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Showing 4 results for Abbasi
Photocatalytic Removal of Methyl Orange in Suspension Containing ZnO and SnO2 Nanoparticles and Investigation the Influence of Effective Variables on the Process
S Abbasi,
Volume 9, Issue 3 (12-2016)
Abstract

Background and Objective: Owing to the extended usage in the safekeeping of environments, the photocatalytic materials have been widely applied. The purpose of the present study was to investigate the photocatalytic activity of ZnO and SnO2 nanoparticles in removal of methyl orange from aqueous media.

Materials and Methods: ZnO and SnO2 nanoparticles were synthesized through sol-gel and chemical precipitation respectively. Methyl orange was selected as model pollutant. The effect of weight fraction on the removal of pollutant was investigated in the range of 0.25, 0.5, and 1 weight percent. Meanwhile, for investigating the effect of radiation time, the suspension containing pollutant and nanoparticles was irradiated. The obtained results were analyzed by MSTATC, Ver 1.42 software and Duncan’s multiple range test.

Results: The analysis of variance results of removal efficiency of methyl orange showed that in the suspension involving ZnO and SnO2, radiation time, weight fraction and the combined effect of them have a significant effect on the removal of methyl orange at 5% level of probability. Meanwhile, by increasing irradiation time from 5 to 25 min, the removal efficiency in suspensions containing ZnO and SnO2 reached 97.42 and 65.55% respectively. Investigation on the effect of concentration on the removal of methyl orange shows that the removal of methyl orange increases with respect to the weight fraction.

Conclusion: According to the obtained results, it was observed that the photocatalytic activity of ZnO is higher than that of SnO2. Therefore, the application of ZnO is more effective for removal of methyl orange from aqueous media.


Exploring distribution of heavy metals in wastewater-irrigated agricultural soil using kriging method and hydrus model: case study in south of Tehran
Y Abbasi, F Mirzaei, T Sohrabi,
Volume 11, Issue 3 (12-2018)
Abstract
Background and Objective: The main objective of this study was to evaluate the surface and deep distribution of Pb, Ni and Cu in the wastewater-irrigated area of south of Tehran using GIS and Hydrus. It was expected to find a comprehensive information of heavy metals distribution and their accumulation in the soil. 
Materials and Methods: This study was carried out in wastewater-irrigated area of south of Tehran. Soil sampling from the top surface layer (0-15 cm) and wastewater channels was done. After sample analysis, ordinary Kriging method using different variogram in GIS was applied to explore the surface distribution of Ni, Pb and Cu heavy metals. Moreover, the deep percolation of heavy metals in the soil profile was simulated by Hydrus-1D in a duration of 210 days and the heavy metals concentrations in the soil were estimated.
Results: Exploration of the distribution of Pb using spherical model showed that the variation of this element was in the range of 20-70 mg/kg. This amount varied to 50-60 mg/kg for Cu and about 30 mg/kg for Ni. Moreover, the simulation of heavy metals deep percolation using Hydrus revealed that the most accumulation of heavy metals happened in the 0-15 cm soil surface layer and for deeper layer, this trend was descending.
Conclusion: Comparing the concentration of Pb, Cu and Ni with the maximum allowable amounts of WHO standards demonstrated that Pb concentration was more than the threshold limit. Finally, the applied models could simulate soil’s heavy metals content for both surface and deep distribution in the studied area.
 

Investigation of seasonal changes in the density and diversity pattern of fungal populations in the air around processing facilities of the composting plant
Fariba Abbasi, Mohammad Reza Samaei, Mahrokh Jalili, Hosein Khodadadi, Ali Karimi,
Volume 13, Issue 4 (2-2021)
Abstract
Background and Objective: The aim of this study was to investigate the effect of seasonal variation on the diversity of fungal airborne species in the composting process.
Materials and Methods: Samples were taken based on the 0800 NIOSH method at a height of 1.5 m above the ground during the waste separation, turning of windrow and stabilization of compost. Air samples were collected in two various seasons; summer (108 samples) and winter (108 samples) at the composting plant in Shiraz. The culture media consisted of Sabouraud Dextrose Agar with chloramphenicol for the selective isolation of fungi, which was further incubated at 37 and 45°C. The results were analyzed by a t-test method using MATLAB 2018.
Results: The highest mesophilic fungi density was related to the segregation process of composting. The variation of fungi observed was higher during summer throughout separation and stabilization process (p < 0.05). The predominant species were found to be Aspergillus flavus (4449.8 CFU/m3) (p < 0.05) and Paecilomyces (1850.9 CFU/m3) (p < 0.05), respectively. Furthermore, the highest varieties of fungal species in the turning of windrow mass were observed during winter (p < 0.05) and the predominant species was yeast (420.6 CFU/m3). At all stages of composting, the varieties of thermophilic fungal species were higher during summer with the large number of Aspergillus fumigatus, Mucoral, and Paecilomyces.
Conclusion: The density and diversity of mesophilic fungi during summer was higher than winter. The concentration of Aspergillus, was beyond the guidelines set by the EPA, ACGIH, NIOSH and EU. Thus, the use of self-protection is essential.

Investigation of heavy metal concentrations in agricultural topsoil of Miandoab landfill area
Nader Abbasi, Mohsen Mohammadi Galangash,
Volume 17, Issue 2 (9-2024)
Abstract
Background and Objective: Heavy metals are regarded as serious contaminants due to their toxicity, persistence in natural conditions, and ability to enter and accumulate (bioaccumulation and biomagnification) in food chains. The aim of this study was to investigate the concentrations of the heavy metals Pb, Cd, Cu, Zn, Cr, Fe and Ni in surface agricultural soils of the Miandoab landfill area.
Materials and Methods: In this study, 57 soil samples were collected from a depth of 0-20 cm. After preparing and digesting in the laboratory, the samples were analyzed using a inductively coupled plasma spectrometer (ICP-OES). The Ecological Risk Potential Index (EPRI), Earth Accumulation Index (Igeo), Principal Components Test (PCA) Pearson's Correlation, Cluster Analysis, and One-T-test were utilized. Statistical processing was conducted using SPSS software.
Results: According to the results of the single T-test, the average concentrations of Pb, Cd, Cu, Zn, Cr, Ni did not significantly differ from their background concentration in the soil (p≥0.05). A significant difference was pbserved only for Fe (p<0.05), indicating a geological origin for this element. The EPRI was within the low-risk range, with an average value of 46.95. PCA revealed that the first factor was positively associated with Cr, Pb and Fe; the second factor with Zn and Cu; and the third factor with Cd. Cluster analysis showed that Fe was predominantly influenced by natural resources. According to the land accumulation index, all metals, except Cu, were classified non-polluted or slightly polluted at stations 2 and 4.
Conclusion: The origin of elements is related to both natural and human factors. Specifically, Cr, Pb and Cd are more likely to originate from man-made sources, while Fe primarily comes from natural sources. The decrease in the concentration of metals can be attributed to continuous and annual ploughing, inactivity of the landfill, biological absorption by crops, soil leaching and transporting to lower depths.
 

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