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Background: 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. Methods: 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. Results: 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. Conclusion: : 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.

Bio-leaching is a non-invasive, relatively affordable and environmentally friendly method through which toxic compounds are decomposed with the help of microorganisms and with the help of enzymatic reactions. This study was conducted in order to use biological leaching in order to rehabilitate soil contaminated and resistant to biological decomposition by heavy metal lead and phenanthrene around the south Tehran oil refinery. The design of the experiment was done with the response surface method. In the bioleaching method, the purified strain (Pseudomonas aeruginosa) was isolated from the soil of the refinery. Environmental pH (3, 5, 7, 9, 11), pollutant to biomass ratio (7.50, 15, 22.50, 30, 37.5 mg/g) and retention time (1, 2, 3, 4, 5 hours) were considered as main variables. pH was the most important parameter influencing the removal of lead and phenanthrene from soil. The highest percentage of lead removal with 96.79% pH is equal to 8, pollutant ratio to Live current equal to 30 W/W and time 2 hours was obtained. In the case of phenanthrene, the highest percentage of phenanthrene removal (97.4%) in pH was equal to 7, the pollutant to living organism ratio was equal to 22.5 W/W and the time was measured for 1 hour. The results of this study showed that the use of bacteria increased the efficiency of the removal process compared to the cleaning process without bacteria (42% for phenanthrene and 67% for lead).

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.

Background and Objective: Double-glazing is one of the methods of sound control. The use of materials other than gas inside double-glazing can develop sound transmission loss. The present study aims to make a double-glazing filled with A200 hydrogel at different ratios and measure the sound transmission loss. Materials and Methods: In the present study, 4 samples of double-glazing were made with water and A200 hydrogel. The mixing ratios of hydrogel with water were 1:20, 1:75, and 1: 150. The sound transmission loss of each sample was measured three times by AvaSina impedance tube using the sound pressure level through two microphones installed on both sides of the sample according to ISO 10534-1. Then, the results were analyzed by SPSS software (version 24) and repeated measures test. Results: According to the results, the highest amount of sound transmission loss was related to the water sample at 250 and 500 Hz and the A200-1:20 sample at 1000 and 2000 Hz. Meanwhile, the A200-1:75 sample had the lowest sound transmission loss at 250, 500, and 1000 Hz, and the water sample at 2000 Hz. Conclusion: The present study indicated that filling empty space of double-glazing with hydrogel increases transmission loss in high frequencies and decreases it in low frequencies compared to that of the water sample. Also, transmission loss of the air sample was found significantly different from all other samples except the A200-1:150 sample by comparing the water and hydrogel samples with the air sample as a control.

Background and purpose: Emerging pollutants such as antibiotics are resistant to biodegradation. The aim of this study was to compare the effect of photocatalytic and Ozonation photolysis on decomposition of Sulfonamide antibiotics (Sulfacetamide, Sulfathiazole, Sulfamethoxazole, and Sulfadiazine) in aquatic environments. Materials and methods: In this study, experiments were conducted discontinuously. The effect of some parameters, including pH, initial antibiotic concentration, ozone concentration, contact time, and concentration of TiO2 on degradation of Sulfonamide antibiotic was investigated. Characteristics of this catalyst were analyzed using FTIR, XRD, SEM, and EDX techniques. The concentrations of antibiotics were measured by an HPLC analyzer equipped with a UV detector at a wavelength of 270 nm. Results: The highest percentage of sulfonamide removal under optimal conditions (pH 5, initial concentration of antibiotics= 10 mg/l, ozone concentration= 0.22 g/h, and catalyst concentration= 1 g/l) were obtained by photocatalytic and photolysis processes (92.1% and 100%, respectively). Intermediate products produced under these conditions included acetic acid, butyric acid, and low molecular weight products. TOC removal efficiencies of sulfonamides by photocatalytic and ozonation photolys were 80% and 79.6%, respectively. Conclusion: The study showed that the rate of ozonation photolysis reaction in the removal of sulfonamides was 2.6 times faster than the photocatalytic process.

The contamination of water by organic pollutant viz. 2,4 DNP compound is recognized as most common environmental concern due to their highly toxic nature, worldwide. Adsorption has attracted much attention as a new technique to remove these contaminants from water and wastewater. The purpose of this study was to introduce an inexpensive adsorbent, dried waste sludge, for removal of 2,4 DNP compound. Material & Methods: At first, sludge was dried at temperature 60 °C. Next, CaCl2 was used to improve adsorption capacity. The removal efficiency of 2,4 dinitrophenol were determined by HPLC at wavelength of 360 nm. In addition, the effects of influencing factors including pH, initial pollutant concentration, contact time, and adsorbent dose were examined. The equilibrium binding were described by Langmuir or Freundlich isotherms and kinetic models. Results: The results obtained from adsorption process indicated that was 60 min is the equilibrium time. The optimum pH for adsorption for both adsorbents was found to be 7. The optimum concentration of 2,4-DNP was found to be 10 ppm. The results obtained from the present research showed that the removal of the contaminant using modified sludge sorbent was increased from 40.4% to 77.9% when dosage increased from 0.1 to 1.5 g. Equilibrium adsorption data for 2,4 DNP were fitted by using Langmuir, Freundlich and Freundlich adsorption isotherms model, respectively. Also it has been found that adsorption kinetics can be described according to the Pseudo-second order model. Conclusion: According to results, chemically modified waste sludge showed reasonable adsorption capacity. Therefore, it and can be used as a native alternative to 2,4 DNP compound removal from aqueous environments.

