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Showing 4 results for Ghodrat
Antimicrobial Efficacy of Zinc Oxide Nanoparticles Suspension Against Gram Negative and Gram Positive Bacteria
Edris Hoseinzadeh, Mohammad Reza Samargandi, Mohammad Yosef Alikhani, Ghodratollah Roshanaei, Ghorban Asgari,
Volume 5, Issue 3 (21 2012)
Abstract
MicrosoftInternetExplorer4 Background and Objectives: Along with the rapid development of human life, controlling   harmful effects of microorganisms would be unavoidable. The objective of this study was to evaluate antibacterial efficacy of zinc oxide nanoparticles on different microbial strains.
Material and Methods: This experimental study was done using gram negative and gram positive bacteria in nutrient media. Nanoparticle characterization was determined using X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM). Bacterial sensitivity to nanoparticles was tested using a disk diffusion test and minimum inhibitory concentration (MIC). Time-kill studies and other tests were carried out using 108 CFU/mL of bacteria at baseline. A point of zero charge, pHzpc, of nanoparticle was investigated using the batch equilibration method. Obtained data were managed by SPSS Ver.16 and were analyzed through the Pearson, analysis of variance (ANOVA) and Student's independent t-tests. 0.05 was selected as significant level for all tests.
Results: Characterization results from XRD, SEM, and TEM showed that particles are in nano range and they do not contain any discernible crystalline impurity. The average ZnO nanoparticles diameter was 20 nm. The pHZPC for ZnO was found to be 7.51. The P. aeruginosa strain exhibited larger diameter inhibition zone (DIZ) to ZnO nanoparticle compared with other strains. Population of P.aeroginosa for 2 x MIC concentration was reduced to zero in the presence of nano ZnO within 150 min. The bacterial CFU had significant difference with contact time, nanoparticles loading, and bacterial strain (P<0.001).
Conclusion: This study demonstrated that antibacterial activity of ZnO can be a candidates for the elimination of gram negative and gram positive bacteria, particularly in nasocomial infection agent control.


The optimization of electrocoagulation process for treatment of the textile wastewater by Response surface Methodology (RSM)
Samaneh Ghodrati, Gholamreza Moussavi,
Volume 7, Issue 2 (10-2014)
Abstract

Background and objectives: Electrocoagulation (EC) as an electrochemical method was developed to overcome the drawbacks of conventional decolorization technologies and is an attractive alternative for the treatment of textile dyes. This study was aimed at the optimization of the EC process for decolorization and COD removal of a real textile wastewater using response surface methodology (RSM). RSM is an important branch of experimental design and a critical technology in developing new processes, optimizing their performance, and improving design and formulation of a new products. Materials and Methods: In this study, a bench scale EC reactor was designed, constructed, and studied for treatment of a textile wastewater. The main operational variables were current intensity, residence time, initial pH, and electrode materials as independent variables color and COD removal were considered as dependent variables. The experimental runs were designed using selected variables using Design Expert 7.0 software and the process was optimized for decolorization and COD removal using the response surface method. Results: The optimal operational conditions in the EC process for attaining the maximum decolorization and COD removal were current density of 0.97 A, initial pH of 4.04, residence time of 48 min, and Fe electrode. The desirability factor for Fe electrode was 1, while decolorization and COD removal were predicted 76.3 and 75.6% respectively, which was confirmed by the experimental results. Conclusion: The experimental results indicated that the EC process is an efficient and promising process for the decolorization and COD removal of textile effluents. Under the optimized conditions, the experimental values had a good correlation with the predicted ones, indicating suitability of the model and the success of the RSM in optimizing the conditions of EC process in treating the textile wastewater with maximum removals of color and COD under selected conditions of independent variables.


Assessing Performance of Walnut Green Hull Adsorbent in Removal of Phenol from Aqueous Solutions
Fatemeh Hashemi, Hatam Godini, Ghodratolah Shams Khorramabadi, Loqman Mansouri,
Volume 7, Issue 2 (10-2014)
Abstract

Background and Objective: Phenol presence in water and wastewater is interesting because of its stability in environment and health problems. Therefore, it must be removed for water pollution prevention. The aim of this study was to evaluate phenol adsorption from aqueous solutions using walnut green hull. Materials and Methods: This was an experimental study in which walnut green hull was used as biosorbent with a range of mesh 40. In this study, stock solution of phenol was prepared and effects of effective parameters such as pH (4,6,8, and10), contact time (3-60 min), adsorbent dosage (0.25-5 g/L), and initial phenol concentration (10,20,40, and 50 mg/L) on adsorption process were evaluated. Moreover results were evaluated using Langmuir and Freundlich isotherms and first order and pseudo-second order kinetics. All experiments were conducted in double and the mean adsorption rate was reported. Results: The maximum adsorption capacity of 30.30 mg/g corresponded with Langmuir model. Kinetic evaluation indicated that the adsorption of phenol by the walnut green hull clearly followed the pseudo-second order reaction. It was found that increasing contact time and adsorbent dosage would lead to increasing of adsorption of phenol and increasing pH and initial phenol concentration lead to decreasing of phenol adsorption. Maximum phenol removal was achieved at pH 4, with more than 99.9 % efficiency. Conclusion: The results of this study show that the walnut green hull can be used effectively in phenol removal, because walnut green hull is agriculture waste and is produced annual in high volume hence, it can be used as adsorbent in phenol removal from wastewater.


Comparative study of the performance of chitosan and chitosan adsorbents modified with Fe3O4 to eliminate erythromycin from aqueous solutions
M Ghodrat, E Asrari,
Volume 10, Issue 4 (3-2018)
Abstract
Background and Objective: Excessive consumption of antibiotics and the entrance of the potentially hazardous substances to the environment has become one of the environmental concerns. Today, adsorption is one of the efficient and reliable methods for the removal of this class of compounds. The aim of this study was to synthesize chitosan-Fe3O4 and to compare the efficacy of removing erythromycin antibiotics from aqueous humorous media by this adsorbent and chitosan.
Materials and Methods: The structural properties of the synthesized adsorbent were analyzed by TEM, PSA, VSM techniques. Various parameters including pH (1-11), contact time (0-60 min), adsorbent concentration (1-5 g/L), and initial concentrations of erythromycin (5-50 mg/L) was evaluated for the removal efficiency. For data analysis, Excel software was used. The equilibrium constant and the kinetic constants were calculated from the first-order kinetic model using Freundlich and Langmuir isotherms.
Results: The results indicated that increased pH and initial concentration of erythromycin increased the dose of adsorbents and the contact time of removal efficiency. The highest absorption efficiency at pH of 3 for both adsorbents, the contact time 30 min for modified chitosan and 50 min for chitosan, the dose of adsorbent 2 g/L for modified chitosan, and 3 g/L for chitosan and the initial concentration of erythromycin for each of the two adsorbents was 10 mg/L and the erythromycin adsorption by both adsorbents follows the Langmuir isotherm and the pseudo second order kinetics.
Conclusion: According to these results, chitosan modified with Fe3O4 can be used as a more effective adsorbent than chitosan for removal of erythromycin by adsorption method.
 

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