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Adsorption of hydrogen fluoride onto activated carbon under vacuum conditions: Equilibrium, kinetic and thermodynamic investigations  [PDF]
Bahrami Hussein,Safdari Jaber,Moosavian Ali Mohammad,Torab-Mostaedi Meisam
Chemical Industry and Chemical Engineering Quarterly , 2012, DOI: 10.2298/ciceq110920027b
Abstract: In this study, the adsorption of HF gas by three types of activated carbon has been investigated under vacuum condition. The effects of experimental parameters such as initial pressure of the HF gas, contact time and temperature on adsorption process have been investigated. The results showed that the adsorption of the HF gas onto activated carbon increased by increasing initial pressure of gas, while it decreased with increase in temperature. The Freundlich isotherm model fitted the equilibrium data better than the other isotherm models. Using Langmuir isotherm model, the maximum adsorption capacities of the first type, the second type and third type of activated carbon were 226.4, 268.8 and 258.9 mg/g, respectively. Experimental data were also evaluated in terms of kinetic characteristics of adsorption and it was found that the adsorption process followed well pseudo-second-order kinetics. Thermodynamic parameters, the change of free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) of adsorption were calculated at the temperature range of 28-55°C. The results showed that the adsorption of HF on activated carbon is feasible, spontaneous and exothermic.
Adsorption of rhodamine B by acid activated carbon-Kinetic, thermodynamic and equilibrium studies  [cached]
Shanmugam Arivoli,M. Thenkuzhali,P. Martin Deva Prasath
Orbital : the Electronic Journal of Chemistry , 2009,
Abstract: A carbonaceous adsorbent prepared from an indigenous waste by acid treatment was tested for its efficiency in removing Rhodamine B (RDB). The parameters studied include agitation time, initial dye concentration, carbon dose, pH and temperature. The adsorption followed first order kinetics and the rate is mainly controlled by intra-particle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity (Qm) obtained from the Langmuir isotherm plots were 40.161, 35.700, 38.462 and 37.979 mg/g respectively at an initial pH of 7.0 at 30, 40, 50 and 60 0C. The temperature variation study showed that the RDB adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying the pH of the RDB solutions. Almost 85% removal of RDB was observed at 60 0C. The Langmuir and Freundlich isotherms obtained, positive ?H0 value, pH dependent results and desorption of dye in mineral acid suggest that the adsorption of RDB by Banana bark carbon involves physisorption mechanism.
Removal of phenol from aqueous solution using carbonized Terminalia chebula-activated carbon: process parametric optimization using conventional method and Taguchi’s experimental design, adsorption kinetic, equilibrium and thermodynamic study
Prateek Khare,Arvind Kumar
Applied Water Science , 2012, DOI: 10.1007/s13201-012-0047-0
Abstract: In the present paper, the phenol removal from wastewater was investigated using agri-based adsorbent: Terminalia chebula-activated carbon (TCAC) produced by carbonization of Terminalia chebula (TC) in air-controlled atmosphere at 600 °C for 4 h. The surface area of TCAC was measured as 364 m2/g using BET method. The surface characteristic of TCAC was analyzed based on the value of point of zero charge. The effect of parameters such as TCAC dosage, pH, initial concentration of phenol, time of contact and temperature on the sorption of phenol by TCAC was investigated using conventional method and Taguchi experimental design. The total adsorption capacity of phenol was obtained as 36.77 mg/g using Langmuir model at the temperature of 30 °C at pH = 5.5. The maximum removal of phenol (294.86 mg/g) was obtained using Taguchi’s method. The equilibrium study of phenol on TCAC showed that experimental data fitted well to R–P model. The results also showed that kinetic data were followed more closely the pseudo-first-order model. The results of thermodynamic study showed that the adsorption of phenol on TCAC was spontaneous and an exothermic in nature.
