Showing 29 results for Toc
Amir Hossein Mahvi, Noushin Rastkari, Ramin Nabizadeh Nodehi, Shahrokh Nazmara, Simin Nasseri, Mahboobeh Ghoochani,
Volume 6, Issue 3 (12-2013)
Abstract
Background and Objectives:Chlorination is the most common method of water disinfection. Chlorine reaction with natural organic compounds nor removed completely during treatment process would result in forming disinfection byproducts. Followed by trihalomethanes, Haloaceticacides are the second main byproducts of chlorination in water. The research works conducted in Iran have assessed trihalomethanes. Hence, this is the first time we are reporting haloacetic acids in Iran.
Materials and Methodology: We collected samples from surface water resources and treated water in Tehran for six consecutive months (first half, 2010). We measured temperature, pH, UV adsorption at 254 nm and TOC in each surface water sample and analyzed pH, residual chlorine, and haloacetic acids in the treated water samples.
Results: We found that TOC in surface water resources is 3.6-4.42 and 1.78-2.71 mg/l in spring and summer respectively. Moreover, haloacetic acids concentration was found to be 41.7-55.56 and 34.83-43.73 μg/l in spring and summer respectively.
Conclusion: Our results revealed that concentration of NOM, TOC, and HAAs was more in spring than summer. In addition, concentration of HAAs was depended up on NOM and TOC. Considering maximum permeable concentration of HAAs (60 μg/l) by EPA, it can be claimed that concentration of HAAs was less than the maximum permissible level in all of the samples. However, the immanency of the monitored values to the standard values can be a warning for concerned authorities in water industry.
M Zamani, N Khorasani, A.r Riahi Bakhtiari, K Rezaei,
Volume 7, Issue 4 (1-2015)
Abstract
Background and Objectives: This study was performed to determine and identify the origin, concentration and source of perylene entry and some PAH compounds in surface sediments of Ghalam Goodeh (A), Siyah Kashim (B), and Talab Markazi (C) in Anzali wetland. Materials and methods: We collected 22 samples of sediments (from each region) and 2 samples of soils (from A region) in April of 2012. Sampling was performed from soil for proving the condition of concentration and origin of perylene in under investigating sediments. GC-MS was applied for extraction of PAH compounds using organic solvents and 2-phase column chromatography. Diagnostic ratios of Ph/An, Flu/Pyr, Flu/Flu+Pyr, BaA/BaA+Chr and IP/IP+BghiP were used to determine the origin of PAH compounds. Results: In all sediment samples, the origin of perylene and PAH compounds were found to be natural and petrogenic, respectively. The total concentration of PAH compounds were ranged between 560.05 to 1051.93 ng/g dry weight and perylene concentration were obtained between 70.65 to 204.41 ng/g dry weight. Total concentration of PAHs and perylene was significantly more in area A compared with other two area, whereas no relationship was found between normalized values of PAHs and TOC in sediments of all areas. Conclusion: With respect to the petrogenic source of PAHs in the surface sediments, the main sources of the PAH compounds entry are the discharge of domestic and industrials wastewater, the port and shipping activities, the exploration, excavation and refining activities of crude oil in offshore region and transportation of fishing and tourism boat but diagnosis of natural origin of perylene in the samples of surface sediment and soil implicated that this compound can be produced in terrestrial section due to activity of termites and fungi on the woody and cellulosic materials of forest floor, decaying wood and their fossilized remains and then their discharge to the wetland.
M.s Mansoury, H Godini, Gh Shams Khorramabadi,
Volume 8, Issue 2 (8-2015)
Abstract
Background and Objective: Natural organic matters (NOM) are known as precursors to disinfection byproducts. As conventional treatment processes cannot get disinfection by-product standards, novel methods have been increasingly applied for the removal of disinfection by-products precursors. The UV/ZnO process is one of the advanced oxidation processes using photocatalytic technology. The present study aims to investigate the effect of UV/ZnO photocatalytic technology on the NOM removal from aqueous solution. Materials and methods: This study was conducted in a lab-scale batch photocatalytic reactor. The volume of reactor was 1liter and covered with UV lamps. Peristaltic pump was used for complete mixing. Humic acid is a key component of natural organic matter and it was used in this study. Each of the samples taken from the UV/ZnO process and other processes were analyzed for their UV absorbance at 254 nm by spectrophotometric. Initial concentration of Humic acid, contact time, pH, and UV irradiation were investigated. Results: The highest efficiency of the UV/ZnO photocatalytic process for removal of Humic acid from aqueous solution was achieved at initial concentration = 2 mg/L, contact time = 120 min, UV irradiation = 3950 µw/cm2, and pH=3. In this process, the removal efficiency for 2 mg/L humic acid was 100 % at 2h retention time. Conclusion: The research showed that performance of system was increased by increasing contact time and UV irradiation and was decreased by increasing HA initial concentration and pH and UV radiation with ZnO agent could not remove NOM lonely. Photocatalytic system using zinc oxide immobilized on glass have high performance to remove humic acid from aqueous solution. The UV/ZnO process was efficient and environmental friendly for natural organic matter removal.
