Adsorbent For Removal Of Cu Research Articles

Kenaf Biochar as an Eco‐Friendly Adsorbent for Removal of Cu(II) and Pb(II): Optimal Temperature, Adsorption Models, and Efficiency Evaluation

ABSTRACTThis study examined the adsorption capacities of biochars derived from kenaf (KF‐BCs) for the removal of heavy metals such as Cu(II) and Pb(II). The thermal decomposition temperature (300–750°C) significantly influenced the morphology and composition of KF‐BCs, enhancing their surface area, pore structure, and alkalinity. Among them, kenaf pyrolyzed at 750°C (KF‐750) was the most effective in removing Cu(II) and Pb(II), as validated by kinetic, equilibrium, and isotherm model analyses. Adsorption kinetics revealed that equilibrium was attained after 24 h, with chemisorption governing the process rate. Equilibrium adsorption conformed to the Langmuir and Freundlich models for Cu(II) and Pb(II), respectively. KF‐750 exhibited midrange adsorption capacities for Cu(II) and Pb(II) (23.47 ± 0.3 mg/g and 50.07 ± 0.9 mg/g, respectively), compared with the literature. The thermodynamic assessment revealed an endothermic process with positive ∆H0, indicating that higher temperatures favor metal adsorption. At low pH, adsorption decreased due to electrostatic repulsion, particularly affecting Cu(II). More than 99.8% of Cu(II) and Pb(II) were removed with a 5.00 g/L KF‐750 dose. The cation effect order on KF‐750 was Ca2+ > Mg2+ > Na+ > K+. Overall, KF‐750 demonstrates promising potential as an adsorbent for the efficient heavy metal removal from aqueous solutions, presenting a viable option for environmental remediation.

P-Morpholinomethylcalix[4]arene incorporated polyacrylonitrile nanofibers as selective adsorbent for removal of Cu+2 from aqueous environment

ABSTRACT In this study, p-morpholinomethylcalix[4]arene (p-MC4) was synthesized using Mannich reaction and utilized for the fabrication of polyacrylonitrile nanofibers impregnated with p-morpholinomethylcalix[4]arene (PAN/p-MC4) using electrospinning. The nanofibers were prepared by blending 12% solution of PAN with 20% solution of p-MC4. The PAN/p-MC4 NFs were thoroughly evaluated for their removal efficiency of Cu2+ from the aqueous media. The selectivity of PAN/-p-MC4 nanofibers was also examined by adsorbing a set of metal ions with same charge and similar ionic radius. The results of distribution ratio showed that PAN/p-MC4 nanofibers have superior selectivity for Cu2+ as compared to other heavy metal ions. The relative selectivity coefficients of PAN/p-MC4 nanofibers were found to be 25.2, 14.1, 8.9, and 4.03 for Cu2+/Ni2+, Cu2+/Co2+, Cu2+/Cd2+ and Cu2+/Pb2+, respectively. This indicates that PAN/p-MC4 nanofibers have a higher selectivity for Cu2+ ions. Numerous parameters such as pH, time, adsorbent dosage and analyte concentration were optimized to evaluate the maximum adsorption capacity of nanofibers for Cu2+. Adsorption isotherm models showed that the adsorption is promising and follows Langmuir adsorption isotherm. Whereas, PAN/p-MC4 nanofibers followed pseudo- second order kinetics during adsorption experiments. The PAN/p-MC4 nanofibers showed excellent adsorption capacity (q o ) of 65.35 mg/g for Cu2+ at pH 5 in 60 min under shaking speed of 120 rpm. Moreover, PAN/p-MC4 nanofibers had been used to remove Cu2+ from real surface water samples. According to the results, PAN/p-MC4 nanofibers are more effective adsorbent for removing Cu2+ from contaminated water.

