Initial Copper Research Articles

Electrochemical Extraction with Supported Liquid Membrane for Removing Copper from Synthetic Wastewater: Optimisation through Response Surface Methodology

In this study, copper was removed from an aqueous solution through electromembrane extraction (EME), a new approach that utilises a two-chamber electrochemical cell. It consists of two electrodes (stainless steel cathode and graphite anode) and a solid liquid membrane (SLM). SLM is composed of supporting polypropylene membrane impregnated with1-octanol as an organic solvent and bis(2-ethylhexyl) phosphate (DEHP) as a carrier. The effects of process parameters such as applied voltage, pH and copper concentration on the removal of copper were investigated. Response surface methodology (RSM) was applied to optimise these parameters and their interactions. Results indicated that pH has the major effect on the removal of copper, followed by applied voltage. The squared interaction term in the RSM model has the highest contribution (70.5%), followed by the linear term, thereby confirming the significant interaction among the variables. The optimum conditions include an applied voltage of 60V, pH of 5.18 and initial copper concentration of 5 ppm, which yield to a removal efficiency of 80% after 6 hours of operation. The findings demonstrate the use of electromembrane extraction as an efficient method for the removal of heavy metals and provide valuable insights for future application to other environmental and water treatment processes.

Copper-perovskite interfacial engineering to boost deNOx activity

By adjusting the Cu doping level and calcination temperature during synthesis of a series of noble metal-free lanthanum copper manganite perovskites LaCuxMn1-xO3, we show the importance of tuning the redox chemistry for optimum steering of the catalytic activity and N2 selectivity in the catalytic reduction of NO by CO. A prerequisite is the in situ formation of an extended copper-perovskite phase boundary. The associated improvement of redox and surface properties by Cu addition leads to an optimized balance of the reduction of the catalyst in the NO+CO reaction mixture. The creation of oxygen vacancies improves the reaction kinetics and initiates the NO dissociation. Strongly dependent on the calcination temperature, the Cu/Mn ratio, the reducing agent, as well as the reaction temperature as parameters for Cu-perovskite interfacial control, surface reduction can induce partial copper exsolution, significant perovskite reduction, agglomeration of exsolved Cu particles and eventual decomposition of the catalyst structure. We show that increasing the amount of initial copper incorporated into the perovskite structure can beneficially extend the phase boundary, but exceeding the amount of copper leads to increased sintering of the copper particles at the expense of catalyst activity, especially in repeated catalytic cycles. Increasing the calcination temperature, in addition to the initial sintering of the catalyst and shifting the reaction onset temperature to higher temperatures in the first cycle, improves the reduction resistance of the catalyst. Consequently, in order to form a higher amount of phase boundary-bound active sites, stronger reducing conditions than provided by the NO+CO reaction mixture are needed. This effect can be counterbalanced by using stronger reduction agents prior to performing subsequent catalytic cycles by inducing the exsolution process.

Copper Ion Removal by Adsorption Using Fly Ash-Based Geopolymers: Process Optimization Insights from Taguchi and ANOVA Statistical Methods.

The present study aimed to use geopolymer materials synthesized from different fly ashes, which are promising for the adsorption of copper ions from aqueous solutions. The characterization of fly ashes and prepared adsorbents was performed by energy-dispersive X-ray spectroscopy (EDS) analysis, Brunauer-Emmett-Teller (BET) surface area analysis, and Scanning Electron Microscopy (SEM). Taguchi and ANOVA methods were used to predict the effect of different working parameters on copper ion removal by prepared geopolymers. Based on data obtained by the Taguchi method, it was found that the factor most influencing the adsorption process is the type of adsorbent used, followed by the solution pH, the reaction time, the adsorbent dose, and the initial copper ion concentration. The ANOVA results agree with the Taguchi method. The optimal conditions of the adsorption process were: fly ash C modified by direct activation with 2 M NaOH, at 70 °C for 4 h, solution pH of 5, initial pollutant concentration of 300 mg/L, 40 g/L adsorbent dose, and 120 min of reaction time. Copper ion removal efficiency was determined experimentally under optimal conditions, achieving a value of 99.71%.

