Effects Of Impregnation Ratio Research Articles

Magnetic pomegranate peels activated carbon (MG-PPAC) composite for Acid Orange 7 dye removal from wastewater

A magnetic pomegranate peels activated carbon (MG-PPAC) nanocomposite (23.46–26.75 nm) was prepared as an effective adsorbent for Acid Orange 7 (AO7) dye removal from wastewater. The effects of impregnation ratio and activation temperatures (600–900 °C) on the specific surface area and pore morphology were studied. BET, SEM, EDX, FT-IR, XRD and VSM are considered the synthesized composite MG-PPAC. The prepared magnetic composite at 700 °C activation temperature and impregnation ratio 1/2 (peels/ZnCl2) exhibited 513.34 m2/g surface area, 0.4025 cm3/g volume of the total pores, and 3.1364 nm mean diameter of the pores. The magnetization saturation, remanence and coercivity of the MG-PPA composite were 14.116 emu/g, 0.50685 emu/g, and 19.705 G, respectively. Also, the composite MG-PPAC was in a super-paramagnetic state at room temperature and could be gathered within 5 S (less than 5 S) with an external magnetic field. The impact of pH, adsorbent dose, initial concentration of adsorbate (AO7 dye), and time of contact have been studied to optimize the removal process. Langmuir, Freundlich and Temkin isotherm models were used to investigate MG-PPAC adsorption behavior for AO7 dye. Applicability of the Langmuir isotherm model demonstrates a monolayer adsorption AO7 dye removal process, and the maximum monolayer capacity (Qm) attained from linear solvation of LIM is 322.58 mg/g. Furthermore, the highest removal was 99.53% at pH 2.25. Also, the adsorption process was tested using like pseudo-first-order, pseudo-second-order, intraparticle diffusion, film diffusion, and Elovich models. The pseudo-second-order model is well-fitted to the operational data of AO7 dye removal.

A mechanism study of methylene blue adsorption on seaweed biomass derived carbon: From macroscopic to microscopic scale

Biomass based active adsorbent can be prepared by activation process to adsorb dyes. In this study, using macroalgae as raw material, the biomass based activated carbon material was prepared by NaOH activation method to adsorb methylene blue. The activated adsorbent with high specific surface area (1238.491 m2 g−1) was characterized by BET, XRD, FTIR and XPS. The effects of impregnation ratio, amount of adsorbent, pH and contact time on the adsorption activity of biochar on MB were evaluated. The adsorption kinetics, molecular dynamics and density functional theory were discussed. The maximum MB removal efficiency of SWAC reached 98.56 % at 30 °C and pH= 5 which is due to its large specific surface area and mesoporous slit structure. MD simulation shows that MB molecules were adsorbed on carbon layer through face-to-face stacking. DFT calculation and subsequent electron structure analysis suggested that a synergistic effect of π-π stacking, cation-π interaction, and electrostatic interaction could help stabilize adsorbed MB molecules. And an excellent adsorption capacity SWAC is due to its graphitic N sites for high electronegativity.

The effect of impregnation ratio on the characteristics of activated carbon made from rubber fruit shells with KOH as the activation medium

The rubber fruit shell (RFS) activated carbon has been made using KOH as a chemical activating agent with several variations of the impregnation ratio (1:3, 1:4, and 1:5). To ascertain the impact of the impregnation ratio on the attributes of the produced activated carbon, analysis was carried out using thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) method, X-ray diffraction, and a field emission scanning electron microscope. In the impregnation ratio, 1:5 was carried out as the best result; the value for BET surface area and nitrogen adsorption isotherms were 160 m2/g and 62 cm3/g, where the average pore size diameter was 4.6 nm. Besides, this activated carbon also has around 78.40% carbon. According to the findings of this investigation, the impregnation ratio affects the performance of using KOH as an activator to produce activated carbon from rubber fruit shells. In addition, it could be indicated that the RFS has the potential to be an alternative source of relatively inexpensive activated carbon because the raw materials are available in large quantities.