Adsorptive removal of Cu(II) ions from aqueous solution using Teff (Eragrostis tef) hay based magnetized biocarbon: RSM-GA, ANN based optimization and kinetics aspects

Abstract Teff (Eragrostis tef) is known as a staple grain crop which grown as edible seeds, remarkably in Ethiopia. However, after removal of its seeds, the hay obtained from this crop, are considered as agro-waste. Such a lignocellulosic agro-waste can be potentially exploited to prepare activated carbon to treat the harmful industrial effluents for detoxification. In this study, Teff hay (TH) was used as a precursor for preparing the activated carbon. The using H2SO4, chemical activation was carried out followed by carbonaceous process was undertaken to prepared activated carbon (AC) by pyrolysis. The prepared AC was modified as magnetized AC and characterized by various characterization methods. Further, as a bio-absorbent, its potency for adsorptive removal of Cu(II) ions was ascertained. Notably, the most studied and important process factors for adsorption, such as, initial concentration of metal ion, adsorbent dosage, pH, and contact time were subjected to optimization using response surface method (RSM). Further, to ensure the statistical optimization of aforementioned factors, the non-statistical techniques, genetic algorithm (GA) and artificial neural network (ANN) tools have been executed. In addition, the use of prepared Teff-hay based magnetized AC for the removal of Cu(II) by adsorption process was evaluated through different isotherms and kinetic approaches.

Multifunctional carboxymethyl cellulose/graphene oxide/polyaniline hybrid thin film for adsorptive removal of Cu(II) and oxytetracycline antibiotic from wastewater

The antibiotics and metal ions in the contaminated water bodies must be removed using appropriate methods for sustainable development. In this study, the multifunctional carboxymethyl cellulose/graphene oxide/polyaniline (CMC/GO/PANI) hybrid thin film was synthesized and utilized for adsorptive scavenging of (Cu(II) and oxytetracycline (OTC) from wastewater. The prepared thin films' morphology, chemical compositions, functionality, and surface charge were analyzed by well-known physicochemical techniques. The adsorption process of the selected model pollutants was examined as a function of reaction time, Cu(II), and OTC solution pH, concentrations, and temperatures. Results showed that CMC/GO/PANI hybrid thin film had higher Cu(II) and OTC adsorption than CMC, GO/CMC, and PANI/CMP thin films due to the multifunctional synergetic effect. The adsorption kinetic data were fitted to the pseudo-second-order model. Redlich-Peterson isotherm model well interpreted Cu(II) and OTC scavenging equilibrium data. Energetically, the adsorption was spontaneous and endothermic for both pollutants. The multifunctional CMC/GO/PANI thin film was recycled and reused seven times during adsorption-desorption cycles. The study outcomes demonstrated that CMC/GO/PANI thin film could be reused multiple times for large-scale wastewater purification.

Apple peels as a potential adsorbent for removal of Cu and Cr from wastewater

Abstract Solid waste management (SWM) is one of the biggest concerns of society and agricultural waste is generated in vast amounts. In this study removal of Cu and Cr from wastewater using chemically modified apple peels was studied by following batch sorption experiments. Effects of metal concentration, adsorbent dose, pH, temperature and contact duration on the adsorption of Cu & Cr were investigated by using atomic adsorption spectrophotometer (AAS). SEM & EDX analysis of the adsorbents were recorded to study the morphology of the prepared adsorbents. Qmax value of apple peels is 25 for Cr and 22 for Cu, while for apple peel charcoal it is 33 for Cr and 47 for Cu, for treated apple peels Qmax is 50 for Cr and 52 for Cu adsorption. The data was processed using pseudo first, second order kinetic and intraparticle diffusion. Results depicted that the calculated adsorption capacities (qecal) were found to be close to the experimental values (qecal) by following pseudo-second-order kinetics. The applicability of the Langmuir and Freundlich adsorption isotherms was tested. Results showed that the Langmuir model is best fitted on adsorption data because regression factor R2 values are good for the Langmuir model.

H2O2 modified peanut shell-derived biochar/alginate composite beads as a green adsorbent for removal of Cu(II) from aqueous solution

In this study, a novel composite bead (MPB-ALG) was prepared by encapsulating H2O2 modified peanut shell-derived biochar (MPB) into alginate matrix through a facile method. The structure and properties of prepared materials were characterized using FTIR, BET, SEM, and XPS. Batch adsorption experiments were performed to compare the Cu(II) adsorption performance of MPB, plain alginate beads (ALG), and MPB-ALG. The effect parameters of the components, solution pH, contact time, initial concentration, and coexisting ions were studied systematically. The results showed that the maximum adsorption capacity of the optimized MPB-ALG-1 (MPB/alginate = 1:1 w/w%) was 117.4 mg g−1 at pH 5, which was much higher than that of MPB (37.4 mg g−1). The adsorption kinetics and isotherms data of Cu(II) on MPB-ALG-1 were well described by Elovich kinetic model and Freundlich adsorption isotherm. Compared with plain ALG beads, MPB-ALG-1 exhibited better reusability and anti-interference of coexisting ions. Finally, the adsorption mechanisms of Cu(II) on MPB-ALG-1 beads were revealed by FTIR and XPS analysis. The experimental results demonstrated that MPB-ALG-1 beads can be used as an environmentally friendly and efficient adsorbent for the removal of Cu(II) from wastewater.

