scholarly journals Study of Fluoride Affinity by Zirconium Impregnated Walnut Shell Carbon in Aqueous Phase: Kinetic and Isotherm Evaluation

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
M. Rajan ◽  
G. Alagumuthu

This paper examines the kinetics of fluoride removal from water by the adsorbent zirconium-impregnated walnut-shell carbon (ZIWSC), exploring the mechanisms involved. The dependence of the adsorption of fluoride on the pH of the solution has been studied to achieve the optimum pH value and a better understanding of the adsorption mechanism. The presence of bicarbonate ions in aqueous solution was found to affect the fluoride removal indicating that these anions compete with the sorption of fluoride on adsorbents. The kinetic profile has been modeled using pseudo-first-order model, pseudo-second-order model, and intraparticle diffusion model. The kinetic sorption profiles offered excellent fit with pseudo-second-order model. Adsorption isotherms have been modeled by Langmuir, Freundlich, and Temkin equations, and their constants were determined. The equilibrium adsorption data were fitted reasonably well for Freundlich isotherm model. XRD and SEM patterns of the ZIWSC were recorded to get better insight into the mechanism of adsorption process.

2013 ◽  
Vol 726-731 ◽  
pp. 2736-2741
Author(s):  
Ming Da Liu ◽  
Ge Tian ◽  
Liang Jie Zhao ◽  
Yao Sheng Wang ◽  
Lei Guo ◽  
...  

Five blast-furnace slags were used as adsorbents to remove Pb (II) from aqueous solution. Kinetic studies showed that the sorption process was best described by pseudo-second-order model. Among Langmuir, Freundlich and Temkin isotherms, the Freundlich isotherm had a better fit with the simulation of the adsorption of Pb (II).


2012 ◽  
Vol 463-464 ◽  
pp. 7-11 ◽  
Author(s):  
Ming Yan Dang ◽  
Hong Min Guo ◽  
Yan Kun Tan

Chitosan was crosslinked using epichlorohydrin as crosslinking agent to prepare crosslinked chitosan which was used as an adsorbent for the removal of Zn(II) from aqueous solutions. The adsorption prosperities of Zn(II) on crosslinked chitosan were studied, including the influence of pH value and the adsorption kinetics. The kinetics of adsorption was discussed using two kinetic models, the pseudo first-order and the pseudo second-order model. Results reveal that the crosslinked chitosan is suitable as adsorbent to remove Zn(II) from dilute solution. The rate parameters for the Zn(II) by crosslinked chitosan were also determined. It was shown that the adsorption kinetics of Zn(II) could be best described by the pseudo second-order model and the adsorption process may involve a physical adsorption.


2020 ◽  
Vol 81 (6) ◽  
pp. 1137-1147
Author(s):  
Elçin Demirhan

Abstract In the present study, removal of Reactive Blue 19 dye by using green pea pod as a low-cost adsorbent was investigated. Box–Behnken design was used to determine the independent and interaction influences of process variables of pH, temperature and adsorbent amount. The variance analysis (ANOVA) results showed that the second order model with high coefficient of determination value (R2 = 0.9997) was statistically significant. The experimental results stated that the removal efficiency increased when the pH value decreased and the adsorbent amount increased. The maximum removal (99.42%) was obtained at pH 2, temperature of 35 °C and adsorbent amount of 1.5 g/100 mL. The equilibrium data investigation showed that the Freundlich isotherm model fitted better for removal of dye than did the Langmuir isotherm model. Furthermore, the adsorption kinetic was also evaluated and it was found that the adsorption followed the pseudo second order model for the Reactive Blue 19 removal onto green pea pod.


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.


Polyethyleneimine supported mesoporous silica (PEI-MPS) has widely been investigated as solid sorbents for CO2 adsorption in laboratory. However, the adsorption kinetics of CO2 on this sorbent is still a disputed problem and the sorbent degradation could be a cause that hinders the sorbent from industrial application. In this study, the PEI-MPS sorbent was prepared by impregnating PEI onto mesoporous silica and then the adsorption kinetics was investigated using the pseudofirst order model, pseudo-second order model and intraparticle diffusion model. Results indicated that the CO2 adsorption kinetics on the sorbent occurred in a 2 stage process. In early stage, it is well fitted by the pseudo-first order model, but in later stage, it is well fitted by the intraparticle diffusion model. The pseudo second-order model proved to be the most suitable one to describe the adsorption of CO2 on the sorbent for the whole adsorption period with less than 5% absolute deviation. The sorbent with a CO2 adsorption capacity of 144.9 mg/g was calculated based on the fitting of the pseudo- second order model. The major degradation issues and their potential effects on the CO2 capture process were also discussed. The degradation significantly impacts on the performance and efficiency of CO2 capture process. The chemical degradation, however, can be considerably minimized by humidification.


