scholarly journals A Statistical Modeling and Optimization for Cr(VI) Adsorption from Aqueous Media via Teff Straw-Based Activated Carbon: Isotherm, Kinetics, and Thermodynamic Studies

2022 ◽  
Vol 2022 ◽  
pp. 1-16
Author(s):  
Surafel Mustefa Beyan ◽  
Sundramurthy Venkatesa Prabhu ◽  
Temesgen Abeto Ambio ◽  
C. Gomadurai
Keyword(s):  
Activated Carbon ◽  
Statistical Modeling ◽  
Aqueous Media ◽  
Thermodynamic Characteristics ◽  
Eragrostis Tef ◽  
Isotherm Models ◽  
Process Conditions ◽  
Order Kinetic ◽  
Modeling And Optimization ◽  
Living Organisms

Currently, the growth of tannery industries causes a significant volume of waste disposal to the environment due to harmful Cr(VI). Long-time exposure to Cr(VI) imposes serious hazards on all living organisms. Hence, the treatment of tannery waste to remove Cr(VI) is not a choice but mandatory. Therefore, this study focused on the removal of Cr(VI) from the aqueous solutions via a teff (Eragrostis tef) straw based-activated carbon (TSAC) which was derived from locally available agricultural solid waste, teff straw (TS). The prepared TSAC was characterized using BET, FTIR, SEM, and XRD. A central composite approach-based RSM analysis was undertaken for statistical modeling and optimization for maximized Cr(VI) removal with respect to four important factors, namely, initial concentration of Cr(VI), the dosage of TSAC, pH, and adsorption time. Optimized values for maximizing adsorption of Cr(VI) (95% of removal) were acquired to be initial Cr(VI) concentration: 87.57 mg/L, TSAC dosage: 2.742 g/100 mL, pH: 2.2, and contact time:109 min. The results from the design of the experiment were also analyzed for the significance of the interaction between the selected process parameters. In addition, the pseudo-second-order kinetic and Langmuir isotherm models were found suitable for describing the adsorption data. The adsorption capacity of Cr(VI) on TSAC was 19.48 mg/g. The observed thermodynamic characteristics reveal that Cr(VI) adsorption on TASC is endothermic in nature. From the results, TSAC had shown a potential Cr(VI) efficiency on optimized process conditions that can be exploited effectively as adsorbent for removal of Cr(VI)-contaminated wastes.

scholarly journals Adsorptive  removal  of  malachite  green  dye  from  aqueous  solution  onto activated carbon of Catha edulis stem as a low cost bio-adsorbent

2020 ◽  
Author(s):  
Gietu yirga Abate ◽  
Adugna Nigatu Alene ◽  
Adere Tarekegne Habte ◽  
Desiew Mekuanint Getahun
Keyword(s):  
Activated Carbon ◽  
Low Cost ◽  
Aqueous Media ◽  
Freundlich Isotherm ◽  
Industrial Effluents ◽  
Aqueous System ◽  
Isotherm Models ◽  
Synthetic Dyes ◽  
Order Kinetic ◽  
Catha Edulis

Abstract Background: The release of hazardous synthetic dyes into industrial effluents has emerged as an environmental problem requiring remediation. The present study focused on the preparation of a new and environmentally-friendly material (adsorbent) for the remediation of aqueous media containing dye. The low cost adsorbent was prepared from locally available khat (Catha edulis) stem which considered as waste and accumulated on waste disposal areas of woldia town, Ethiopia. Comprehensive characterization studies were carried out on the bio-adsorbent such as proximate analyses, specific surface area, and Fourier-Transform Infrared (FTIR) spectroscopy (which shows functional groups on adsorbents surface). Results: The proximate analysis shows the prepared adsorbent has very high fixed carbon content (83.65%), which refers to high quality of the adsorbent. The adsorption performance of the prepared activated carbon was optimize by varying operating parameters such as initial dye concentration (10 mg/L), pH (10), dosage (0.5 g), and contact time (60 min). The maximum removal efficiency of the prepared adsorbent at those optimum conditions was 98.8%. The experimental data was tested by most common kinetics and isotherm models. It was observed that the pseudo-second-order kinetic model fits better with good correlation coefficient and the equilibrium data fitted well with the Freundlich isotherm model. Conclusion: In summery this study demonstrated that the waste bio sorbent could be employed as an effective and eco-friendly alternative for the cleanup of dye-polluted aqueous system.

