جستجوی مقالات مرتبط با کلیدواژه « photocatalytic process » در نشریات گروه « پزشکی »

Antibiotics are among the environmental pollutants with stable effects during consumption, they are rarely completely metabolized in the body and 30-90% of them are excreted through urine and feces and enter into the environment. The present study was conducted to evaluate the degradation of cefixime pollutant by photocatalyst Fe3O4@SiO2@TiO2@rGO + UV in the presence of persulfate (PS) from synthetic wastewater.

Fe3O4@SiO2@TiO2 (F@ST) photocatalyst was synthesized by co-precipitation method, and then fixed on reduced graphene oxide (rGO). The structural properties of magnetic photocatalyst were evaluated using FESEM, XRD, TEM, VSM techniques. The effect of variables such as solution pH, catalyst dosage, persulfate concentration and initial pollutant concentration on the performance of the FS@T/rGO/PS/UV process in the degradation of cefixime pollutant was investigated. After determining the optimal conditions, the influence of interfering ions and scavengers on the process, as well as the amount of recovery and reuse of the catalyst were investigated.

The synthesized photocatalyst had features such as excellent magnetic properties, crystalline and relatively spherical structure in nano size, high purity, photocatalytic properties in both ultraviolet and visible ranges. Under optimal conditions (pH=6.5-7, PS= 2mM and photocatalyst dosage= 0.1 g/L), after 60 min of oxidation time, cefixime antibiotic with a concentration of 50 mg/L and TOC, respectively, with efficiency > 98% and 55.7% were removed. The performance of the process was affected by the presence of organic scavengers (TBA, NaN3, KI and CH3OH) and interfering ions (Cl-, SO4-2, NO3- and CO3-2); so that the pollutant degradation efficiency decreased in the presence of organic scavengers and interfering ions. The effective reaction species were included h⁺, 1O2, OH• and SO4•⁻ in the degradation of cefixime by photocatalytic process in the presence of PS. The synthesized photocatalyst could be used for 4 consecutive steps, and in the fourth step, cefixime was degraded with an efficiency of 70.1%. The behavior of the photocatalytic degradation of cefixime antibiotic per unit time was a function of the pseudo-first-order kinetic model.

: FS@T/rGO/UV/PS photocatalytic process with features such as high efficiency in antibiotic degradation, easy and fast separation, pollutant mineralization, production of side products with simple molecular structure and good performance on the real wastewater sample could be used as a suitable method for industrial wastewater post-treatment as well as pre-treatment in order to reduce organic load and increase biodegradability.

 The present study investigates the kinetic and thermodynamic parameters in removing one of the essential phenolic derivatives (2-chlorophenol) by zinc oxide nanocatalysts synthesized by the green method, during photocatalytic and sonocatalytic progress.

 The present study is an experimental study conducted in the research laboratory of the Department of Chemistry of Ardabil Islamic Azad University. In order to evaluate the efficiency of the photocatalytic and ultrasonic process in the removal of 2-chlorophenol, the first nanocatalyst was prepared by the green method using a paper flower species called Bougainvillea spectabilis. After ensuring the synthesis accuracy with the help of various technologies, essential parameters affecting the removal efficiency of 2-chlorophenol, such as concentration, amount of nanocatalyst, solution pH, and temperature, were investigated, and the most suitable conditions for removal during photocatalytic and ultrasonic processes were identified.

 The XRD spectrum confirms the synthesis of zinc oxide nanocrystals. The uniform hexagonal nature of ZnO nanoparticles with a size between 12 and 31 nm was confirmed using SEM and TEM images. Elemental analysis (EDX) showed that the synthesized pure nanoparticles contained 74.94 wt. % of zinc and 25.06 wt. % of oxygen. Examination of 2-chlorophenol removal from aqueous solution in dark conditions showed that the Langmuir and Freundlich isotherm models best follow the removal process. Investigation of the removal kinetics of the studied phenolic derivative with high line regression coefficient introduced pseudo-second-order kinetics for the removal process of 2-chlorophenol.

 According to the thermodynamic parameters obtained in this study, the negative values of Gibbs free energy changes (ΔG°) at all temperatures studied during the photocatalytic and sonocatalytic removal process showed that the removal reaction is spontaneous. Also, the positive enthalpy changes (ΔH°) during the removal process by the nanoparticles synthesized from the paper flower indicated that the removal process is endothermic. Our research showed that the synthesized nanoparticles could be used for photocatalytic and sonocatalytic removal of 2-chlorophenol from the aqueous medium with an efficiency of 90.21 and 82.54%, respectively.