REAKTOR ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 117-124
Author(s):  
Hargono Hargono ◽  
Angga Mei Sarah ◽  
Feninda Nevrita ◽  
Bakti Jos

The sorption of Cu (II) particle from aqueous solution onto chitosan and cross-connected chitosan-bentonite (CTS-BTN) as adsorbent were conducted in batch conditions. The impact of different test parameters: starting pH, sorption time was assessed. Equilibrium studies have been completed to decide the limit of chitosan and CTS-BTN for Cu (II) particle. The Langmuir and Freundlich isotherm models were used in the examination of the trial information as linearized conditions. It was discovered that the isotherm information were all around portrayed by the Langmuir isotherm. Chitosan and CTS-BTN showed an adsorption capacity of 125 mg/g and 142.86 mg/g, respectively. The constant of adsorption rate was investigation utilizing a pseudo first order and a pseudo second order model. The pseudo second order model brought about the best fit with test information (R2= 0,991 for CTS and R2= 0,995 for CTS-BTN), additionally giving a constant rate k2, ads= 8.85 x 10-5 g/mg min for CTS and 3.72 x 10-4 g/mg min for CTS-BTN. Recommending that this model could be used in design and applications.Keywords:  adsorption; Cu(II) ion; chitosan; cross-linked; isotherm; kinetics


2010 ◽  
Vol 152-153 ◽  
pp. 791-796
Author(s):  
Hui Jun Xie ◽  
Qiang Ma ◽  
Wei Tan ◽  
Jian Zhang

Removal of Phthalate Easters (PAEs) by softstem bulrush carbon (SBC) in aqueous solution was studied. In this work, the effects of pH, adsorbent dosage (0.8-2.8g), and initial DMP concentration (20-100 mg/L) on the adsorption system were investigated. It turned out that the effective pH was 7.0 and the optimum adsorbent dose was 2.0 g/L. Equilibrium experimental data at 283, 293 and 308 K were better represented by Freundlich isotherm than Langmuir isotherm. In addition, adsorption kinetics was determined using pseudo-first-order model, pseudo-second-order model. The results indicated that the adsorption of DMP onto SBC followed 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.


2013 ◽  
Vol 367 ◽  
pp. 45-49
Author(s):  
Ying Hong ◽  
Ze Hui Zhong ◽  
You Shi Liu

Chitosan nanoparticles were prepared by crosslinkingusing TPP. SEM showed that chitosan nanoparticles were successfully obtained.The adsorption characteristics of chitosan nanoparticles were evaluated. Theresults demonstrated that chitosan nanoparticles were suitable for adsorbent toremoval Pb2+. The parameters for the adsorption of Pb2+by chitosan nanoparticles were also determined. It was shown that chitosannanoparticles were fit for Langmuir’s isotherm model and that the adsorptionkinetics of Pb2+ described by the pseudo-second-order model could bebest.


Author(s):  
Tasrina R. Choudhury ◽  
Snahasish Bhowmik ◽  
M. S. Rahman ◽  
Mithun R. Nath ◽  
F. N. Jahan ◽  
...  

Sawdust supported nano-zerovalent (NZVI/SD) iron was synthesized by treating sawdust with ferrous sulphate followed by reduction with NaBH4. The NZVI/SD was characterized by SEM, XRD, FTIR and Chemical method. Adsorption of As (III) by NZVI/SD was investigated and the maximum uptake of As (III) was found at pH value of 7.74 and equilibrium time of 3 hrs. The adsorption isotherm modelling revealed that the equilibrium adsorption data were better fitted with the Langmuir isotherm model compared with the Freundlich Isotherm model. This study revealed that the maximum As (III) ions adsorption capacity was found to be 12.66 mg/g for using NZVI/SD adsorbent. However, the kinetics data were tested by pseudo-first-order and pseudo-second-order kinetic models; and it was observed that the adsorption data could be well fitted with pseudo-second-order kinetics for As (III) adsorption onto NZVI/SD depending on both adsorbate concentration and adsorption sites. The result of this study suggested that NZVI/SD could be developed as a prominent environment-friendly adsorbent for the removal of As (III) ions from aqueous systems.


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