Leila Moradi Pasand, Bita Ayati,
Volume 6, Issue 3 (12-2013)
Abstract
Background and Aim: In this study, the removal of dye blue reactive-171 by combination of advanced oxidation processes UV/H2O2 and SBAR has been investigated. Methods: The efficiency of chemical and biological system was first investigated separately. In chemical system, the kind, power, initial dye concentration and hydrogen parasitize and in biological system, hydraulic detention time, aeration rate, initial dye concentration and the percent removal of dye and COD were investigated. In order to investigate the hybrid system, after determination of the optimum conditions and the capabilities of each system, the removed chemical system effluent from residual hydroxide peroxide, was entered into the biological reactor. Results: In the chemicals process, 100 ppm dye using 150 Watt-UV-C lamp and 0.1 mM hydrogen peroxide at pH= 9 was completely removed in 25 minutes. COD removal was 86.7 percent at the end of the experiment (135 min). Biological system with adsorption mechanism has shown 44 percent dye removal with initial COD of 50 mg/L that indicated the system inability in biodegradation and breaking down of the dye molecule. In comparison to separate chemical and biological processes, hybrid system has shown better dye removal efficiency. The results indicated that in addition to the complete dye removal achievement, 81% of COD in the first hybrid system and 52% of COD in the second hybrid system was removed, respectively. Conclusion: According to the results, because of complexity of dye structure, biological system was not able to remove the dye as efficient as hybrid system of advanced oxidation processes UV/H2O2 with SBAR.
S Bita, M Mesbah, A Shahryari, M Ghorbanpoor Najafabadi,
Volume 10, Issue 3 (12-2017)
Abstract
Background and Objective: Nanoparticles are already widely used in technology, medicine and consumer products, but there are limited data on their effects on the aquatic environments. The aim of this study was to evaluate the response of antioxidant defense system in common carp gills exposed to silver nanoparticles, which are produced by bioreduction method.
Materials and Methods: Common carp fish were exposed to the silver nanoparticles at concentrations of 0.11, 1.13 and 5.67 mg/L for 14 days. A treatment without silver was considered as a control. After sampling, 1 g of gill was weighed and homogenized in 5 mL phosphate buffer. The homogenized samples were analyzed for measuring the activity of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), total antioxidant capacity (TAC) and malondialdehyde (MDA).
Results: CAT activity in gill at the concentrations of 1.13 and 5.67 mg/L AgNPs was significantly reduced compared to that of the control (p<0.05). When the activities of GSH and TAC of different treatments and the control were compared, no significant difference (p>0.05) was observed. Activity of SOD and MDA of all treatments sampled at different days was fluctuated, that is, it was either increased or decreased. However, superoxide dismutase activity was significantly higher in exposure to concentrations of 5.67 mg/L and 1.13 mg/L.
Conclusion: According to the results, fish gills are one of the most susceptible organs of oxidative damage in exposure to silver nanoparticles. This can affect the health of common carp and thus increase the risk of disease in the fish.
