Equilibrium and Kinetic Studies on Adsorption of Neutral and Ionic Species of Organic Adsorbates from Aqueous Solutions on Activated Carbon
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PROVIDER: S-EPMC11243464 | biostudies-literature | 2024 Jun
REPOSITORIES: biostudies-literature
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Project description:The adsorption of methyl orange (MO) from aqueous solutions onto a KOH-activated polypyrrole-based adsorbent (PACK) was investigated using batch and fixed-bed column techniques. The structural, thermal, and morphological properties of the PACK, analyzed by various methods, support its applicability as an adsorbent. An adsorption kinetic study revealed a preferably pseudo-second-order (R2 = 0.9996) and rate-limiting step controlled by both film and intra-particle diffusions. The thermodynamic adsorption tests resulted in negative ΔG°, ΔH°, and ΔS° values, which decreased as the temperature and concentration increased, indicating the spontaneous and exothermic adsorption over 25-45 °C. The adsorption isotherms fit the experimental data in the order of Langmuir ≈ Freundlich > Temkin, with evidence of adsorption operating well via the monolayer physical adsorption process, and maximum monolayer adsorption ranging from 520.8 to 497.5 mg/g. The breakthrough curve of the fixed-bed column experiment was modeled using the Thomas, Yoon-Nelson, and Hill models, resulting in an equilibrium capacity of 57.21 mg/g. A 73% MO recovery was achieved, indicating the possibility of column regeneration. Compared to other adsorbents reported, PACK had comparable or even superior capacity toward MO. For cost-effectiveness, similar nitrogen-containing polymeric wastes could be exploited to obtain such excellent materials for various applications.
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Project description:The lack of adequate treatment for the removal of pollutants from domestic, hospital and industrial effluents has caused great environmental concern. Therefore, there is a need to develop materials that have the capacity to treat these effluents. This work aims to develop and characterize an activated charcoal from olive pomace, which is an agro-industrial residue, for adsorption of Nimesulide in liquid effluent and to evaluate the adsorption kinetics and equilibrium using experimental design. The raw material was oven dried at 105 °C for 24 h, ground, chemically activated in a ratio of 1:0.8:0.2 of olive pomace, zinc chloride and calcium hydroxide and thermally activated by pyrolysis in a reactor of stainless steel at 550 °C for 30 min. The activated carbon was characterized by Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffractometry (XRD), Brunauer, Emmett and Teller (BET) method, Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), density and zero charge potential analysis. The surface area obtained was 650.9 m2 g-1. The kinetic and isothermal mathematical models that best described the adsorption were PSO and Freundlich and the highest adsorption capacity obtained was 353.27 mg g-1. The results obtained showed the good performance of activated carbon produced from olive pomace as an adsorbent material and demonstrated great potential for removing emerging contaminants such as Nimesulide.
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Project description:The present study is aimed to assess the adsorptive potential of carbonaceous material for the acyclovir (ACVR) removal from the aquatic environment using batch and fixed-bed processes. In batch mode, the impact of various process conditions (contact time, pH, adsorbent dose, initial ACVR concentration, and temperature) on ACVR adsorption was investigated. Experimental results revealed that Langmuir isotherm and the pseudo-second-order kinetic model adequately represent the ACVR adsorption mechanism, indicating homogeneous adsorption. The process was found exothermic and spontaneous. Thermodynamic studies concluded that adsorption is a result of both physisorption and chemisorption. To understand the dynamic regime for the design of large-scale column studies, experimental data obtained from breakthrough curve were fitted to various analytical kinetic models. Yan model followed by Thomas model demonstrated a greater correlation of breakthrough data, confirming that the results are significant and are in line with Langmuir isotherm and pseudo-second-order kinetic. G-AC exhibits sufficient adsorption capacity for ACVR. Hence, it is concluded that it can be used in a fixed-bed column in continuous mode for the treatment of ACVR-contaminated wastewater.Graphical abstractSupplementary informationThe online version contains supplementary material available at 10.1007/s11696-023-02810-7.
