جستجوی مقالات مرتبط با کلیدواژه « Central Composite Design (CCD) » در نشریات گروه « شیمی »

In the present study, NiO-MgO nanocomposite was synthesized by the Sol-gel process. Activated carbon was incorporated with the nanocomposite to yield activated carbon coupled Bimetallic Nanocomposites NiO-MgO-AC. The nanocomposite was utilized in an ultrasonic adsorption process to remove Methylene Blue (MB) dye from the simulated Dye effluent. FT-IR, EDS, and SEM were used to determine the chemical composition and structural morphology. The surface neutrality was calculated using PHPZ C, which was found to be 5.5. The experiments were carried out using a four-factorial central composite design with variables such as sonication time, MB dye concentration, pH, and adsorbent dose. To find Optimal Operating Parameters (OOP), the Response Surface Methodology (RSM) was employed. At a pH of 5.0, sonication time of 6.23 minutes, 0.02 g of the nanocomposite, and 10 mg/L concentration of MB dye. The removal efficacy was found to be 93.983%. Various isotherm models, including Freundlich, Langmuir, Temkin, and Dubinin Radushkevichat 303-313K temperatures, were used to study the adsorption equilibrium. The RL values were less than one, suggesting that the adsorption technique was suitable. Furthermore, the values of n were found to be larger than one, indicating that the Freundlich adsorption model was appropriate. The D-R isotherm provides values of E that were seen to be below 8.0kJ/mole at all temperatures indicating a physisorption process.  The thermodynamics of dye removal were also studied in order to obtain the system's DHo, DSo, and DGo values. The pseudo-first and pseudo-second-order, intraparticle diffusion, Elovich, and Boyd kinetic models were used to determine the kinetics of adsorption. The current study's findings indicated that nanocomposites can be efficiently utilized in waste treatment operations. The simulated dye wastewater treatment system was designed locally and can be efficiently employed on a commercial scale for the treatment of effluent before discharge into main streams to minimize its toxicity to the ecosystem.

The applicability of Zeolitic Imidazolate-67, Modified by Fe3O4 Nanoparticles, was studied for the removal of benzyl paraben from wastewater by adsorption method studied using response surface methodology (RSM). For the adsorption characterization of the adsorbent used in benzyl paraben adsorption, BET, FTIR, XRD, and SEM analyses were performed. The impacts of variables including initial benzyl paraben concentration (X1), pH (X2), adsorbent dosage (X3), and sonication time (X4) came under scrutiny using response surface methodology (RSM). The values of 10 mg L-1, 0.03 g, 7.0, and 4.0 min were considered as the ideal values for benzyl paraben concentration, adsorbent, pH, and contact time, respectively. Adsorption equilibrium and kinetic data were fitted with the Langmuir monolayer isotherm model and pseudo-second-order kinetics (R2: 0.999) with maximum adsorption capacity (92.0 mgg-1), respectively. The predicted values were in agreement with experimental values obtained for the components of the mixture. The values at the optimized process conditions indicated a commercially viable route for optimal removal of dyes from wastewater.

In the present study, the applicability of PSF/Fe2O3 mixed matrix membrane synthesis for eliminating humic acid rapidly from aqueous solutions. Identical techniques, including FT-IR, XRD and SEM has been utilized to characterize this novel material. The investigation showed the applicability of PSF/Fe2O3 mixed matrix membrane as an available, suitable and low-cost adsorbent for proper deletion of humic acid from aqueous media. Also, the impacts of variables including initial humic acids (HAs) concentration (X1), pH (X2), adsorbent dosage (X3), sonication time (X4) came under scrutiny using central composite design (CCD) under response surface methodology (RSM). Additionally, the impacts of the pH of the solution, the amount of nanoparticles, concentration of humic acids (HAs), and contact time were investigated. The experiments have been designed utilizing response surface methodology. In this current article the values of 12 mg L-1, 0.03g, 7.0, 4.0 min were considered as the ideal values for humic acids (HAs) concentration, adsorbent mass, pH value and contact time respectively. The kinetics and isotherm studies proved the appropriateness of the second-order and Langmuir models for the kinetics and isotherm of the adsorption of humic acids (HAs) on the adsorbent. The adsorbent was proved to be recyclable for more than once. Since almost 99.5% of humic acids (HAs) was deleted with ideal adsorption capacities of 105 mg g−1 for humic acid (HAs). The overall results confirmed that PSF/Fe2O3 mixed matrix membrane could be a promising adsorbent material for humic acids (HAs) removal from aqueous solutions.

