scholarly journals Study on isotherm, kinetics, and thermodynamics of adsorption of crystal violet dye by calcium oxide modified fly ash

2020 ◽  
Vol 26 (1) ◽  
Author(s):  
Sagnik Chakraborty ◽  
Anupam Mukherjee ◽  
Subhabrata Das ◽  
Naga Raju Maddela ◽  
Saima Iram ◽  
...  

The natural Fly ash modified with calcium oxide has been employed to eliminate the crystal violet dyestuff from the simulated solution. Herein, the effect of different physicochemical factors like primary dye concentration, sorption contact time, the quantity of the adsorbent, temperature, along with initial simulated solution pH, evaluated for illustrating the mechanism of adsorption. Furthermore, the equilibrium study was conducted, and equilibrium models like Langmuir, Freundlich, and Dubinin- Raduskevich (D-R) were fitted to obtain analytical results to endow with more insight into the process. The results acknowledged that the Langmuir model is well apt and suggests that the adsorption mechanism happens in a monolayer on the fly ash surface. Pseudo-first order, Pseudo-second order, and the intraparticle diffusion model evaluated, and the interpretation suggests the sorption method is obeying the Pseudo-second order and intraparticle diffusion model. The ascertained negative values of Gibbs free energy affirmed the unconstrained process for all symbiotic associations, and the obtained data 78.70 kJ mol<sup>–1</sup> enthalpy values manifested that exothermic mechanism was governing the reaction. The above assessment confirms the application of Calcium oxide pre-treated fly ash as a cheap adsorbent to eliminate the crystal violet dyestuff from the simulated solution.

2014 ◽  
Vol 68 (6) ◽  
pp. 793-799 ◽  
Author(s):  
Mirjana Brdar ◽  
Marina Sciban ◽  
Dragana Kukic ◽  
Tatjana Dosenovic

Adsorption kinetics is of great significance to evaluate the performance of adsorption process. The kinetics of copper ions adsorption onto different sized sugar beet shreds has been considered. Sugar beet shreds are very promising adsorbents due to their convenient chemical composition and availability in relatively large quantities in many countries. Experimental data were fitted with pseudo-first and pseudo-second-order kinetic models. Also, we used the intraparticle diffusion model for further analysis of kinetics. The coefficient of determination indicates that, the pseudo-second-order equation obtained by using non-linear least square method, was the most appropriate model for the description of copper ions adsorption onto sugar beet shreds. The adsorption capacities at equilibrium, for a particle size of 224 - 400 ?m, 400 - 750 ?m and 750 - 1000 ?m, are 10 mg/g, 9 mg/g and 8.6 mg/g, respectively. By using intraparticle diffusion model proposed by Weber and Morris, it was obtained that there exist two different stages in adsorption: fast initial adsorption which is further limited by intraparticle diffusion.


2018 ◽  
Vol 20 (2) ◽  
pp. 408-416

Mesophilic biomass and thermophilic biomass samples were isolated and used to remove Dorasyn Red dye from aqueous solutions. The biosorption kinetics of dye uptake by four different types of biomass at three temperatures (20, 30, and 40 °C) were investigated using pseudo-first order kinetics, pseudo-second order kinetics, intraparticle diffusion, Elovich, and Bangham models. The pseudo-second-order kinetics model and the first stage of the intraparticle diffusion model were effective in describing the experimental kinetics data. The biosorption results showed that the mesophilic biomass samples could be useful for removing dye under acidic conditions.


2020 ◽  
Vol 15 ◽  
pp. 155892502091984
Author(s):  
Moussa Abbas ◽  
Zahia Harrache ◽  
Mohamed Trari

This study investigates the potential use of activated carbon, prepared from pomegranate peels, as an adsorbent activated using H3PO4 and its ability to remove crystal violet from an aqueous solution. The adsorbent was characterized by the Brunauer–Emmett–Teller method (specific surface area: 51.0674 m2 g−1) and point of zero charge (pHPZC = 5.2). However, some examined factors were found to have significant impacts on the adsorption capacity of activated carbon derived from pomegranate peels such as the initial dye concentration (5–15 mg L−1), solution pH (2–14), adsorbent dose (1–8 g L−1), agitation speed (100–700 r/min), and temperature (298–338 K). The best adsorption capacity was found at pH 11 with an adsorbent dose of 1 g L−1, an agitation speed at 400 r/min, and a contact time of 45 min. The adsorption mechanism of crystal violet onto activated carbon derived from pomegranate peels was studied using the pseudo-first-order, pseudo-second-order, Elovich, and Webber–Morris diffusion models. The adsorption kinetics were found to rather follow a pseudo-second order kinetic model with a determination coefficient ( R2) of 0.999. The equilibrium adsorption data for crystal violet adsorbed onto activated carbon derived from pomegranate peels were analyzed by the Langmuir, Freundlich, Elovich, and Temkin models. The results indicate that the Langmuir model provides the best correlation with qmax capacities of 23.26 and 76.92 mg g−1 at 27°C and 32°C, respectively. The adsorption isotherms at different temperatures have been used for the determination of thermodynamic parameters like the free energy, enthalpy, and entropy to predict the nature of adsorption process. The negative values Δ G0 (−5.221 to −1.571 kJ mol−1) and Δ H0 (−86.141 kJ mol−1) indicate that the overall adsorption is spontaneous and exothermic with a physisorption process. The adsorbent derived from pomegranate peels was found to be very effective and suitable for the removal of reactive dyes from aqueous solutions, due to its availability, low-cost preparation, and good adsorption capacity.