N Rastkari, F Izadpanah ,
Volume 9, Issue 1 (6-2016)
Abstract
Background and Objective: Formaldehyde is a toxic volatile organic compound, which its removal from polluted air is essential. One of the techniques available for removing such compounds is photocatalytic degradation. The aim of this study was to investigate the photocatalytic degradation of gaseous formaldehyde on TiO2 nanoparticles coated on reduced graphene oxide
Materials and Methods: The synthesized reduced graphene oxide- TiO2 nanocomposite was characterized using SEM, EDS, and FTIR spectra. The photocatalytic activity of prepared reduced graphene oxide- TiO2 nanocomposite was investigated for degradation of gaseous toluene under different operational conditions such as different initial concentration, flow rate, and time.
Results: The photocatalytic degradation efficiency of the RGO-TiO2 nanocomposite was much higher than P25 TiO2. The photocatalytic degradation efficiency of the RGO-TiO2 nanocomposite decreased by increasing the flow rate so the flow rate is a key factor for the use of RGO-TiO2 nanocomposite as a photocatalyst. The results showed that the photocatalytic degradation rates decreased from 89 to 30% with increasing formaldehyde initial concentration from 0.1 to 1 ppm.
Conclusion: This research indicated that RGO-TiO2 nanocomposite can be effectively used as suitable photocatalyst to remove gaseous pollutants. One of the advantages of the as-prepared composite was using visible light instead of UV to activate the oxidation process.
M Jalili, M Mokhtari, Aa Ebrahimi, F Boghri,
Volume 9, Issue 3 (12-2016)
Abstract
Background and Objective: About 1.35×105 tons of pistachio waste are produced in annually Iran that can result in environmental problems if managed improperly. . The purpose of this study was to investigate in-vessel composting of pistachio residuals with addition of cow manure and dewatered sludge as a recycling alternative.
Materials and Methods: Pistachios wastes were combined with weight ratio of 5.5:10 (dewatered sludge: pistachio waste) and weight ratio of 1:10 (Cow manure: pistachio waste) to achieve the carbon to nitrogen ratio of 25:1. The parameters measured were pH, EC, percentage of moisture, total and volatile solids, ash, organic carbon, temperature, and phenol. The 20th edition of SPSS software was used for t-test statistical analysis and comparing the results with standards and Microsoft Excel 2007 was used for drawing the plots.
Results: During the 60-days process of in-vessel composting of pistachio residuals with addition of cow manure, the ratio of carbon to nitrogen reduced from 25:1 to 13:1, dewatered sludge from 25:1 to 14:1; phenol amount in cow maneuver decreased from 4980 to 254 ppm and in dewatered sewage sludge from 6100 to 254 ppm. The maximum temperature in cow manure and dewatered sewage sludge treatments in the composting process reached to 51.9 and 48.9 ˚C respectively.
Conclusion: Results showed that the produced compost with cow manure has a higher fertilizing value compared with the dewatered sewage sludge due to its better organic degradation.
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.
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.
N Golchinpour, N Rastkari, R Nabizadeh Nodehi, M Abtahi, A Azari, E Iravani, K Yaghmaeian,
Volume 10, Issue 4 (3-2018)
Abstract
Background and Objective: Triclosan is one of the substances as anti-microbial that is used in many of these pharmaceutical products. This compound can affect human such as reduction of thyroid hormone levels, antibiotic resistant, and increasing skin cancer. This study evaluated the performance nanophotocatalysis process UV/Xe/TiO2-GO on triclosan removal from aqueous solutions.
Materials and Methods: Synthesis of TiO2@GO and its structure was analyzed by SEM, EDX and FTIR. The effects of pollutant concentration, catalyst dosage, and contact time on the removal of Triclosan were studied by DOE software according to response surface methodology. Analysis of variance test was considered for the influence of parameters. Optimum process condition was determined by desirability factor.