The effect of impregnation ratio on the yield of corn cob activated carbon by chemical activation

Agricultural waste biomass as a precursor for the synthesis of activated carbons has increased in recent years. In spite of transportation cost, agricultural waste biomass is one of an environmentally friendly, readily available and known as renewable sources compared to conventional activated carbon which is very expensive and exhaustible. That is the main reason activated carbon derived from agricultural waste biomass has been widely used in a variety of applications in the environment and industry for the separation, retrieval, modification, and removal of diverse substances in the liquid and gas phases. The purpose of this research is to produce activated carbon (AC) from corncob through carbonization followed by chemical activation with sodium hydroxide. Initially, the corncob was ground and sieved into a powder form with a mesh size of 500 µm. Later, the powder was chemically activated with sodium hydroxide at different impregnation ratios (1:1, 1:2, and 1:4) under activation temperatures of 200 oC. The percentage of carbon yield and ash content were evaluated using a mathematical approach. The results revealed that the sample impregnated at ratio of NCAC 1:4 showed the lowest ash content (6.58 %) with highest carbon yield of 20.52 %. As the impregnation ratios of sodium hydroxide increases, these entrapped chemicals in the activated corncob contributed in high carbon yield and reduced ash content.

Comprehensive characterization of high surface area activated carbon prepared from olive pomace by KOH activation

The use of abundant and inexpensive biomaterials such as agricultural by-products/wastes in the production of activated carbon has attracted considerable attention in recent years. Olive pomace (OP) is a solid waste resulting after extracting oil from olives in the olive oil production processes. OP was used as a precursor for the preparation of activated carbon as it is low-cost and abundantly available. In the experimental study, OP was chemically activated at various impregnation ratios using KOH as an activating agent. The effects of impregnation ratio and activation temperature on textural and morphological structure, surface chemistry, and surface area of prepared activated carbons were investigated. The OP-based activated carbons were characterized by SEM-EDX, BET surface area, iodine number, FTIR, pHpzc, and elemental analysis. The activated carbons prepared had a specific surface area from 385.481 m2/g to 2451.770 m2/g, micropore volume from 0.1440 cm3/g to 0.8670 cm3/g, and mesopore volume from 0.1108 cm3/g to 0.7540 cm3/g. The increase in both activation temperature and impregnation ratio resulted in a higher specific surface area and micropore volume. Activation temperature and impregnation ratio significantly influenced the characteristics and yield of activated carbon. Based on the results obtained by the characterization studies, we can suggest that the high surface area activated carbons can be produced from olive pomace by KOH activation.

Activated carbon preparation from bagasse and banana stem at various impregnation ratio

The effects of impregnation ratio on characteristics of activated carbon from bagasse and banana stem were analyzed. The precursors were impregnated using phosphoric acid (H3PO4) solution as the activator at a ratio of the activator to the precursor (w/w) of 1:1, 2:1 and 3:1. Pyrolisis was conducted at 400 °C for 15 minutes. The results showed that activated carbon from bagasse has better yield, surface area and total pore volume compared to activated carbon from banana stem. The increased of impregnation ratio decreased the yield and surface area, but increased the total pore volume and pore radius. The highest yield of activated carbon from bagasse and banana stem were 61.87% and 45.53%, respectively. Whereas the highest surface area of activated carbon from bagasse and banana stem were 1,070 m2/g and 915 m2/g, respectively. The activated carbon produced from both precursors contained both micropores and mesopores structures.

Synthesis of Activated Carbon from Citric Acid Residue by Phosphoric Acid Activation for the Removal of Chemical Oxygen Demand from Sugar-Containing Wastewater

