ABSTRACT
Background: Dyes are visible materials and are considered as one of the hazardous components that make up the industrial waste. Dye compounds in natural water, even in very low concentrations, will lead to environmental problems. Azo dyes are compounds with one or more -N=N- groups and are used in textile industry. Because of its low price, solubility, and stability, azo dyes are widely used in the textile industry. Direct Red 81 [DR81] is one of the azo dyes, which is removed from bodies of water, using various methods. This study aimed to assess DR81 dye removal by Fenton oxidation and the effects of various parameters on this process
Methods: Decolorization tests by Fenton oxidation were performed at dye concentrations of 50, 500, 100 and 1000 mg/L; hydrogen peroxide concentrations of 0, 10, 30, 60 and 120 mg/L; iron [II] sulfate heptahydrate concentrations of 0, 3, 5, 20 and 50 mg/L; and pH levels of 3, 5, 7 and 10 for durations of 5, 10, 20, 30, 60 and 180 minutes
Results: The optimal condition occurred at a dye concentration of 20 mg/L, hydrogen peroxide concentration of 120 mg/L, bivalent iron concentration of 100 mg/L, pH of 3, and duration of 30 minutes. Under such conditions, the maximum dye removal rate was 88.98%
Conclusion: The results showed that DR81 could be decomposed and removed by Fenton oxidation. In addition, the removal of Direct Red 81 [DR81] depends on several factors such as dye concentration, reaction time, concentrations of hydrogen peroxide and iron, and pH
ABSTRACT
Background: Atrazine is one of the most widely used triazine herbicides which has been used for controlling broadleaf and grassy weeds for many years. Its widespread use in water has caused environmental concern because of frequent detection of atrazine in aquatic systems where this herbicide has been spilled. Therefore, the purpose of this study was to determine the herbicide removal efficiency at the optimal conditions
Methods: The effect of different parameters including pH at three different levels [3-11], the initial concentration of atrazine at three different levels [0.1-10 mg/L], and reaction time at five different levels [0-120 min] on the removal of atrazine in the aqueous phase using ultraviolet radiation [1020 microw/cm[2]] was investigated. Finally, the data were analyzed using SPSS software [version 16]
Results: The results demonstrated that atrazine removal rate increased by increasing pH, initial atrazine concentration, and reaction time. The maximum rate of atrazine removal [99.2%] at optimal condition occurred in pH=11, atrazine concentration=10 mg/L at 30 min
Conclusion: According to the findings, it can be concluded that the UV-A process is an effective and commodious method for reducing atrazine in polluted water resources
ABSTRACT
Background: The consumption of healthy food is considered as an essential need to devoid the physical, chemical, and biological hazards. The importance of this issue is more conspicuous in places such as hospitals where people with somehow compromised immune systems are under treatment. Therefore, this research aimed to evaluate the microbiological quality of food contact surfaces in a kitchen in one of the hospitals of Shiraz University of Medical Sciences
Methods: In the present study, samples were taken from 48 food contact surfaces according to ISO 18593:2004[E] and placed into the bags containing diluting solution; they were then transferred to the laboratory for microbial analysis in the cold chain. The microbial analysis was carried out according to ISO 4833-1:2013 and BS ISO 4832:2006 for enumeration of total bacterial count and coliform
Results: Based on the results presented here, 39.6% and 85.7% of the samples showed acceptable contamination with regard to the enumeration of total bacterial and coliform count. Besides, 18.2% and 72.7% of work surfaces groups [cutting board, table, and hand] showed acceptable contamination with regard to the enumeration of total bacterial count and coliform in comparison to the standards. Furthermore, 45.9% and 89.2% of other surfaces showed acceptable total bacterial and coliform count, respectively
Conclusion: The results showed that safe management of the kitchen, education of the staff and also improvement of the equipment used are necessary
ABSTRACT
Background: Amoxicillin is widely used as an antibiotic in the modern medicine. Due to its chemical structure, polarity, activity level, antibiotic specifications, and environmental sustainability, Amoxicillin leaks into the groundwater, surface waters, and drinking water wells. Many physical and chemical methods have been suggested for removing Amoxicillin from aquatic environments. However, these methods are so costly and have many performance problems