scholarly journals Removal of organic pollutants from produced water by batch adsorption treatment

2021 ◽  
Author(s):  
Eman Hashim Khader ◽  
Thamer Jassim Mohammed ◽  
Nourollah Mirghaffari ◽  
Ali Dawood Salman ◽  
Tatjána Juzsakova ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Produced Water ◽  
Oxygen Demand ◽  
Powdered Activated Carbon ◽  
Pollutant Removal ◽  
Operating Conditions ◽  
Isotherm Models ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Zeolite X

AbstractThis paper studied the adsorption of chemical oxygen demand (COD), oil and turbidity of the produced water (PW) which accompanies the production and reconnaissance of oil after treating utilizing powdered activated carbon (PAC), clinoptilolite natural zeolite (CNZ) and synthetic zeolite type X (XSZ). Moreover, the paper deals with the comparison of pollutant removal over different adsorbents. Adsorption was executed in a batch adsorption system. The effects of adsorbent dosage, time, pH, oil concentration and temperature were studied in order to find the best operating conditions. The adsorption isotherm models of Langmuir, Freundlich and Temkin were investigated. Using pseudo-first-order and pseudo-second-order kinetic models, the kinetics of oil sorption and the shift in COD content on PAC and CNZ were investigated. At a PAC adsorbent dose of 0.25 g/100 mL, maximum oil removal efficiencies (99.57, 95.87 and 99.84 percent), COD and total petroleum hydrocarbon (TPH) were identified. Moreover, when zeolite X was used at a concentration of 0.25 g/100 mL, the highest turbidity removal efficiency (99.97%) was achieved. It is not dissimilar to what you would get with PAC (99.65 percent). In comparison with zeolites, the findings showed that adsorption over PAC is the most powerful method for removing organic contaminants from PW. In addition, recycling of the consumed adsorbents was carried out in this study to see whether the adsorbents could be reused. Chemical and thermal treatment will effectively regenerate and reuse powdered activated carbon and zeolites that have been eaten. Graphic abstract

scholarly journals Effective Removal of Malachite Green from Aqueous Solutions Using Magnetic Nanocomposite: Synthesis, Characterization, and Equilibrium Study

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Ali Q. Alorabi
Keyword(s):  
Surface Area ◽  
Malachite Green ◽  
Chemical Activation ◽  
Aqueous Media ◽  
Kinetic Studies ◽  
Cost Effective ◽  
Magnetic Nanocomposite ◽  
Bet Surface Area ◽  
Isotherm Models ◽  
Order Kinetic

In this work, magnetized activated Juniperus procera leaves (Fe3O4@AJPL) were successfully prepared via chemical activation of JPL and in situ coprecipitation with Fe3O4. A Fe3O4@AJPL nanocomposite was successfully applied for the elimination of malachite green (MG) dye from aqueous media. The prepared Fe3O4@AJPL adsorbent was characterized by SEM, EDX, TEM, XRD, FTIR, TGA, and BET surface area analyses. The BET surface area and pore size of the Fe3O4@AJPL nanocomposite were found to be 38.44 m2/g and 10.6 nm, respectively. The XRD and FTIR results indicated the formation of a Fe3O4@AJPL nanocomposite. Different parameters, such as pH of the solution (3–8), adsorbent dosage (10–100 mg), temperature (25–45°C), contact time (5-240 min), and initial MG concentrations (20–350 mg/L), for the elimination of the MG dye using Fe3O4@AJPL were optimized and found to be 7, 50 mg, 45°C, 120 min, and 150 mg/L, respectively. The nonlinear isotherm and kinetic studies exhibited a better fitting to second-order kinetic and Langmuir isotherm models, with a maximum monolayer adsorption capacity of 318.3 mg/g at 45°C, which was highly superior to the previously reported magnetic nanocomposite adsorbents. EDX analyses confirmed the presence of nitrogen on the Fe3O4@AJPL surface after MG adsorption. The calculated thermodynamic factors indicated endothermic and spontaneous processes. The desorption of MG dye from Fe3O4@AJPL was performed using a solution of 90% ethanol. Finally, it could be concluded that the designed Fe3O4@AJPL magnetic nanocomposite will be a cost-effective and promising adsorbent for the elimination of MG from aqueous media.