Results: Optimum conditions regarding concentration of pollutant, contact time, and catalyst dosage were determined as 0.205 g/L, 14.898 min, and 0.487 mg/L, respectively. Maximum removal efficiency in optimum condition was 97.542 percent. The catalyst dosage was the most effective parameter in removal of Triclosan.
Conclusion: Using of TiO2@GO and xenon lamp had acceptable efficiency for the removal of Triclosan. The use of Xenon lamps alone was economically affordable.
M Sabonian, Ma Behnajady,
Volume 11, Issue 2 (9-2018)
Abstract
Background and Objective: Chromium is present in two oxidation forms of Cr(III) and Cr(VI). Cr(III) is less toxic than Cr(VI). The aim of this article was to optimize an artificial neural network structure in modeling the photocatalytic reduction of Cr(VI) by TiO2-P25 nanoparticles.
Materials and Methods: In this work, an artificial neural network (ANN) for the modeling photocatalytic reduction Cr(VI) by TiO2-P25 nanoparticles were used and its structure was optimized. The operating parameters were initial concentration of chromium, amount of photocatalyst, ultraviolet light irradiation time and pH. All the experiments were conducted in a batch photoreactor. The Cr(VI) concentration was measured with a UV/Vis spectrophotometer. ANN calculations were performed using Matlab 7 software and the ANN toolbox.
Results: The results show that the optimization of the ANN structure and the use of an appropriate algorithm and transfer function could significantly improve performance. The proposed neural network in modeling the photoactivity of TiO2-P25 nanoparticles in reducing Cr(VI) was acceptable, based on a good correlation coefficient (0.9886) and a small mean square error (0.00018). All the input variables affected the reduction of Cr(VI), however the effect of pH with an impact factor of 34.15 % was more significant than the others. The results indicated that pH = 2 was the best pH for photocatalytic reduction of Cr(VI). Increasing photocatalyst dosage and irradiation time in the investigated range increased Cr(VI) photocatalytic reduction.
Conclusion: Optimized structure of the ANN includes a three-layer feed-forward back propagation network with 4:10:1 topology and the most appropriate algorithm is a scaled conjugate gradient backpropagation algorithm.
Sakine Shekoohiyan, Mobina Hadadian, Mohsen Heidari,
Volume 14, Issue 3 (12-2021)
Abstract
Background and Objective: Changes in the quantity and quality of waste produced as a result of compliance with health protocols are the result of the COVID-19 outbreak. The present study aimed to determine the quantity of personal protection equipment produced in Tehran and people’s knowledge of its management.
Materials and Methods: The present cross-sectional and descriptive-analytical study was carried out on 2560 participants in Tehran through an online survey in spring 2020. Based on the percentage of using masks and gloves, the amount of produced waste was calculated, and Mann-Whitney and Kruskal-Wallis statistical tests were run to explore the relationship between the variables.
Results: The overall Cronbach's alpha coefficient of the questionnaire was 0.94, and the rate of mask and glove use was 90.7% and 65.7%, respectively. 70.3% and 52% of the population used two masks and one pair of gloves on a daily basis. The number of daily produced masks and pairs of gloves was 14530407 and 5262666, respectively. Mann-Whitney U-test showed a statistically significant difference between gender and marital status with people’s knowledge of waste management (p <0.05). Kruskal-Wallis test showed a significant difference between the economic status and people’s knowledge of separating the produced waste (p <0.05). People with an increasing income tended to separate the waste more.
Conclusion: Due to the high volume of personal protective wastes and the lacking knowledge of one-third of the participants about the transmission of the virus through contaminated waste, it is necessary to raise awareness of breaking the virus transmission chain.
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.
Narjes Khodaygani, Roya Mafigholami,
Volume 14, Issue 4 (3-2022)
Abstract
Background and Objective: 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.
Materials and Methods: 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.
Results: 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.
Conclusion: According to the standards provided by the Environmental Protection Agency (EPA), the effluent from the combined process can be discharged into the environment.
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.
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.
Maryam Heidari Yeganeh, Soudabeh Ghodsi, Sajad Mazloomi,
Volume 15, Issue 4 (3-2023)
Abstract
Background and Objective: One of the basic strategies to reduce the prevalence of diseases among people in society, especially children and adolescents, during the epidemic of COVID-19 disease, is to observe hygiene and personal protection behaviors. The present study was conducted to determine the level of compliance with health protocols in primary schools of Ilam city during the outbreak of the SARS-CoV-2 in 1400-1401.