Today, the production of effluents containing medicinal compounds, including tetracyclines, is one of the major threats to the environment and endanger human health. Accordingly, the need for an efficient system to remove these compounds from aquatic environments is felt. Therefore, the aim of this study was to optimize and model the removal of tetracycline antibiotics using TiO2 / N / S nanocatalyst in the presence of visible light in aqueous solutions.

In this experimental study conducted in 2019, nanocatalyst was synthesized by sol-gel method and then its characteristics were analyzed using SEM, XRD, EDS and BET analyzes. Secondly, by changing the reaction conditions such as changing the synthesized photocatalyst dose (0.1-2) g/l, antibiotic concentration (1-50) mg/l, reaction time (2-90) minutes and solution pH (2-10) and by visible light irradiation to remove tetracycline from synthetic effluent and the effect of these variables on process performance by response surface method and CCD method and determination of optimal conditions, investigation of reaction kinetics, tetracycline mineralization and photocatalyst performance in real wastewater treatment Was evaluated. Tetracycline was determined by reverse phase high performance liquid chromatography (HPLC). The collected data were analyzed using analysis of variance.

The software has proposed a complete quadratic model as the best model, based on ANOVA analysis of variance. The maximum removal efficiency of tetracycline with this process in optimal conditions with a pH of 6 and a time of 56 minutes and a concentration of tetracycline of 13 mg/l was the catalyst value of 1.2 g/l was 77%. The mineralization efficiency of tetracycline antibiotics under optimal conditions was 47% and the kinetic study presented that the data followed the quasi-first-order model well and eliminate the tetracycline process in the wastewater of Imam Sajjad Hospital of Yasuj by 72%.

The results indicated that the efficiency of TiO2/N/S photocatalytic process exposed to visible light radiation in the removal of tetracycline due to lack of by-products as well as mineral end products (carbon dioxide and water) as a desirable process.

Antibiotics are stable compounds with low biodegradability that are generally not removable by conventional wastewater treatment processes. The aim of this study was to investigate the ability of Fe-doped TiO2@Fe3O4 magnetic nanoparticles in the presence of ultraviolet irradiation to photocatalytic removal of ciprofloxacin from aqueous solutions. 

The sol-gel method was used for the synthesis of Fe-doped TiO2@Fe3O4 nanoparticles and the physical and chemical properties of the catalyst were investigated by SEM, EDX, XRD, VSM and DRS analyzes. Then, the effect of different parameters including pH (3-9), initial concentration of ciprofloxacin (25-75 mg/l) and catalyst dose (0.6 to 0.2 g/l) at different times in photocatalytic elimination of ciprofloxacin were studied.

The results showed that the highest removal efficiency 99.1 % and reaction rate constant of ciprofloxacin the presence of 15-watt UVC radiation was obtained at pH 9, initial concentration of 25 mg/l, catalyst dose of 0.6 g/l and contact time of 60 min, respectively. The stability of nanoparticles after 5 reuses had a good removal rate.

Due to the appropriate removal efficiency of ciprofloxacin by the integrated system Fe-doped TiO2@Fe3O4 + UVC, the application of this process in water and wastewater treatment processes is recommended.

Pharmaceutical wastewater has a high level of pollution load that should be treated before discharging to the environment. Integrated processes using different mechanisms are one of the most fruitful methods in wastewater treatment. In this study, combined Integrated Fixed Film Activated Sludge (IFAS) and photocatalytic processes are utilized using of Fe3O4/TiO2 nanocatalysts to decrease the COD value of pharmaceutical wastewater.

In this study, the variables of each process are optimized using Response Surface Methodology (RSM). In the IFAS process, the variables were dissolved oxygen (DO), media filling percentage and hydraulic retention time (HRT); while in the photocatalytic process, the effects of pH of wastewater, catalyst dose and reaction time were investigated.

In optimal conditions (DO 3 mg/L, HRT 24 h and media filling percentage 65%), COD removal rate was obtained 59.15%. With the initial concentration of 1725 mg/L COD and the mentioned efficiency, the concentration of COD in the effluent diminished to 704 mg/L. However, in the photocatalytic process, during optimal conditions (pH 6.8, reaction time 105 min and catalyst dose 60 mg/L), The efficiency of the process was determined 81%, which by considering the input COD (704 mg/L), the output concentration was reduced to 134 mg/L.

According to the standards provided by the Environmental Protection Agency (EPA), the effluent from the combined process can be discharged into the environment.

