 0.01412 min−1, respectively. The results antimicrobial activities showed that the CS/TiO2 NP/Ag NP nanocomposite@cellulosic fiber showed excellent antibacterial activity against S. aureus (95 ± 2 %) and E. coli (93 ± 3 %) as well as good antifungal activity against C. albicans (77 ± 2 %).

Enhanced decomplexation of Cu(II) complexes and Cu removal by the nFe3O4/persulfate coupled microbial system: Synergistic effect, validation, and mechanism

The enhancement of decomplexation efficiency whilst minimizing subsequent microbial process impact is essential in the treatment of refractory heavy metal complexes. Herein, we developed the nano-Fe3O4 (nFe3O4)/peroxydisulfate (PDS) coupled microbial system for the removal of Cu(II)-citrate. Other Cu(II) complexes, such as tartrate, oxalate, and EDTA, were also selected to validate the effectiveness of the coupled system. In batch experiments, the coupled system facilitated the Cu(II)-citrate removal from 21.9 %, 18.9 % to 96.8 % within 120 min as compared to individual nFe3O4 + PDS or biosorption, respectively. Meanwhile, the coupled column was able to remove 86.9 % of copper after fifteen days under continuous flow operation. Impressively, microorganisms could promote the Fe(II)/Fe(III) cycling, thus reducing the usage of PDS. High-throughput sequencing analyses suggest that the coupled system has a higher microbial abundance, which played key roles in eliminating complexed Cu(II). The removal of Cu(II)-citrate in the coupled system involves de-complexation and biosorption, followed by precipitation of all remaining free metal ions. This work provides a feasible strategy potentially applied in efficient treatment of heavy metal complex wastewater.

Effect of precursors on structural, optical and surface properties of ZnO thin film prepared by spray pyrolysis method: efficient removal of Cu (II) from wastewater

Effect of precursors on structural, optical and surface properties of ZnO thin film prepared by spray pyrolysis method: efficient removal of Cu (II) from wastewater

Coal gangue geopolymers as sustainable and cost-effective adsorbents for efficient removal of Cu (II)

Coal gangue geopolymers (GP) were employed to eliminate Cu (II) as an economical absorber. This study explores the feasibility of employing coal gangue geopolymers (GP) to be an economical absorber with a function of eliminating Cu (II). The results showed that GP is a mesoporous structure, which pore size distribution is around 5.60 nm. The optimal adsorption capacity of Cu (II) was achieved when the ratio n(SiO2)/n(Na2O) was 1.2. Cu (II) adsorption capacity of GP may achieve a maximum of 72.3 mg/g. Silicon and aluminum hydroxide groups of GP facilitated strong interactions and effective trapping of Cu (II). Data analysis discovered that the adsorption procedure in examinations followed a pseudo-second-order kinetic model, with the Langmuir model providing the best appropriate to the adsorption isotherm data. These confirm that charge and chemisorption simultaneously appeared in the spontaneous Cu (II) adsorption on GP. The intra-particle diffusion model (IPD) and Boyd models supported by observation that positive relationships result in initial Cu (II) adsorption onto the outer layer of GP, followed by subsequent diffusion into internal pores. Internal and external diffusion processes jointly dominate the Cu (II) adsorption rate. Furthermore, the adsorption-related characteristics of a combination of Cu (II) and Cr (VI) demonstrated that GP effectively removes Cr (VI) without compromising its adsorption performance for Cu (II), without any discernible competition or synergy between the two. Notably, the GP could be reused for five times, and Cu (II) removal rate is 80.88%, indicating the possibility of its application as an effective, sustainable Cu (II) removal absorbent.