Synthesis of chitosan‐nTiO2 nanocomposite, application in adsorptive removal of Cu(II)—Adsorption and desorption study, mechanism, scale‐up design, statistical, and genetic algorithm modeling

The present study comprises the preparation of chitosan‐nTiO2 nanocomposites and their characterization with the help of scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), and thermogravimetric analysis (TGA). Various adsorbent samples are prepared with different weight ratios of chitosan to nTiO2. The adsorption capacity of the prepared adsorbents towards Cu(II) in an aqueous solution is also tested. The adsorption experiment is performed in batch mode under varying experimental conditions. Several isotherm and kinetic models are analyzed with the experimental data, and thermodynamic conditions required for adsorption are also determined. The highest elimination of Cu(II) was 39.19% with the adsorbent chitosan without nTiO2 (CWT) with 20 mg L−1 initial Cu (II) concentration at adsorbent dosage 3 gL−1 and 98.5% with the adsorbent CTNC1‐1 (chitosan/nTiO2 nanocomposite with the mass proportions of chitosan:nTiO2 = 1:1) and 93% with CTNC2‐1 (chitosan/nTiO2 nanocomposite with the mass proportions of chitosan:nTiO2 = 2:1) with 10 mg L−1 initial Cu(II) concentration at adsorbent dosage 5 g L−1. The isotherm model confirmed the monolayer adsorption. Maximum Langmuir adsorption capacities (qL) of the adsorbents for Cu(II) were given as CTNC1‐1 > CTNC2‐1 > CWT. The pseudo‐second‐order model excellently depicted the kinetic process with good correlation for all adsorbents. The statistical (R‐square is more than 0.99) and genetic algorithm (GA) model (R‐square is more than 0.99) effectively predicted the percentage removal of Cu(II).

Adsorption of Cu(II) and Zn(II) onto Activated Carbon from Oil Palm Empty Fruit Bunch Prepared by Two-Step Acid Treatment and Microwave-Assisted Pyrolysis

This study explores the feasibility of biochar-based activated carbon derived from oil palm empty fruit bunch (EFB) as a potential precursor for the preparation of activated carbon via 2-step H3PO4 activation under microwave-assisted pyrolysis (2ACEFB). The characterization of EFB and 2ACEFB was observed by FTIR and BET, and chemical composition was determined using proximate and elemental analysis data. The adsorptive removal of Cu(II) and Zn(II) from an aqueous solution was studied, and the effects of metal concentration and solution pH were also investigated. The pseudo-second-order equation was properly described, providing the best fit to the observed experimental data. The adsorption capacities of Cu(II) and Zn(II) onto the EFB were 20.28 and 18.06 mg/g, respectively, and improved by 2.04- and 1.89-fold onto the 2ACEFB. The potential of 2ACEFB was also proved by adsorbent reusability with five consecutive circles of the batch experiment without regeneration or treatment. This study demonstrated that 2ACEFB is an efficient adsorbent for eliminating heavy metals from aqueous solutions.

Biosilica/Silk Fibroin/Polyurethane biocomposite for toxic heavy metals removal from aqueous streams