The applicability of Zeolitic Imidazolate-67 Modified by Fe3O4 Nanoparticles, was studied for eliminating butyl paraben dye from aqueous solutions. Identical techniques including BET, IR, XRD, and SEM have been utilized to characterize this novel material.  The impacts of variables including initial butyl paraben concentration (X1), pH (X2), adsorbent dosage (X3), and sonication time (X4) came under scrutiny using central composite design (CCD) under response surface methodology (RSM). Additionally, the impacts of the pH of the solution, the amount of nanoparticles, concentration of butyl paraben dye, and contact time were investigated. The experiments have been designed utilizing response surface methodology. In this current article the values of 10 mgL-1 , 0.03 g, 7.0, 4.0 min were considered as the ideal values for butyl paraben concentration, adsorbent mass, pH value and contact time respectively. The kinetics and isotherm studies proved the appropriateness of the second-order and Langmuir models for the kinetics and isotherm of the adsorption of butyl paraben on the adsorbent. The adsorbent was proved to be recyclable for more than once. Since almost 99.5% of butyl paraben was deleted with ideal adsorption capacities of 110 mgg−1 for butyl paraben in no time, therefore not only the short-time adsorption process was considered an advantage but also vantages in using Zeolitic Imidazolate-67 Modified by Fe3O4 Nanoparticles like being recyclable, safe, and cost-efficient made it a promising and powerful material for the aqueous solutions.

In this study, TiO2/Ag nano photocatalyst was synthesized by sol-gel method and used for degradation of Chloridazon (CLZ) in aqueous media. The prepared catalyst was characterized using powder X-ray diffractometry (XRD), Fourier transform infra-red (FTIR), and field emission scanning electron microscopy (FESEM) techniques. The Crystallite size of pure TiO2 and Ag/TiO2 nanoparticles was 20 and 60 nm, respectively. The Central Composite Design (CCD) was employed for experimental design and statistical analysis of independent operational parameters. According to the results of Response Surface Methodology (RSM) plots of Design-Expert software, the optimal conditions for each critical variable were as the follows: time at 113 min, pH at 6.8, initial concentration of CLZ at 40 mg/l, and catalyst concentration at 0.83gr/l. The maximum effectiveness in the experimental and predicted CLZ removal was 94.2 and 93.5%, respectively. The outcomes of Analysis of variance (ANOVA) demonstrated high determination coefficient quantities (R2 = 0.9997, Predicted R2=0.9989, and Adjusted R2=0.9994) which validated the reliability of the second-order regression model.

The applicability of Albizia Stem Bark Lebbeck Modified by Fe2 (MoO4)3 nanocomposite synthesis for removing Rhodamine B dye from aqueous solutions has been reported. Identical techniques including BET, IR, XRD, EDX, and SEM have been utilized to characterize this novel material. Also, the impacts of variables including initial Rhodamine B dye concentration (X1), pH (X2), adsorbent dosage (X3), and Sonication time (X4) came under scrutiny using central composite design (CCD) under response surface methodology (RSM).The values of 10 mg L-1, 0.025g, 6.0, 5.0 min were considered as the ideal values for Rhodamine B dye concentration, adsorbent mass, pH value, and contact time respectively. The adsorption equilibrium and kinetic data were fitted with the Langmuir isotherm model and pseudo-second-order kinetics (R2: 0.999) with maximum adsorption capacity (qmax: 98.0 mgg-1) respectively. Thermodynamic parameters (R2: 0.998, ΔG°: -95.58 kJ mol-1, ΔH°: -29.24 kJ mol-1, ΔS°: -131.49 kJ mol-1 K-1) also indicated Rhodamine B dye adsorption is feasible, spontaneous and exothermic. The overall results confirmed that Albizia Stem Bark Lebbeck Modified by Fe2 (MoO4)3 nanocomposite could be a promising adsorbent material for Rhodamine B dye removal from aqueous solutions.

The applicability of Albizia Stem Bark Lebbeck Modified by Fe2(MoO4)3 nanocomposite, was studied for eliminating Methyl Violet dye from industrial wastewater. Identical techniques including (IR, XRD, and SEM) have been utilized to characterize this novel material. The impacts of variables including initial Methyl Violet concentration (X1), pH (X2), adsorbent dosage (X3), and sonication time (X4) came under scrutiny using central composite design (CCD) under response surface methodology (RSM). The values of 20 mgL-1, 0.03 g, 5.0, 3.0 min were considered as the ideal values for Methyl Violet concentration, adsorbent, pH, and contact time, respectively. Adsorption equilibrium and kinetic data were fitted with the Langmuir monolayer isotherm model and pseudo-second-order kinetics (R2: 0.999) with maximum adsorption capacity (120.4 mgg-1), respectively. Thermodynamic parameters (ΔG°: -9.26 kJ mol-1, ΔH°: -29.24 kJ mol-1, ΔS°: -131.49 kJ mol-1 K-1), also indicated Methyl Violet adsorption is feasible, spontaneous and exothermic. Overall results confirmed that Albizia Stem Bark Lebbeck Modified by Fe2(MoO4)3 nanocomposite is an effective adsorbent for removing the toxic dyes from an wastewater.