Copper (II) Level in Musts Affects Acetaldehyde Concentration, Phenolic Composition, and Chromatic Characteristics of Red and White Wines.

Copper (II), a vital fungicide in organic viticulture, also acts as a wine oxidation catalyst. However, limited data are currently available on the impact that maximum allowed copper (II) ion doses in wine grapes at harvest can have on aged wine quality. This was the focus of the present study. We investigated the copper (II) effects by producing both white and red wines from musts containing three initial metal concentrations according to the limits set for organic farming. In detail, the influence of copper (II) on fermentation evolution, chromatic characteristics, and phenolic compounds was evaluated. Interestingly, the white wine obtained with the highest permitted copper (II) dose initially exceeded the concentration of 1.0 mg/L at fermentation completion. However, after one year of storage, the copper (II) content fell below 0.2 ± 0.01 mg/L. Conversely, red wines showed copper (II) levels below 1.0 mg/L at the end of fermentation, but the initial copper (II) level in musts significantly affected total native anthocyanins, color intensity, hue, and acetaldehyde concentration. After 12-month aging, significant differences were observed in polymeric pigments, thus suggesting a potential long-term effect of copper (II) on red wine color stability.

Design of a new home-made ultrasonic extraction system

Innovative, sensitive, and accurate method for liquid-liquid extraction using an ultrasonic device is presented in this work. A working system was created, consisting of two basic components: the ultrasonic device and the pump device, to pump or withdraw the organic layer. a study of the key variables derived from the liquid-liquid system was carried out in the system containing Dithizone (1×10^ ̄ 3 M) in (Chloroform) CHCl₃ solvent. and aqueous copper (II) chloride(CuCl2.2H2O) (1×10^ ̄6 M) solution to determine the degree to which they affect the extraction performance attained in this manner. The effect of initial sample copper concentration and ultrasonic time, temperature effect, and pump speed, were studied, establishing the best conditions for a sample of (10 mL) aqueous solution of Cu (II) chloride, the optimum copper (II) concentration in the analyzed sample is (1×10^ ̄ 6 M), the ultrasonic time for the device is (8 min), and the flow rate of the pump is (3mL/30sec) and a temperature (27ºC) and (pH=1). The extraction degree was optimum under these conditions (96±2%) and the relative standard deviation (RSD)% (0.29%), In this work, a simple method is proposed to extract and concentrate copper in aqueous copper chloride using an ultrasonic device in the presence of dithizone solvent. The main parameters affecting the extraction method such as copper ion concentration, pump speed, temperature, device time, and the effect of equal and different volumes were evaluated. The proposed method was applied for the determination of copper in aqueous copper chloride samples. Accuracy was assessed by comparing the results with a conventional extraction method (traditional methods).

Batch adsorption studies on copper removal from an aqueous solution using natural zeolite: Process optimization

Abstract The ability of natural zeolite to remove copper ions from an aqueous solution was examined. The research aims to optimize adsorption operational variables, which include the amount of zeolite, pH, contact time, and initial heavy metal concentration for copper removal using zeolite. The research was conducted in batch experiments. The ranges of operational conditions are as follows: 0.2 - 1.0 g of zeolite, pH 4 - 8, 2 - 60 minutes of contact time, and 5 - 50 mg/L of initial concentration of copper. The outcomes indicated that the percentage removal of copper using zeolite achieved the best performance at an optimized adsorbent dosage of 1.0 g, a pH of 6, a contact time of 20 minutes with 135 rpm, and an initial copper concentration of 5 mg/L. To sum up, zeolite is an efficient adsorbent that is capable of separating copper from water-based solutions.