Background: Ibuprofen is one of the most widely used non-steroidal anti-inflammatory drugs that enter the water resources through manufacturing plants and disposal of hospital effluents and even domestic wastewater. The aim of this study was to removal of ibuprofen using biodegradation process by Saccharomyces Cerevisiae yeast fixed on alginate substrate from aqueous solutions. Method: This research was an experimental-laboratory study. The effect of parameters including yeast concentration (0.1-0.3 g/100ml), Initial concentration of ibuprofen (50-350 mg/l), contact time (1-30 hours), initial pH (4-7) on the biodegradation of ibuprofen with stabilized yeast on alginate substrate was investigated. Experiments were designed and optimized using response surface methodology in Design Expert 7 software. Results: The findings of this study showed that the maximum removal of ibuprofen by fixed yeast on alginate at pH = 5.5, yeast concentration 0.2 (g /100ml), time 30 hours, and initial concentration of ibuprofen=50 mg/L was 93.5%. Conclusion: Based on the results of this study, it can be concluded that the fixed Saccharomyces cerevisiae is capable to biodegradation of ibuprofen at low cost and high efficiency and this cost-effective method can be used for the treatment of pharmaceutical wastewater.

Background & Objectives: Ceftriaxone is an antibiotic which is extensively used to treat a number of various infections. It is mainly accumulated in water and sewage resulting in the environmental and health problems. This study is centered on the evaluation of the efficiency of a photocatalytic process using Fe3O4@SiO2@TiO2 in the removal of ceftriaxone from aqueous solutions. Methods: This research was based on an experimental-practical study. Fe3O4 @ SiO2 @ TiO2 was initially synthesized via a sol-gel method and characterized by SEM, XRD and EDX analyses. The effects of variables such as pH, catalyst concentration, ceftriaxone concentration, contact time, reusability tests (n=7) and degree of mineralization were separately assessed in a laboratory scale. The concentration of ceftriaxone was measured by HPLC at 240 nm. Results: Based on the results obtained, the highest process efficiency of 96.7% was obtained under the following optimal conditions: concentration of ceftriaxone 10 mg/L, pH=3, the catalyst dosage of 2 g/L and a time contact of 120 min. At the end of the process, the degree of mineralization was determined to be 83.7%. Additionally, the data regarding the reusability of the nanocatalyst demonstrated that a 5.2% loss in the removal efficiency was observed after 7 times of reuse. Finally, the results revealed that the removal process of ceftriaxone follows the first-order kinetic model. Conclusion: The results demonstrated that the photocatalytic process using the magnetic nanocatalyst (Fe3O4 @ SiO2 @ TiO2) could be effectively used for the removal of ceftriaxone from aqueous media.

Background: Organophosphates are one of the most common pesticides in the world. One of the most commonly used toxins in this group is malathion, which is classified by the EPA as Group III carcinogenic substances. Therefore, due to the high consumption of this pesticide and its pathogenicity, it should be eliminated in an appropriate manner. One of the elimination ways is the use of advanced oxidation processes. The aim of this study was to determine the photocatalytic removal of malathion pesticide by g-C3N4/Fe3O4/Ag nanocomposite. Method: In this study, g-C3N4/Fe3O4/Ag nanocomposites synthesized by hydrothermal method were used for photocatalytic removal of malathion. The variables studied were pH, nanocomposite dose, and contaminant concentration. Furthermore, the radical effects of ammonium oxalate, tert-butanol, and benzoquinone were analyzed on the experiment procedure. Results: The best removal efficiency of malathion at pH = 7, the dose of 0.5 g/l, and contaminant concentration 10 mg/l at 60 min was 100%. By increasing the catalyst dose up to 0.5 g/L, the efficiency increased. However, with increasing contaminant concentration, the removal efficiency decreased. Additionally, the removal efficiency of malathion in the presence of ammonium oxalate, tert-butanol, and benzoquinone radicals was 93.36%, 44.78%, and 90.71%, respectively, and the reaction kinetics followed the first equation with R2 = 0.9852. Conclusion: Therefore, g-C3N4/Fe3O4/Ag has a high potential for malathion removal moreover can be used to remove various pollutants from aqueous solutions.

Introduction: Nowadays, due to the extended use of the high speed Internet, online games have become one of the most common interests among adolescents. Therefore, determining the advantages and disadvantages of these games are basically valuable. The purpose of this study is to investigate the relationship between online game addiction and family emotional climate, academic achievement, and academic adjustment in students. Materials and Methods: This was a descriptive correlational study with the statistical population consisting of all secondary school students in Ardabil City, Iran, who were studying at Ardabil schools during 2019. 216 individuals were selected through the convenience sampling method. Data were collected using the online game addiction questionnaire, family emotional climate questionnaire, academic craving questionnaire, and academic adjustment scale. The data collected were then analyzed using Pearson’s correlation coefficient and regression models. Results: There was a significant negative correlation between family emotional climate, academic achievement, and academic achievement with online game addiction (-0.27 ≤ r ≤ 0.54, P ≤ 0.001). With beta values of respectively -0.638, -0.409, -0.332, these values directly predicted addiction to online games. Conclusion: It seems that the family's emotional climate and adolescents' educational longing and adjustment may well predict addiction to online games. Therefore, it is recommended to consider these three factors to reduce the tendency of young people to play such games and to identify the damage caused as a result of excessive playing of these games.