Through the widespread use of antibiotics including metronidazole, they are continuously released to the environment, while traditional treatment processes unable to remove them. Therefore, they are accumulated in the environment and led to unpredictable risks to human health and ecosystem. In recent years, advanced oxidation processes have been introduced as effective technology for the destruction of pollutants from the aquatic environment. The aim of this study was to evaluate the efficiency of catalyst g-C3N4-TiO2 in the removal of metronidazole from aqueous environment. In this fundamental-applied study, the catalyst g-C3N4-TiO2 was first synthesized. The SEM, EDX and DRS analysis were used to determine the characteristics of the nanocomposite. Then, the effect of factors such as the content of g-C3N4 in the structure g-C3N4-TiO2 catalyst, the initial concentration of metronidazole (10, 15, and 20 mg/l), pH (4, 7, and 10) were investigated. Finally, the mechanism of function of synthesis photocatalyst was investigated by conducting in the presence of radical scavenger agents experiments. Findings: Based on the results of this study, catalyst TC3 shows more photocatalytic degradation efficiency mineralization. Maximum efficiency of this process at optimal conditions (pH=10, C0=10 mg l-1) after 360 minutes was 83%. The results of this study showed that the photocatalytic process based on catalyst g-C3N4-TiO2 is an effective method for removing metronidazole from the aqueous environment, and the use of g-C3N4 effectively enhances the photocatalytic activity of TiO2.

The continuous introduce of antibiotics, including amoxicillin into the environment, has created potential health risks, especially resistance to pathogenic microorganisms. In recent years, several efforts have been made by researchers to develop methods that lead to the destruction of antibiotics, including photocatalytic processes based on TiO2. The aim of this study was to evaluate the efficiency of catalyst Bi2O3-TiO2 in the removal of amoxicillin from aqueous environment. In this fundamental-applied study, the catalyst Bi2O3-TiO2 was first synthesized by hydrothermal method. The SEM, EDX and DRS analysis were used to determine the characteristics of the nanocomposite. Then, the effect of factors such as the content of bismuth in the Bi2O3-TiO2, the initial concentration of amoxicillin (10, 15, and 20 mg L-1), pH (3 to 11), and mineralization rate were investigated. Findings: Based on the results of this study, catalyst BT-5%, show more photocatalytic degradation efficiency of amoxicillin under visible light irradiation. The optimum pH and amoxicillin concentration in this process were determined 11 and 10 mg L-1 reapectively. Maximum efficiency thise process at optimal conditions after 120 minutes was 85%. The results of this study showed that the photocatalytic process based on Bi2O3-TiO2 compared to pure TiO2 is an effective method for removing amoxicillin from the aqueous environment(p > 0.05), and the use of Bi2O3 will effectively increase the photocatalytic activity of TiO2 in visible light.

Excessive consumption of antibiotics and their incomplete metabolization in human and animals, as well as inadequate removal by conventional waste water system leads to the release of these chemicals into the environment. Antibiotics have adverse effects including bacterial resistance, digestive disorders and genotoxic. Therefore the aim of this study was to survey amoxicillin removal by photocatalytic process using magnesium oxide nanoparticles. This experimental study was carried in the form of batch in the laboratory. In this study, independent parameters including pH (3, 7, 11), magnesium oxide nanoparticles concentration (250, 500, 750 ml/L) and reaction time (30, 60, 90) were evaluated for getting high mineralization efficiency.  In order to achieve the optimal experimental conditions, response surface methodology (RSM) model was designed and applied. Analysis of variance (ANOVA) was used for data analysis. According to the obtained results, the effect of independent parameters including pH and nanoparticles on removal process was significant (p-value<0.05) and the highest efficiency for mineralization of amoxicillin was achieved 79.0% in optimum condition pH: 11, nanoparticle concentration: 500 mg/L and reaction time: 90 min. Photocatalytic process using magnesium oxide can be considered as an effective method for amoxicillin removal from aqueous solution.

Volatile organic compounds (VOCs) are of environmental concern because of their adverse effects on human health. VOCs contain a large group of substances like toluene. Today application of catalytic beds is one the ways to control these kinds of emissions. In this study photocatalytic removal of toluene vapour by titanium dioxide nanoparticles immobilized on ZSM-5 zeolite have been investigated.
First, the bed of ZSM-5 was prepared in the form of granules. Next, titanium dioxide nanoparticles with ratios of 5 wt% were stabilized on it. To determine their characteristics, samples were used from BET, BJH and SEM analyses. Finally, the performance of the beds in the removal of toluene vapors at two concentrations of ppm 50 and 300 ppm in the dynamical system was investigated.
The result of tests showed that ZSM-5 has a porous surfaces with surface area of 356.4 m2/g. That after the calcination at temperature of 450°c it decreased to 332.5 m2/g. The results of the photocatalytic degradation process showed that the best performance of ZSM-5/TiO2 bed was at concentration of 50 ppm, so that was able to remove 42% toluene vapors.
According to the results obtained in this study, it can be concluded that stabilization of titanium dioxide nanoparticles on the ZSM-5 zeolite can be a good method to remove toluene vapors and other similar pollutants.

