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Ghaedi M.,Yasouj University | Heidarpour S.,Payame Noor University | Nasiri Kokhdan S.,Islamic Azad University at Yasuj | Sahraie R.,Ilam University | And 2 more authors.
Powder Technology | Year: 2012

The objective of this study was to assess and compare the usability of silver and palladium nanoparticles loaded on activated carbon (Ag NPs-AC and/or Pd NPs-AC) for the removal of Methylene blue (MB) molecules from aqueous solutions. Following the optimization of the effect of variables (batch method) including pH, contact time, initial dye concentration and Ag NPs-AC and Pd NPs-AC amounts on MB removal method the kinetic and isotherm studies have been carried out. Based on difference in MB contents (using a UV-vis spectrophotometer) before and after MB adsorption the removal percentage was calculated. The sorption processes followed the pseudo-second-order in addition to intraparticle diffusion kinetic models with good correlation coefficient. The equilibrium experimental data well fitted to the Langmuir models with maximum adsorption capacity of 71.4 and 75.4. mg/g for Ag NPs-AC and Pd NPs-AC, respectively. The obtained results showed that both adsorbents due to their high MB adsorption capacity in short equilibrium times are good alternative as low-cost sorbent in wastewater treatments. © 2012.

Marahel F.,Islamic Azad University | Ghaedi M.,Islamic Azad University | Nasiri Kokhdan S.,Islamic Azad University at Yasuj
Fresenius Environmental Bulletin | Year: 2012

In this research adsorption and removal of Sudan red 7B (SR7B) from aqueous solution using silver nanoparticle loaded on activated carbon (Ag-NP-AC) has been investigated. Equilibrium data are mathematically modeled using the Freundlich Langmuir, Tempkin and Dubinin-Radushkevich (D-R) adsorption models. The SR7B adsorption kinetics on to Ag-NP-AC was studied in terms of pseudo-first-order, pseudo-second-order, Intraparticle diffusion and Elovich models. A maximum adsorption capacity of 90.909 mg.g -1 based on Langmuir as most applicable model at equilibrium is achieved. The high capacity and low removal time show the suitability and usefulness of Ag-NP-AC alternative adsorbent for the removal of SR7B in wastewater treatment. © PSP Volume 21 - No 1a.2012.

Ghaedi M.,Yasouj University | Kokhdan S.N.,Islamic Azad University at Yasuj
Desalination and Water Treatment | Year: 2012

Oxidized multiwalled carbon nanotubes (MWCNT) were used for the removal of methyl red (MR) from aqueous solutions. The effects of variables, such as initial solution pH, initial dye concentration, temperature, and sorption time, on MR removal were studied and optimized. Fitting the experimental equilibrium data to various investigated isotherm models, such as Langmuir, Freundlich, Tempkin, and Dubinin-Radushkevich (D-R) models, showed the suitability of the Langmuir model with the highest correlation coefficients. The calculated thermodynamic parameters indicated that the removal of MR by MWCNT is an entropy-driven and endothermic process. The experimental data were analyzed by different kinetic models, such as pseudo-first order, pseudo-second order, and Elovich and intraparticle diffusion models. It was found that the second-order equation and intraparticle diffusion models are the rate-limiting factor and control the kinetic of the adsorption process. © 2012 Desalination Publications. All rights reserved.

Ghaedi M.,Yasouj University | Shokrollahi A.,Yasouj University | Hossainian H.,Yasouj University | Kokhdan S.N.,Islamic Azad University at Yasuj
Journal of Chemical and Engineering Data | Year: 2011

The objective of this study was to assess the suitability and efficiency of activated carbon (AC) and multiwalled carbon nanotube (MWCNT) for the removal of Eriochrome Cyanine R (ECR) molecules from aqueous solutions. The effect of different variables in the batch method as a function of solution pH, contact time, initial dye concentration, AC and MWCNT amount, temperature, electrolyte, and so forth by the optimization method has been investigated. ECR contents were determined using a UV-vis spectrophotometer before and after ECR adsorption on the AC and MWCNT, and the removal percentage was calculated using the difference in absorbance. The sorption processes followed the pseudosecond order in addition to intraparticle diffusion kinetics models with a good correlation coefficient with the overall entire adsorption of ECR on both adsorbents. Equilibrium data fit well with the Langmuir and Tempkin models with a maximum adsorption capacity based on the Langmuir equation of (40.6 and 95.2) mg·g-1 for AC and MWCNT, respectively. Thermodynamic parameters such as change in enthalpy (δH°) and entropy (δS°), activation energy (Ea), sticking probability (S*), and Gibbs free energy changes (δG°) were also calculated. Judgment based on the obtained results of thermodynamic values shows the spontaneous and endothermic nature adsorption processes on both adsorbents. © 2011 American Chemical Society.

Naderi M.,Khorramshahr Marine Science and Technology University | Wong M.Y.L.,University of Wollongong | Gholami F.,Islamic Azad University at Yasuj
Aquatic Toxicology | Year: 2014

In the recent years, there has been a growing concern about the production and use of bisphenol-A substitute, namely bisphenol-S (BPS). Due to its novel nature, there have been few studies addressing the ability of BPS to disrupt the endocrine system of animals. In the present study, zebrafish (Danio rerio) embryos were exposed to and reared in various concentrations of BPS (0, 0.1, 1, 10 and 100. μg/l) for 75 days. Then adult males and females were paired in spawning tanks for 7 days in clean water and the consequent effects on fish development, reproduction, plasma vitellogenin (VTG), sex steroids and thyroid hormone levels were investigated as endpoints. After 75 days of exposure, there was a skewed sex ratio in favor of females. The results also showed that body length and weight significantly decreased in males exposed to 100. μg/l of BPS. Gonadosomatic index was significantly reduced in fish at ≥10. μg/l. Hepatosomatic index exhibited a significant increase in both male and female fish. At ≥1. μg/l of BPS, plasma 17β-estradiol levels were significantly increased in both males and females. However, plasma testosterone showed a significant reduction in males exposed to 10 and 100. μg/l of BPS. A significant induction in plasma VTG level was observed in both males and females at ≥10. μg/l of BPS. Plasma thyroxine and triiodothyronine levels were significantly decreased at 10 and 100. μg/l of BPS in males, and at 100. μg/l in females. Egg production and sperm count were also significantly decreased in groups received 10 and 100. μg/l of BPS. Moreover, once time to hatching and hatching rates were calculated for fertilized eggs the postponed and decreased rates of hatching were observed. Taken together, these results suggest that developmental exposure to low concentrations of BPS has adverse effects on different parts of the endocrine system in zebrafish. © 2014.

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