Background and Objective: 2,4 dinitrophenol is observed in sewage produced from chemical and petrochemical industries. Contamination of drinking water with these pollutants causes toxicity, health problems and change in taste and odor. The present study was developed to evaluate the efficiency of removal 2,4-DNP through dried sludge adsorbent and modified calcium chloride sludge adsorbent. Materials and Methods: At first, sludge was dried at temperature of 60 °C. Next, CaCl2 was used to improve adsorption capacity. The removal efficiency of 2,4 dinitrophenol were determined by HPLC at wavelength of 360 nm. The effects of influencing factors including pH, initial pollutant concentration, contact time, and adsorbent dose were examined. Results: The optimum pH of adsorption for both adsorbents was found to be 7. The optimum concentration of 2,4-DNP was 10 ppm. The results obtained from the present research showed that the removal of the contaminant using dried and modified sludge sorbent was increased from 72.6% to 86% at a dosage of 1.5 g. The adsorption kinetics were fitted with the pseudo second order kinetics model for both adsorbents. The isotherm data also showed that the adsorption of this pollutant on both adsorbents is fitted with the Freundlich model. Conclusion: Results obtained from the present study indicated that the efficiency of the modified sludge ash is more than the non-modified sludge in 2,4 dinitrophenol removal. This can reduce adsorbent consumption in industrial treatment plants.

Background & aim: The discharge of pharmaceutical effluent containing antibiotics into water resources is a great of concern associated with environmental pollution. In addition, conventional treatment systems are not capable of eliminating these antibiotics which commonly used in dealing with treatment of humans. Furthermore, over-consuming of antibiotics over the past few decades has forced researchers to find new techniques in order to deal with this environmental issues of great concern. In the present work, TiO2 was employed as a catalyst in the non-homogenous catalytic ozonation process for removal of Ceftazide antibiotics from synthetic sewage. Materials and Methods: This fundamental-practical study was conducted in a pilot scale. The magnetic TiO2 nano-sized particles were synthesized through a sol-gel method. The properties of magnetized titanium dioxide nanoparticles as catalyst were characterized using SEM, XRD and EDX. The effects of variables: pH, catalyst dose, reaction time, pollutant concentration on the performance of catalytic process were investigated. The residual concentration of Ceftazide was analyzed by a high performance liquid chromatography (HPLC). Results: The findings of present study indicated that the high removal efficiency of Ceftazide occurs in alkaline conditions and a direct relation was observed between removal efficiency and pH. The catalyst dose of 2 g/l was determined as optimum dosage and the Ceftazide removal efficiency was improved by decreasing the initial concentration as time proceeded. The results showed that the removal of Ceftazide by this catalytic process are fitted with the first-order model. Conclusion: The results show that the catalytic ozonation process with magnetized titanium dioxide nanoparticles has high efficiency for removal of Ceftazide from aqueous media. The catalytic ozonation process can be considered as an effective way to remove Ceftazide antibiotics from aqueous environment.

Background and Objective: The activities of various industries produce a wide range of pollutants and toxic compounds. One of these compounds is the catechol, a cyclic organic compound with high toxicity and resistant to degradation. Therefore, the purpose of this study was to investigate efficiency of powder activated carbon magnetized with Fe3O4 nanoparticles in the removal of catechol from aqueous solutions by response surface methodology. Materials and Methods: The co-precipitation method was used to synthesize magnetic powder activated carbon and its properties were analyzed by SEM and XRD analysis. Then, the effect of the parameters such as pH, contact time, absorbent dose, initial concentration of catechol and temperature on the efficiency of adsorption process were investigated using a response surface methodology (Box–Behnken). The residual concentration of catechol was measured by HPLC at 275 nm. Results: The results showed that the maximum efficiency of the adsorption process was obtained at concentration of 20 mg/L, pH=3, contact time 90 minutes, at 25 °C and absorbent dose of 1.5 g/L. The study of isotherm and kinetics showed that the experimental data of the catechol adsorption process correlated with the Langmuir and pseudo-second order models, respectively. Thermodynamic study of the reaction also expresses the Exothermic and Spontaneous process. Conclusion: The results showed that the adsorption process using powder activated carbon magnetized with Fe3O4 nanoparticles at acidic pH had better efficiency. As a result, the studied process as an effective, rapid and inexpensive method for removal of catechol from aqueous solutions is proposed. Due to its short reaction time, it is economically affordable process.

