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Showing 3 results for Daraei

H Daraei, M Manshouri, A.r Yazdanbakhsh,
Volume 20, Issue 79 (Sep 2010)
Abstract

Background and purpose: Phenol is an organic pollutant that is found in industrial effluents and is very toxic to human and the environment. The purpose of this study was to use the ostrich feathers ash as a natural absorbent to remove phenol from aqueous solution.
Materials and methods: For this study, ostrich feather ash was used as a new adsorbent in removal of phenol at different doses (0.2, 0.3, 0.5, 0.7, 1, 1.5, 2 and 3 g). Çhanges following the effect of contact time, pH, adsorbent dose, temperature and initial phenol concentration have been recorded. Then, the adsorption data were described with Langmuir and Freundlich adsorption isotherms and Ëxcel software was used for data analysis.
Results: There is a dose-dependent relationship between phend adsorption by absorbent at doses ranging from 0.2-2 g. The adsorption of phenol decreases following an increase in the pH of the solution. Âlso, it is observed that the contact time significantly affects the rate of phenol adsorption (77%) from solution.
Çonclusion: Generally, the studied adsorbent was applied successfully for treating industrial water samples and aqueous solution.
Afshin Maleki, Mohammad Ahmadi Jebelli, Bagher Hayati, Hiva Daraei, Fardin Gharibi,
Volume 25, Issue 124 (5-2015)
Abstract

Background and purpose: There is growing application of dendrimers in the world, therefore, this study was conducted to evaluate the effect of antibacterial properties of generation-2 and 4 poly (amidoamine) dendrimer (PAMAM) on some bacteria isolated from water resources. Materials and methods: Water samples were collected from drinking water resources. Bacteria were isolated and identified using differential biochemical tests. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against gram-positive and gram-negative bacteria were calculated. Standard discs were prepared by different concentrations of dendrimer (0.5, 5, 50 and 500 μg/ml) and evaluated through disc agar diffusion method on Muller-Hinton agar plates. Finally, the inhibition zone diameter was measured and the effect of temperature and pH was investigated on antimicrobial activity of dendrimers. Results: The main isolated bacteria from water resource were Escherichia coli, Pseudomonas aeruginosa, klebsiella oxytoca, Bacillus subtilis, and staphylococcus aureus. The results showed completely similar MIC and MBC for each isolated bacteria in both generations which were as follows: Escherichia coli 1250 and 2500 μg/ml, klebsiella oxytoca 500 and 1250 μg/ml, staphylococcus aureus 1 and 5 μg/ml, and Bacillus subtilis 2.5 and 5 μg/ml, respectively. No MIC and MBC were observed on Pseudomonas aeruginosa. Also, it was found that PAMAM dendrimer was more potent towards the gram positive bacteria than the gram negative bacteria. Although amino terminated G4 PAMAM dendrimer has more functional groups, but no significant difference was observed in its antimicrobial activity compared to that of the G2 PAMAM dendrimer. Conclusion: Amino-terminated generation 2 poly(amidoamine) dendrimer exhibited a positive impact on the removal of main isolated strains. Therefore, it might be used as a safe and effective material for water disinfection in future.
Hamide Mirzamohammadi, Hiua Daraei, Behzad Shahmoradi, Fardin Gharibi, Afshin Maleki,
Volume 27, Issue 147 (4-2017)
Abstract

Background and purpose:Diazinon is an organophosphorus insecticide, which is classified as a relatively dangerous product by the World Health Organization. Entrance of this pollutant into water resources can have detrimental effects on human health and environment. The aim of the present study was to evaluate the performance of pulsed alternative current and the electrocoagulation-flotation (ECF) processes in removal of diazinon from aqueous solutions.

Materials and methods:An applied laboratory-scale experiment was designed. Diazinon removal was performed using ECF and pulsed alternative current in a 750 ml borosilicate glass intermittent flow reactor, equipped with a magnetic stirrer, an electrical source, a pulsar, and four aluminum electrodes. The optimized operating conditions were also assessed using 10-500 mg/L of diazinon.

Results:According to the results, the removal efficiency of diazinon was found to range between 5% to 85%. Investigation of ­the operational parameters demonstrated significance of the initial concentration of diazinon, current density, the number of pulses, and electrical conductivity in efficiency of ECF process. The maximum removal efficiency of diazinon was found to be 85% (213 mg of diazinon), which was achieved in an operating condition with pH=7, current density of 46.7 A/m2, electrical conductivity of 600 μS/cm, and process time of 45 min.

Conclusion:According to this study, ECF method could be used along with pulsed alternative current for removal of high concentrations of diazinon from wastewater.Additional processes are needed to meet the standards of drinking water.



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