Over 2 million tons of citric acid residue (CAR) are generated from citric acid production in China each year. Thus, it is of great significance to find a suitable method for recycling the waste products of citric acid fermentation. Herein, activated carbon (AC) samples were prepared from CAR with phosphoric acid activation. Effects of impregnation ratio, activation time, and activation temperature on pore structure and surface functional group formation were evaluated. AC prepared by 1.5 h of pyrolysis in nitrogen at 550°C from CAR and phosphoric acid at an impregnation ratio of 2.0 (CAR-AC-2.0) had the largest specific surface area (786 m2/g) and total pore volume (0.71 mL/g). The surface morphologies and chemical properties of AC samples were characterized by scanning electron microscopy, thermogravimetric analysis, elemental analysis, and Fourier transform infrared spectroscopy (FTIR), and their adsorption capacities for methylene blue (MB) and iodine were tested. There were rare functional groups on the surfaces of CAR-AC-2.0, and the adsorption amounts of CAR-AC-2.0 for iodine and MB reached up to 729 and 121 mg/g, respectively. CAR-AC-2.0 was an ideal adsorbent for removing organic matters from solutions and wastewater. Adsorption efficiency of CAR-AC-2.0 for chemical oxygen demand (COD) from sugar-containing wastewater was 291.6 mg/g, and the removal efficiency was 80.9% when the dosage was 15 g/L. This study provided a new strategy for removing COD from fermentation wastewater with high efficiency and low cost.

Adsorption of cadmium (II) from simulated wastewater using <i>Albizia saman</i> pod activated carbon in fixed bed columns

The possibility of using Albizia saman pod activated carbon (ASPAC) as an adsorbent in fixed down flow adsorption columns to remove Cd (II) from wastewater was investigated for the purpose of converting the waste to a valuable product. The effects of impregnation ratio, particle size, carbon height, pressure head and initial cadmium Cd (II) concentration on the adsorption of Cd (II) from wastewater were investigated. The obtained adsorption data from the experiment was then fitted into the Hutchin’s bed depth service time (BDST) model to study the columns performance at 15% and 90% breakthrough concentrations. The BDST model constants were determined. An optimal pressure head of 5 cm, impregnation ratio of 1:6, packing height of 3.5 cm, particle size of 75 μm and initial Cd (II) concentration of 0.029 mg/L were found to be the most effective combination, which removed 100 % of the Cd (II) within a service time of 14 hrs. There was a gradual decrease in the percentage of adsorbed Cd (II) with time; the percentage adsorbed became zero at 44, 56 and 86 hours respectively for 2.5 cm, 3 cm and 3.5 cm carbon heights. The breakthrough curves for Cd (II) adsorption maintained the characteristic S-curve for most dynamic studies. Chi-squared test performed on the developed BDST models revealed the goodness of fit of the models for the prediction of the columns performance at all breakthrough concentrations investigated. The use of ASPAC as adsorbent for the removal of Cd (II) from wastewater in adsorption columns is therefore recommended.Key words: Activated carbon, cadmium (II), fixed bed columns, Albizia saman pod, wastewater.

Adsorption Performance and Evaluation of Activated Carbon from Coconut Shell for the Removal of Chlorinated Phenols in Aqueous Medium

In this study, the removal of 2,4-dichlorophenol (2,4-DCP) from aqueous solutions was performed using coconut shell activated carbon prepared by a two-stage self-generated atmosphere method. Coconut shell was first semi-carbonized at 300 °C for an hour followed by chemical activation with zinc chloride (ZnCl2) as activating agent at 500 °C for 2 h. The effect of impregnation ratio on the physical and chemical properties of activated carbons (ACs) was studied. The morphology and surface chemistry of the prepared carbons were characterized using Scanning Electron Microscope (SEM) and Fourier Transform Infrared spectroscopy (FTIR) respectively. The percentage of yield for the prepared AC was found to be in the range of 26.40-38.82 %. AC registered the highest adsorption capacity and was used in subsequent batch adsorption studies consisting of parameters such as initial concentration, adsorbent dosage and solution pH. The maximum surface area of the best produced AC was recorded as 1482 m2 g-1. The adsorption capacity was found to increase in proportional to the initial concentration and adsorbent dosage, while acidic solution pH was more favourable for the adsorption of 2,4-DCP by the prepared AC. The equilibrium time for the adsorption of 20 mg L-1 of 2,4-DCP on 0.5 g of AC was achieved in 180 min. Adsorption isotherms such as Langmuir, Freundlich and Temkin isotherm models were employed to examine the experimental isotherms while the reaction kinetic data was analysed using pseudo-first-order, pseudo-second-order and intraparticle diffusion model. The 2,4-DCP adsorption results fitted best in the Freundlich isotherm as indicated by the high correlation coefficient value (R2 > 0.9949) while the adsorption kinetic fitted to the pseudo second-order model (R2 > 0.9621).