Development of green, eco-friendly, and efficient adsorbents for wastewater treatment is highly researched to mitigate the alarming rate of water pollution. In this work, a novel biocomposite of biosilica (BS)/silk fibroin (SF)/polyurethane foam (PUF) was prepared and studied for the adsorptive recovery of toxic copper (Cu 2 + ) and chromium (Cr 6＋ ) ions from synthetic wastewater. XRD and FTIR studies confirmed the formation of biocomposite with amorphous structure and –OH, –NH, C=O surface functionalities. SEM results confirmed the successful incorporation of SF and PUF into BS. The biocomposite possessed a specific surface area of 751.9 m 2 /g and a mean pore size of 7.21 nm. Further, effects of pH, adsorbent dose, contact time, and initial metal ion concentration on the adsorptive removal of Cu 2 + and Cr 6＋ metal ions by the BS/SF/PUF biocomposite were studied in detail. Equilibrium and kinetic analysis showed that the metal ions sequestration by the BS/SF/PUF biocomposite followed the Freundlich isotherm and Elovich model, respectively. Maximum adsorption capacities of 331.69 mg/g and 201.56 mg/g were estimated for the Cu 2 + and Cr 6＋ ions, respectively. A plausible mechanism for the adsorption of the metal ions onto BS/SF/PUF biocomposite is postulated. Reusability studies of the biocomposite using EDTA eluent showed that the biocomposite could be efficiently reused up to four consecutive adsorption/desorption cycles. Thus, this study provides comprehensive data for applying the BS/SF/PUF biocomposite to treat Cu 2 + and Cr 6＋ metal ions polluted wastewater streams. • Amorphous BS/SF/PUF biocomposite was prepared through polymer blending. • Specific surface area and pore size of BS/SF/PUF were 751.9 m 2 /g and 7.21 nm. • High adsorptive removal efficiency of >80% for Cu 2+ and Cr 6+ heavy metal ions. • Freundlich isotherm & Elovich kinetic model best described adsorption operation. • BS/SF/PUF biocomposite was successfully reused up to 4 cycles through EDTA washing.

Preparation of nitrogen-enriched pine sawdust-based activated carbons and their application for copper removal from the aquatic environment

In this research study, compressed pellets of pine wood sawdust were carbonized at a temperature of 600 °C and then physically activated at 800 °C to obtain activated carbons (ACs). Then, some of the samples were enriched with nitrogen by reaction with urea at 300 °C. The AC samples prepared in this way were examined for the removal of Cu(II) in adsorption processes. Pine wood sawdust is waste resulting from processing in the wood industry and is a promising material to be reused for metal ions recovery. For this purpose, firstly, the AC was characterized using several analytical methods, including ash content, elemental composition, TGA, specific surface area and pore diameter (BET), pore size distribution (BJH), micropore volume, the content of surface acidic and basic functional groups, pH, FTIR and SEM morphology. Secondly, these materials before and after modification with nitrogen were used in experiments on the adsorptive removal of Cu(II) ions from aqueous solutions. The influence of parameters, such as initial pH, adsorbent dosage, initial Cu(II) concentration and contact time on the process, was investigated. Thirdly, adsorption kinetics and sorption isotherms were analyzed. According to the research results, it was reported that maximum sorption efficiency was equal to 99.9 and 99.8% at pH 5 for activated carbon AC (TK6AF1/2) and nitrogen-modified activated carbon NMAC (TK6MAF1/2), respectively. This proves that the examined waste materials exhibit satisfactory sorption properties in relation to Cu(II) ions and can be used as low-cost adsorbents in industrial wastewater treatment processes. These studies are in line with current global trends in sustainable and circular economy. Future research may focus on performing adsorption processes of copper and other metals at various temperatures as well as dynamic flow, studying metal ion competition, performing regeneration to reuse the adsorbents, carrying out realistic wastewater studies and cost estimation of entire processes on a laboratory and industrial scale.

Adsorptive removal of Cu(II) from aqueous solution by fermented sweet sorghum residues as a novel biosorbent

Sweet sorghum straw is a kind of natural wood cellulose with high porosity and high specific surface, which is theoretically conducive to the physical adsorption of heavy metal ions. In this paper, we reported a new biosorbent, the fermented sweet sorghum residues (FSSR), which is a byproduct of bioethanol production by fermentation of sweet sorghum straw, for the removal of Cu(II) from aqueous solution. The properties of the adsorption of Cu(II) on SSR and FSSR were studied and compared. The adsorption process of Cu(II) by SSR and FSSR conformed to the Elovich kinetic model. The isothermal adsorption process conformed to the Freundlich and the Tempkin models. The adsorption capacity of FSSR for Cu(II) was increased with the increase of pH. The adsorption mechanism of Cu(II) by FSSR was mainly attributed to ion exchange. SSR and FSSR were characterized by SEM-EDS, FTIR and XRD. The surface of FSSR had microporous structure, the content of –OH and other active functional groups increased. The fermentation has a certain destructive effect on the crystal structure of cellulose with the increase of amorphous structure. Therefore, fermentation process could be regarded as an effective means of microbial modification, to destroy the structure of the straw and result in the porous structure, which improved the adsorption capacity of SSR for heavy metals. FSSR could be used as a potential biosorbent for heavy metal removal from aqueous solution. Ethanol fermentation might be an effective method to improve performance of biosorbent for Cu adsorption.

