scholarly journals Study on efficient removal of clopyralid from water using resorcinol-formaldehyde carbon cryogel

2014 ◽  
Vol 79 (4) ◽  
pp. 481-494 ◽  
Author(s):  
Milan Momcilovic ◽  
Marjan Randjelovic ◽  
Antonije Onjia ◽  
Aleksandra Zarubica ◽  
Biljana Babic ◽  
...  
Keyword(s):  
Amorphous Structure ◽  
High Specific Surface Area ◽  
Isotherm Models ◽  
Experimental Conditions ◽  
Resorcinol Formaldehyde ◽  
Intraparticle Diffusion Model ◽  
Equilibrium Data ◽  
Carbon Cryogel ◽  
Pseudo Second Order ◽  
In The Beginning

Resorcinol-formaldehyde carbon cryogel has been prepared, characterized and used for the removal of commonly used herbicide clopyralid from the aqueous solutions under varying experimental conditions. Carbon has shown a relatively high specific surface area, significant mesoporosity and an amorphous structure. A set of the following isotherm models has been used to interpret the equilibrium data: Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Jovanovic, Hurkins-Jura, and Helsey model. Several models have fitted well although the calculated values for qmax poorly correlate with the data obtained experimentally. The kinetic models of the pseudo-first and pseudo-second-order, the models of Elovich, Bangham and the intraparticle diffusion model have been used for fitting the kinetic data. The rate of the process is fast in the beginning while adsorption equilibrium is attained not until 24 hours. Adsorption was found to be pH dependent and favored in acidic solutions.

Lead (II) Pollution Enhances the Binding of Transgenic Toxin in Brown and Red Soils: Equilibrium and Kinetics

2013 ◽  
Vol 11 (1) ◽  
pp. 501-509
Author(s):  
Xueyong Zhou ◽  
Huifen Liu ◽  
Xianzhi Lu ◽  
Lili Shi ◽  
Jianchao Hao
Keyword(s):  
Genetically Modified Crops ◽  
Red Soil ◽  
Second Order ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Free Energy Of Adsorption ◽  
Intraparticle Diffusion Model ◽  
Equilibrium And Kinetics ◽  
Equilibrium Data ◽  
Pseudo Second Order

Abstract Genetically modified crops, which produce insecticidal toxins from Bacillus thuringiensis (Bt), release the toxins into soils. Although the phenomena of persistence and degradation of Bt toxins have been documented, the effect of heavy metals on the fate of these toxins in soil has not yet been elucidated. The effect of Pb(II) on the adsorption behaviors of Bt toxin in brown and red soil was investigated. With the increase of Pb(II) concentration, the adsorption of Bt toxin in brown and red soil increased. The Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models gave better fitting to the experimental equilibrium data. Values of KL, KF and n increased but RL decreased with the increase of Pb(II) concentration, showing that the Pb(II) promoted the adsorption of Bt toxin in soils. The mean free energy of adsorption (E) ranged from 10.43 to 16.44 kJ mol−1 may correspond to a chemical ion-exchange mechanism. Three kinds of kinetic models, the pseudo-first-order, pseudo-second-order and intraparticle diffusion model, were used to test the experimental data. The results showed that the adsorption of Bt toxin by brown and red soil followed the pseudo-second-order kinetic model. The addition of Pb(II) during the adsorption led to a decrease of the desorption of Bt toxin from soils, indicating that the residual risk of Bt toxin may become larger if soil is polluted by lead.

Caffeine Removal by Adsorption: Kinetics, Equilibrium Thermodynamic and Regeneration Studies

2021 ◽  
Vol 47 (1) ◽  
pp. 95-103
Author(s):  
Ivone Vanessa Jurado Dávila ◽  
Júlia Viola Matzenbacher Hübner ◽  
Keila Guerra Pacheco Nunes ◽  
Liliana Amaral Féris
Keyword(s):  
Adsorption Equilibrium ◽  
Isotherm Models ◽  
Equilibrium Thermodynamic ◽  
Reversible Process ◽  
Experimental Conditions ◽  
First Order ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Adsorption Equilibrium Data ◽  
Influence Of Ph