Structural and Electrochemical Characterization of Activated Carbon for Supercapacitors

Electrochemical double layer capacitors (EDLC) are energy storage devices that utilize ion adsorption at the double layer. Their typical electrodes are porous, conductive materials, such as activated carbon. In the present study, activated carbon is derived from pine cone (pinus pinea). The activation process is carried out with the aid of ZnCl2 activating agent. High temperature vacuum treatment is conducted to increase the conductivity of activated carbon. The effects of impregnation ratio (mass of activating agents/mass of precursor), on the resulting porosity, pore size distribution and texture of the activated carbon are examined. Surface area and pore volume are measured by N2 adsorption at 77 K. Raman spectroscopy is used for characterizing the order of the resulting carbon. To achieve high energy density, organic electrolyte (acetonitrile) is used with TEABF4 dissolved in it. Galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy are applied to assess electrochemical behavior. The effect of porous structure and conductivity on the energy and power characteristics of the EDLC is determined and by manipulating the activation process of AC, the properties of EDLC are optimized.

Box-Behnken statistical design to optimize preparation of activated carbon from Limonia acidissima shell with desirability approach

Response surface methodology (RSM) coupled with Box-Behnken design (BBD) was employed to optimize the experimental conditions for the preparation of activated carbon from lignocellulosic biomass, Limonia acidissima shell by chemical activation method using phosphoric acid (H3PO4) as the activating agent. The effects of impregnation ratio, activation temperature and activation time were studied extensively. The obtained activated carbon was evaluated based on the total yield and iodine adsorption value. Each response had been described by a second-order polynomial regression model developed by ANOVA, which could properly determine the experimental data. Using desirability approach in multi-response optimization technique, following optimal conditions had been found such as impregnation ratio (24.21%), activation time (39.83min) and activation temperature (432.35°C). The carbon yield and iodine adsorption value approached 42.6324% and 951.889mg/g under these experimental conditions. The predicted responses presented a good agreement with the experimental data. The results showed that activated carbons prepared by chemical activation method had a high yield as well as high iodine adsorption value. The optimized activated carbon was further characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR).

Effect of Porous Structure of Electrodes on the Properties of AC/AC Edlc with Organic Electrolyte

Electrochemical double layer capacitors (EDLC) are energy storage devices that utilize ion adsorption at the double layer. Their typical electrodes are porous, conductive materials, such as activated carbon. In the present study, activated carbon is derived from pine cone (pinus pinea). The activation process is carried out with the aid of activating agents ZnCl2 and H3PO4. The effects of impregnation ratio (mass of activating agents/mass of precursor), and activation temperature on the resulting porosity, pore size distribution and texture of the activated carbon are examined. Surface area and pore volume are measured by N2 adsorption at 77 K. Textural properties are characterized by HRTEM. To achieve high energy density, organic electrolyte (acetonitrile) is used with TEABF4 dissolved in it. Galvanostatic charge-discharge, cyclic voltammetry and electrochemical impedance spectroscopy are applied to assess electrochemical behavior. The effect of porous structure on the energy and power characteristics of the EDLC is determined and by manipulating the activation process of AC, the properties of EDLC are optimized.

Microwave-assisted preparation and characterization of mesoporous activated carbon from mushroom roots by phytic acid (C6H18O24P6) activation

The present study explored the viability of preparing activated carbon from phytic acid (PA, C6H18O24P6) activation of mushroom roots (MR) via microwave irradiation. Effects of impregnation ratio (IR, g PA: g MR of 1:1, 1.5:1, 2:1) and radiation power (600, 700 and 800W) on porous activated carbon evolution were investigated. The surface area and porous property, surface morphology, and surface chemistry of activated carbons were investigated by nitrogen adsorption/desorption isotherms, scanning electron microscopy (SEM) and Boehm's titration. The yields obtained at all conditions were relatively high, from ∼47% to ∼59%. Well-developed mesoporous structure was prepared with the maximum surface area up to 1024m2/g (IR=1.5:1, 800W). With increasing IR, the mesoporous structure of the activated carbons was more developed, with Sext/Smic up to 95% at IR of 2. The produced activated carbons also showed favorable to surface chemistry with surface acidity higher than 1.85mmol/g. The amounts of total surface functional groups were more approachable with IR increasing. These findings provide a strong evidence to support the potential of developing activated carbon alternatives from PA activation of MR via microwave irradiation.