Adsorptive removal of Cu(II) by fly ash based geopolymer material

Geopolymer are aluminosilicate inorganic polymer synthesized by polymerization of aluminosilicate with alkaline solutions. These materials possess high surface area hence promising adsorbent. In this paper fly ash and rice husk-based geopolymer type hybrid mass is applied for remediation of Cu(II) ions. Various adsorptive parameters for example contact /reaction time, effluent metal ions concentration, dose of hybrid mass, pH and operating temperature are optimized and fixed for getting maximum removal of aqueous Cu(II) ions. Equilibrium isotherm and kinetic studies revealed that the isotherm data were best described by Langmuir adsorption isotherm and the rate of adsorption follows the pseudo second-order. Thermodynamic studies carried out by applying Van’t Hoff equation, which revealed that the process was exothermic and spontaneous. Results indicate encouraging performance of hybrid mass towards removal of Cu(II) ions.

Effective biosorption of Cu(II) using hybrid biocomposite based on N-maleated chitosan/calcium alginate/titania: Equilibrium sorption, kinetic and thermodynamic studies

In this research work, a hybrid biocomposite based on N-maleated chitosan, amino-thiocarbamate functionalised calcium alginate and anhydrous Titania nanoparticles (NMC-MCA-TiO2) was fabricated. The study involves the one pot facile synthesis of N-maleated chitosan and amino-thiocarbamate functionalised alginate under moderate conditions. Sorbent was conditioned in the form of hydrogel beads and characterized through FT-IR and SEM analysis. Newly grafted functional groups could act as potential chelating sites for enhanced Cu(II) sorption. Modified biopolymers were organo-functionalised which provided excellent support for immobilization of Titania nanoparticles (TiO2) as inorganic filler. Kinetic data illustrated the manifestation of intrinsic chemisorption instead of simple bulk/film diffusion. Equilibrium sorption data fitted well with Freundlich adsorption model (R2 ≈ 0.99) which designated the heterogeneous nature of sorbent. Maximum sorption capacity of biosorbent was found 192 mg/g at 298 K and pH = 6.0. Standard Gibbs free energy change ∆Go (−21.53, −21.97, and − 22.42 kJ/mol), standard enthalpy change ∆Ho (5.12 kJ/mol) and standard entropy change ∆So (0.09 kJ/mol K−1) values suggested that the sorption process to be spontaneous and endothermic. The sorbent 3NMC-MCA-TiO2 could be competitive candidate for economical and rapid adsorptive removal of Cu(II) from dilute contaminated liquids.

Synthesis of hybrid biosorbent based on 1,2-cyclohexylenedinitrilotetraacetic acid modified crosslinked chitosan and organo-functionalized calcium alginate for adsorptive removal of Cu(II)

The present study is based on the synthesis of a novel hybrid biosorbent using 1,2-cyclohexylenedinitrilotetraacetic acid modified crosslinked chitosan and amino-thiocarbamate moiety functionalized sodium alginate (CDTA-CS/TSC-CA). The fabricated sorbent was employed to investigate the efficient recovery of Cu(II) from aqueous media. CDTA-CS/TSC-CA was characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Analysis confirmed the successful modification of both biopolymers and subsequent loading of Cu(II) ions. CDTA-CS/TSC-CA was casted in the form of hydrogel beads having different CDTA-CS to TSC-CA mass ratios i.e., 10.0–40.0% by mass. The hydrogel beads 4CDTA-CS/TSC-CA with CDTA-CS/TSC-CA mass ratio of 40.0% was found most effective for copper sorption. Equilibrium sorption results showed that initial concentration of copper, medium pH, contact time, sorbent dosage and temperature influenced the sorption capacity (qe). Rate of sorption data was interpreted using different kinetic models and found best fitted with pseudo second order rate expression (R2 ≈ 0.99), illustrating that the rate determining step includes the electron density transfer from sorbent coordination sites to central copper ions. Crank's RIDE equation and Elovich chemisorption model (ECM) revealed the presence of two sorption phases, initially rapid sorption followed by comparatively a slow uptake. Equilibrium sorption data was well depicted by Langmuir model and maximum monolayer adsorption capacity (qm) was computed as 276.53 mg·g−1 at 298 K. Standard Gibbs free energy change, ∆G° (−19.99, −20.18 and −20.36 kJ/ mol), standard enthalpy change, ∆H° (−8.95 kJmol) and standard entropy change, ∆S° (0.04 kJ/mol K−1) values suggested that the adsorption process is spontaneous and exothermic. Hence, 4CDTA-CS/TSC-CA was found efficient biosorbent for copper removal from its dilute effluents.

