Showing 11 results for Catalyst
M Malakootian, M. M Amin, H Jaafari Mansourian, N Jaafarzadeh,
Volume 4, Issue 4 (3-2012)
Abstract
Background and Objectives: Microbial fuel cells are the electrochemical exchangers that convert the microbial reduced power, generated via the metabolism of organic substrate, to electrical energy. The aim of this study is to find out the rate of produced electricity and also treatment rate of simulated wastewater of food industries using dual chamber microbial fuel cell (MFC) without mediator and catalyst.
Materials and Methods: MFC used in this study was consisted of two compartments including anaerobic anode chamber containing simulated food industries wastewater as synthetic substrate and aerobic cathode chamber containing phosphate buffer, respectively. These two chambers were separated by proton exchange membrane made of Nafion. Produced voltage and current intensity were measured using a digital ohm meter and the amount of electricity was calculated by Ohm's law. Effluent from the anode compartment was tested for COD, BOD5, NH3, P, TSS, VSS, SO42- and alkalinity in accordance with the Standard Methods.
Results: In this study, maximum current intensity and power production at anode surface in the OLR of 0.79 Kg/m3.d were measured as 1.71 mA and 140 mW/m2, respectively. The maximum voltage of 0.422 V was obtained in the OLR of 0.36 Kg/m3.d. The greatest columbic efficiency of the system was 15% in the OLR of 0.18 Kg/m3.d. Maximum removal efficiency of COD, BOD5, NH3, P, TSS, VSS, SO42- and alkalinity, were obtained 78, 72, 66, 7, 56, 49, 26 and 40%, respectively.
Conclusion: The findings showed that the MFC can be used as a new technology to produce electricity from renewable organic materials and for the treatment of different municipal and industrial wastewaters such as food industries.
Somayeh Alijani, Mohammad Vaez, Abdolsamad Zaringhalam Moghadam,
Volume 6, Issue 2 (9-2013)
Abstract
Background and Objectives: The development a low-cost and high efficiency water treatment technology to decolorize the organic dye effluents is desirable due to overwhelming discharge of organic synthetic dyes into the natural water cycle during the dying process. In this study, the decolorization of Acid Black 26, as the model organic contaminant, was investigated using immobilized nano-sized TiO2 particles as the photocatalyst. Material and Methods: Sackcloth fiber was used as a support to immobilize TiO2 nanoparticles. The structural properties of the immobilized photocatalysts were characterized by XRD and SEM. UV-Vis absorption spectroscopy and the measurement of the chemical oxygen demand (COD) were also used for the process performance studies. Moreover, we investigated the effects of the oxidant H2O2, initial dye concentration, the presence of anion and pH on the photocatalytic degradation efficiency. Results: The XRD results did not show significant changes in the structure of TiO2 as a consequence of the immobilization procedure. The formation of titania crystallites in the sackcloth fiber was confirmed by SEM. Experimental results showed that after 60 min, the degradation percentage of Acid Black 26 with the immobilized TiO2 particles was about 60%, which was higher than that with TiO2 slurry. Based on the COD results, after 3 h, the TiO2-coated sackcloth fiber effectively decomposed 94% of the organic compounds presenting in dye solution during the degradation of Acid Black 26. Conclusion: The titania nanoparticles immobilized on the sackcloth fiber can be used as an effective and environmental friendly photocatalyst in the degradation of colored wastewater.
M Hoseini, Gh.h Safari, H Kamani, J Jaafari, A.h Mahvi,
Volume 8, Issue 2 (8-2015)
Abstract
Background and Objectives: Among the different types of antibiotics, tetracycline antibiotics are the second most common group around the world that their entrance into domestic sewage can result in contamination of water sources. The aim of this study was to investigate the efficacy of the nano-sonocatalytic process on removal of tetracycline antibiotics from aqueous solutions. Materials and Methods: In this study, the effectiveness of ultrasonic irradiation without and with TiO2 nanoparticles and hydrogen peroxide were studied in tetracycline antibiotics removal. For this purpose, a reactor different concentrations of tetracycline was exposed to two irradiation frequencies of 35 and 130 KHz. Concentration of residual antibiotic was measured using HPLC equipped with a C18 reverse phase column and a UV detector. Results: It was found that the efficacy of ultrasonic irradiation alone in removal of this pollutant was negligible and at the best conditions only 20.3% removal was achieved at the frequency of 35 KHz. Addition of TiO2 nanoparticles improved the removal efficiency the removal rate increased with the increase in TiO2 concentration until 250 mg/L, after which it remained approximately stable. The best removal efficiency was achieved by adding 100 mg/l hydrogen peroxide to US/TiO2 process at pH 4 in which 94.3% removal was achieved after 60 minute. Conclusion: The results of this study showed that the sonocatalytic process using TiO2 nanoparticles and along with adding H2O2 as an oxidant is very effective and can be used for removal of tetracycline antibiotics from aqueous solutions.
