Adsorption Kinetics of Pb2+ Ions Using Chitosan Nanoparticles

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.

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.


2011 ◽  
Vol 347-353 ◽  
pp. 281-284
Author(s):  
Peng Ge ◽  
Li Juan Wan ◽  
Ya Jing Xu

Among the investigated clays and minerals (kaolinite, natural zeolite, manual zeolite, bentonite, sepiolite, sepiolite amianthus, tremolite amianthus, vermiculite and baritite), the baritite clay was selected as the optimal adsorbent for aqueous Cr (VI). The Cr (VI) adsorption capacity on baritite clay reached as high as 39.01 mg∙g−1 at 20°C. Then the adsorption kinetics of Cr (VI) by the baritite clay were investigated in details. Results showed that the pseudo-second-order model was a suitable description for the adsorption kinetics and fitted well with the experimental data.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaoli Yuan ◽  
Wentang Xia ◽  
Juan An ◽  
Jianguo Yin ◽  
Xuejiao Zhou ◽  
...  

The efficiency of dolomite to remove phosphate from aqueous solutions was investigated. The experimental results showed that the removal of phosphate by dolomite was rapid (the removal rate over 95% in 60 min) when the initial phosphate concentration is at the range of 10–50 mg/L. Several kinetic models including intraparticle diffusion model, pseudo-first-order model, Elovich model, and pseudo-second-order model were employed to evaluate the kinetics data of phosphate adsorption onto dolomite and pseudo-second-order model was recommended to describe the adsorption kinetics characteristics. Further analysis of the adsorption kinetics indicated that the phosphate removal process was mainly controlled by chemical bonding or chemisorption. Moreover, both Freundlich and Langmuir adsorption isotherms were used to evaluate the experimental data. The results indicated that Langmuir isotherm was more suitable to describe the adsorption characteristics of dolomite. Maximum adsorption capacity of phosphate by dolomite was found to be 4.76 mg phosphorous/g dolomite. Thermodynamic studies showed that phosphate adsorption was exothermic. The study implies that dolomite is an excellent low cost material for phosphate removal in wastewater treatment process.


Author(s):  
Dan Wu ◽  
Yaxiu Zhao ◽  
Qiang Liu ◽  
Chein-Chi Chang ◽  
Wei Hou

Abstract A graphene film deposited on titanium substrate was successfully prepared by a facile solution evaporation method, as electrode exhibiting superior electrosorption property toward methylene blue (MB) from aqueous solution. The fabricated graphene film on titanium substrate was characterized in detail by scanning electron microscopy (SEM) and FTIR techniques. As electrode (GTE) for electrosorption of MB, some experimental parameters, such as applied potential, concentration of electrolyte, solution initial pH and temperature, were systematically investigated and discussed. The experimental results demonstrated that the maximum adsorption capacity using GTE can reach 86.06 mg· g−1 under the optimized conditions of −600 mV of applied potential, pH of 7.5, 293 K and 0.01 mg· L−1 Na2SO4 solution, which is 1.40 times of that obtained under open circuit condition in 10 mg· L−1 MB solution. The adsorption isotherm of MB on GTE was analyzed with Langmuir and Freundlich isotherm equations, Pseudo-first-order model, pseudo-second-order model, and intra-particle diffusion model were applied to depict the adsorption kinetics process. The electrosorption of MB preferably fitted Langmuir isotherm, indicating a single-layer adsorption of MB molecules on graphene film followed pseudo-second-order model. Moreover the electrosorption of MB on GTE was found to be spontaneous and endothermic process. This work would be helpful to design and fabricate high performance carbon-based electrodes for high efficiency electrosorption treatment of dye wastewaters.


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.


2014 ◽  
Vol 16 (4) ◽  
pp. 690-698 ◽  

<div> <p>In this work, three samples of nitrogen-doped TiO<sub>2 </sub>prepared at different calcination temperatures (400, 450 and 500 &deg;C) were applied for the adsorption of Direct Black 38. Kinetic studies about the adsorption of Direct Black 38 on nitrogen-doped TiO<sub>2 </sub>were performed under different initial dye concentrations<br /> (75-175 mg l<sup>-1</sup>). Pseudo-first and pseudo-second order models were fitted with the experimental data. The results revealed that nitrogen-doped TiO<sub>2 </sub>synthesized at 400 &deg;C presented the more adequate characteristics for adsorption purposes, such as specific surface area of 151 m<sup>2</sup> g<sup>-1</sup>. The adsorption kinetics agreed with the pseudo-second order model, at initial dye concentrations from 75 to 175 mg l<sup>-1</sup>. The maximum adsorption capacity predicted by the pseudo-second order model was 138.3 mg g<sup>-1</sup>, and was obtained using nitrogen-doped TiO<sub>2</sub> synthesized at 400 &deg;C. In summary, these results revealed that nitrogen-doped TiO<sub>2</sub> is a good material for the removal Direct Black 38 from aqueous solutions by adsorption.&nbsp;</p> </div> <p>&nbsp;</p>


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.


2014 ◽  
Vol 809-810 ◽  
pp. 907-911
Author(s):  
Jun Long Wang ◽  
Jie Hou ◽  
Ting Jiang ◽  
Yong Jun He ◽  
Yao Dong Liang

Dry waters with an average diameter of 82 μm were prepared by a high speed mixed route. The formaldehyde absorption kinetics of dry waters was investigated by simulating indoor formaldehyde pollution in glass chamber. The results showed that pseudo-second order model could be used to simulate the adsorption process; the adsorption rate was highest in the initial 60 minutes; when the adsorption lasted for 180 minutes, the adsorption reached equilibrium.


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