A sustainable generated hydrochar from pomegranate residues for remediation of process water contaminated with Cu(II) ions

An eco-friendly, flexible and sustainable valorization of pomegranate residue (PR) was studied by hydrothermal technology. PR was used as a feedstock for producing hydrochar (PRHC) and the effects of treatment temperature (TT; 180, 200, 220 °C) and treatment time (Tt; 6, 12, 24 h) on the elemental composition, yield, higher heating value (HHV) and energy density (DE) parameters were examined. The most suitable production conditions were recommended as TT of 220 °C and Tt of 12 h with a HHV of 23.23 MJ/kg and DE of 1.22 GJ/m3. A broad spectral survey including FTIR, SEM/EDX, XPS, XRD, Raman and 13C MAS-NMR techniques were performed to define its physicochemical characteristics. PRHC was applied as an adsorbent for removal of Cu(II) ions from water and adsorption kinetics indicated well-suitability of the data to the pseudo second order model while the Langmuir model best described the equilibrium data with a 113.64 mg/g. Thermodynamics evaluation displayed the spontaneous, feasible and endothermic adsorption of Cu(II) ions. In addition, regeneration studies have shown efficiently usage of PRHC for multiple times in wastewater treatment.

Green Synthesis of Silver Nanoparticles using Delonix regia Extract, Characterization and its Application as Adsorbent for Removal of Cu (II) Ions from Aqueous Solution

In this research synthesis of silver nanoparticles by a green method is studied. The high importance of silver nanoparticles using extract of Delonix regia (DREAgNs) is due to their unique properties, such as non-expensive, easily available and have application in water treatment. Synthesized silver nanoparticles AgNPs were characterized using UV-Visible Spectrophotometer to indicate the synthesis of AgNPs by green methods. The maximum absorbance of UV-Vis. analysis at wavelength 464 nm. (FT-IR) spectra to indicate the functional groups of phytochemical compounds at Delonix regia extract (DRE) and the silver nanoparticles (DREAgNPs) and also shows the role of active chemical constituents in stabilization and reduction of (DREAgNPs). Based on the transmission electron microscopy image analyses (TEM) confirmed the formation of spherical DREAgNPs with a particle size range of 20-50 nm with an average particle size of 35 nm. The Cu2+ ion adsorption process was studied by (DREAgNPs). The Cu2+ ions removal efficiency (R. E.) is 88.4 % at an initial concentration 15 ppm. Removal efficiency (R. E.) decreases as the Cu2+ ion concentration increases. Furthermore, thermodynamic studies confirmed that the biosorption process was endothermic and the positive value of ΔG° is quite common when an ion-exchange mechanism applies in the biosorption. The Positive value of ΔS◦ suggested an increase in randomness during the biosorption. The Freundlich isotherm has a good fit with the experimental data (R2 =0.99) compared to Langmuir isotherm (R2 = 0.90). This study shows that DREAgNPs are available, low cost, effective and environment friendlly biosorbent for the removal of Cu2+ ions from aqueous environment.