H Irvani, H Shojaee - Farah Abady, M Shahryari, M Nakhaei Pour,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: Styrene monomer is a volatile organic compound that is used in the various industries. Due to the hazardous effects of this chemical substance on the environment and humans, control and elimination of this vapour is necessary. Therefore, the aim of this study was to remove the styrene vapors from air flow using photocatalytic activity of zinc oxide immobilized on ZSM-5 zeolite.
Materials and Methods: In this experimental study, the fabricated catalysts were characterized using analysis of BET, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Dynamic Concentrator System were used to generate styrene vapors at a certain concentration and flow, and then removal efficiency of the styrene vapors was investigated using UV/ZnO and UV/ZSM-5/ZnO.
Results: The results of XRD analysis and SEM images showed that produced zinc oxide had nano dimensions. In addition, these nanoparticles was successfully stabilized on ZSM-5 zeolite. The results of the photocatalytic removal showed that ZnO and ZSM-5/ZnO catalysts at the concentrations of 50 ppm eliminated the styrene vapor 14% and 37%, respectively.
Conclusion: Findings of this study showed that stabilization of zinc oxide nanoparticles on ZSM-5 zeolite had an ssynergistic effect on the photocatalytic degradation of styrene. According to this finding, the use of adsorption-photocatalyst hybrid systems can be an appropriate technique to remove styrene vapors and other similar pollutants.
F Akhlaghian, H Azadi,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: All around the worlds, wastewater containing dye pollutants are considered serious problem. Rhodamine B dye which is used in textile, leather, drug, and cosmetic industries exert carcinogenic and strong toxic effects. The aim of this research was to remove of Rhodamine B dye by nanowires of zinc oxide doped with lanthanum.
Materials and Methods: In this work, nanowire of zinc oxide doped with lanthanum was synthesized by hydrothermal method. The obtained photocatalyst was characterized by XRF, XRD, and SEM method. Effects of batch process variables such as pH, initial concentration of Rhodamine B, and photocatalyst dose were investigated. The kinetics of the reaction was also studied.
Results: The SEM images showed a hexagonal structure of ZnO, and La/ZnO nanowires. XRD results also confirmed the formation of ZnO with wurtzite hexagonal structure in both samples (ZnO and La/ZnO). The kinetics studies showed that the reaction was a pseudo first order. The apparent constants of ZnO and 2%La/ZnO nanowires were 0.0045 min-1 and 0.0074 min-1; respectively. In a batch experiment, the degradation yield of 99.8% was obtained at operating conditions of 1.25 g/L of 2% La/ZnO photocatalyst, initial concentration of Rhodamine B solution 4.78 mg/L, and pH=9 under ultra violet irradiation for 4 h.
Conclusion: The nanowire of La/ZnO with an optimum load of lanthanum has a better photocatalytic activity than nanowire of ZnO for degradation of Rhodamine B in aqueous solution.
Somaye Akbari, Gholamreza Moussavi, Stefanos Giannakis,
Volume 14, Issue 4 (3-2022)
Abstract
Background and Objective: Imidacloprid, a neonicotinide plant toxin, is used as an insecticide in agriculture. Due to its high degradation resistance and water solubility it is of highly concerns. Therefore, the aim of this study was to investigate the degradation of imidacloprid by modified magnesium oxide catalyst under irradiation of light and peroxymonosulfate.
Materials and Methods: In this study, modification of magnesium oxide with nitrogen was made by sol-gel method and then iron oxide nanoparticles was used as a magnetic source. Operational parameters were catalyst loading, peroxymonosulfate concentration, reaction time and common anions (nitrate, bicarbonate and chloride). Residual concentration of contaminant was measured by high performance liquid chromatography (HPLC) and mineralization rate was evaluated by measuring TOC.
Results: The results of the study showed that the photocatalytic degradation of the pollutant in the optimal condition was as following: catalyst concentration= 150 mg/L, peroxymonosulfate = 75 mg/L and reaction time= 60 min was 88%. Moreover, at optimum condition, the rate of mineralization was obtained 52%. Results comparison for prepared catalyst under light and dark condition indicated that the as-made catalyst is photocatalytic.