Application of Cotton Stalk as an Adsorbent for Copper(II) Ions in Sustainable Wastewater Treatment

The capacity of untreated cotton stalk to remove and adsorb Cu2+ ions in synthetic and natural aqueous solutions was evaluated. The influence of three sensitive parameters of the adsorption process—solution pH, adsorbent dosage, and contact time—on the percentage of Cu2+ removal in agricultural wastewater, livestock wastewater, and synthetic samples was studied. Physicochemical and morphological properties were studied using thermogravimetry, Fourier infrared spectrophotometry, and scanning electron microscopy. The elemental composition, proximal composition, zero charge point, and acid–base sites were determined. In addition, kinetic studies were performed, and the adsorption equilibrium was analyzed. The optimum conditions for Cu2+ adsorption were the following: solution pH = 5.5, adsorbent dosage of 0.6 g, and contact time of 60 min. Under these conditions, the percentage of Cu2+ removal in synthetic samples was 66.5% when the initial copper concentration was 50 mg/L. The removal percentage in agricultural and livestock wastewater samples was 87.60% and 85.05%, respectively, when the initial copper concentration was 25 mg/L. The adsorption data are consistent with the Freundlich isotherm model, which achieved a quadratic fit of 0.991 compared to 0.5542 for the Langmuir model. The experimental results indicate that the adsorption adequately fits the pseudo-second-order kinetic model. The results suggest that cotton stalks are a promising adsorbent for the ecological and economical removal of Cu2+ in wastewater. This research, therefore, provides relevant information that contributes to the sustainable management of agricultural waste and instills hope for a reduction in water pollution from heavy metals derived from agricultural activities.

In-situ construction of epitaxial phase for boosting zinc nucleation on three-dimensional interface

Interface modification of zinc (Zn) metal anode with conductive three-dimensional (3D) structure is widely utilized in zinc ion batteries. However, the uniformity of zinc nucleation on surface microstructure is rarely investigated which exacerbates the tip effect and raises unstable risk. Herein, a strategy via the initial copper (Cu) alloying and following sulfurization treatment is reported to accomplish boosted uniform nucleation of zinc on the modified layer with dense microstructures. This epitaxial sulfide phase not only improves the wetting area to revitalize the microstructural surface, but also forms a bifunctional zincophilic Cu2S/CuZn alloy interface layer, which combines the merits of guided local ions diffusion and improved zinc nucleation environment. As a result, a homogeneous growth of zinc on the 3D structural substrate can be realized, and cycling stability of the achieved Cu2S/CuZn electrode with a practical capacity of 1 ​mAh cm−2 under 1 ​mA ​cm−2 or amplified current density of 10 ​mA ​cm−2 is significantly enhanced. This work provides an epitaxial strategy in constructing a bifunctional zincophilic interface layer for boosting zinc nucleation, and offers a new perspective on the modification of 3D surface structure for stabilization of zinc anode.

Utilization of organic-rich materials for the adsorption of copper ions from aqueous environments

This study investigated the suitability of moss peat and compost as adsorbents for removing copper ions from aqueous systems. Kinetic experiments were conducted at pH 4, 20 °C, and an initial copper ion concentration of 20 mM. Under these experimental conditions, moss peat and compost had a maximum adsorption capacity of 45.8 and 41.9 mg/g, respectively. The kinetic data was assessed using several models, and the data fitted well with the pseudo-second-order model for both adsorbents. Moreover, the analysis of the isotherm data showed that the Langmuir model could fit the data, suggesting that copper ions are chemically adsorbed onto moss peat and compost. The pH value of 4.5 was the most effective for the adsorption of copper ions onto moss peat and compost. At this pH value, the maximum adsorption capacities were 60.0 mg/g for moss peat and 56.9 mg/g for compost. The characterization of moss peat and compost before and after the interaction with copper ions indicated that surface precipitation was the dominant mechanism by which copper ions were removed from aqueous systems. Copper precipitation on the surface of moss peat was higher than that on the surface of compost, and it was found to be 7.7 wt% and 3.8 wt%, respectively. Overall, these findings highlight the potential of using moss peat and compost as effective adsorbents for copper ions in highly contaminated water, particularly industrial and mining effluent.