Background: Cr (VI) is a highly toxic and carcinogenic contaminant and that are used in the steel industry and other chemical industries such as the leather industry, pigment production, electroplating of metals and the production of anticorrosive compounds. Its waste enters the environment and subsequently enters the water and food sources. Therefore, in order to protect the environment as well as human health, it is necessary to remove this pollutant from the environment, including soil, using appropriate methods. Material and Methods: Chromium resistant bacteria were isolated from the chromium contaminated soil and adapted by serial culture in Cr (VI) concentrations of 50-400 mg/L and microorganism growth and Cr (VI) reduction were measured. Then the soil was artificially contaminated at the laboratory by Cr (VI) compound (CrO3) and Organic compounds were added to soil at the Specified amount. Finally, a separated bacterial mix was added to the soil to initiate the bioaugmentation process. Results: After 3 stages of sampling and data analysis, the results of the study showed that Cr (VI) reduction efficiency by the bacterial mix reduced decrease by Cr (VI) concentration increase. So, under similar conditions, the efficiency of Cr (VI) reduction of soil, at a concentration of 50 , 200 and 350 mg / l, is about 86%, 51% ,and 26% respectively .Organic compound adding also increase bioaugmentation efficiency. Conclusion: The results of this study showed that optimizing soil conditions could improve the biodegradation process, especially in low concentrations of contaminants.

Background: Aniline is a toxic compound characterized by high solubility in water (3.5 percent; 35000 mg/l) leading to increased presence risk of aniline in wastewater. The presence of this compound in the blood causes the formation of met hemoglobin and prevent oxygen uptake and plays a key role in chemical asphyxiation, moreover, it has been thought as a carcinogenic risk factor to humans. Therefore, this study aims to synthesizes chitosan graphene oxide and determine the usefulness of using this absorbent to remove aniline from aqueous solutions. Methods: Chitosan Graphene Oxide (CGO) which was prepared from graphite powder by adapting the procedure used by Hummer, doped with chitosan and the characterization of CGO were determined by Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Powder Diffraction (XRD). To optimize the conditions, parameters including adsorbent dosage (g / L 0/2, 0/4, 0/6, 0/8, 1, 1/25,1/5), pH (2, 4, 6, 8, 10), contact time (5, 15, 30, 45, 60, 90, 120 min) and aniline concentrations (mg/L 50, 100, 150, 200, 300) were evaluated in a total of 126 tests. Finally Chitosan Graphene Oxide was used for aniline removal from aqueous solutions. Results: The results of present study showed that with increase in contact time and absorbent dosage and with decrease in aniline concentration, removal efficiency tend to increase. PH=6, time=30min, absorbent dose=1 g/l and concentration of aniline=50 mg/l were obtained as optimum conditions. Under optimum condition (pH=6, time=30min, absorbent dose=1 g/l and concentration of aniline=50 mg/l) the highest efficiency of aniline removal is %93.14. The adsorption isotherm showed that absorption process correlates well with Langmuir adsorption isotherm (R2>0.9996). Reaction kinetics complies with Pseudo-second order model with correlation coefficient of (R2=0.9799). In the study of thermodynamics, negative values of ΔH0 and ΔG0 respectively illustrate that reactions are exothermic and spontaneous. Conclusion: chitosan graphene oxide composite has the ability to remove aniline effectively from aqueous solutions. And also it can be used as an efficient adsorbent for related aqueous solutions.

Introduction and purpose: Chlorophenol is known as one of the toxic and dangerous pollutants in industrial wastewaters that’s a essential to it’s removal from industrial wastewaters and ground waters. The aim of this study was to investigate the efficiency of 4-Chlorophenol (4-CP) degradation using Ultraviolet/Hydrogen Peroxide process (UV/H2O2). Methods: The variables of the present study included initial concentration of pollutant, contact time, pH, and H2O2 concentration on 4-Chlorophenol removal on a laboratory scale. The concentration of residual 4-Chlorophenol was determined using UV/Visible at a wavelength of 280nm. In addition, the amount of mineralization in optimal conditions was evaluated using the measurement of total organic carbon (TOC) removal range according to the standard method 5310- B. Synthetic models of the process were also investigated. Results: The optimum removal efficiency of 4-CP by UV/H2O2 process regarding the concentration of hydrogen peroxide was 580 mg/L. pH of 3 and initial 4-CP concentration was obtained as 380 mg/L, and the presence of UV rays with a wavelength of 254 nm during 30m contact was 84.92% . In addition, 84.69% of the TOC was removed under the optimal condition. Moreover ,it was found that the data followed the first-order synthetic models. Conclusion: Considering the growing use of UV radiation in water treatment processes and the considerable efficiency of UV/ H2O2 process in removing 4-CP, this method can be proposed for the elimination of 4-CP after performing cost-benefit analyses. It can be concluded that with regard to purification goals and standards for wastewater treatment, UV/ H2O2 process can be used as a pre or final treatment.

Background and purpose: Photocatalysis process with TiO2 is a well-known method for removal of pollutants from water. However, the small particle size of TiO2, and therefore difficulty in its separation after treatment impede its commercialization. The aim of this study was to synthetize the Fe3O4@SiO2@TiO2 magnetic nanoparticles (NPs) and evaluation of its efficiency in removal of metronidazole (MNZ) from aqueous solutions. Materials and methods: The NPs were synthetized via sol-gel method, and characterized using SEM, XRD, VSM, and BET analysis. Then, the effect of operational parameters, including catalyst dosage, pH, and initial concentration of MNZ on removal efficiency were examined. The order of reaction and kinetic model, as well as the reusability potential of the catalyst were all investigated in the optimum run. Finally, comparison was made between the adsorption, direct photolysis, application of commercial Degussa P25 TiO2 (p25), and Fe3O4@SiO2@TiO2 NPs. Results: The so-synthesized catalyst showed good superparamagnetic properties. The optimum conditions for the MNZ removal were pH=8, the catalyst dosage=1.5 g/L, and initial concentration of MNZ=40 mg/L under 180 min UV irradiation time. The kinetic study revealed that the photocatalytic degradation of MNZ followed the pseudo- first order (R2= 0.9912) and the Langmuir-Hinshelwood model (R2= 0.9976). Conclusion: According to the results, the Fe3O4@SiO2@TiO2 NPs were almost as effective as commercial catalyst Degussa P25 TiO2 in removal of MNZ (P> 0.05). Due to the simple separation with external magnetic field and reusability potential, Fe3O4@SiO2@TiO2 NPs can be considered as a suitable alternative for Degussa P25 TiO2.