Malathion known as one of the most used organophosphates, with contact, digestive, fumigants and non-systemic properties has detrimental effects on ones nervous system. Recently use of photocatalyctic processes has grown widely because of its desirable ability to remove organic pollutants. In this study efficiency of photocatalytic process with persulfate and hydrogen peroxide for the removal of malathion was studied.
this study was carried out in laboratory scale and in batch flow reactors of steel which the low-pressure mercury vapor lamps of 55 watts was placed in it. The influence of parameters such as pH(3-9), H2O2(1-8Mm/l), perslfate dose(0.01-0.05 gr/l), and malathion (1-60 mg/l) was investigated. The malathion concentration in solution has been determined with the HPLC.
the results of this study showed that the discussed process has high efficiency in compare with other done studies, so that in optimum conditions – pH=3, concentration of persulfate 0.03 gr, consumed hydrogen peroxide 3mM and initial concentration of malathion 30mg/l – this process after 30 and 60 minutes, removed respectively 99.94% of malathion and 88.31% of COD.
photocatalytic process with persulfate and hydrogen peroxide as one of the advanced oxidation process alternatives has a high potential in reducing pollution load of different industries, including manufacture of pesticides and can be effective as a method for wastewater treatment and reduce the environmental problems.

Background and Among the numerous chemicals utilized in agriculture, 2,4-Dichlorophenoxyacetic acid (2,4-D) is widely used to control weeds. This herbicide is considered as a carcinogen and high toxic pollutant which is very difficult to remove due to its biological and chemical stability. This study aimed at photocatalytic degradation of 2,4-D using indium oxide nanoparticles in the presence of ultraviolet light.
This study was carried out in bench scale and batch system. The effect of operating parameters such as pH (2-11), contact time (5-240 min), catalyst dose (0.1-2 g/l) and initial concentration of herbicide (5-40 m/l) on the efficiency of the process were studied. The experimental data were fitted to a pseudo-first-order kinetic model.
Increasing the pH and initial concentration of herbicide led to reduced efficiency while increasing the contact time and catalyst dose increased the efficiency. The best result (70% efficiency) was achieved at pH 3, 1 g/l catalyst dose, 120 min contact time, and 5 mg/l initial concentration. The process data well followed the pseudo-first-order kinetic model (R2 = 0.915).
The results demonstrated that the photocatalytic process using indium oxide nanoparticles in the presence of ultraviolet light have a relatively good efficiency in removing 2,4-D.

Background and Nickel is one of the heavy metals that originates from various industries such as plating and dyeing and leads to many environmental problems، thus، it is important to remove it. The aim of this study was to assess the photocatalytic process by silica and zirconia nanoparticles in nickel removal. In this applied-fundamental study after construcring photoreactor، the performance of silica and zirconia nanoparticles in the removal of nickel were studied by changing variables such as the amount of nanoparticles (0. 5-2. 5 g/L)، pH (3،7،11)، nickel concentration and exposure time of UV (15-75 min). After assessing the synthetic wastewater (n=50) real wastewater (n=10) samples were evaluated according to the resultant optimum conditions. Nickel adsorption isotherm was determined. SPSS was used to analyze the data. Nickel was removed completely under optimum condittions (pH= 11)، 1g/L zirconia، 0. 5g/L silica with exposure time of 30min and 5mg/L synthetic nickel. Removal efficiency of nickel in concentrations of 5، 10، 15، 20 and 25 mg/L at pH= 11 and 1g/L zirconia nanoparticles was 100، 91، 88، 87. 5 and 84%، respectively and with 0. 5g/L dose of silica nanoparticles was 100، 100، 90. 90 and 87%، respectively. According to the coefficient of determination (R2)، Freundlich isotherm for zirconia nanoparticle (R2= 0. 883) and the Langmuir model for silica (R2= 0. 949) were found to be more relevant. Increase in the amount of nanoparticles، UV exposure and pH increased the efficacy of photocatalytic process in nickel removal through production of hydroxyl radicals. Nickel concentration reduced the process efficiency due to inhibition of the reaction of holes (h+) and hydroxyl radicals. Efficiency of photocatalytic process in removal of nickel from a real wastewater due to the presence of other substances (cyanide and zinc) was far less compared to the synthetic solutions. According to nickel removal efficiency from real wastewater (49. 6% and 56% by zirconia nanoparticles and silica، respectively) photocatalytic processes was able to remove about 50% nickel from actual wastewater.