Adsorption Behavior and Thermodynamic Characteristics of p,p’- DDT on Expanded Graphite

2011 ◽  
Vol 287-290 ◽  
pp. 1653-1658 ◽  
Author(s):  
You Ya Zhou ◽  
Zeng Guang Yan ◽  
Kinam Kim

The adsorption of p,p’-DDT onto expanded graphite (EG) in aqueous solutions was investigated under varying conditions of p,p’-DDT concentrations, adsorbent doses, pH, and contact time. The removal efficiency of p,p’-DDT from the aqueous solutions remained constant in a range of pH 2 to 10, and the thermodynamic data followed the type II adsorption isotherm characterized by a spontaneous process. At lower concentrations, adsorption equilibrium of p,p’-DDT onto EG was fitted to Freundlich isotherm. Dynamic modeling of the adsorption showed that the first order reversible kinetic model was held for the adsorption process within the range of experimental concentration. It was suggested that expanded graphite can be used for efficient removal of p,p’-DDT from water and wastewater.

2011 ◽  
Vol 8 (2) ◽  
pp. 917-923
Author(s):  
Som Shankar Dubey ◽  
Battula Sreenivasa Rao ◽  
B. S. A. Andrews ◽  
B.Venkata Kiran

Radiotracer technique has been used to study the removal behavior of Ce(III) and Eu(III) ions from aqueous solutions by local clay. Adsorptive concentration (10-4–10-6mol dm-3), pH (ca2.0-9.0) and temperature (303-333 K) were examined for assessing optimal conditions for removal of these ions. The adsorption phenomenon was highly dependent on the amount of the adsorbent concentrations. The uptake of ions, which fitted well for Freundlich isotherm, increased with increase in the temperature and no significant desorption took place in the studied temperature range. The energy of adsorption process for the both cations indicates that the adsorption phenomenon is of chemisorption type. The rate kinetics of the adsorption followed the first order rate kinetics.


2013 ◽  
Vol 726-731 ◽  
pp. 1659-1663
Author(s):  
Ning Xin Chen ◽  
Yong Bing Huang ◽  
Jing Dong

Using manganese ore coated with small stones to adsorb arsenic from the contaminated water samples of Yangzonghai Lake, and several factors that may have impacts on the arsenic removal efficiency are analyzed. The result shows that the new adsorbent material has a great effect on arsenic removal. Temperature's effect on arsenic removal efficiency is not obvious. The arsenic removal efficiency increased dramatically in accordance with residence time within 0-660s, and then stabilized. The adsorption process is better when conducted in acidic conditions, the maximum adsorption rate reached 83.0% with the pH of 3.0 and it reached the minimum value of 14.7% when pH is 10. Fe3+ and Ca2+ can slightly promote manganese ore's adsorption of arsenic, and with anions CO32-, SiO32- , efficiency was slightly reduced. When fitting the kinetics data of arsenic removal by coated manganese ore, the adsorption process is correspondent with first-order reaction kinetics model. The adsorption isotherm is more close to the Freundlich isotherm model.


2017 ◽  
Vol 13 ◽  
pp. 323-329 ◽  
Author(s):  
Anastasiya E. Kucherova ◽  
Irina V. Romantsova ◽  
Alexandr E. Burakov ◽  
Nariman R. Memetov ◽  
Mikhail N. Krasnyansky

The present paper describes an investigation of the adsorption of lead ions (Pb2+) on graphene-based nanocomposites obtained via exfoliation of hydrolyzed expanded graphite intercalation compound. Three types of these nanocomposites - suspension of graphene nanoplatelets (SGN), paste of multi-layered oxidized graphene (PMOG), and paste of few-layered oxidized graphene (PFOG) - were used to extract Pb2+ from 1,040 mg L-1 aqueous solutions of Pb (NO3)2, and the kinetic of the Pb2+ adsorption was studied. It was found that the kinetic data are best fitted by the pseudo-second-order model. The adsorption equilibrium was achieved within 30 min under normal conditions. The maximum Pb2+ adsorption capacity of SGN, PMOG and PFOG was found to be 457, 103 and 38 mg g-1, respectively. Considering the obtained results, it can be assumed that the phenolic and hydroxyl oxygen-containing functional groups located at the surface of the adsorption materials under study play an important role in the Pb2+ removal process.


2018 ◽  
Vol 56 (2) ◽  
pp. 158
Author(s):  
Truong Dang Le ◽  
Hoang Vinh Tran ◽  
Le Dieu Thu ◽  
Tran Ngoc Quang ◽  
Nguyen Thi Minh Hang ◽  
...  

In this research, the potential of chitosan/Fe3O4/graphene oxide (CS/Fe3O4/GO) nanocomposite for efficient removal of Fe(III) a cationic metal ion from aqueous solutions was investigated. The synthesized CS/Fe3O4/GO was characterized by XRD, VSM and SEM techniques. Also, the various parameters affecting Fe3+ removal were investigated. Fe(III) adsorption equilibrium data were fitted well to the Langmuir isotherm and the maximum monolayer capacity (qmax), was calculated from the Langmuir as 6.5 mg.g-1. The results show that, CS/Fe3O4/GO nanocomposite, can be used as a cheap and efficient adsorbent for removal of heavy metal ions from aqueous solutions.


