Preparation of Alkali-Treaded Fly Ash Adsorbent and its Application for Cd2+ Removal from Aqueous Solution

2012 ◽  
Vol 550-553 ◽  
pp. 2155-2159 ◽  
Author(s):  
Bei Gang Li ◽  
Li Yuan Zhao ◽  
Chen Wang

The modified fly ash (MFA) was prepared by calcining raw coal fly (FA) ash with Na2CO3 at high temperature. The preparation conditions of MFA and Effects of important parameters such as contact time, adsorbate concentration, pH and temperature on the sorption were researched, respectively. MFA obtained at calcining temperature of 550°C and FA/Na2CO3 mass ratio of 12 shows the effective removal for Cd2+ from aqueous solution, and the maximum removal was close to 100% with the adsorbent dosage of 10 g/L, initial Cd2+ concentration of 200 mg/L at 25°C. The adsorption kinetics of Cd2+ on MFA followed the pseudo-second-order model well and adsorption processes might be mainly controlled by intra-particle diffusion. The sorption is favourable at high temperature and the adsorption apparent activation energy was 68.08 kJ/mol which indicates the chemical nature of the adsorption.

2020 ◽  
Vol 10 (7) ◽  
pp. 676
Author(s):  
Huu Son Ta ◽  
Khu Le Van ◽  
Thu Thuy Luong Thi ◽  
Thanh Hoa Ha

The kinetics of phenol adsorption from aqueous solution on activated carbons (ACs) obtained from coffee husk by potassium Hydroxide (KOH) activation at 650 and 750<sup>o</sup>C have been studied in the range of     100-250 mg L<sup>-1</sup> initial phenol concentrations and at the temperatures range of 10 – 40<sup>o</sup>C. Kinetic models for phenol adsorption were evaluated using pseudo-first-order, pseudo-second-order, and Elovich models. The adsorption mechanism was investigated using Reichenberg, Boyd, and Weber and Morris models. The adsorption on coffee husk activated carbon was found to be a fast or speedy process with the adsorption rate, k<sub>2</sub>q<sub>e</sub>, in the range of 0.130 to 0.977 min<sup>-1</sup>. The adsorption process was mainly physical and promoted by chemical sorption and controlled not only by intra-particle diffusion but also by pore diffusion throughout the entire adsorption period.


2020 ◽  
Vol 69 (5) ◽  
pp. 438-452 ◽  
Author(s):  
Mazen K. Nazal ◽  
Durga Rao ◽  
Nabeel Abuzaid

Abstract Many industries produce 2,4-dimethylphenol (DMP) compound in the wastewater which is persistent, toxic, and carcinogenic. Therefore, an adsorbent was prepared by carbonizing a dried Sargassum boveanum macroalgae. The prepared biosorbent was investigated for adsorptive removal of DMP from aqueous solution. After carbonization, the biochar derived from S. boveanum macroalgae (BCM) removed almost 100% of DMP adsorbate. Effects of contact time, solution pH, adsorbate concentration, adsorbent mass, and temperature have been studied. It has been found that, within the experimental conditions, the maximum adsorption capacity is 17 mg/g, rate of adsorption follows pseudo-second order kinetics and the adsorption isotherm experimental data fit the Freundlich model. The thermodynamic parameters were calculated and it has been found that the adsorption of DMP on BCM is endothermic and thermodynamically favorable, and in addition the surface of BCM adsorbent shows affinity to the DMP molecules. The BCM adsorbent has the capability to remove around 65% of DMP from high saline seawater contaminated with DMP. Moreover, the prepared BCM adsorbent was reusable for at least four times in seawater for removal of DMP contaminant.