Background and purpose: There are several methods for removing oil contaminations from the polluted environments. Bioremediation could be considered as one of the best and most practical methods in the removal of oil contaminations. The aim of this research was to determine the bioremediation efficiency for soils contaminated with diesel by the biological stimulation of bioreactors containing vermicompost and activated sludge. Materials and methods: In an experimental study, the soil samples were collected from an area which was free of any oil pollution and 5 reactors containing one kilogram of soil were contaminated with diesel at the mass concentration of 1%. Two reactors were mixed with vermicompost at 15% and 20% mass concentrations and two reactors were mixed with activated sludge at 5% and 10% mass concentrations. Additionally, one control reactor was used to control the process. The pH of the reactors was between 7.5 and 8 and the C:N:P ratio was 100:5:1. The amount of TPH was measured at seven retention times within three months with two repetitions. The total removal of petroleum hydrocarbons (TPHs) was evaluated by GC-FID device. Results: The highest removal efficiency of TPH (40.24%) was observed in bioreactors containing vermicompost at a 20% mass concentration. In this reactor, the highest percentage of removal was observed in lighter hydrocarbons (50.49%). In reactors containing activated sludge, the average percentage of TPH removal was 32% which was observed in the reactor containing the 10% concentration of sludge. In this reactor, the highest percentage of removal (44.86%) was also observed in lighter hydrocarbons. Conclusion: Vermicompost and activated sludge can be used in the bioremediation of soils contaminated with diesel. In current study, the performance of vermicompost was found to be more efficient. Also, the results showed that by increasing the concentration of biological modifiers, the removal rate would increase.

BACKGROUND AND OBJECTIVE: Phthalic acid has high toxicity and low degradability which has put treatment of wastewater containing this compound prior to prevent its health and environmental hazards. Present study was conducted to Optimization of (UV/Na2S2O8/Fe2+) process for phthalic acid removal from aqueous solutions with response surface methodology. METHODS: This is an experimental study which was conducted at laboratory scale and synthetically in the cylindrical reactor containing UV-C lamp with 16 Watt power. Effects of variables including pH of solution (3-11), reaction time (0-60 min), concentration of persulfate (0.1-0.5 mmol/L), concentration of Fe2+ (0.1-0.2 mmol/L) and initial phthalaic acid (5-50 mg/L) on efficacy of process were investigated by response surface method (box Behnken method). The residual concentration of phthalic acid was measured by HPLC at a wavelength of 254 nm FINDINGS: The removal efficiency of phthalic acid increased by increasing pH level and reaction time. The maximum removal efficiency of phthalic acid attained as 98 percent at pH of 11, reaction time of 60 min, 0.15 mmol/L of Fe2+ concentration, persulfate concentration of 0.3 mmol/L and 5 mg of phthalic acid. The process of removing phthalic acid followed from first-order kinetic (R2=0.9766). The effects of all studied independent variables with p

Background and purpose: Phenol is amongst the dangerous environmental pollutants with wide applications in today’s life and industry. Nanoparticles have recently received attention for decomposition of these organic compounds. The aim of this study was to evaluate the efficiency of silver doped titanium dioxide stabilized on concrete bed via photocatalytic process Ag-TiO2/UV in removal of phenol from synthetic wastewater. Materials and methods: In this experimental-applied study, the volume of sample was 1000 ml. Initial concentrations were 10, 20, 50, and 100 mg/l and the samples were separately investigated under the effect of UV radiation and Ag-TiO2. The experiment was then performed under both conditions simultaneously. The variables included pH, initial phenol concentration, storage time, and photocatalyst loading. Phenol analysis was carried out by direct light metering with 4-aminoantipyrine reagent at 500 nm wavelength spectrophotometer according to standard method D5530. We studied the pH in three ranges (5, 7, and 10) and photocatalyst in three regions (20, 60, and 80 g/m2). Results: Based on the results, the highest levels of phenol decomposition were achieved by initial concentrations of 10 and 20 mg/l in optimal pH (3) at 40 and 80 minutes (100%), and initial concentrations of 50 and 100 mg at 180 and 200 minutes retention time in optimal pH (65% and 50%, respectively). The optimal photocatalyst loading rate was 80 g/m2. Conclusion: This study showed that the Ag-TiO2 nanophotocatalyst stabilized on a concrete bed, is efficient in phenol decomposition in presence of UV light.