Materials and Methods: This descriptive-cross-sectional study was conducted in primary schools of Ilam city with a statistical sample of 49 schools (25 girls' schools and 24 boys' schools). In this study, the 2019 new coronavirus disease care and control checklist was used in schools, which has 15 questions with a total score of 100. Data with Kolmogorov-Smirnov and T-Test statistical tests using SPSS software. V21 was analyzed.
Results: The results of this study showed that the highest and lowest scores are respectively related to the parameters of school health assessment before reopening (100 percent) and screening of people in terms of vaccination by PCR test (zero percent). The average score of compliance with the checklist was 74.3 in girls' schools and 74.38 in boys' schools. Also, the results of the T-Test showed that there is no significant relationship between the mean scores of girls' and boys' schools (p<0.05).
Conclusion: The results of the present study showed that the score obtained for compliance with the checklist parameters of all schools in Ilam city is less than 85 points, and the main reason for this is the non-compliance of the screening parameter of people in terms of vaccination/PCR test in schools.
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.
Raziyeh Zandipak, Nader Bahramifar, Habibollah Younesi, Mohammad Ali Zolfigol,
Volume 17, Issue 4 (3-2025)
Abstract
Background and Objective: Dyes are significant pollutants that pose serious hazards to humans, animals and other organisms. They are not biodegradable through aerobic treatment processes, making their removal from industrial wastewater through photocatalytic processes essential. This research aimed to synthesize an imide-conjugated polymer photocatalyst for the first time and evaluate its effectiveness in removing Rhodamine B dye from aqueous solutions.
Materials and Methods: In this applied research, an imide conjugated polymer was synthesized and employed as a photocatalyst for the removal of Rhodamine B from aqueous solutions. The polymer was characterized using Scanning Electronic Microscopy (SEM), Transmission electron microscopy (TEM), Atomic force microscopy (AFM), X-Ray Diffraction (XRD), Thermogravimetric Analysis, Fourier transform infrared spectroscopy (FTIR), and Diffuse reflectance spectroscopy (DRS) methods. The study also assessed the influence of variables, including pH (4-9), photocatalyst concentration (0.01-0.04 g/L), and contact time (0-120 min), on the removal efficacy of Rhodamine B.
Results: The findings indicated that removal efficiency increased to 99% at a contact time of 45 minutes and a photocatalyst concentration of 0.02 g/L. The optimal pH for Rhodamine B removal was found to be 7.
Conclusion: The imide conjugated polymer proved to be an effective and accessible photocatalyst for the removal of rhodamine B from industrial wastewater under visible light.
Ramazanali Dianati Tilaki, Roghayeh Kaseb, Esmaeil Babanejad Arimi, Mohammad Dianati,
Volume 18, Issue 3 (12-2025)
Abstract
Background and Objective: Benzene is a carcinogenic volatile organic compound commonly found in polluted air. This study aimed to remove benzene from air using a TiO₂–Bi2O₃ composite photocatalyst immobilized on glass foam under ultraviolet (UV) light irradiation.
Materials and Methods: Glass foam coated with the TiO₂– Bi2O₃composite was placed in a quartz reactor, which was connected to an air pump inside a sealed glass chamber. A UV lamp (254 nm) was installed next to the reactor. Known volumes (µL) of benzene were injected into the chamber through a septum. When the pump was activated, benzene-contaminated air passed through the photoreactor. Benzene concentration was measured by collecting air samples from the chamber and analyzing them using a GC-FID device.
Results: XRD spectra and SEM images confirmed the presence of TiO₂ and Bi2O₃, while BET analysis verified the mesoporous structure of the composite photocatalyst. The surface adsorption of benzene by the composite was 15% and followed the Langmuir model. The process kinetics were first-order, and the removal efficiency decreased with increasing benzene concentration. At a benzene concentration of 39 ppm, the removal efficiency after 75 minutes of TiO₂ and UV irradiation was 75%, whereas for TiO₂– Bi2O₃ under similar conditions, the efficiency increased to approximately 90%.
Conclusion: Using a TiO₂– Bi2O₃ composite photocatalyst under UV-A irradiation improved benzene removal efficiency by about 15% compared with TiO₂alone.
