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Showing 6 results for Assadi

Roya Alimoradzadeh, Ali Assadi, Fatemeh Afshar, Ali Reza Rahmani, Mohammad Reza Samarghandi,
Volume 1, Issue 1 (12-2015)

Background: Titanium dioxide (TiO2)-mediated photocatalysis has been found to be an efficient method of water treatment and is capable of degrading a wide range of organic pollutants and microbial agents with high efficiency. The microorganism Pseudomonas aeruginosa is resistant to chemicals and UV irradiation. Bacteria which are resistant to UV-induced oxidative damage of the cell membrane are susceptible to photocatalytic technology. The main objective of this research was to examine the photocatalytic removal of P. aeruginosa upon UV irradiation in the presence of TiO2 nanoparticles.
Methods: Polluted water samples were prepared by the addition of P. aeruginosa colonies into water, followed by contact with UV, TiO2, or a combination of the two in separate stages. The effect of various parameters, including contact time, pH, and TiO2 concentration, on reaction efficiency was examined.
Results: The highest efficiency of bacterial disinfection was achieved with UV irradiation in the presence of TiO2 nanoparticles, with complete (100%) removal of P. aeruginosa observed upon irradiation for 60 min in the presence of 0.4 g/L TiO2 under conditions of neutral pH.
Conclusions: The results of this study suggest that from a technical and economic perspective, the UV/TiO2 process may be effectively applied for the disinfection of polluted water. This process could be considered a promising method of cleaning and purification, and applicable for water disinfection.

Ali Assadi, Armita Soudavari, Mehran Mohammadian,
Volume 1, Issue 3 (6-2016)

Background: Conventional chemical coagulation is considered as the old method to color and COD removal in textile effluent. Electrocoagulation (EC) process is a robust method to achieve maximum removal.
Methods: This work was designed to compare the result of operational parameters including optimum pH and coagulant concentration for chemical coagulation with ferric chloride and alum. Also, the effect of voltage, electrolysis time, initial pH, and conductivity for EC with iron electrodes on removal of reactive red 196 (RR 196).

Results: The results show that ferric chloride and alum at optimum concentration were capable of taking away color and COD equal to 79.63 %, 84.83%, 53%, and 55% respectively. In contrast, EC process removed the color and COD equal to 99.98% and 90.4%, respectively.
Conclusion: The highest treatment efficiency was obtained by increasing the voltage, electrolysis time, pH and conductivity. Increase in initial dye concentration reduces removal efficiency. Ultimately, it could be concluded that EC technology is an efficient procedure for handling of colored industrial wastewaters.

Fardin Assadi, Hamidreza Amirmoghaddami, Mojghan Shamseddin, Keivan Nedaeei, Azam Heidari,
Volume 1, Issue 4 (9-2016)

Background; In recent years, nanoparticles have been increasingly used in industries. However, there is a serious lack of information concerning their impact on human health and the environment. This study was investigated the effect of MoO3 NPs on thyroid hormones in female rats.
Methods; In this study, 21 female Wistar rats were selected and divided into three groups of untreated control, sham and treatment group with seven rats in each group. During 28 days the sham group received normal saline and treatment group received 5 mg/kg (MoO3 NPs) in normal saline. After the final injection, blood samples were collected and serum levels of total thyroxine (T4), triiodothyronine (T3), and thyroid-stimulating hormone (TSH) were measured and groups were compared together.

Results; The results showed that the serum levels of T4 decreased significantly in group of 5 mg (MoO3 NPs) in comparison with the control group (< 0.05). However, there was insignificant difference observed in T3 levels when compared with the control group (p>0.05). The serum levels of TSH increased significantly in group of 5 mg/kg (MoO3 NPs) when compared with the both groups of sham and control (p<0.05).
Conclusion; The results showed that MoO3 NPs exposure induces the risk of thyroid dysfunction.

Ali Assadi, Sevda Naseri, Mehran Mohammadian Fazli,
Volume 2, Issue 4 (9-2017)

Background: Phenol as an aromatic hydroxyl compound are considered as a priority pollutant.  Because of their stability, solubility in water and high toxicity had health important.
Methods: In the present experimental study, electrocoagulation reactor by iron electrodes are used in the presence of hydrogen peroxide to phenol removing from aqueous solutions. Effects of variables including H2O2 dosage, reaction time, pH, current density and initial phenol concentration were evaluated to estimate the efficiency of the process.
Results: The results showed that pH and H2O2 have the most important role in the removal of phenol. Increasing of H2O2 concentrations from 0.0125 to 0.025 M increased removal efficiency from 74% to 100%. Maximum removal was achieved at pH=3. However, increasing the pH to 9 lead to reducing removal efficiency to 9.8%.  Also, by increasing of current density removal efficiency was increased. But with increasing initial concentration of phenol removal efficiency was reduced.
Conclusion: Proxy-electrocoagulation process as an effective and robust process can be used for handling of phenol containing wastewater.

Zahra Abedi, Mohammad Reza Mehrasbi, Ali Assadi,
Volume 2, Issue 4 (9-2017)

Background: Natural organic matters (NOMs) have the main role in formation of trihalomethanes. These compounds are in natural water sources due to biological activities. In the presented study, adsorption and separation of humic acid as an index of natural organic matters using multi-walled carbon nanotubes is evaluated.
Methods: The experiments were carried out in bath adsorption reactors with different concentrations of humic acid. The effects of pH, adsorbent dose, national concentrations of humic acid and contact time as study variables were tested in separated experiments, as well as, kinetic and isotherm models of the adsorption process were determined.
Results: The results showed that the adsorption follows Freundlich isotherm model and pseudo second-order kinetic equation. The removal percent of humic acid reached to higher than 90% with dosage of 1g/l of nanotube.
Conclusion: Adsorption of humic acid from water by multi-walled carbon nanotubes is an efficient alternative pretreatment method in water treatment plants.

Ali Assadi, Tohid Soltani, Mohammad Reza Mehrasbi,
Volume 3, Issue 1 (12-2017)

 Nowadays, underground water is the main source of drinking water that contamination to organic pollutants such as MTBE is an important issue. One of the suitable methods for these types of pollutants is the advanced oxidation methods. Advanced oxidation processes (AOPs) are involved in the production of highly reactive hydroxyl radicals that oxidize organic matter such as MTBE and even lead to its full mineralization. The use of light in the presence of catalysts is one of the methods of advanced oxidation processes. Photocatalytic methods widely used for a wide range of toxic and none degradable pollutants. Recent advances in the fabrication and characterization of Nano scale materials have extensively developed research into methods for the preparation of highly effective Nano-sized catalysts for the removal of chemical contaminants. This review article discusses the work on the photo catalysis of MTBE in water using different types of photo catalysts.

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