Nanoparticle Fe3O4 magnetized activated carbon from Armeniaca sibirica shell for the adsorption of Hg(II) ions

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6100-6120
Author(s):  
Yinan Hao ◽  
Yanfei Pan ◽  
Qingwei Du ◽  
Xudong Li ◽  
Ximing Wang
Keyword(s):  
Activated Carbon ◽  
Adsorption Capacity ◽  
Ph Value ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Entropy Change ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Initial Concentration

Armeniaca sibirica shell activated carbon (ASSAC) magnetized by nanoparticle Fe3O4 prepared from Armeniaca sibirica shell was investigated to determine its adsorption for Hg2+ from wastewater. Fe3O4/ASSAC was characterized using XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), and BET (Brunauer–Emmett–Teller). Optimum adsorption parameters were determined based on the initial concentration of Hg2+, reaction time, reaction temperature, and pH value in adsorption studies. The experiment results demonstrated that the specific surface area of ASSAC decreased after magnetization; however the adsorption capacity and removal rate of Hg2+ increased 0.656 mg/g and 0.630%, respectively. When the initial concentration of Hg2+ solution was 250 mg/L and the pH value was 2, the adsorption time was 180 min and the temperature was 30 °C, and with the Fe3O4/ASSAC at 0.05 g, the adsorption reaching 97.1 mg/g, and the removal efficiency was 99.6%. The adsorption capacity of Fe3O4/ASSAC to Hg2+ was in accord with Freundlich isotherm models, and a pseudo-second-order kinetic equation was used to fit the adsorption best. The Gibbs free energy ΔGo < 0，enthalpy change ΔHo < 0, and entropy change ΔSo < 0 which manifested the adsorption was a spontaneous and exothermic process.

scholarly journals Comparative study between activated carbon and biochar for phenol removal from aqueous solution

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 6781-6790
Author(s):  
Moammar Elbidi ◽  
Agab Hewas ◽  
Rajab Asar ◽  
Mohamad Amran Mohd Salleh
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Freundlich Isotherm ◽  
Sorption Process ◽  
Isotherm Models ◽  
Phenol Removal ◽  
Order Kinetic ◽  
Fast Kinetics ◽  
Pseudo Second Order ◽  
Maximum Removal

Removal of phenol from wastewater using local biochar (BC) was investigated, while using activated carbon (AC) as a reference material. The main parameters affecting the sorption process were initial concentration, contact time, pH, and temperature. Statistical analysis of the results showed that the maximum removal percent when using AC and BC were 95% and 55%, respectively. Experimental data showed that the removal of phenol has fast kinetics and reached equilibrium within 5 minutes. The Langmuir and Freundlich isotherm models were applied to fit the adsorption experimental data. Pseudo-first order and pseudo-second order kinetic models were employed.

scholarly journals Interpretation of Isotherm Models for Adsorption of Ammonium onto Granular Activated Carbon

2020 ◽  
Vol 11 (2) ◽  
pp. 9227-9241
Keyword(s):  
Activated Carbon ◽  
Granular Activated Carbon ◽  
Freundlich Isotherm ◽  
Solute Concentration ◽  
Isotherm Model ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Synthetic Solution ◽  
Engineering Practices

High amounts of ammonium (NH4+) discharged in receiving water can lead to eutrophication. The adsorption of NH4+ from synthetic solution onto granular activated carbon (GAC) was scrutinized with respect to initial solute concentration (10 mg L−1), solution volume (0.2 L), adsorbent dosage (4 – 20 g), and contact time. Experimental data can be well described by the pseudo-second-order kinetic model (R2 > 0.994) and Freundlich isotherm model (R2 = 0.936), suggesting that chemisorption and multilayer adsorption occurred. Furthermore, this study explored the feasibility of using the Freundlich isotherm model to estimate the removal efficiency or required amount of adsorbent. The result findings indicated that GAC has a good potential to adsorb NH4+ from water and thus giving new insights into environmental engineering practices.