Application of fluidized bed homogeneous crystallization for simultaneous recovery of Fe(II) and Cu(II) as particles from wastewater

The mixture of copper and iron often results in materials with favorable properties. The material production processes involving these metals including electroplating produce hazardous wastewater. In this study, the Fluidized Bed Homogeneous Crystallization (FBHC) process was applied to treat iron and copper-containing wastewater. The initial iron copper particles were successfully recovered from synthetic wastewater with [Fe]0:[Cu]0 of 2:1, the total metal concentration of 3 mM, at effluent pH = 7.75 ± 0.75, with the upflow velocity (U) of 1.76 m/h. The agglomerates hardening process is a crucial step for initial particle synthesis. The SEM analysis reveals the spherical particle's densified crust and porous core. The particle formation mechanism which includes the formation of the nucleus, attachment of precipitate flakes, and densification of particles was proposed after microscopic observation. The initial particles synthesized were used to initiate the treatment of synthetic wastewater at the operating condition pH = 7.75 ± 0.5, [Fe]0:[Cu]0 of 2:1, the total metal concentration of 3 mM, [CO32−]0:[M]0 = 1.2:1, and U of 28.66 m/h which results in the total metal removal of 99% and crystallization ratio of 90% and 88% for iron and copper respectively. The conditions were then applied to treat electroplating wastewater and resulted in the total metal removal of 99% for both iron and copper and a crystallization ratio of 83% and 79% for iron and copper, respectively. The treatment provided advantages in terms of treating larger amounts of sludge while eliminating the need to provide seed thus yielding a higher purity of product.

Exploring the sustainable synthesis pathway and comprehensive characterization of magnetic hybrid alumina nanoparticles phase (MHAl-NPsP) as highly efficient adsorbents and selective copper ions removal

This study introduces a novel method for producing magnetic hybrid alumina nanoparticles phase (MHAl-NPsP) tailored specifically for efficient copper (II) ion removal from wastewater. The synthesized MHAl-NPsP underwent comprehensive characterization, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) revealing its rough and porous surface morphology, X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) analysis, BET analysis for surface area measurements, TGA analysis confirming high thermal stability, vibrating sample magnetometry (VSM) analysis confirming successful synthesis through detection of magnetic properties, and X-ray Photoelectron Spectroscopy (XPS) analysis. Remarkably, MHAl-NPsP demonstrated an exceptional adsorption capacity of 52.5 mg/g under optimized conditions of pH 3.5 and an initial copper concentration of 30 mg/L, surpassing previous results significantly. Detailed investigation into adsorption kinetics revealed a pseudo-second-order model, suggesting a predominant chemisorption mechanism. Moreover, analysis using the Langmuir isotherm model showed excellent fitting with an R² value of 0.994, indicating monolayer coverage as the primary adsorption mode. Notably, pH dependency studies indicated enhanced adsorption efficiency with decreasing pH levels, highlighting the significant role of electrostatic interactions. This study underscores the effectiveness and environmental sustainability of the green synthesis approach employed for MHAl-NPsP. Utilizing their magnetic properties, MHAl-NPsP facilitate easy separation and retrieval of adsorbed copper ions, making them highly promising for practical applications in wastewater treatment. The findings advocate for the development of eco-friendly adsorbents to tackle water pollution challenges, providing promising solutions for sustainable environmental remediation.

Comparison of Acid- and Base-Modified Biochar Derived from Douglas Fir for Removal of Copper (II) from Wastewater