Preparation of activated carbons from poplar wood by chemical activation with KOH

Low-cost activated carbons were prepared from poplar wood by chemical activation with KOH as a chemical activating agent. The thermal behavior of KOH-impregnated poplar wood was analyzed in detail via the Thermogravimetric analysis (TG, DTG and DSC). Moreover, the effects of impregnation ratio, activation temperature and activation time on the porous structure were investigated. Results showed that KOH has catalytic effect which could promote the pyrolysis of poplar wood at lower activation temperature. The activated carbons from poplar wood with KOH activation could be formed at 550–700 °C. The specific surface area and pore volume of activated carbon increased with increasing the impregnation ratio, activation temperature and activation time. Moreover, influence of increasing impregnation ratio on the porosity of activated carbon is sensitive to activation time. The maximum specific surface area (1551 m2/g) activated carbon with uniform micropores distribution was obtained at activation temperature of 700 °C, impregnation ratio of 3/1 and activation time of 30 min. Carbon skeleton could break seriously when activation temperature is higher than 750 °C.

Synthesis of Activated Carbon from Cocos Nucifera Leaves Agrowaste by Chemical Activation Method

Activated carbon from Cocos nucifera leaves agrowaste was derived. The effect of impregnation ratio was studied by chemical activation method using phosphoric acid as an activating agent. Activated carbon was produced at the activation temperature of 673 K by slow pyrolysis. Nitrogen adsorption isotherms study was performed. Effect of impregnation ratio on the yield, methylene blue number, iodine number, and acid adsorption was studied. The FT-IR spectra show the presence of activated carbon. The TGA investigation reveals that activated carbon is thermally stable at 723 K. The SEM images show the incorporation of activated carbon particles which lead to the systematic change in the morphology of activated carbon. Surface chemistry study predicts the acidic and basic functional groups of Cocos nucifera leaves activated carbon.

Adsorption of copper(II) from aqueous solutions on activated carbon prepared from grape bagasse

Activated carbons were prepared from grape bagasse by chemical activation using phosphoric acid and the prepared activated carbons were used to remove copper(II) from aqueous solutions. The effects of impregnation ratio (IR) and activation temperature on activated carbon production were investigated. The produced activated carbons were characterized by N2 adsorption, scanning electron microscopy (SEM), Boehm titration and Fourier transform infrared (FTIR) techniques. The highest surface area (1455 m2/g) and total pore volume (0.88 cm3/g) were obtained at a carbonization temperature of 500 °C with an impregnation ratio of 5/1. The resulting activated carbon was used for removal of copper(II) from aqueous solution. The effects of initial pH, temperature and contact time were investigated. The adsorption isotherm studies were performed and the obtained data were analyzed using Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D–R) equations. The Langmuir and Dubinin–Radushkevich isotherm equations showed better fit for all temperatures and the maximum adsorption capacity of copper(II) was obtained as 43.47 mg/g at 45 °C. Pseudo first order, pseudo second order, Elovich and intraparticle diffusion kinetic models were used in this study to describe the adsorption process. The rate of adsorption was found to conform to the pseudo second-order kinetic model.

Nanoporous carbon materials with enhanced supercapacitance performance and non-aromatic chemical sensing with C1/C2 alcohol discrimination