The Kinetics and Equilibrium Thermodynamics Study on the Removal of Direct Blue and Titan Yellow Dyes from Aqueous Media by Modified Rice Husk Char

2020 ◽  
Vol 234 (3) ◽  
pp. 485-503
Author(s):  
Abdul Malik ◽  
Abbas Khan ◽  
Nasrullah Shah ◽  
Muhammad Sufaid Khan
Keyword(s):  
Rice Husk ◽  
Adsorption Process ◽  
Aqueous Media ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
X Rays ◽  
Experimental Conditions ◽  
Titan Yellow ◽  
Direct Blue

AbstractThe use of indigenous natural materials and their modification toward fruitful application is one of the important subjects. Thermal modification of Rice Husk at 400 oC resulted into Rice Husk Char (RHC) which was chemically modified with KOH and was labeled as KOH Modified Rice Husk Char (KMRHC). Both RHC and KMRHC were characterized by using, Fourier transformed infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-rays (EDX) and X-ray diffraction (XRD) before and after their use as adsorbents. The prepared material was applied for the removal of toxic dyes, Direct Blue (DB) and Titan Yellow (TY) from aqueous media. The maximum adsorption capacity of DB and TY dyes on KMRHC were inspected as 30.9 mg/g and 28.6 mg/g, respectively at pH 4 using initial dye concentrations of 80 mg/L containing 2500 mg/L of the adsorbent dose with agitation speed of 240 rpm at 303 K. At the same experimental conditions the highest percentage removal of DB and TY on the adsorbent were observed as 96.6% and 89.3%, respectively. Thermodynamics studies of the adsorption of DB and TY dyes on KMRHC inferred for exothermic and spontaneous process. The value of ΔS is negative which suggested that randomness decreases at the interface of adsorbent-adsorbate during the adsorption. The kinetics study indicated that the experimental data of the adsorption process for both dyes, best fits to pseudo-second order kinetic model. The equilibrium data was tested on Langmuir, Freundlich and Temkin adsorption isotherm models. It was observed that the data are best fit to the Langmuir isotherm model (R2 > 0.99), which suggested that the adsorption process is dominated by chemisorption approach. The overall results suggest that various parameters of the adsorption process were not only affected by the variation in experimental conditions but also by the chemical structure of the adsorbate molecules for the same adsorbent.

scholarly journals Nitrate sorption on activated carbon modified with CaCl2: Equilibrium, isotherms and kinetics

2015 ◽  
Vol 21 (1-1) ◽  
pp. 23-33 ◽  
Author(s):  
Odivan Zanella ◽  
Isabel Tessaro ◽  
Liliana Féris
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Nitrate Removal ◽  
Sorption Process ◽  
Isotherm Model ◽  
Coefficient Of Determination ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Test Statistic ◽  
Chi Square

In this study, nitrate (NO3-) removal from aqueous solutions was investigated using granular activated carbon (GAC) modified with CaCl2. Batch sorption studies were performed as a function of sorbent dose, initial nitrate concentration and pH. Sorption was maximized between pH 3 and 9. Studies on the effect of pH showed that the ion exchange mechanism might be involved in the sorption process. The percentage of nitrate removed increased with increasing sorbent concentration, and the ideal sorbent dose was found to be 20 g?L-1. Four isotherm models-Langmuir, Freundlich, Redlich-Peterson and Sips-were used to fit the experimental data. The Redlich-Peterson isotherm model explained the sorption process well and showed the best coefficient of determination (0.9979) and Chi-square test statistic (0.0079). Using the Sips isotherm model, the sorption capacity (qe) was found to be 1.93 mg nitrate per g of sorbent. Kinetic experiments indicated that sorption was a fast process, reaching equilibrium within 120 min. The nitrate sorption kinetic data were successfully fitted to a pseudo-second-order kinetic model. The overall results demonstrated potential applications of modified GAC for nitrate removal from aqueous solutions.