Copper is a non-biodegradable heavy metal, and high levels in water bodies cause serious environmental and health issues. Douglas fir biochar has a higher number of carboxylic, phenolic, and lactonic groups, which provide suitable active sites for copper removal. Douglas fir biochar (BC) was modified using 20% solutions of KOH (KOH/BC), H2SO4, (H2SO4/BC), and Na2CO3 (Na2CO3/BC). All materials were characterized using SEM, SEM-EDS, FTIR, TGA, XRD, BET, and elemental analysis. These modifications were done to compare the activations of those sites by measuring copper removal efficiencies. KOH/BC, H2SO4/BC, and Na2CO3/BC materials gave surface areas of 389.3, 326.7, and 367.9 m2 g−1, respectively, compared with pristine biochar with a surface area of 578.9 m2 g−1. The maximum Langmuir adsorption capacities for Na2CO3/BC, KOH/BC, BC, and H2SO4/BC were 24.79, 18.31, 17.38, and 9.17 mg g−1, respectively. All three modifications gave faster kinetics at 2 mg/L initial copper concentrations (pH 5) compared with pristine BC. The copper removal efficiency was demonstrated in four different spiked real water matrices. The copper removals of all four water matrices were above 90% at 2 mg/L initial concentration with a 2 g/L biochar dosage. The competitive effects of Pb2+, Zn2+, Cd2+, and Mg2+ were studied at equimolar concentrations of Cu2+ and competitive ions for all four materials.

Kinetic and thermodynamic investigations of copper (II) biosorption by green algae Chara vulgaris obtained from the waters of Dal Lake in Srinagar (India)

Intake of copper (II) heavy metal ions beyond certain permissible limit raises the risk of cancer, liver damage, stomach discomfort and kidney failure. In present study dead green algae Chara vulgaris was used as a sorbent for the elimination of copper (II) from eutrophicated water of Dal Lake in Srinagar India. The roles of pH, equilibrium time and initial copper (II) concentration were evaluated in the said biosorption process. Various analyses, including FTIR, FE-SEM/EDX, HR TEM, XRD, and BET tests, were conducted to understand the copper (II) biosorption mechanism. In present investigation the adsorption of copper (II) ions (from 100 ppm concentration of copper (II) solution) was maximum (about 70 %± 1.5) under conditions; pH 5, equilibrium time 60 min, adsorbent dosage 0.5 g in 50 mL of copper (II) solution, and temperature of 20 °C. The adsorption was better fitted by the pseudo-second-order rate model. The experimental findings indicated the Langmuir model was better suited to the given adsorption processes. The said model demonstrated the involvement of both physical and chemical factors underlying the mechanism of process. The values of thermodynamic parameters ΔG0, ΔH0, and ΔS0under given experimental conditions indicated the process to be spontaneous. Moreover, this work presents a fresh approach for environmentally friendly and affordable extraction of copper (II) from wastewater, utilizing algae Chara vulgaris as a biosorbent. The unique biochemical composition of Chara vulgaris demonstrates a remarkable affinity for copper (II) ions, offering a sustainable approach to mitigate copper pollution.

Copper recovery from treatment of simulated copper-iron wastewater using fluidized-bed homogeneous crystallization technology

Electroless plating wastewater contains highly soluble Cu-EDTA complex which poses challenges for copper recovery using conventional methods. These complexes are destroyed first using Fenton process producing treated solutions with iron concentrations that may interfere copper recovery. The purpose of this study was to confirm the influence of trace amount of iron on copper removal, crystallization, and copper salt recovery using fluidized-bed homogeneous crystallization (FBHC) process. By varying several parameters like pH, initial copper and iron concentrations, and metal and precipitant inlet flowrate and molar ratio, the optimized conditions include pHe of 6.5–7.0, inlet flowrate of 15 mL min−1, and MR of 1.5. The effects of variable copper (3.15–9.44 mM) and iron concentrations (0.36–1.08 mM) were examined. The addition of iron had no significant impact on copper removal mainly due to its minimal presence in the solution, but a trend of decreasing, then increasing, copper crystallization ratio was observed at higher iron concentrations. The study recorded copper removal and crystallization rates from 88% to 96% and 75% to 95%, respectively, with varying iron concentrations. Characterization analyses of precipitates confirmed predominant presence of malachite and azurite. The FBHC's ability to obtain high purity spheroidal solid salts enables resource recovery and catalyzes strategies for circular economy practices.