We have investigated the textural properties, electrochemical supercapacitances and vapor sensing performances of bamboo-derived nanoporous carbon materials (NCM). Bamboo, an abundant natural biomaterial, was chemically activated with phosphoric acid at 400 °C and the effect of impregnation ratio of phosphoric acid on the textural properties and electrochemical performances was systematically investigated. Fourier transform-infrared (FTIR) spectroscopy confirmed the presence of various oxygen-containing surface functional groups (i.e. carboxyl, carboxylate, carbonyl and phenolic groups) in NCM. The prepared NCM are amorphous in nature and contain hierarchical micropores and mesopores. Surface areas and pore volumes were found in the range 218–1431 m2 g−1 and 0.26–1.26 cm3 g−1, respectively, and could be controlled by adjusting the impregnation ratio of phosphoric acid and bamboo cane powder. NCM exhibited electrical double-layer supercapacitor behavior giving a high specific capacitance of c.256 F g−1 at a scan rate of 5 mV s−1 together with high cyclic stability with capacitance retention of about 92.6% after 1000 cycles. Furthermore, NCM exhibited excellent vapor sensing performance with high sensitivity for non-aromatic chemicals such as acetic acid. The system would be useful to discriminate C1 and C2 alcohol (methanol and ethanol).

Removal of Methylene Blue from Aqueous Solution using Porous Biochar Obtained by KOH Activation of Peanut Shell Biochar

Biochar from peanut shell was used as the precursor for the preparation of porous biochar by KOH activation. The pore structures of porous biochar also were characterized by scanning electron microscopy (SEM) and N2 adsorption/desorption. The adsorption performance for the removal of methylene blue (MB) was deeply investigated. The effects of impregnation ratio (KOH/biochar: w/w), activation temperature, and activation time on the removal of methylene blue by porous biochar were evaluated. In addition, the effects of initial MB concentration and pH value on the adsorption process were also studied. The optimum conditions for preparing porous biochar were obtained with 1.5:1 of impregnation ratio, 800 °C of activation temperature, and 90 min of the holding time in activation. Results indicated that the adsorption capacity was high even at higher initial MB concentrations. The adsorption process followed pseudo-second-order kinetics. The experimental adsorption isotherm was found to be best fitted with the Langmuir model, which implying that the adsorption of MB by porous biochar proceeded as a monolayer adsorption, and the maximum monolayer adsorption capacity of MB was 208 mg∙g-1.

Preparation and evaluation of adsorptive properties of micro-mesoporous activated carbon via sodium aluminate activation

A novel activating agent, sodium aluminate (Na[Al(OH)4]), was successfully employed to prepare activated carbon with microporous and mesoporous structure from marine Enteromorpha prolifera biomass waste. The effects of impregnation ratio, activation temperature and activation time during the preparation process, on the properties of produced activated carbon, including BET surface area, micro-mesopore surface area and average pore size, were investigated in detail. In addition, the pyrolysis behavior during the activation process was simulated by thermo-gravimetric analysis. The BET surface area and pore volume of the produced carbon could reach as high as 1374.3m2g−1 and 1.150cm3g−1, respectively. With the acid brilliant scarlet as model adsorbate, adsorption behavior of the obtained activated carbon was studied, and it was found that, the adsorption isothermal data were better fitted by Langmuir model and the maximum monolayer adsorption capacity towards GR was 1000mgg−1. This study confirms the potential of the sodium aluminate as a successful activating agent, which could expand the synthesis methods of activated carbon.

Production and characterization of activated carbons from pumpkin seed shell by chemical activation with ZnCl2

In this study, an activated carbon with high surface area was prepared from pumpkin seed shell by chemical activation with ZnCl2. The effects of impregnation ratio (IR) and activation temperature on the pore structure of the activated carbon were investigated. The activation temperatures and IRs were in the range of 400–600°C and 1:1–4:1, respectively. The chemical and physical properties of the obtained activated carbons were determined. Elemental analysis was applied to determine the C, H, N, and O contents, and Fourier transform infrared spectrophotometry was used to analyze the functional groups. The surface area, pore volumes, pore size distribution, and average pore diameter of the activated carbons were characterized by N2 adsorption at 77 K using the Brunauer–Emmett–Teller (BET), t-plot, and density functional theory methods. The surface morphologies of the pumpkin seed shell and the activated carbon were investigated by scanning electron microscope. The highest BET surface area and total pore volume of the activated carbon were obtained as 1,564 m2/g and 0.965 cm3/g, respectively, at 500°C and with an IR of 3:1. According to the experimental results, pumpkin seed shell is a suitable raw material for activated carbon production.