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Project description:A molecular simulation study is reported on glucose recovery from aqueous solutions by adsorption in metal-organic framework MIL-101. The F atom of MIL-101 is identified to be the most favorable adsorption site. Among three MIL-101-X (X = H, NH2 or CH3), the parent MIL-101 exhibits the highest adsorption capacity and recovery efficacy. Upon functionalization by -NH2 or -CH3 group, the steric hindrance in MIL-101 increases; consequently, the interactions between glucose and framework become less attractive, thus reducing the capacity and mobility of glucose. The presence of ionic liquid, 1-ethyl-3-methyl-imidazolium acetate, as an impurity reduces the strength of hydrogen-bonding between glucose and MIL-101, and leads to lower capacity and mobility. Upon adding anti-solvent (ethanol or acetone), a similar adverse effect is observed. The simulation study provides useful structural and dynamic properties of glucose in MIL-101, and it suggests that MIL-101 might be a potential candidate for glucose recovery.
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Project description:A Metal-Organic Framework (MOF), iron-benzenetricarboxylate (Fe(BTC)), has been studied for the adsorptive removal of azo-dye Orange II from aqueous solutions, where the effect of various parameters was tested and isotherm and kinetic models were suggested. The adsorption capacities of Fe(BTC) were much higher than those of an activated carbon. The experimental data can be best described by the Langmuir isotherm model (R² > 0.997) and revealed the ability of Fe(BTC) to adsorb 435 mg of Orange II per gram of adsorbent at the optimal conditions. The kinetics of Orange II adsorption followed a pseudo-second-order kinetic model, indicating the coexistence of physisorption and chemisorption, with intra-particle diffusion being the rate controlling step. The thermodynamic study revealed that the adsorption of Orange II was feasible, spontaneous and exothermic process (-25.53 kJ·mol-1). The high recovery of the dye showed that Fe(BTC) can be employed as an effective and reusable adsorbent for the removal of Orange II from aqueous solutions and showed the economic interest of this adsorbent material for environmental purposes.
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Project description:The variables examined were initial fluoride concentration, ZIF-8 and Uio-66 dosage, pH, and contact time. The residual concentration of fluoride was measured by a spectrophotometer. According to BET, the specific surface area of the ZIF-8 and Uio-66 was 1050 m2/g and 800 m2/g, respectively. Total pore volume and average pore diameter of the ZIF-8 and Uio-66 were 0.57 cm3/g, 0.45 cm3/g and 4.5 nm, 3.2 nm, respectively. The best pH for fluoride adsorption was neutral conditions. By increasing the ZIF-8 and Uio-66 dose, the fluoride uptake increased at first, but then decreased. Also, the maximum adsorption for ZIF-8 and Uio-66 was observed in adsorbent dose 0.2 and 0.6 g/L, respectively. The best model for describing kinetic and isotherms of fluoride adsorption were the pseudo-second-order model and Langmuir isotherm model, respectively. Based on the Langmuir model, the adsorption capacity of fluoride by ZIF-8 and Uio-66 was reported to be 25 mg/g and 20 mg/g, respectively.
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Project description: Not available
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Project description:For this data article the adsorption of Basic Blue 41 (BB 41) dye by activated carbon derived from filamentous algae (AAC) of available in agriculture waste as cheap adsorbents were examined. Activated carbon has been widely used as an adsorbent regard to its massive specific surface area, high porosity, reusability and thermal stability for the removal of pollutants from effluent. These filamentous algae grow widely in irrigation streams, causing decreasing speed of water flow and are not even eaten by livestock so are considered agricultural wastes. They can be used as precursors for activated carbon preparation and as adsorbent for the dye removal. The data of initial dye concentration (50-200 mg//L), pH of dye solution (3-9), adsorbent dosage (0.25-2 g/L), and contact time (5-200 min), were assessed. The structure of AAC was characterized by X-ray diffraction and Fourier transforms infrared spectroscopy. Activated carbon with a 94% removal of dye at concentration of 100 mg/L, pH 9, and adsorbent dose 1 g/L after 90 min. The data of isotherms and Kinetics indicated that the experimental data are fitted to Langmuir and second-pseudo-order models. Under the optimum conditions, maximum adsorption capacity of the AAC in Langmuir model enhanced to amount of 125 mg/g. According to the experimental data, filamentous algae are a suitable raw material for activated carbon production.
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