DYNA ◽  
2016 ◽  
Vol 83 (196) ◽  
pp. 223-228 ◽  
Author(s):  
Jhonnathan Machado-Infante ◽  
Gustavo Ramírez-Caballero ◽  
Martha Juliana Barajas Meneses

<p>In Colombia, a mineral rich in MnO<sub>2</sub> is extracted from the mines of Mallama, Nariño. In this work we studied the adsorption capacity of this mineral for Fe(II) dissolved in aqueous solution of open systems. The characterization was done through ICP-AES, XRF and Raman spectroscopy. The effect of different pretreatments on the mineral with oxidizing agents such as KMnO<sub>4</sub> and NaClO was evaluated. Studies of equilibrium and kinetics of adsorption showed that the mechanism fits well to the Langmuir isotherm and its kinetics to a model of pseudo-second order. At the conditions studied was found that the adsorption capacity for the mineral modified with KMnO<sub>4</sub> and NaOCl were 59.209 and 51.279 mg/g respectively. It is concluded that the mineral is a potential alternative in water treatment.</p>


2020 ◽  
Vol 74 (1) ◽  
pp. 65-70
Author(s):  
Bojana Obradovic

Adsorption processes are widely used in different technological areas and industry sectors, thus continuously attracting attention in the scientific research and publications. Design and scale-up of these processes are essentially based on the knowledge and understanding of the adsorption kinetics and mechanism. Adsorption kinetics is usually modeled by using several well-known models including the pseudo-first and pseudo-second order models, the Elovich equation, and the intra-particle diffusion based models. However, in the scientific literature there are a significant number of cases with the inappropriate use of these models, utilization of erroneous expressions, and incorrect interpretation of the obtained results. This paper is especially focused on applications of the pseudo-second order, intra-particle diffusion and the Weber-Morris models, which are illustrated with typical examples. Finally, general recommendations for selection of the appropriate kinetic model and model assumptions, data regression analysis, and evaluation and presentation of the obtained results are outlined.


2019 ◽  
Vol 80 (5) ◽  
pp. 884-891
Author(s):  
Daying Chen ◽  
Nasi Tu ◽  
Changkun Si ◽  
Meilin Yin ◽  
Xiaohui Wang

Abstract Mesoporous TiO2 has been prepared by a brief and simple sol–gel processing and applied for the removal of Cu(II) from aqueous solution. The adsorption behavior of mesoporous TiO2 for Cu(II) was investigated using batch experiments. Results showed that the pseudo-second-order model and Langmuir isotherm were more accurate to describe the kinetics process and adsorption isotherm. Mesoporous TiO2 adsorbent displayed excellent Cu(II) adsorption efficiency (195.52mg g−1). The thermodynamic parameters showed that the adsorption was spontaneous and endothermic. It was also found that mesoporous TiO2 could be used at least seven times without obvious loss of its original adsorption efficiency. Therefore, the obtained mesoporous TiO2 could be employed as an effective and low-cost adsorbent for removal of Cu(II) from contaminated effluents.


2019 ◽  
Vol 80 (8) ◽  
pp. 1549-1561
Author(s):  
R. Saravanan ◽  
R. Mahalakshmi ◽  
M. S. Karthikeyan ◽  
L. Ravikumar

Abstract Cellulose bearing pendant Schiff base with heterocyclic chelating groups (CMC-Bz) was synthesized, which were fully characterized using various instrumental techniques such as solid state carbon-13 nuclear magnetic resonance (13C-NMR), Fourier transform infrared (FTIR), scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX) spectra. The adsorption of toxic metals onto cellulosic material was tested in a batch mode operation. The adsorption functional factors such as pH, adsorbent dose, metal ion concentration, equilibrium time and temperature were experimentally optimized for the maximum removal of Cu(II) and Pb(II) ions. Adsorption isotherms were evaluated with Langmuir, Freundlich, Temkin and Redlich–Peterson isotherms. Kinetic parameters and equilibrium adsorption capacities were investigated for pseudo-first-order, pseudo-second-order and intra-particle diffusion models. Thermodynamic parameters and reusability were also evaluated.