Central composite design for the removal of copper by an Adansonia digitata

Biosorption, an alternative to traditional methods such as precipitation, ion exchange, electrochemical treatment, and evaporative recovery, is being considered as a potential means for removing heavy toxic metals from waste solution. This method is especially effective when the concentration of the heavy metal ion is low. A central composite design (CCD) was used in this study to maximize copper removal utilizing Adansonia digitata (baobab) as a biosorbent. Using response surface approach, the impacts of initial copper content, biosorbent dose, Temperature and pH were examined. The CCD enabled the discovery of optimal copper removal conditions. The percentage of metal clearance (CCD) was examined as a result of the influence of various process parameters utilizing a central composite design. A quadratic model based on the CCD was used to model the reaction. The analysis of variance (ANOVA) identified the most significant experimental design response factor. The optimal circumstances for Adansonia digitata (baobab) were pH of 7.1, bio sorbent dose of 0.3 g, beginning copper content of 48.4 mg/L, Temperature 390 C and metal removal of 84.26%. Under these optimal conditions, the experimental biosorption percentage was 76.93. The findings suggest that Adansonia digitata has the capacity to efficiently remove copper from aqueous solutions. This study adds to our understanding of the use of natural materials for heavy metal cleanup.

An energy efficient hybrid membrane technique for the removal of toxic metals from aquatic environment

Electrodeionization (EDI), integrates electrodialysis (ED) and ion exchange (IE) technology. The purpose of this study is to utilize an EDI unit for eliminating copper from wastewater. This process was demonstrated using a three-compartment system, comprising a central compartment filled with a cation exchange resin (CER), separated from the anodic and cathodic chambers by two cationic exchange membranes (CEM), with the anode and cathode placed in the anodic and cathodic chambers, respectively. Purolite C 160 was used to showcase how operational variables, such as initial concentration, contact duration, resin dosage, and temperature, were optimized for the most effective copper removal during batch mode operation. The optimized conditions were an initial concentration of 100 ppm, a Purolite C dose of 0.5 g/L, a contact time of 1 h, and a pH of 8. At an initial copper concentration of 100 ppm and a supply voltage in the range of 10 to 25 V, the highest copper removal achieved was close to 99.98 per cent. For this study, copper was eliminated in the described experiments up to 99.98%, with energy consumption in the EDI unit varying between 3.87 and 25.29 kWh per kg of removed copper.

Copper(II) ion removal from aqueous solutions using alginate nanoparticles/ carboxymethyl cellulose/ polyethylene glycol ternary blend: Characterization, isotherm and kinetic studies

This study addresses the critical issue of removing copper(II) ions from water using an eco-friendly approach with natural biomaterials. Alginate, a natural polysaccharide, is employed as the primary adsorption material. The study involves the conversion of alginate into nanoparticles, and a ternary blend is prepared by mixing alginate nanoparticles with carboxymethyl cellulose and polyethylene glycol (AL-NPs/CMC/PEG). The blend's morphological and structural transformations have been comprehensively investigated using techniques such as DLS, FT-IR, XRD, TGA, and SEM. Batch experiments were conducted systematically to investigate crucial parameters, such as contact time (60–300 min), initial copper concentration (62.5 ppm–1000 ppm), solution pH (2–8), and adsorbent dosage (1–5 g). The results obtained are highly encouraging, revealing an impressive 80.9 % efficiency in the removal of copper ions. The acquired experimental data were then subjected to analysis with Langmuir and Freundlich, isotherm, as well as pseudo-first and pseudo-second-order kinetics studies. The outcomes from these isotherm and kinetics models indicated a favorable fit with the Freundlich isotherm, suggesting a strong affinity between the adsorbent and the metal ions. Furthermore, the kinetic studies revealed that the adsorption process closely adheres to pseudo-second-order kinetics, underlining the efficiency and reliability of the adsorption process. From desorption studies, 0.1 M HCl was an extremely effective eluant when compared to HNO3 and EDTA. It could be reused three time with appreciate efficiency. The research underscores the potential for an environmentally sustainable solution to address the persistent environmental challenge posed by copper ion contamination.