Background and purpose: Antibiotics are extensively used in treatment of diseases. Metronidazole is an antimicrobial agent and is a nitroimidazole derivative, which is widely used in treatment of infectious diseases caused by bacteria and protozoa. This compound is irrefrangible, toxic, carcinogenic, mutagenic, and has high solubility in water. Advanced oxidation process is an effective method for removal of metronidazole from aqueous solutions. The aim of this study was to evaluate the efficacy of advanced oxidation process based on persulfate (UV / Na2S2O8) to remove metronidazole from aqueous solutions. Materials and methods: In this research, the effect of some variables such as pH, persulfate concentration and contact time was studied by a UV-C lamp (16 watts). Also, the remaining concentration of metronidazole was measured by UV-Vis spectrophotometer Cecil model CE7400. Results: The optimum conditions in this study were obtained at pH=9، persulfate concentration of 0.7 mmol/l, and contact time of 30 min. The removal of metronidazole by advanced oxidation process based on persulfate (UV / Na2S2O8) followed the first-order kinetic model. Conclusion: Persulfate-based advanced oxidation process (UV/Na2S2O8) is an effective method for removal of metronidazole from aqueous solution. It is recommended as an effective and efficient process that could be used for purification of aqueous solutions.

Background and Objective: Discharge of industrial wastewater containing Catechol has adverse effects on human and environmental health. Purpose of this study was to determine the effects of catechol toxicity before and after advanced oxidation process (ozonation process) by bioassay test with Daphnia Magna. Materials and Methods: This study is an applied research in which the toxicity of catechol was determined by Daphnia Magna bioassay test during the ozonation process. First, Catechol stock solution was prepared at a concentration of 250 mg/L. Then, 10 samples were prepared that each contained 0 (control), 0.5, 1, 3, 6, 12, 25, 50, 75 and 100% of volume of primary solution. Initial samples were prepared from reactor effluent in the same volume as those of the samples. According to standard method, 10 Daphnia infants were added to each sample. The samples were observed after 24, 48, 72 and 96 hours. Finally, lethal concentration (LC50) and toxicity unit (TU) were calculated using Probit analysis. Results: According to the results, Daphnia magna was affected by the toxicity of catechol. LC50 (24-hour) for raw effluent was increased from 13.30 mL/100 mL to 30.4 mL/100 mL after 60 minutes Treatment. The toxicity unit was decreased from 7.51 TU to 3.29 TU accordingly, showing reduction of 56% in toxicity. The toxicity of the treated effluent decreased during ozonation process of catechol. Conclusion: Based on the bioassay test, ozonation process was able to reduce the toxicity of catechol. Therefore, this process can be used as an option to treat wastewater that contains catechol.

Background and purpose: Paraquat (PQ) is a bipyridinium herbicide that is very soluble in water. This non-selective contact herbicide is widely used in agriculture for weed control. In addition to the environmental impact, paraquat affects the entire body, especially the respiratory system, central nervous system and lymph nodes. In this study degradation of paraquat was investigated using Fenton and Fenton like processes. Materials and methods: This research was an experimental study in laboratory scale batch reactor (1L). During these processes, the effects of pH, Fenton and Fenton like agent concentrations (Fe2 +, Fe3+and H2O2) and initial concentration of paraquat in the removal efficiency were studied. The residual PQ concentration and the amount of organic carbon removal were measured by HPLC (259nm) and TOC measurement device, respectively. Results: Fenton like and Fenton processes could remove 86.44% and 84.53% of paraquat under optimal condition (pH=3, H2O2=29.4 mM, Fe=0.9 mM, PQ=0.194 mM) in 120 minutes, respectively. The TOC removal in Fenton like and Fenton processes was 52.15% and 45%, respectively. The PQ removal by Fenton and Fenton like process followed a pseudo-first order reaction kinetic model. Conclusion: Fenton process showed better performance in removal of PQ than Fenton process. So, it can be used as an appropriate and a supplementary treatment process in removing PQ from aqueous solution or final purification in a longer reaction time.

Background and aims: Survay of the particulates, biological molecules and other harmful materials which enter into Earthchr('39')s atmosphere as airborn agents is one of research intrest of health sciences. Animal housing laboratories for producing malodor especially near residential, educational and official areas can cause neighbors complainant. In order to overcome this challenge qualitative and quantitative evaluation of airborn contaminants of Iran university of medical scienses animal housing had been done. Method: In order to sampling and evaluation of the airborne contaminants in the animal housing the ASTM D3686-95 (for VOCs), ASTM D 4490-90 (for NH3, CO2 and, H2S) and, NIOSH 0500 (for total dusts) standard methods had been used. According to the survey goals apparatus and equipment were prepared and calibrated. Results: According to the results, the unspesified mixed dusts need controling measures and, also showed the presence of the toxic substances like xylene and ethyl benzene, 1, 2, 3-trimethyl Benzene. However the analyses of these show trace concentration of mixture exposure in the air. High number of animals in the small areas and large animal such as rabbits are responsible for more ammonia production. Conclusion: More frequently passing through the salons and geographical condition of the building and also natural ventilation of the laboratory all are good methods reducing the concentration of pollutions. In the other hand long times presence of employees in the laboratory could cause reduce sensitively. Nevertheless in order to increase employees and researcher welfare the implementation of general ventilation is recommended