Toxins ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 344 ◽  
Author(s):  
Marina Sajid ◽  
Sajid Mehmood ◽  
Chen Niu ◽  
Yahong Yuan ◽  
Tianli Yue

Patulin (PAT) is a major threat to many food products, especially apple and apple products, causing human health risks and economic losses. The aim of this study was to remove PAT from apple juice by using the heat-inactivated (HI) cells and spores of seven Alicyclobacillus strains under controlled conditions. The HI cells and spores of seven strains adsorbed PAT effectively, and the HI cells and spores of Alicyclobacillus acidocaldarius DSM 451 (A51) showed maximum PAT adsorption capacity of up to 12.6 μg/g by HI cells and 11.8 μg/g by HI spores at 30 °C and pH 4.0 for 24 h. Moreover, the PAT adsorption process followed the pseudo-first order kinetic model and the Freundlich isotherm model; thermodynamic parameters revealed that PAT adsorption is a spontaneous exothermic physisorption process. The results also indicated that PAT adsorption is strain-specific. The HI cells and spores of Alicyclobacillus strains are non-cytotoxic, and the bioadsorption of PAT did not affect the quality of the juice. Furthermore, the cell wall surface plays an important role in the adsorption process.


2015 ◽  
Vol 93 (10) ◽  
pp. 1083-1087 ◽  
Author(s):  
Ali Issa Ismail

Graphene is a newly discovered material and is considered to be the new wonder material for many applications. The recent possibility of obtaining pure and fully characterized graphene opens the door to the study of the adsorption of toxic materials on graphene. The adsorption behavior of p-nitrophenol on graphene was studied in aqueous medium. The effect of each of pH, temperature, and dosage was emphasized. The highest calculated adsorption capacity of 4-nitrophenol was found to be 15.5 mg/g, assuming Langmuir fitting starting from 11.1 mg/g initial concentration at 298 K and pH = 6. Fitting the data using the Freundlich isotherm model predicted a favorable adsorption process (n > 1). The rise and saturation areas of the isotherms were fitted as pseudo first-order and pseudo second-order processes, respectively, with relatively good fit (k1 = 0.0023/s, k2 = 0.68 g mg−1 s−1). The thermodynamic properties indicated a spontaneous and exothermic process.


2021 ◽  
Vol 55 (9-10) ◽  
pp. 1131-1142
Author(s):  
BENGÜ ERTAN ◽  

Stinging nettle was used as lignocellulosic adsorbent for the removal of cationic dye – malachite green (MG), and anionic dye – Congo red (CR), from aqueous solution, without any chemical pretreatment. The adsorption equilibrium data fitted well with the Langmuir model for the adsorption of both dyes, with the calculated maximum adsorption capacity of 270.27 mgg-1 and 172.14 mgg-1 for MG and CR, respectively. The adsorption process was controlled by the pseudo-second-order model in the adsorption of MG and by the pseudo-first-order model in the adsorption of CR. The thermodynamics modelling displayed that the process was spontaneous and endothermic. The π–π electron–donor interaction, hydrogen bonds and pore diffusion may also be effective, besides electrostatic interaction between the adsorbate and the adsorbent in the mechanism of MG and CR uptake.


2016 ◽  
Vol 11 (2) ◽  
pp. 105
Author(s):  
Ali Omnia M. ◽  
El-Kashif H.H. ◽  
Sayed S.A. ◽  
Shalabi M.E.H.

<p>The adsorption behavior of uranium and thorium from aqueous solutions by By-pass cement dust (BCD) has been investigated by a batch technique. The uranium and thorium adsorption on BCD was studied as a function of initial concentration, weight of BCD, pH, shaking time and temperature. The uptake of uranium and thorium at the determined optimum conditions follows Freundlich isotherm. The adsorption control of both thorium and uranium are first order and uptake energy of activation E<sub>a</sub> =10 and 15 kJ/mol for thorium and uranium respectively. Thermodynamic parameters such as ΔH<sup>o</sup>, ΔS<sup>o</sup> and ΔG<sup>o</sup> were also investigated.</p>


2013 ◽  
Vol 726-731 ◽  
pp. 1827-1832
Author(s):  
Hong Mei Deng ◽  
Yong Heng Chen ◽  
Cui Qin Wu ◽  
Xue Xia Huang ◽  
Tao Liu

Fir sawdust, a low-cost residual agricultural material, was used as adsorbent for the removal of Cu2+from aqueous solutions. Factors affecting the adsorption behavior of Cu2+, such as pH, initial metal concentration, contact time and temperature, have been carried out. The Cu2+removal was pH-dependent, reaching a maximum at pH 5. The adsorption capacity of the fir sawdust from Langmuir adsorption isotherm was 38.6 mg/g at 25°C. The adsorption process followed pseudo-second-order kinetics. The equilibrium data fitted very well to the Freundlich isotherm. The negative ΔGovalues at various temperatures confirm that the adsorption processes are spontaneous.


2019 ◽  
Vol 79 (10) ◽  
pp. 1922-1933 ◽  
Author(s):  
Hee-Jeong Choi

Abstract Hybrid adsorbents (ES) were prepared with mixing of eggshell and sericite as binders, and Pb(II) was removed from aqueous solutions. Sericite has the advantage of not only serving as a binder for hybrid adsorbent but also having a negative charge on the surface to improve the removal efficiency of heavy metals. Various parameters affecting the removal of Pb(II) from aqueous solutions were investigated using the optimal conditions derived. In addition, adsorption kinetics, adsorption isotherms and thermodynamic analyses were performed using the experimental results of each parameter. The ES had a more specific surface area and porosity than sericite or eggshell and contained a large number of OH groups favoring heavy metal adsorption. As a result of the adsorption of Pb(II) using the ES, the adsorption process was physical and suitable for the Freundlich isotherm. In addition, the adsorption process of Pb(II) by the ES was a spontaneous endothermic reaction. The ES can quickly reach the adsorption equilibrium and strong adsorption strength. In addition, the CaOH contained in the ES can neutralize the pH of wastewater, and it is possible to treat heavy metal ions in industrial wastewater and acid mine wastewater without controlling the pH. ES adsorbents using waste eggshells are very economic because they recycle what would otherwise be waste and have great significance in terms of resource reuse.


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