Adsorption of Quaternary Ammonium Compounds onto Activated Sludge  [PDF]
Rong Ren, Dongfang Liu, Kexun Li, Jie Sun, Chong Zhang
Journal of Water Resource and Protection (JWARP) , 2011, DOI: 10.4236/jwarp.2011.32012
Abstract: The performance of activated sludge in the removal of tetradecyl benzyl dimethyl ammonium chloride (C14BDMA) by adsorption from aqueous solution was investigated with different PH, contact time, ionic strength and temperature. Equilibrium was achieved within 2 h of contact time. The adsorption capacity increased largely with increasing solution pH and remained constant above pH 9. The ionic strength had a negative effect on C14BDMA removal. The adsorption isotherms were analyzed by Langmuir and Freundlich isotherm models, and equilibrium partitioning data was described well by both models. Kinetics data was best described by the pseudo second-order model. Experimental results indicated that the adsorption was favorable at lower temperatures. Thermodynamic parameters, including the Gibbs free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0), were also calculated. These parameters indicated that adsorption of C14BDMA onto activated sludge was feasible, spontaneous and exothermic in the temperature range of 15-35℃. The activated sludge was shown to be an effective adsorbent for C14BDMA.
Hexavalent chromium removal from aqueous solution via adsorption on granular activated carbon: Adsorption, desorption, modeling and simulation studies
Mina Gholipour,Hassan Hashemipour,Maryam Mollashahi
Journal of Engineering and Applied Sciences , 2011,
Abstract: Hexavalent chromium is one of the contaminants recognized as a carcinogenic and mutagenic agent. Therefore, it is essential to remove these components from wastewater before disposal. In this study, removal of hexavalent chromium via adsorption on commercial granular activated carbon (GAC) was investigated as a function of adsorbent dosage, initial solution pH, initial Cr(VI) concentrations, contact time and temperature. The batch experiments were conducted at three temperatures (17, 27 and 37°C) and the results showed that Cr(VI) removal kinetics obeys pseudo second order rate equation. Equilibrium studies showed that the experimental data fitted well with Longmuir isotherm adsorption model. Thermodynamic parameters were also determined and results suggest that the adsorption process is a spontaneous and endothermic. reversibility of Cr(VI) adsorption and repeated availability performance of the adsorbent, was investigated by desorption process. In addition, artificial neural network (ANN) was utilized to simulate the experimental data. The results showed that the training step of the network was successful and therefore, the simulation could be applied to predict hexavalent chromium removal with high accuracy.
Application of activated carbon derived from scrap tires for adsorption of Rhodamine B

Li Li,Shuangxi Liu,Tan Zhu,

环境科学学报(英文版) , 2010,
Abstract: Activated carbon derived from solid hazardous waste scrap tires was evaluated as a potential adsorbent for cationic dye removal. The adsorption process with respect to operating parameters was investigated to evaluate the adsorption characteristics of the activated pyrolytic tire char (APTC) for Rhodamine B (RhB). Systematic research including equilibrium, kinetics and thermodynamic studies was performed. The results showed that APTC was a potential adsorbent for RhB with a higher adsorption capacity than most adsorbents. Solution pH and temperature exert significant influence while ionic strength showed little e ect on the adsorption process. The adsorption equilibrium data obey Langmuir isotherm and the kinetic data were well described by the pseudo second-order kinetic model. The adsorption process followed intra-particle di usion model with more than one process a ecting the adsorption process. Thermodynamic study confirmed that the adsorption was a physisorption process with spontaneous, endothermic and random characteristics.
Serum Ovarian Steriod Hormones and Some Minerals Concentration in Pregnant Nili-Ravi Buffaloes with or without Pre-Partum Vaginal Prolapse  [PDF]
M. S. Akhtar*, L. A. Lodhi1, I. Ahmad1, Z. I. Qureshi1 and G. Muhammad2
Pakistan Veterinary Journal , 2012,
Abstract: The present study was designed with the objective to determine the hormones (estradiol, progesterone) and minerals (calcium, phosphorus, magnesium, sodium and potassium) in serum of buffaloes suffering from pre-partum vaginal prolapse. A total of 200 buffaloes were included in this study, half of these were suffering with pre-partum vaginal prolapse (affected group) between 7th to 10th months of gestation while the remaining were normal pregnant buffaloes (healthy group). Blood samples were collected to procure serum from each animal. Serum hormones and minerals were determined by ELISA technique and direct colorimetric method, respectively. The mean serum estradiol and magnesium concentrations were significantly higher (P<0.01) whereas progesterone, calcium and phosphorus concentrations were significantly lower (P<0.01) in buffaloes suffering with pre-partum vaginal prolapse as compared to healthy pregnant buffaloes. It was concluded that the serum hormones (estradiol and progesterone) and minerals (magnesium, calcium and phosphorus) concentrations differ between the vaginal prolapse affected and healthy buffaloes.