In this work, it was studied the caffeine removal through the adsorption on granular activated carbon (CAG). The influence of pH, contact time and CAG dosage were analyzed by batch experiments. Adsorption Kinetic was studied using the models of pseudo-first-order and pseudo-second-order. The adsorption equilibrium data was studied with Langmuir, Freundlich, and Redlich-Peterson isotherm models. The process thermodynamic also was studied. It was obtained 88 % of removal under the experimental conditions of natural pH, 60 min of adsorption and 8 g.L-1 of CAG. The kinetic model that showed the best results was the pseudo-secondorder and Langmuir was the isotherm model that best described the adsorption behavior. The thermodynamic parameters obtained showed a spontaneous, endothermic and reversible process. The desorption efficiency also was studied by regenerant solvents. The best results were obtained using a solvent combination of ethyl acetate, ethanol, and water (50:25:25), and it was obtained a caffeine removal of 57 %, achieving 70 % when a new solution is used in each regeneration step.

scholarly journals Adsorption of Phenol from Aqueous Solution Using Lantana camara, Forest Waste: Kinetics, Isotherm, and Thermodynamic Studies

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
C. R. Girish ◽  
V. Ramachandra Murty
Keyword(s):  
Lantana Camara ◽  
Isotherm Models ◽  
Order Model ◽  
Experimental Conditions ◽  
Batch Studies ◽  
Forest Waste ◽  
Monolayer Adsorption ◽  
Experimental Parameters ◽  
Equilibrium Data ◽  
Pseudo Second Order

The present work investigates the potential of Lantana camara, a forest waste, as an adsorbent for the phenol reduction in wastewater. Batch studies were conducted with adsorbent treated with HCl and KOH to determine the influence of various experimental parameters such as pH, contact time, adsorbent dosage, and phenol concentration. The experimental conditions were optimized for the removal of phenol from wastewater. Equilibrium isotherms for the adsorption of phenol were analyzed by Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich isotherm models. Thermodynamic parameters like the Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were also determined and they showed that the adsorption process was feasible, spontaneous, and exothermic in the temperature range of 298–328 K. The kinetic data were fitted with pseudo-second-order model. The equilibrium data that followed Langmuir model with the monolayer adsorption capacity was found to be 112.5 mg/g and 91.07 mg/g for adsorbent treated with HCl and KOH, respectively, for the concentration of phenol ranging from 25 to 250 mg/L. This indicates that the Lantana camara was a promising adsorbent for the removal of phenol from aqueous solutions.

Adsorption Characteristics of Phenol in Aqueous Solution by Pinus massoniana Biochar

2013 ◽  
Vol 295-298 ◽  
pp. 1154-1160 ◽  
Author(s):  
Guo Zhi Deng ◽  
Xue Yuan Wang ◽  
Xian Yang Shi ◽  
Qian Qian Hong
Keyword(s):  
Aqueous Solution ◽  
Ph Value ◽  
Pinus Massoniana ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Adsorbent Dosage ◽  
Salt Ions ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The objective of this paper is to investigate the feasibility of phenol adsorption from aqueous solution by Pinus massoniana biochar. Adsorption conditions, including contact time, initial phenol concentration, adsorbent dosage, strength of salt ions and pH, have been investigated by batch experiments. Equilibrium can be reached in 24 h for phenol from 50 to 250 mg• L-1. The optimum pH value for this kind of biochar is 5.0. The amount of phenol adsorbed per unit decreases with the increase in adsorbent dosage. The existence of salt ions makes negligible influence on the equilibrium adsorption capacity. The experimental data is analyzed by the Freundlich and Langmuir isotherm models. Equilibrium data fits well to the Freundlich model. Adsorption kinetics models are deduced and the pseudo-second-order kinetic model provides a good correlation for the adsorbent process. The results show that the Pinus massoniana biochar can be utilized as an effective adsorption material for the removal of phenol from aqueous solution.

scholarly journals Utilization to Remove Pb (II) Ions from Aqueous Environments Using Waste Fish Bones by Ion Exchange

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Bayram Kizilkaya ◽  
A. Adem Tekınay
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Mechanism ◽  
Cost Effective ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Fish Bones ◽  
Adsorption Capacities ◽  
Aqueous Environments ◽  
Equilibrium Data ◽  
Pseudo Second Order