Conclusion: The as-prepared catalyst can be activated as a photocatalyst under LED light and proxymonosulfate for removal of organic pollutants.
Nahid Rashtchi, Soheil Sobhanardakani, Mehrdad Cheraghi, Amirreza Goodarzi, Bahareh Lorestani,
Volume 15, Issue 2 (8-2022)
Abstract
Background and Objective: Amoxicillin (AMX) is one of the commonly used commercial antibiotics due to its high resistance to bacteria and its large spectrum against a wide variety of microorganisms, which it´s existence in the wastewater from pharmaceutical industries and hospital effluents causes unpleasant odor, skin disorder, and microbial resistance among pathogen organisms, and it can lead to the death of microorganisms which are effective in wastewater treatment. Therefore, this study was conducted to investigate of removal efficacy of AMX from aqueous solutions using GO@Fe3O4@CeO2.
Materials and Methods: In this descriptive study, GO@Fe3O4@CeO2 was synthesized and then used as a photocatalyst for the removal of AMX from aqueous solution. GO@Fe3O4@CeO2 was characterized using X-Ray Diffraction (XRD), Scanning Electronic Microscopy (SEM), SEM-EDX elemental analysis, Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometry (VSM) methods. Additionally, the influence of variables including pH (3-11), amount of photocatalyst (0.006-0.04 g), contact time (0-150 min), and temperature (25-55 °C) was assessed on the efficacy of AMX removal.
Results: The results indicated that removal efficiency increased up to 90 min contact time, 0.02 g of photocatalyst, and at the temperature of 25 °C. The optimum pH for AMX removal was 10.
Conclusion: GO@Fe3O4@CeO2 could be an effective and available photocatalyst for the removal of AMX from industrial wastewater under UV light.
Mehrab Aghazadeh, Amirhesam Hasani, Mehdi Borghei,
Volume 15, Issue 3 (12-2022)
Abstract
Background and Objective: Based on its unique characteristics, oil industry wastewater must be treated before discharging into the environment. The study aimed to optimize the catalytic sonopraxone process in the treatment of petroleum wastewater using a statistical method.
Materials and Methods: The synthesis of Iron Oxide-Zinc Oxide was carried out by air oxidation and layer-by-layer self-assembly method. XRD, SEM, EDAX, FT-IR, BET, DRS, VSM and TGA techniques were used to investigate the structure. In this study, applied CCD method optimization of pH parameters, reaction time, ozone gas concentration, hydrogen peroxide concentration and catalyst amount in the process. In optimal conditions, BOD5 and TPH removal values, reaction kinetics and synergistic effect of mechanisms were studied. COD, TPH and BOD5 were measured by spectrophotometer (DR6000), GC-FID and incubator, respectively.
Results: The results indicated that the Fe3O4@ZnO structure is well formed. A quadratic model was proposed to model the process based on the correlation coefficient. Based on ANOVA analysis and p and f indices, the proposed model was reported to be significant. Optimum conditions include pH 6.4, ozone concentration 1.3 mg/L.min, hydrogen peroxide concentration 2.5 mL/L, reaction time 51 min and catalyst amount equal to 0.64 g/L. In these conditions, the amount of COD reduction was 82.3 and 70% theoretically and experimentally, respectively. Also, in optimal conditions, BOD5 and TPH removal rates were 90.5% and 85.8%, respectively. The kinetics of the process follows the kinetics of the first order (R2=0.98) and the presence of different mechanisms together causes a synergistic effect and increases the efficiency of the process.
Conclusion: This process can improve the quality of oil effluent based on COD, BOD5, and TPH removal.
Anasheh Mardiroosi, Hanieh Fakhri, Ali Esrafili, Masoumeh Hasham Firooz, Mahdi Farzadkia,
Volume 15, Issue 4 (3-2023)
Abstract
Background and Objective: Pharmaceutical compounds can cause potential risks to aquatic and terrestrial organisms. So far, different methods have been used to eliminate these pollutants, photocatalytic processes are one of the most efficient processes to eliminate pharmaceutical compounds. In this study, the efficiency of a novel MOF-based nanocomposite, PMo/UiO-66 as a photocatalyst for amoxicillin degradation under visible light irradiation was evaluated.