The applicability of the synthesized CM-β-CD-Fe3O4NPs as a novel adsorbent for eliminating Crystal Violet (CV) dye from aqueous media was investigated. This paper focuses on the development of an effective methodology to obtain the optimum removal conditions assisted by ultrasonic to maximize removal of (CV) dye onto CM-β-CD-Fe3O4NPs in aqueous solution using response surface methodology (RSM). This novel material was characterized by different techniques such as FT-IR, XRD and SEM. The influences of variables such as initial (CV) dye concentration (X1), pH (X2), adsorbent dosage (X3), sonication time (X4) investigated by central composite design (CCD) under response surface methodology. The process was empirically modeled to reveal the significant variables and their possible interactions. The optimization conditions were set as: 10.0 mg L-1, 6.0, 5 min and 0.025 g, for ultrasound time, pH, adsorbent mass, (CV) dye concentration respectively. Finally, it was shown that the adsorption of (CV) dye removal by adsorbent was at pH 6.0. This issue that the sorption of (CV) dye conforms to the pseudo-second-order rate equation and the Langmuir model explains equilibrium data was clearly proven. The maximum monolayer capacity (qmax) was found to be 100.0 mgg-1 for (CV) dye at optimum conditions. The application of Isotherms in obtaining the thermodynamic parameters like free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) of adsorption were confirmed. The exothermicity of the process was proven by negative value of (ΔGo, ΔHo and ΔSo) which showed the affinity of CM-β-CD-Fe3O4NPs synthesis for Crystal Violet (CV) dye deletion.

An economic process was developed via the batch scale for the uranium (VI) stripping in the presence of iron (III) from loaded alamine-336 by ammonium carbonate solution. The optimum conditions were assessed for the uranium (VI) stripping using the central composite design method, which is a subset of response surface methodology. The R-squared, U (VI), and Fe (III) stripping percentages with a value of equal 0.989, 72.61%, and 0.1% were obtained, respectively in the optimum conditions of the U (VI) and Fe (III) stripping from loaded alamine-336. The optimum stripping conditions led to the obtaining of the ammonium carbonate concentration equal to 0.64 mol/L, the phase ratio of 0.8 (O/A), the temperature of 53 , the contact time of 2510 seconds, and the shaking speed of 1100 rpm. Moreover, the stripping kinetics, equilibrium constant, and thermodynamic data were determined to describe the nature of the U (VI) and Fe (III) stripping from loaded alamine-336 by the ammonium carbonate solution. The temperature-dependent data showed that the U (VI) stripping was an endothermic process.

In this work, a novel chemically adsorbent based on Zn2Al-layered double hydroxide (LDH) that modified by indigo carmine (IC) (Zn2Al-LDH/IC) was synthesized. The chemical composition and morphology of the synthesized Zn2Al-LDH/IC were investigated using the X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy analysis. Response surface methodology (RSM) using the central composite design (CCD) is applied to optimize the adsorption process parameters for Cd(II) removal from the aqueous solution using a novel chemically modified nano Zn2Al-layered double hydroxide (Zn2Al-LDH/IC). The combined effect of adsorption parameters such as contact time, initial Cd(II) concentration, adsorbent amount and initial pH of solution were studied. The results obtained by ANOVA analysis displayed the relative significance of the process parameters in the adsorption process. The optimum conditions to remove Cd(II) from aqueous solution were at the initial Cd(II) concentration of 52 mg/L-1, pH 4.13, the adsorbent dose 0.06 g, temperature of 36.5 °C and contact time 36 min. In optimum conditions, high adsorption efficiency and maximum adsorption capacity were 47.3% and 6.11 mg/g, respectively.  Adsorption of Cd(II) by nano Zn2Al-LDH/IC could be well examined with Langmuir and Freundlich isotherms and the pseudo second-order kinetic model was fitted to the adsorption kinetic data. Furthermore, the thermodynamic data exhibited that the adsorption process of Cd(II) by nano Zn2Al-LDH/IC was spontaneously and exothermic.

In the present work a pH-dependent cloud point extraction procedure using pH-sensitive hydrogel polymer was applied for preconcentration and spectrophotometric determination of the Hg(II) as its Thio micher's ketone complex. Central composite design (CCD) and response surface method were applied to design the experiments and find out the optimum conditions. Four factors entitled concentration of hydrogel, HCl, TMK and KCl (to study the salting out effect) were investigated. At the optimum conditions, the analytical characteristics of the method (e.g., limit of detection, linear range, Relative standard deviation) were obtained. Linearity was obeyed in the range of 5-200 ng ml-1 of Hg(II) with a correlation coefficient of 0.987. The detection limit of the method was 1 ng ml-1 for Hg(II) ion. Relative standard deviation (RSD) for 7 replicate determinations of complex mercury with Thio micher's ketone was 3.37%. The interference effect of some anions and cations was also investigated.