فهرست مطالب ziaeddin bonyadi

Nitroaniline is a derivative of aniline known for its high toxicity, potential carcinogenicity, and mutagenic effects. A practical method for removing these compounds from aqueous solutions is applying advanced oxidation processes (AOPs). This study aims to investigate the efficiency of the activated persulfate process in removing nitroaniline from aqueous solutions under controlled laboratory conditions.

To conduct this study, the impact of various variables, including pH levels (ranging from 3 to 11), contact time (15 to 120 minutes), nitroaniline concentration (ranging from 1 to 30 mg/L), and persulfate concentration (ranging from 100 to 800 mg/L), on synthetic samples was examined. Post-treatment, the remaining nitroaniline concentration was measured using a UV-vis spectrophotometer at 530 nm. Independent t-tests and descriptive statistics, including mean and standard deviation, were employed to analyze the acquired data.

The activated persulfate process with pulsed light achieved the highest nitroaniline removal efficiency at 98.2%. This result was obtained under specific conditions: a contact time of 90 minutes, a pH level of 8, an activated persulfate concentration of 600 mg/L, and a nitroaniline concentration of 1 mg/L. Our findings indicate that the photocatalytic process of persulfate activated by pulsed light adheres to the second-order kinetic model.

Based on the outcomes of this study, the persulfate process activated by pulsed light displayed significant effectiveness in removing nitroaniline from aqueous solutions. Therefore, owing to its high removal efficiency, cost-effectiveness, and straightforward management, it is recommended to employ this process to remove organic and resistant pollutants from aqueous solutions.

Human activities, especially in construction and agriculture, introduce large amounts of nitrogen, phosphorus and organic matter into aquatic ecosystems.

In this study, municipal and industrial wastewater samples were obtained from wastewater treatment plant No. 1 of Parkand Abad and wastewater treatment plant of Kalat industrial park, respectively. Before starting the reactor, wastewater samples were allowed to settle for 2 h to remove coarse suspended solids and then sterilizes in autoclave. Chlorella vulgaris was purchased from Jahad Daneshgahi of Mashhad and grown in specific culture media under temperature 25±2°C, photoperiod of 14 h light and 10 h dark, monochrome light with intensity of 5000±350 lux, pH of 7-8.5 and time of 10 d. Then 1 L of the above solution were transferred to three 10 L reactors loaded with municipal, industrial and culture media and aerated under sterile conditions in the presence of light for 10 d. In predetermined time intervals (each 2 d), 100 mL sample were taken from reactors and COD, total phosphorous, total nitrogen, pH and chlorophyll a measured.

Removal efficiency of COD, total nitrogen, and phosphorus in municipal, industrial and culture media by Chlorella vulgaris was 63.69, 12.52, and 13.79%, 66.57, 34, and 50.18%, respectively. According to results, the efficacy of algae for removal of COD was higher than other parameters, while that for total nitrogen was lowest. Efficacy of algae for removing pollutants from industrial was better than those in domestic wastewater.

The results of this study showed that municipal and industrial media could be a suitable culture media for growing Chlorella vulgaris algae. It also has the ability to remove nutrients from wastewaters.

Today, due to the dangers of chemical preservatives in food, alternative and safe methods such as the use of natural extracts of natural plants have increased. The aim of this study was to evaluate the antibacterial effects of Kenar fruit extract on the bacteria of Salmonella, Shigella, Escherichia coli and Bacillus cereus.

We prepared Kenar fruit extract by soaking or immersing in methanol. After concentrating by rotary device, we prepared 9 concentrations of the extract serially, then performed antibiogram by well method and determined MIC and MBC. We also used volumetric-volumetric solution of methanol and dimethyl sulfoxide in equal proportions as negative control and control disks and standard commercial antibiotics as positive control.

Based on the results, the diameter of inhition zone for dropletsfor Shigella, Salmonella, Bacillus cereus and Escherichia coli at a concentration of 80 mg/mL of methanolic extract of the plant was 24, 17, 59 and 19 mm, respectively. It was also found that methanolic extract of Kenar fruit had very good antibacterial effects on gram-positive bacterium Bacillus cereus compared to other target bacteria (which are gram-negative) and had significant growth inhibition and bactericidal effects at very low concentrations.

The results showed that methanolic extract had very favorable antibacterial effects against four target bacteria. Therefore, it can be said that the compounds of methanolic extract of this plant can be used as important components of various products in the food, pharmaceutical, cosmetic and health industries.

Today, fluorescent lamps are the most common light source in the world and Iran. Mercury in these lamps may enter the environment and cause harmful effects. The aim of the present study was to investigate the effect of heterotrophic wastewater bacteria on the mercury removal from fluorescent lamps.

In this study, different components of lamps were separated using a crushing machine and then mercury was separated from phosphorus powder by acid washing. Bacteria isolated from wastewater were exposed to mercury from acid wash and the mercury content in the lamps was measured by atomic absorption spectrophotometer. The highest concentrations of mercury extracted from lamps was 86.03 ppb in the ratio of 4 HCL: 1 HNO3, and the lowest mercury concentration was14.03 ppb in the 1HCL: 1HNO3 ratio.

The results of this study showed that heterotrophic bacteria can reduce mercury levels to less than 5 µg / L. 19 bacteria purified from wastewater were resistant to mercury chloride at concentrations of 5 and 10 mg. Also, 10 bacteria were able to reduce mercury. The highest rate of mercury reduction (92.24%) was related to Pseudomonas marginalis and the lowest rate (62.47%) was related to Pseudomonas simiae.

This study showed that heterotrophic sewage bacteria can be used as an efficient, low-cost, and environmentally friendly method for detoxification of mercury from out-of-date fluorescent lamps.