K2CO3-Activated Pomelo Peels as a High-Performance Adsorbent for Removal of Cu(II): Preparation, Characterization, and Adsorption Studies

Activated carbons (ACs) were prepared from pomelo peels by K2CO3 activation and used as an adsorbent (PAC) for the removal of Cu(II) from aqueous solutions. BET, SEM, and FT-IR were employed for the characterization of the obtained ACs. The optimum ACs were reported at activation temperature of 850°C, activation time of 60 min, and impregnation ratio of 3, which had a high surface area (1213 m2/g) and total pore volume (0.57 cm3/g). The resulting ACs were used for the adsorption of Cu(II) from aqueous solutions in the batch mode and yielded a superior adsorption capacity of 139.08 mg/g. The pH of optimum adsorption was determined as 5. Pseudo first-order model, pseudo second-order model, and intraparticle diffusion model were applied to describe the adsorption processes. The adsorption kinetic data were found to follow the pseudo second-order model. The adsorption isotherms data were analyzed using Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models. The Langmuir model was found to provide the best fit, and the calculated adsorption capacity was 151.35 mg/g.

Rapid Adsorption of Magnetite Nanoparticles from Recycled Mill Scale Waste as Potential Adsorbent for Removal of Cu(II) Ions

The present study was conducted to establish adsorbent potential of magnetite nanoparticle ferrous ferric oxide (Fe3O4) for removal of Cu(ll) ions in wastewater. In the study, Fe3O4 was prepared by synthesizing low-cost recycled mill scale waste in an aqueous solution. Samples of scale wastes were milled and ground using high-energy ball milling (HEBM) at three milling times of 5, 7 and 9 hours. Extraction of Fe3O4 was accomplished by magnetic separation technique (MST) and Curie temperature separation technique (CTST). The morphologies and structural properties of Fe3O4 were characterized by using X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Fourier-transform infrared spectroscopy (FTIR). HRTEM yielded images in the range of 10-22 nm. Maximum adsorption capacity, qe,and percentage removal of Cu(II) ions were achieved at 4.45 mg/g and 62.61% respectively after 7 hours of milling time. The present study recorded the smallest particle size of Fe3O4 imparting high qe, and percentage removal of Cu (II) ion in an aqueous solution, suggesting its high adsorbent potential.

Copper(II) removal from aqua solution using rice straw derived biochar

Biochar derived from rice straw has potential application as a cheap adsorbent for removal of Cu(II) from aqueous solution. In this study, rice straw was used to derive biochar by operating at different pyrolysis temperatures (300, 400, and 500 °C) and studied different biochar physicochemical properties. Biochar yield decrease from 57.87 to 37.19% by increasing temperature from 300 to 500 °C. The content of carbon and ash, pH, and surface area of biochar increased from 68.72 to 81.48%, 32.70–46.52%, 8.23–11.4, 48.3–101.29, respectively. Batch adsorption was adopted for biochar produced at different temperatures, and biochar derived at 500 °C showed the greater adsorption capacity (29.8 mg g−1). RBC500 was selected to study the initial metal concentration effects (5–320 mg L−1) and time of contact (30–240 min) on removal efficiency of Cu(II). The optimum results from the study showed that for Cu adsorption was pH = 5, adsorbent dose 0.1 g L−1, and contact duration of 180 min. A strong fit to the kinetics (R2 = 0.99) was shown by pseudo-second-order model, and strong fit to the adsorption isotherms was shown by Langmuir model (R2 = 0.99) of Cu(II) adsorption.

Adsorption Study of Cu2+ Ions from Aqueous Solutions by Bael Flowers (Aegle marmelos)

In the present study, batch mode adsorption was carried out to investigate the adsorption capacity of dried bael flowers (Aegle marmelos) for the adsorptive removal of Cu(II) ions from aqueous solutions by varying agitation time, initial metal concentration, the dose of adsorbent, temperature, and initial pH of the Cu(II) ion solution. The percentage removal of 98.7% was observed at 50 ppm initial metal ion concentration, 0.5 g/100.00 cm3 adsorbent dosage, within the contact time of 120 minutes at 30 ºC in the pH range of 4 – 7. The sorption processes of Cu(II) ions was best described by pseudo-second-order kinetics. Langmuir isotherm had a good fit with the experimental data with 0.97 of correlation coefficient (R2), and the maximum adsorption capacity obtained was 23.14 mg g-1 at 30 ºC. The results obtained from sorption thermodynamic studies suggested that the adsorption process is exothermic and spontaneous. SEM analysis showed tubular voids on the adsorbent. FTIR studies indicated the presence of functional groups like hydroxyl, –C-O, –C=O, and amide groups in the adsorbent, which can probably involve in metal ion adsorption. Therefore, dried bael flowers can be considered an effective low-cost adsorbent for treating Cu(II) ions.