Methods: In this study, biodegradation of Amoxicillin by submerged biological aerated filter [SBAF] was evaluated in the aquatic environment. In order to assess the removal of Amoxicillin from the aquatic environment, this bioreactor was fed with synthetic wastewater based on sucrose and Amoxicillin at 3 concentration levels and 4 hydraulic retention times [HRTs]
Results: The maximum efficiency for Amoxicillin and Soluble Chemical Oxygen Demand [SCOD] removal was 50.8% and 45.3%, respectively. The study findings showed that Stover-Kincannon model had very good fitness in loading Amoxicillin in the biofilter [R[2]> 99%]. There was no accumulation of Amoxicillin in the biofilm and the loss of Amoxicillin in the control reactor was negligible. This shows that removal of Amoxicillin from the system was due to biodegradation
Conclusions: It can be concluded that there was no significant inhibition effect on mixed aerobic microbial consortia. It was also observed that Amoxicillin degradation was dependent on the amount of Amoxicillin in the influent and by increasing the initial Amoxicillin concentration, Amoxicillin biodegradation increased, as well
ABSTRACT
Background: Groundwater nitrate pollution is an important environmental problem in water resources management. In this regard, specific measures aiming at prevention of water pollution will be helpful to managers and decision-makers. Identification of aquifers' vulnerable areas and determination of groundwater protection zones using most widely used models, such as DRASTIC and CD, are one of the most useful approaches in water resources' hygiene
Objective: The present study aimed to assess the vulnerability of Shiraz plain's unconfined aquifer using the above-mentioned models
Methods: The main hydro-geologic factors affecting the transmission of pollution, including depth to water table, net recharge, aquifer media, soil media, topography, impact of the vadose zone, aquifer hydraulic conductivity, and land use parameters were rated, weighted, and integrated using GIS 9.3. Finally, the maps of Shiraz plain's unconfined aquifer vulnerability were prepared
Results: The vulnerability maps based on these two indexes showed very similar results, identifying the southeastern part of the aquifer, around Maharlu Lake, as the vulnerable zone. The observed nitrate concentrations from the wells in the underlying aquifer were in accordance with these findings. The results of sensitivity analyses indicated the depth parameter as the most effective parameter in vulnerability assessment of Shiraz plain
Conclusion: As Shiraz plain has been covered with fine-grained sediments, except for some central and south-east regions which have moderate vulnerability and high nitrate concentration, its vulnerability is low. Given the intensive agricultural activities and also the rise in groundwater level in southeastern regions, more attention should be paid to these areas
ABSTRACT
Background and Objectives: Activated carbon is an adsorbent which is mostly employed in order to remove dye from aqueous solutions; however, commercial activated carbon is expensive and this is considered as an obstacle for its usage. Therefore, the present study aimed to use waste paper as an inexpensive precursor to produce activated carbon
Materials and Methods: In the present study, KOH was used for the chemical activation process; in order to prevent the precursor oxidation during the carbonization process, a completely sealed furnace was used. In order to determine the characteristics of the prepared activated carbon texture, N[2] gas adsorption and BET isotherm were used. Moreover, Langmuir, Freundlich, Temkin, and Redlich-Peterson isotherm models as well as Pseudo-first order, Pseudo-second order, and intra-particle diffusion kinetic models were used to determine the characteristics of Methylene Blue adsorption on the prepared adsorbent
Results: According to the results, S[BET] and V[TOTAL] were 66.01m[2]/g and 0.063cc/g, respectively. Ferudlich and pseudo-second order models were the best isotherm and kinetic models for prediction of the Methylene Blue adsorption on the produced adsorbent. Furthermore, the q[max] constant from the Langmuir model was obtained as 68.03 mg/g
Conclusion: In comparison to other studies, the produced activated carbon in the present study had a desirable surface area and adsorptive capacity for methylene blue adsorption in aquatic environments. Moreover, it seems that preparing activated carbon from waste newspaper is inexpensive, effective, and environment friendly