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Showing 2 results for Shirzad Siboni
Reza Rezaie, Dr Afshin Maleki, Mehdi Shirzad Siboni , Marzieh Rahimi, Mahnaz Mohammadi, Volume 16, Issue 1 (Scientific Journal of Kurdistan University of Medical Sciences 2011)
Abstract
ABSTRACT
Background and Aim: One of the important sources of environmental pollution existing in different industrial wastewater, including loom wastewater are dyes which are harmful for human health and environment. The purpose of this study was to investigate the efficiency of photochemical and sonochemical processes combined with hydrogen peroxide in removal of DB71 from aqueous solution.
Material and Methods: This study was an experimental - laboratory study. At first, a reactor was designed and made. Then, optimum pH was determined which was 7 for photochemical and 3 for sonochemical process in constant condition. The effects of initial concentration of hydrogen peroxide, DB71 and contact time were studied at the constant optimum pH. Then data were interpreted and analyzed by use of Excel software and regression coefficient.
Result: The results of this study showed that with increased initial concentration of DB71, its removal decreased. But removal efficiency of DB71 increased by increasing contact time and initial concentration of hydrogen peroxide. In addition, kinetic parameters were obtained by application of first–order (Langmuir-Hinshelwood) equations.
Conclusion: The results showed that UV/ H2O2 and US/H2O2 processes can be effective in the removal of DB71 from aqueous solutions. Considering dye removal efficiency and availability, photochemical process combined with hydrogen peroxide can be recommended as a fast effective method for removal of dyes from aqueous solutions.
Key word: Direct Blue 71, Photochemical process, Sonochemical process, Aqueous solution, Kinetic
Conflict of Interest: Nill
Received: Dec 22, 2010 Accepted: Jan 12, 2011
Dr Afshin Maleki, Dr Amir Hosien Mahvi, Reza Rezaie, Mehdi Shirzad Siboni , Volume 16, Issue 3 (Scientific Journal of Kurdistan University of Medical Sciences 2011)
Abstract
ABSTRACT
Background and Aim: Heavy metals pollution represents a serious problem for human health and for life in general and bacterial biofilms are able to adsorb heavy metals from dilute aqueous solutions and accumulate them within their cell structure. The aim of this study was to investigate the ability of Escherichia coli biofilm (an effective agent for metal adsorption) supported on clinoptilolite for the removal of cadmium from aqueous solutions.
Materials and Methods: Adsorption experiments were carried out in a laboratory-scale batch model with clinoptilolite alone and clinoptilolite covered by a bacterial biofilm. The effects of initial heavy metal concentrations, pH, and agitation time on the removal efficiency were studied. Finally, experimental results were analyzed using isotherm equations.
Results: The results of this study revealed that cadmium adsorption to clinoptilolite was lower than that of clinoptilolite covered by biofilm and adsorption of the cadmium was influenced by several parameters such as initial concentration of cadmium, biosorption time and solution pH. The uptake values for clinoptilolite and for clinoptilolite covered by biofilm were 6.8 mg/g and 9.6 mg/g respectively in the batch model, for initial cadmium concentrations of 25 and 100 mg/L. It was also observed that as the initial cadmium concentration increased, the uptake increased, but the removal rate decreased. Maximum adsorption efficiency was achieved at pH value of 6. The biosorption equilibrium for cadmium was best described by the Freundlich and Longmuir models.
Conclusion: It is concluded that the presence of biofilm increased the uptake efficiency of clinoptilolite and the biofilm tested in our study seems very promising for the removal of cadmium from aqueous solution.
Key words: Adsorption, Heavy metal, Biofilm, E. coli
Conflict of Interest: Nill
Received: Mar 9, 2011 Accepted: May 18, 2011
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