Author(s):  
F. B. Okanlawon ◽  
O. A. Okon- Akan ◽  
O. A. Adegoke ◽  
O. A. Olatunji

This study was carried out using Alfisol as an adsorbent to adsorb Cadmium and Glyphosate both of which are common inorganic and organic contaminants. The soil samples were air-dried and allowed to pass through 2mm sieve before use while its analysis was done following the standard procedures. The kinetic data were tested with pseudo-first-order and pseudo-second-order models, and it was concluded that both adsorbates adsorption followed the pseudo-second-order kinetics, while the nature and the mechanism of adsorption processes were studied by using an intraparticle diffusion model. A complete linear plot of intraparticle diffusion was obtained for glyphosate which suggests that intraparticle diffusion was the rate-controlling step in its adsorption but the opposite is the case for cadmium adsorption. The peak removal of cadmium occurred after 50 minutes with equilibrium attained over 250 minutes while peak glyphosate removal was achieved after 30 minutes. It can be concluded that Alfisol can be effectively used for the adsorption of both Cadmium and Glyphosate thus showcasing a potential environmental remediation process.


Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3584
Author(s):  
Gabriela Buema ◽  
Nicoleta Lupu ◽  
Horia Chiriac ◽  
Tiberiu Roman ◽  
Marieta Porcescu ◽  
...  

Wastes are the sustainable sources of raw materials for the synthesis of new adsorbent materials. This study has as objectives the advanced capitalization of fly ash, by sulphuric acid activation methods, and testing of synthesized materials for heavy metals removal. Based on the previous studies, the synthesis parameters were 1/3 s/L ratio, 80 °C temperature and 10% diluted sulphuric acid, which permitted the synthesis of an eco-friendly adsorbent. The prepared adsorbent was characterized through SEM, EDX, FTIR, XRD and BET methods. Adsorption studies were carried out for the removal of Cd2+ ions, recognized as ions dangerous for the environment. The effects of adsorbent dose, contact time and metal ion concentrations were studied. The data were tested in terms of Langmuir and Freundlich isotherm and it was found that the Langmuir isotherm fitted the adsorption with a maximum adsorption capacity of 28.09 mg/g. Kinetic data were evaluated with the pseudo-first-order model, the pseudo-second-order model and the intraparticle diffusion model. The kinetics of cadmium adsorption into eco-friendly material was described with the pseudo-second-order model, which indicated the chemisorption mechanism.


Author(s):  
Fulya Aydın Temel

In this study, the removal efficiency of Pb(II) from industrial leachate was investigated by using expanded perlite by adsorption. The effects of pH, contact time, and adsorbent dosage were examined on the Pb(II) removal. The adsorption kinetics were tested to understand the adsorption mechanism using three kinetic models, i.e., Elovich, intraparticle diffusion, and the pseudo second order reaction kinetic models. As the result, the best conformity kinetic model for Pb(II) adsorption on expanded perlite was described as the pseudo second-order (R2>0.99). It is indicated that chemisorption is the determining step of adsorption process rather than mass transfer from industrial leachate. According to the data obtained from intraparticle diffusion model, the adsorption is composed of more than one step. This can be attributed to the fact that the adsorption in the final portion was the intraparticle diffusion while the adsorption in the first portion was the film diffusion. Both film diffusion and intraparticle diffusion processes in the adsorption of Pb(II) on expanded perlite are significant. This study indicated that expanded perlite was an influential alternative adsorbent for the removal of Pb(II) by adsorption from industrial leachate.