Comparative studies on adsorptive removal of heavy metal ions by biosorbent, bio-char and activated carbon obtained from low cost agro-residue

2015 ◽  
Vol 73 (2) ◽  
pp. 423-436 ◽  
Author(s):  
Çisem Kırbıyık ◽  
Ayşe Eren Pütün ◽  
Ersan Pütün
Keyword(s):  
Activated Carbon ◽  
Metal Ion ◽  
Low Cost ◽  
Chemical Activation ◽  
Second Order ◽  
Isotherm Models ◽  
Standard Entropy ◽  
Order Kinetic ◽  
Solution Ph ◽  
Pseudo Second Order

In this study, Fe(III) and Cr(III) metal ion adsorption processes were carried out with three adsorbents in batch experiments and their adsorption performance was compared. These adsorbents were sesame stalk without pretreatment, bio-char derived from thermal decomposition of biomass, and activated carbon which was obtained from chemical activation of biomass. Scanning electron microscopy and Fourier transform–infrared techniques were used for characterization of adsorbents. The optimum conditions for the adsorption process were obtained by observing the influences of solution pH, adsorbent dosage, initial solution concentration, contact time and temperature. The optimum adsorption efficiencies were determined at pH 2.8 and pH 4.0 for Fe(III) and Cr(III) metal ion solutions, respectively. The experimental data were modelled by different isotherm models and the equilibriums were well described by the Langmuir adsorption isotherm model. The pseudo-first-order, pseudo-second-order kinetic, intra-particle diffusion and Elovich models were applied to analyze the kinetic data and to evaluate rate constants. The pseudo-second-order kinetic model gave a better fit than the others. The thermodynamic parameters, such as Gibbs free energy change ΔG°, standard enthalpy change ΔH° and standard entropy change ΔS° were evaluated. The thermodynamic study showed the adsorption was a spontaneous endothermic process.

scholarly journals Preparation of Activated Carbon from the Wood of Paulownia tomentosa as an Efficient Adsorbent for the Removal of Acid Red 4 and Methylene Blue Present in Wastewater

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1453
Author(s):  
Sultan Alam ◽  
Muhammad Sufaid Khan ◽  
Wahida Bibi ◽  
Ivar Zekker ◽  
Juris Burlakovs ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Second Order ◽  
Raw Material ◽  
Experimental Result ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Paulownia Tomentosa ◽  
Adsorbent Dosage ◽  
Pseudo Second Order

Paulownia tomentosa, a woody plant that is widely found in Pakistan and in other regions of the world, was used as a raw material to prepare activated carbon using chemical and physical activation methods. Adsorption of the dyes- acid red 4 and methylene blue onto the prepared activated carbon were analyzed by batch experiments. The impacts of different adsorption parameters such as pH, temperature, contact time, initial dye concentration and adsorbent dosage were also evaluated. Equilibrium data were fitted into various isotherm models such as: Langmuir, Temkin and Freundlich. High regression values were achieved with Langmuir isotherm model. Different kinetic adsorption models such as pseudo-first-order, pseudo-second-order and intra-particle diffusion model models were applied. The adsorption kinetics was found to be best-fitted into pseudo-second-order kinetic model. The optimum pH for acid red 4 was around 1 while for methylene blue it was 8. The optimum adsorbent dosage was 0.3 g for both dyes used. The activation energy (Ea) values were 30.57 and 3.712 kJ/mol, respectively for acid red 4 and methylene blue while the enthalpy (ΔH) and entropy (ΔS) values were correspondingly as 24.88/1.1927 kJ/mol and −2843.32/−0.329 J·mol/K for the mentioned dyes. The experimental result showed that the prepared activated carbon was the best in the removal of acid red 4 and methylene blue from aqueous media and therefore, could be preferably used as cheap adsorbent in wastewater treatment.

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