Removal of lead (II) from aqueous solutions was studied by using pretreated fish bones as natural, cost-effective, waste sorbents. The effect of pH, contact time, temperature, and metal concentration on the adsorption capacities of the adsorbent was investigated. The maximum adsorption capacity for Pb (II) was found to be 323 mg/g at optimum conditions. The experiments showed that when pH increased, an increase in the adsorbed amount of metal of the fish bones was observed. The kinetic results of adsorption obeyed a pseudo second-order model. Freundlich and Langmuir isotherm models were applied to experimental equilibrium data of Pb (II) adsorption and the value ofRLfor Pb (II) was found to be 0.906. The thermodynamic parameters related to the adsorption process such asEa,ΔG°,ΔH°, andΔS° were calculated andEa,ΔH°, andΔS° were found to be 7.06, 46.01 kJ mol−1, and 0.141 kJ mol−1K−1for Pb (III), respectively.ΔH° values (46.01 kJmol−1) showed that the adsorption mechanism was endothermic. Weber-Morris and Urano-Tachikawa diffusion models were also applied to the experimental equilibrium data. The fish bones were effectively used as sorbent for the removal of Pb (II) ions from aqueous solutions.

scholarly journals Synthesis of New Cyclodextrin-Based Adsorbents to Remove Direct Red 83:1

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1880
Author(s):  
José A. Pellicer ◽  
María Isabel Rodríguez-López ◽  
María Isabel Fortea ◽  
Vicente M. Gómez-López ◽  
David Auñón ◽  
...  
Keyword(s):  
Room Temperature ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Freundlich Isotherm ◽  
Intraparticle Diffusion ◽  
Isotherm Models ◽  
Intraparticle Diffusion Model ◽  
Pseudo Second Order ◽  
Physical Interactions ◽  
Resonance Particle

Two cyclodextrins (CDs), γ– and hydroxypropyl (HP)–γ–CDs were used to synthesize new adsorbents by using epichlorohydrin (EPI) as cross-linking agent in order to remove Direct Red 83:1 (DR) from water. Both polymers were characterized in terms of Fourier spectroscopy, nuclear magnetic resonance, particle size distribution and thermogravimetric analysis. Experimental data for both polymers were well fitted to the pseudo-second order and intraparticle diffusion model, indicating that in the adsorption both chemical and physical interactions are essential in the removal of DR. Three different isotherm models were analyzed, concluding that γ–CDs–EPI followed the Temkin isotherm and HP–γ–CDs-EPI the Freundlich isotherm, these results suggested that the adsorption was happening onto heterogeneous surfaces. The results of the Gibbs free energy showed that the adsorption was spontaneous at room temperature. In order to eliminate the remaining dye after the polymer treatment, and advanced oxidation process (AOP) was considered, achieving more than 90% of removal combining both mechanisms.

scholarly journals Investigation on adsorption capacity of TiO2-P25 nanoparticles in the removal of a mono-azo dye from aqueous solution: A comprehensive isotherm analysis

2014 ◽  
Vol 20 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Mohammad Behnajady ◽  
Shahrzad Yavari ◽  
Nasser Modirshahla
Keyword(s):  
Aqueous Solution ◽  
Crystallite Size ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Correlation Coefficients ◽  
Average Crystallite Size ◽  
Isotherm Models ◽  
Equilibrium Data ◽  
Pseudo Second Order

In this work TiO2-P25 nanoparticles with high surface area have been used as adsorbent for the removal of C.I Acid Red 27 (AR27), as an organic contaminant from aqueous solution. Characteristics of phases and crystallite size of TiO2-P25 nanoparticles were achieved from XRD and the surface area and pore size distribution were obtained from BET and BJH techniques. TiO2-P25 nanoparticles with almost 80% anatase and 20% rutile phases, the average crystallite size of 18 nm, have specific surface area of 56.82 m2 g-1. The effect of various parameters like initial AR27 concentration, pH, contact time and adsorbent dosage has been carried out in order to find desired adsorption conditions. The desired pH for adsorption of AR27 onto TiO2-P25 nanoparticles was 3. The equilibrium data were analyzed with various 2-, 3- and 4-parameter isotherm models. Equilibrium data fitted very well by the 4-parameter Fritz-Schluender model. Results of adsorption kinetics study indicated that the pseudo-second order kinetics provided the best fit with correlation coefficients close to unity.

scholarly journals Characterization and Evaluation of Zeolite A/Fe3O4 Nanocomposite as a Potential Adsorbent for Removal of Organic Molecules from Wastewater

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Emmanuel Nyankson ◽  
Jonas Adjasoo ◽  
Johnson Kwame Efavi ◽  
Reuben Amedalor ◽  
Abu Yaya ◽  
...  
Keyword(s):  
Adsorption Process ◽  
Isotherm Models ◽  
Adsorption Efficiency ◽  
Ferrous Chloride ◽  
X Ray ◽  
Intraparticle Diffusion Model ◽  
Adsorption Processes ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Chloride Salts