2013 ◽  
Vol 803 ◽  
pp. 157-160
Author(s):  
Zhen Zhen Kong ◽  
Dong Mei Jia ◽  
Su Wen Cui

The composite weakly basic resin (D301Fe) was prepared and examined using scanning electron microscopy and Fourier transform infrared spectroscopy. The adsorption kinetics of glyphosate from aqueous solution onto composite weakly basic resin (D301Fe) were investigated under different conditions. The experimental data was analyzed using various adsorption kinetic models like pseudo-first order, the pseudo-second order, the Elovich and the parabolic diffusion models to determine the best-fit equation for the adsorption of glyphosate onto D301Fe. The results show that the pseudo-second order equation fitted the experimental data well and its adsorption was chemisorption-controlled.


2012 ◽  
Vol 518-523 ◽  
pp. 2307-2314 ◽  
Author(s):  
Bei Gang Li ◽  
Li Yuan Zhao

Alizarin Red (AR) has been shown to be effectively removed from aqueous solution using the ultrafine fly ash (UFA) prepared by ball milling from raw fly ash (FA), a low-cost industrial solid waste. The maximum removal rate was 91.04% in a solution of initial AR concentration of 700 mg/L, adsorption time of 60 min at pH 5.0 and temperature of 25°C. Compared with FA, the adsorption capacity of UFA is higher for AR removal. Effects of important parameters, contact time, adsorbate concentration, pH and temperature, were investigated. The UFA and AR-loaded UFA were characterized by FT-IR. The equilibrium, kinetics and thermodynamics of AR adsorption onto UFA were evaluated. The AR uptake process followed the pseudo-second-order rate equation well, but the pseudo-first-order rate equation and intra-particle diffusion equation could only be applied to describe the initial stage of adsorption, furthermore, intra-particle diffusion might be the rate-controlling step of fast adsorption process. The sorption decreased with increasing temperature and the adsorption apparent activation energy was 8.28kJ/mol. Langmuir isotherm equation could better describe the adsorption equilibrium at different temperatures, compared with Freundlich model. Thermodynamic parameters, ΔG, ΔH and ΔS, were also calculated. The results inferred that the adsorption of AR/UFA system was feasible, spontaneous and exothermic nature of the process which was mainly controlled by physical adsorption.


Author(s):  
Qingqing Liu ◽  
Xiaoyan Li

The activated MgO was synthesized by microwave homo-precipitator method and characterized by SEM, EDS and FT-IR methods. It was used to adsorption of U(VI) from aqueous solution with batch system. The paper discussed the effect of pH, temperature, contact time, adsorbent dose and initial U(VI) concentration on the adsorption. The results showed that activated MgO has good adsorption capacity for U(VI), the removal rate and equilibrium adsorption capacity reached 83.5% and 84.04mg·g−1 at pH 5.0, 15mg dose and 313K,respectively. The adsorption kinetics of U(VI) onto activated MgO were better fitted with pseudo-second-order kinetic.The adsorption isotherm data were fitted well to Freundlich isotherm model.The thermodynamic parameters showed that the adsorption process is endothermic and spontaneous.


2015 ◽  
Vol 17 (3) ◽  
pp. 70-77 ◽  
Author(s):  
M. Kumar ◽  
G. Elangovan ◽  
R. Tamilarasan ◽  
G. Vijayakumar ◽  
P.C. Mukeshkumar ◽  
...  

Abstract This article presents the feasibility for the removal of Aniline Blue dye (AB dye) from aqueous solution using a low cost biosorbent material Zizyphus oenoplia seeds. In this study, a batch mode experiments of the adsorption process were carried out as a function of pH, contact time, concentration of dye, adsorbent dosage and temperature. The experimental data were fitted with Freundlich and Langmuir isotherm equations. The feasibility of the isotherm was evaluated with dimensionless separation factor (RL). The kinetic data of sorption process are evaluated by using pseudo-first order and pseudo-second order equations. The mode of diffusion process was evaluated with intra-particle diffusion model. The thermodynamic parameters like change in enthalpy (ΔHº); change in entropy (ΔSº) and Gibbs free energy change (ΔGº) were calculated using Van’t Hoff plot. The biosorbent material was characterized with Fourier Transform Infrared (FTIR) spectroscopy and the morphology was identified with Scanning Electron Microscope (SEM) in before and after adsorption of AB dye.


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