Adsorption Kinetics and Thermodynamics Study of Butylparaben on Activated Carbon Coconut Based  [PDF]
Patrick Atheba, N’Guadi Blaise Allou, Patrick Drogui, Albert Trokourey
Journal of Encapsulation and Adsorption Sciences (JEAS) , 2018, DOI: 10.4236/jeas.2016.82003
Abstract: In this work, low cost coconut biochar based activated carbon (CBAC) was used for adsorption of Butylparaben (BPB) from aqueous medium. The prepared CBAC was characterized using BET, Boehm analysis and the adsorption equilibrium, kinetics and thermodynamics studies of BPB adsorption were carried out. During batch adsorption runs, the effects of factors, such as contact time (0 - 300 min), CBAC dose (200 - 800 mg), pH (3 - 11) and solution temperatures (303 - 348 K) were investigated on BPB removal. Experimental results reveal that the BPB removal efficiency on CBAC is higher than 97% under acidic and neutral conditions. Equilibrium data were fitted by Langmuir, Freundlich and Temkin isotherm models with correlation coefficient more than 0.9. The pseudo-second order kinetic model was observed to fit well the adsorption data. Thermodynamic analysis shows positive values of standard Gibb’s free energy, suggesting the non-spontaneity of the process. The changes in enthalpy (0.2 J.mol-1) and entropy (19 J.mol-1) were found to be endothermic with an increase of randomness. The high adsorption efficiency of the synthesized coconut biochar materials with low cost indicates that it may be a promising adsorbent for removing organic compounds.
Experimental, Thermodynamic and Kinetic Studies for the Adsorption of Phenolic Compounds Derived from Oilfield Wastewater by the Corncob Hydrochar  [PDF]
Liangcheng Xie, Kangle Ding, Yan Liu, Mei Zou, Chao Han
Open Journal of Yangtze Oil and Gas (OJOGas) , 2019, DOI: 10.4236/ojogas.2019.44023
Abstract: The corncob hydrochar is prepared by using a stainless autoclave at 230°C for 8 h. The products are characterized by elemental analyzer, Fourier Transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The effects of hydrochar dosage, pH, adsorption time and phenol concentration on the adsorption performance of hydrochar are investigated by means of single-factor experimental analysis. Based on the experiments the adsorption thermodynamic and kinetics are tentatively discussed. The results show that abundant oxygen-containing functional groups are scattered on the surface of the corncob hydrochar. The adsorption kinetics of phenol on the hydrochar corresponds well with pseudo-second-order kinetic model. Thermodynamic studies indicate that Freundlich adsorption isotherm model is much better than Langmuir model in describing the adsorption of phenol on the corncob hydrochar at 25°C - 45°C. This study provides scientific basis for the development of cheap and efficient adsorbents for the removal of phenols derived from oilfield wastewater.
Adsorption and correlation with their thermodynamic properties of triazine herbicides on soils
YANG Wei-chun,LIU Wei-ping,LIU Hui-jun,LIU Guang-shen,
YANG Wei-chun
,LIU Wei-ping,LIU Hui-jun,LIU Guang-shen

环境科学学报(英文版) , 2003,
Abstract: Adsorption of atrazine, prometryne and prometon was determined on six soils with different physical and chemical properties. The adsorption isotherms of three herbicides could well fit Freundlich equation. On all of six soils, adsorption of herbicides increased in the order: atrazine approximately = prometon < prometryne. This order is quite the same to the calculation result of by means of excess thermodynamic properties of triazine. The Freundlich adsorption constants, Kf, showed to have good correlation with organic matter (OM%) of soils for each of these herbicides, suggesting that OM is the main factor, which dominates in the adsorption process of these triazine herbicides.
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