In this work, zeolite (Z) and Z-Fe3O4 nanocomposite (Z-Fe3O4 NC) have been synthesized. The Fe3O4 nanoparticles were synthesized using the extract from maize leaves and ferric and ferrous chloride salts and encapsulated into the zeolite framework. The nanocomposite (Z-Fe3O4 NC) was characterized using X-ray diffractometer (XRD), Fourier-transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray (EDX) spectroscopy, and scanning electron microscopy (SEM). The potential of Z-Fe3O4 NC as an adsorbent for removing methylene blue molecules (MB) from solution was examined using UV-Vis and kinetic and equilibrium isotherm models. The adsorption data fitted best with the pseudo-second-order model and Weber and Morris model, indicating that the adsorption process was chemisorption, while the Weber and Morris described the rate-controlling steps. The intraparticle diffusion model suggests that the adsorption processes were pore and surface diffusion controlled. The Langmuir isotherm model best describes the adsorption process indicating homogeneous monolayer coverage of MB molecules onto the surface of the Z-Fe3O4 NC. The maximum Langmuir adsorption capacity was 2.57 mg/g at 25°C. The maximum adsorption efficiency was 97.5%. After regeneration, the maximum adsorption efficiency achieved at a pH of 7 was 82.6%.

scholarly journals Orthophosphoric Acid Activated Babul Seed Carbon as an Adsorbent for the Removal of Methylene Blue

2008 ◽  
Vol 5 (4) ◽  
pp. 742-753 ◽  
Author(s):  
M. Sujatha ◽  
A. Geetha ◽  
P. Sivakumar ◽  
P. N. Palanisamy
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Adsorption Kinetics ◽  
Orthophosphoric Acid ◽  
Chemical Activation ◽  
Bet Surface Area ◽  
Isotherm Models ◽  
Blue Dye ◽  
Equilibrium Data ◽  
Pseudo Second Order

An Experimental and theoretical study has been conducted on the adsorption of methylene blue dye using activated carbon prepared from babul seed by chemical activation with orthophosphoric acid. BET surface area of the activated carbon was determined as 1060 m2/g. Adsorption kinetics, equilibrium and thermodynamics were investigated as a function of initial dye concentration, temperature and pH. First order Lagergren, pseudo-second order and Elovich kinetic models were used to test the adsorption kinetics. Results were analyzed by the Langmuir, Freundlich and Temkin isotherm models. Based on regression coefficient, the equilibrium data found fitted well to the Langmuir equilibrium model than other models. The characteristics of the prepared activated carbon were found comparable to the commercial activated carbon. It is found that the babul seed activated carbon is very effective for the removal of colouring matter.

scholarly journals Study of the mechanism of nitrophenols sorption on expanded perlite ‒ equilibrium and kinetics modelling

2012 ◽  
Vol 31 (1) ◽  
pp. 101 ◽  
Author(s):  
Zvezdana Yaneva ◽  
Bogdana Koumanova ◽  
Nedyalka Georgieva
Keyword(s):  
Correlation Coefficients ◽  
Isotherm Models ◽  
Expanded Perlite ◽  
Multilayer Adsorption ◽  
Kinetics Modelling ◽  
Equilibrium And Kinetics ◽  
Equilibrium Data ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order ◽  
Basic Characteristics

The adsorption behavior of 2-nitrophenol (2-NP) and 2,4-dinitrophenol (2,4-DNP) on expanded perlite (EP) at equilibrium and kinetic conditions was investigated. The experimental equilibrium data were interpreted by Langmuir, Freundlich, Redlich–Peterson, Temkin and the multilayer isotherm models. Both the Temkin and the multilayer models gave the most satisfactory representation of the experimental data for 2-NP sorption on EP covering the whole concentration range, presuming high initial sorption rate, presence of adsorbent-adsorbate chemical interactions and multilayer adsorption, as the basic characteristics featuring the equilibrium behavior of the system studied. The experimental kinetic results were analyzed by the pseudo-first, pseudo-second order models, Bangham’s model, intra-particle diffusion model, and Elovich kinetic equation. The values of the calculated rate, mass transfer parameters and correlation coefficients proved that chemisorptions/intraparticle diffusion could be outlined as the basic rate controlling mechanisms during 2-NP/2,4-DNP sorption on expanded perlite. Uptake of nitrophenols increased in the order 2-NP < 2,4-DNP.

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