Enhanced synergistic removal of Cu(II) and Cr(VI) with multifunctional biomass hydrogel from strong-acid media

Simultaneous recovery of heavy metal ions (HMIs) such as Cu(II) and Cr(VI) from strong-acid media was a great challenge due to the inhibition of protons. Herein, a novel biomass hydrogel (CMC/PEI-PD) containing various groups (bis-picolylamine, amino, and hydroxyl groups) was newly prepared by a facile two-step process. The static experiments relating pH, kinetics and isothermal co-adsorption confirmed the synergistic effect towards Cu(II) and Cr(VI) consistently. Specifically, the adsorption capacities of Cu(II) and Cr(VI) at pH 2.0 increased by 23.73% and 40.18% in comparison with the single systems. Moreover, coexistence of inorganic anions and cations could further increase the adsorption of Cu(II) and Cr(VI) by 59.90% and 43.39%, respectively. At the same time, the adsorption and desorption ratios for both HMIs remained stable. The superior performance came from the two dominant mechanisms of co-removal. On the one hand, Cu(II) chelated by bis-picolylamine group attracted Cr(VI) in the form of cation bridge, thus promoting Cr(VI) adsorption. On the other hand, the protonated amine group attracted Cr(VI) by electrostatic interaction and weakened the inter-cationic repulsion by electrostatic shielding, thus promoting Cu(II) adsorption. In addition, the dynamic column experiment towards simulated acidic electroplating wastewater involving Cu(II)–Cr(VI)–Ni(II) certified the high efficiency and feasibility of the co-removal. Therefore, CMC/PEI-PD owned great potential in the separation of typical HMIs even directly from strong-acid media.

Selective solvent extraction of Cu(II) from aqueous solutions using an acyl-based thiourea: Extraction study and DFT analysis of reaction mechanism

Currently, copper-containing wastewater poses a great threat to the surrounding living areas due to its toxic and non-biodegradable properties. The solvent extraction technique for removing copper(II) from wastewater has been identified as a straightforward and effective method. In this study, novel acyl-containing thiourea extractants, namely N-benzoyl-N′,N′-diethyl thiourea (BDETU), N-benzoyl-N′,N′-dibutyl thiourea (BDBTU) and N-benzoyl-N′-butyl thiourea (BBTU), were prepared and employed as extractants for the efficient removal of Cu(II) ions from aqueous solution. Experimental results indicated that the highest extraction efficiency of Cu(II) by BDETU was 99.4% under the optimal extraction conditions, which surpassed the performance of both BDBTU and BBTU. The reusability and selectivity experiments further confirmed the enduring high extraction efficiency of BDETU over 8 consecutive extraction-stripping cycles. These findings suggest that BDETU exhibits promising prospects for wide-ranging applications owing to its excellent extraction stability and selectivity. The investigation into the extraction mechanism of Cu(II) with acyl thiourea molecule revealed that one mole of Cu(II) was extracted with two moles of extractants through the formation of Cu-O-C and Cu-S-C bonds.

Multi-principles analysis of Cu(II) adsorption in water on magnetic microspheres and modified Chitosan

In this study, magnetic composite microspheres (SCFP) were prepared by cross-linking chitosan (CS), sodium alginate (SA), poly(vinyl alcohol) (PVA), and ferric tetraoxide (Fe3O4) in a CaCl2 solution. CS and Fe3O4 were encapsulated in gel spheres formed by cross-linking SA with Ca(II), while PVA facilitated the dispersion of CS in SA. SCFP was utilized as an adsorbent to remove Cu(II) from water. The effects of the initial pH of the solution, SCFP dosage, and initial Cu(II) concentration on the adsorption efficiency were investigated through batch experiments. The results demonstrated that the adsorption capacity reached 58.260 mg/g (removal rate = 97.1%) after 100 min of adsorption at a pH of 5. The removal rate remained above 90% even after 6 cycles of the cycling experiment. The incorporation of CS with other functional materials allowed SCFP to compensate for its inherent drawbacks such as low mechanical strength, poor acid resistance, and short service life. The pseudo-first-order kinetic model and Freundlich adsorption isotherm provided better descriptions of the adsorption process. A comprehensive analysis was conducted on the structure and adsorption mechanism of SCFP using characterization techniques such as SEM-EDS, FTIR, BET, XRD, etc. In summary, SCFP has the potential to be an excellent environmentally friendly material for the removal of Cu(II).