Materials and Methods: The study of the chemical decomposition of amoxicillin using the PMo/UiO-66 system was conducted at different stages. First, the PMo/UiO-66 MOF nanocomposite was synthesized using the solvothermal method, then the properties of the synthesized nanocomposite were investigated using XRD, FTIR, and SEM techniques. The effect of different operational parameters such as pH (3, 6, and 9), catalyst concentration (15, 20, 25, and 30 %w/w), initial concentrations of amoxicillin (20, 30, 40, and 50 mg/L) at different times on the removal efficiency was investigated. The reusability of the catalyst for four cycles was assessed.
Results: The results showed that PMo/UiO-66 nanocomposite at pH 6, 25 %w/w nanocomposite concentration, and the amoxicillin concentration of 20 mg/L led to complete decomposition of amoxicillin after 120 min. The kinetic of amoxicillin removal followed the first-order model. Reusability tests showed that the photocatalytic efficiency of the synthesized catalyst was not substantially reduced after four cycles.
Conclusion: The current study confirmed that the PMo/UiO-66 system has an appropriate efficiency for photocatalytic removal of amoxicillin under optimized test conditions.
Mojtaba Yeganeh, Sevda Fallah, Hanieh Fakhri, Mahdi Farzadkia,
Volume 17, Issue 1 (6-2024)
Abstract
Background and Objective: Phenol compounds are commonly applied as raw materials in the production of pesticides, herbicides, and dyes. These compounds are toxic to animals, plants, and microorganisms. In this study, the sonophotocatalytic degradation of 2,4-dinitrophenol in aqueous solutions was investigated using organic-mineral polymer catalysts containing Zink and Cobalt oxides under visible light and ultrasonic (US) irradiation.
Materials and Methods: The characteristics of the synthesized catalyst were determined using XRD, FTIR, and SEM techniques. The effect of several key parameters, including pH (3-9), catalyst dosage (0.3-1 g/L), time (0-90 min), US power (100-200 W/m2), and initial concentration of 2,4-dinitrophenol (20-100 mg/L), on the degradation efficiency was also investigated.
Results: After 75 minutes of sonophotocatalytic processing, complete degradation of 2,4-dinitrophenol (20mg/L) was achieved with catalyst dosage of 0.5 g/L, pH of 9.0, and US intensity of 200 W/m2. Kinetic studies indicated that the sonophotocatalytic degradation process followed a first-order kinetic model. The results of radical scavenging experiments confirmed that HO° and O2˚- radicals are the main oxidative species involved in the degradation of 2,4-dinitrophenol. Furthermore, the reuse of the catalyst for five consecutive tests showed a slight decrease in removal efficiency.
Conclusion: The results demonstrate that the sonophotocatalytic process, using the modified organic-mineral polymers with mixed Zink and Cobalt oxides catalyst, can be an effective method for removing 2,4-dinitrophenol from aqueous media.
Seyed Khabat Naynava, Bahareh Lorestani, Mehrdad Cheraghi, Soheil Sobhanardakani, Behzad Shahmoradi,
Volume 17, Issue 3 (12-2024)
Abstract
Background and Objective: Fenitrothion is a phosphorus-based pesticide that enters water resources through various sources,including industrial wastewater and agricultural effluent. its non-biodegradability, which results from the formation of strong chemical complexes, advanced oxidation methods are required to remove it from environmental matrices. This study aimed to evaluate the performance of a magnetic graphene oxide nanocomposite functionalized with cerium dioxide in the removal fenitrothion from aqueous solution.
Materials and Methods: In this applied research, GO@Fe3O4@CeO2 was synthesized and subsequently used as a photocatalyst for the removal of Fenitrothion from aqueous solutions. Characterization of GO@Fe3O4@CeO2 was conducted using X-Ray Diffraction (XRD), Scanning Electronic Microscopy (SEM), SEM-EDX elemental analysis, Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometry (VSM) methods. The effects of various parameters, including pH (2-9), photocatalyst dosage (10-40 mg), and contact time (0-90 min), were assessed to determine their influence on fenitrothion removal efficiency.
Results: The results demonstrated that the removal efficiency increased up to 60 min contact time, 20 mg of photocatalyst. The optimal pH for fenitrothion removal was found to be 4. Additionally, kinetic analysis of the photocatalytic removal process indicated that it followed a pseudo first-order (PFO) model.
Conclusion: The GO@Fe3O4@CeO2 nanocomposite proved to be an effective and accessible photocatalyst for the removal of fenitrothion from industrial wastewater under UV light.