Author(s):  
Hutaf M. Baker

In this study a Jordanian Zeolite was modified using anionic surfactant which is sodium dodecyl sulfate (sodium dodecyl sulfate). The sorption of Pb(II) from synthetic wastewater by surfactant modified  Zeolite (SMZ) was investigated as a function of temperature. The experimental data was analysed using isotherm models namely Langmuir, Freundlich, Redlich-Peterson and Temkin and kinetic models such as the pseudo- second-order, intraparticle diffusion and the Elovich models in order to understand the mechanism of the interaction between this SMZ and the lead ions. All the isotherm models showed good correlation with the experimental results but Freundlich was the best. The calculated DH was obtained using Langmuir constant (aL), its value of 8.29kJ/mol revealed that the type of sorption is physical oneThe values of RL at all temperatures reflect the favorability of this interaction. The calculated activation energy was 21.126 kJ/mol using the pseudo-second order constant (k2), which indicates that the sorption is physisorption. The intraparticle diffusion model showed multilinearity which means multiple stages there occurred to achieve the removal of lead ions, the first linear curve is due to the boundary layer diffusion and the second linear curve isfor the intraparticle diffusion effect. The adsorption kinetics data fitted also Elovich model.


2017 ◽  
Vol 23 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Javad Ahmadishoar ◽  
Hajir Bahrami ◽  
Barahman Movassagh ◽  
Hosein Amirshahi ◽  
Mokhtar Arami

In this study modified montmorillonite was used as an adsorbent for the removal of two selected disperse dyes i.e., Disperse Blue 56 (DB) and Disperse Red 135 (DR) from dye dispersions. The adsorption equilibrium data of dyes adsorption were investigated by using Nernst, Freundlich and Langmuir isotherm models. The adsorption kinetics was analyzed by using different models including pseudo-first-order, pseudo-second-order, Elovich and Intraparticle diffusion model. The Freundlich isotherm was found to be the most appropriate model for describing the sorption of the dyes on modified nanoclay. The best fit to the experimental results was obtained by using the pseudo-second-order kinetic equation, which satisfactorily described the process of dye adsorption. Although different kinetic models may control the rate of the adsorption process, the results indicated that the main rate limiting step was the intraparticle diffusion. The results showed that the proposed modified montmorillonite could be used as an effective adsorbent for the removal of disperse dyes even from highly concentrated dispersions.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Öznur Dülger ◽  
Fatma Turak ◽  
Kadir Turhan ◽  
Mahmure Özgür

Sumac Leaves (SL) (Rhus Coriaria L. ) were investigated as an inexpensive and effective adsorbent for the adsorption of methylene blue (MB) from aqueous solution. The effects of initial dye concentration, initial solution pH, phases contact time, and adsorbent dose on the adsorption of MB on SL were investigated. The amount of dye adsorbed was found to vary with initial solution pH, Sumac Leaves dose, MB concentration, and phases contact time. The Langmuir and Freundlich adsorption models were evaluated using the experimental data and the experimental results showed that the Langmuir model fits better than the Freundlich model. The maximum adsorption capacity was found to be 151.69 mg/g from the Langmuir isotherm model at 25°C. The value of the monolayer saturation capacity of SL was comparable to the adsorption capacities of some other adsorbent materials for MB. The adsorption rate data were analyzed according to the pseudo-first order kinetic and pseudo-second order kinetic models and intraparticle diffusion model. It was found that kinetic followed a pseudo-second order model.


2019 ◽  
Vol 9 (1) ◽  
pp. 37-44
Author(s):  
Amira AM ◽  
Fatima Ouzidan ◽  
Tarik Ainane ◽  
Mohamed Talbi ◽  
M'hammed El Kouali

This paper evaluates the ability of a natural rock found in Morocco to remove the pollutant properties of methylene blue (MB) dye. In this regard, the experiments were conceived to test the hypothesis that the rock native of the country’s region of Khenifra can be used as a new abundant adsorbent to remove cationic dyes from water through the adsorption technique in order to avoid extra cost and contribute to the valorization of this material. For this, several factors such as pH of the solution, granulometry, mass of adsorbent, initial dye concentration and stirring rate were tested. The adsorption kinetics process was tested through three models, namely, the pseudo-first-order model, pseudo-second-order model and the intraparticle diffusion model, to predict which type of adsorption is best suited in the removal of dye pollution. The batch study proves that only the granulometry (G ≤ 63µm = 91%, G ≤ 80µm = 88.4% and G ≤ 100µm=70.7%) and the adsorbent mass (the more the mass of the adsorbent increases the more the elimination is achieved) can influence the elimination rate of our rock. Meanwhile, the data of the adsorption kinetics test show that the experimental adsorption could be described by the mechanism of the pseudo-second-order model (correlation coefficients near the unit ‘R 2 = 0.99’ ), confirming chemical sorption as a rate-limiting step of the intraparticle diffusion mechanism. According to the results of this study, the rock collected from the area of Khenifra can be used as a new and efficient adsorbent in the field of wastewater treatment.


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