Uranium separation and removal are important from environmental, public health, and strategic veiwpoints. Scientits have put great efforts to develop technologies for uranium removal and regeneration because of its important applications and beneficial uses. In this study, efforts have been made to synthesize a modified form of Fe3O4@SiO2 and benzamide uranium complexes that can be exploited to remove and adsorb uranium onto an adsorbent that can be recycled. In the first step, Fe3O4@SiO2 was synthesized and later modified with trimethoxysilane. The adsorbent was subsequently characterized by SEM and FTIR. In a second step, experiments were performed to determine optimum stirring speed, contact time, ion strength, and adsorbent reusability. Finally, the performance of the adsorbent was tested in samples of real wastewater. SEM and FTIR analyses confirmed the satisfactory synthesis and modification of Fe3O4@SiO2 Nps. Statistical analyses revealed that although contact time, ion strength, and stirring speed were effective in adsorbent performance, they only led to a removal enhancement of 5% and a decrease of only 17% with increasing RPM to 250 and the enhancement of ion strength to 1.5M. The highest U(VI) removal efficiency in the synthetic solution was found to be 97%, which reduced to 49% in real wastewater samples. It was concluded that the nano-composite C14/SiO2_Fe3O4 adsorbent with its magnetic core and resistant surface not only offers the possibility for easy separation of urnaium from solutions but is also reusable and is only slightly affected by changes in stirring speed or ion strength. It, therefore, has a good capability for use as a U(VI) adsorbent in wastewater treatment.

Background and Purpose: Parabens are a group of Para-hydroxy Benzoic acid alkyl esters which extensively used as preservative in personal care products. Parabens have been recently found in wastewater, rivers, soil and dust. Therefore, the purpose of this study aimed to Monitor the occurrence of parabens from selected wastewater treatment plants (Shahrak Ghods and south of Tehran) and evaluate the performance of different treatment methods for removing these compounds. Methods: In this study, the samples from influent and effluent were collected from Shahrak Ghods and South of Tehran wastewater treatment plant as Seasonal and Three samples per season. Concentration of Para-hydroxy Benzoic acid esters was determined by HPLC, CECIL, 4100 at 242 nm. Result: After sampling in the different seasons from the west and south treatment plants, two selective paraben concentrations (Methyl paraben and Ethyl paraben) were measured. The results showed that average concentration of Methyl paraben (MeP) and Ethyl paraben) EtP( respectively were 740.7 and 277.7 ng/L in the Influent and 179.3 and 45.8 ng/L in the effluent of Shahrak Ghods treatment plant. Also, the average concentration of MeP and EtP respectively were 835.3 and 295.3 ng/L in Influent and 132.8 and 29.7 ng/L in the effluent of South of Tehran treatment plant. In the next step, Risk assessment of effluent treatment plants discharging to environment with comparing the studies was done. According to the paraben concentration in the effluent of both treatment plants, discharge of effluent treatment plants whit selective contaminants, have little biological effects on ecosystems. Conclusions: The removal efficiency of Shahrak Ghods treatment plant in removing parabens, was lower than the South of Tehran. But the effluent quality of both treatment plant was less than the Effluent discharge standard. So both of treatment plant have appropriate performance to removal contaminants.

Background and aims: Today, using magnetic adsorbents and the subsequent magnetically separation of pollutants is highly considered by researchers due to it’s ease of use, low cost and rapid results. Therefore the aim of this study was the synthesis of a magnetic composite of activated carbon/Fe3O4 nanoparticles (Fe3O4/PAC), and its application as a magnetic adsorbent for simultaneous removal of lead and aniline from industrial wastewater. Methods: Physical, surface and morphological features of the adsorbent, as well as, the performance of adsorption process were studied in a batch system by investigating the changes in parameters such as pH, contact time, adsorbent and adsorbate concentrations, and temperature. In order to explain experimental data, Freundlich and Langmuir equilibrium isotherms, in addition to Lagergren, Ho and Elovich kinetic equations were applied. Results: Results of this study demonstrated that 90 % of lead and 94 % of aniline were removable by the synthesized adsorbent under the optimal conditions (pH 6, a contact time 60 min and adsorbent dose of 2 g/L). Experimental data from adsorption were better described by both Langmuir and Freundlich isotherm models, and the pseudo-second-order kinetic model. Conclusion: According to these results, it can be claimed that Fe3O4/PAC had an effective adsorption capacity for simultaneous adsorption of lead and aniline, and thus, it is recommended

Background and objective: The chemical industries develepment causes discharge of synthetic chemical compounds such as organic esters and plasticizers into the environment. Phthalic acid esters (PAEs) are refractory, hazardous, and emerging compounds that they produce dysfunction in hormones and endocrine, reproductive problems and cancer. Also this compounds enter into the environment through industrial effluent and causing environmental problems. The purpose of this study was evaluating the the application of UV/ Na2S2O8 / Fe2+ for DMP removal from aqueous solution. Materials and Methods: In the present study, effects of variables including, pH, persulfate concentration, Fe2+ concentration and time were studied as laboratory scale in batch method. Residual concentrations of DMP were determined by HPLC at 254 nm. The impacts of in dependent parameters on DMP removal percent were evaluated with Multi simplex and the response level(box Behnken method). Results: In this study, pH = 11, persulfate concentration of 0.51 Mmol/L, Fe2+ concentration 0.08 Mmol/L for 90 minutes, as conditions were optimized. The results showed that the DMP removal by UV/ Na2S2O8 / Fe2+ process follows first order reaction. Conclusion: The obtained results showed that UV/ Na2S2O8 / Fe2+ process for removing DMP from aquatic environments, has high efficiency (98% removal under optimal conditions). According to the results of study, the UV/ Na2S2O8 / Fe2+ can be used as an effective method for removing DMP from the chemical industries.