Kinetic Modeling of Electromembrane Extraction of Copper using a Novel Electrolytic Cell Provided with a Supported Liquid Membrane

The aim of this study is to investigate the kinetics of copper removal from aqueous solutions using an electromembrane extraction (EME) system. To achieve this, a unique electrochemical cell design was adopted comprising two glass chambers, a supported liquid membrane (SLM), a graphite anode, and a stainless-steel cathode. The SLM consisted of a polypropylene flat membrane infused with 1-octanol as a solvent and bis(2-ethylhexyl) phosphate (DEHP) as a carrier. The impact of various factors on the kinetics constant rate was outlined, including the applied voltage, initial pH of the donor phase solution, and initial copper concentration. The results demonstrated a significant influence of the applied voltage on enhancing the rate of copper mass transfer across the membrane. As the applied voltage increased, the rate constant also increased. Additionally, increasing the pH of the solution led to an initial elevate in the rate constant, reaching a maximum value at pH 5, after which it started to decline. Moreover, higher initial copper concentrations had an adverse effect on the rate constant. Notably, the concentration decay profiles observed under different operating conditions followed first-order kinetics, with correlation coefficients exceeding 0.99. The elucidation of this discovery emanated from a remarkable and striking congruence between the experimental data and the mathematical underpinnings of the first-order kinetics model. This serendipitous alignment profoundly reinforced the robustness, veracity, and unwavering reliability of meticulously obtained results, amplifying the credibility and trustworthiness of the present comprehensive study.

Adsorption of Copper Ions from Aqueous Systems Using Moss Peat: Reaction Kinetics and Adsorption Isotherm

The removal of copper ions from aqueous systems using moss peat was investigated. Kinetic experiments were conducted at a constant temperature, pH, and initial copper concentration. The data obtained from the kinetic experiments were analysed and fitted well using the pseudo-second-order model. The data of the isotherm experiment were modelled and fitted well with the Langmuir models. This finding suggests that copper ions are chemically adsorbed on the moss peat and assume monolayer adsorption. The optimum pH for copper ion adsorption by moss peat was investigated over a range of (2-4.5), and it was found that the maximum adsorption capacity of moss peat was achieved at pH 4.5. The results of this study suggest the potential use of moss peat as an effective material for the adsorption of copper ions from aqueous solutions under a range of environmental conditions.

Influence of impeller clearance, impeller size and baffles on copper sorption on zeolite NaX: Do the size and position really matter?

Even though optimal mixing parameters may significantly influence the sorption process and its costs, the influence of hydrodynamics on sorption in a batch reactor hasn't yet been adequately studied. In this study, the hydrodynamic conditions produced by pitched blade turbine (PBT) impellers of various diameters and positions in baffled and unbaffled reactors were investigated. The objective was to investigate their influence on the just suspended impeller speed (NJS), power consumption per zeolite mass and the sorption process at the same temperature, initial copper solution concentration, and zeolite particle size in all the experiments conducted. The results show that NJS generally decreases as impeller diameter increases and is lower in the reactor without baffles. A transient multiphase computational fluid dynamics model was developed to provide valuable insight into the complex flow kinetics and it was found that the further the impeller is from the bottom of the baffled reactor the wider is the secondary suspension flow and the intensity of the flow below the impeller decreases. For this reason, complete suspension of the NaX zeolite particles in the solution was achieved at a higher PBT impeller speed. Due to the swirling motion of the suspension, this phenomenon is not observed in the unbaffled reactor for all the impellers used besides the smallest one. The power consumption per zeolite mass, at the state of complete zeolite suspension, increases in baffled reactor and decreases in unbaffled reactor with increasing impeller diameter having significantly lower values in the unbaffled reactor. The significantly lower power consumption per zeolite mass in an unbaffled system could be attributed to, not only the generally lower NJS values, but also to the resistance force which baffles make to the tangential fluid flow. The Ritchie model and Mixed surface reaction and diffusion controlled adsorption kinetic model were used for the kinetic analysis of the experimental kinetic data. The kinetic results indicate that the process is faster when the impeller is at the standard of bottom clearance, regardless of the presence of the baffles.