Background and Objectives: The use of surfactants enhance the bioavailability of nonbiodegradable contaminants such as PAHs. Biosurfactants are more environmental friendly. In this study the ability of removing phenenthrene from soil by biosurfactant was assessed and compared with that of chemical surfactant. Materials and Methods: A soil sample free of any organic or microbial contamination was artificially spiked with phenanthrene at two concentrations. Then, mineral salt medium at constant concentration of chemical surfactant TritonX-100 and rhamnolipid MR01biosurfactant was added to it in order to have the proportion of 10% w:v (soil:water). A microbial consortium with a potential of phenanthrene biodegradation was inoculated to the soil slurry in two densities (OD=1 and 2) and then it was aerated on a shaker. After eight weeks, the residual concentration of phenanthrene in the soil was extracted by ultrasonic and was analyzed using HPLC. MPN test was used for measuring microbial population. This study was conducted based on the two level full factorial design of experiment. Results: It was found that chemical surfactant exhibited higher PHE removal efficiency than the biosurfactant. Using 120 mg/L of TritonX-100 and rhamnolipid, the PHE removal for the soil contaminated with 50 mg PHE/kg dry soil was 98.5 and 88.7% respectively, while the removal efficieny was decreased to 87 and 76% respectively for the soil contaminated with 300 mg PHE/kg. In the absence of surfactant, the removal efficiency at concentrations of 50 and 300 mg PHE/kg dry soil was achieved 60.76 and 51% respectively. The phenanthrene removal efficiency in OD=2 was more higher than OD=1. In the presence of rhamnolipid, the maximum microbial populations was observed in the second week, while it decreased in the presence of TritonX-100. Conclusion: Use of biosurfactants can be considered as a suitable option in low level pollutant sites. Chemical surfactants as ex-situ has achieved more satisfactory results in high level contaminant sites.

Background and Objectives: Increased growing nuclear industry has increased the researchers concerns on uranium presence in the environment and its effects on human health. Uranium is a dangerous radioactive heavy metal with high half-life and chemical toxicity. Therefore, the main objective of this study was to removal uranium (VI) from aqueous solution by uranium benzamide complex using AC_Fe3O4 nanocomposite. Materials and Methods: AC_Fe3O4 nanocomposite was synthesized using co-precipitation method. The experiments were designed as one factor at the time method. The optimum range of pH, contact time, amounts of adsorbent, and concentration of benzamide were determined. Then, kinetic and isotherm of uranium adsorption were studied. In addition, the properties of this adsorbent were characterized using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). Results: The SEM and FTIR analysis confirmed that activated carbon is coated with Fe3O4 nanoparticles and the magnetic property of AC-Fe2O3 was approved. According to the results, the optimum conditions were pH =6, contact time =30 min, and 0.06 g of adsorbent dose. The adsorption of uranium on the AC_Fe3O4 nanocomposite fitted to Langmuir isotherm and pseudo-second order kinetic model. The removal of U(VI) was increased about 6% with increasing in benzamide concentration to 50 mg/L. The best percentage removal of uranium in aqueous solution was 95%. Conclusion: The removal of U(VI) on AC_Fe3O4 nanocomposite with the aid of benzamide is a rapid and highly pH depended process. The maximum sorption capacity (15/87 mg/g) of AC_Fe3O4 nanocomposite shows that this method is a suitable method for Uranium removal.

Background and Objective: The presence of natural organic materials (NOM) in water resources affects its quality (i.e. color, odor, and taste). In addition, it leads to the fouling of filters and membranes and reduces water treatment efficiency during flocculation/ coagulation. Moreover, NOM reacts with disinfectants and produces byproducts (DBPs), which are harmful to human health. Magnetic nanoparticles have been reported as effective adsorbents for the removal of pollutants from the aqueous media. In this study, we applied SiO2coating on these nanoparticles in order to enhance their stability and dispersion in aqueous media and investigated their capability in NOM adsorption from water. Materials and Methods: Iron oxide magnetic nanoparticles were prepared by co-precipitation. Then, we added Tetraethoxysilane (TEOS) to the solution in order to coat it with SiO2 . The adsorbent characteristics were determined by SEM and XRD. Then, we carried out the adsorption experiments under different pH(3-12) and contact time (5-240 min)performance conditions. The adsorption kinetic was determined with respect to different Humic acid adsorption times. Later, we determined the effect of different concentrations of adsorbent on different concentrations of Humic acid, and Langmuir and Freundlich coefficients based on the optimum conditions. Results: The morphology investigation of adsorbent showed the average size of Fe3O4/SiO2nanoparticles was 30-130 nm. The pH value of 10.5 and the contact time of 90 min at room temperature were determined as optimum conditions for removal of humic acid using Fe3O4/SiO2 nanoparticles. The maximum adsorption capacity of Fe3O4/SiO2 was192.30. The adsorption isotherm was fitted well by Langmuir model (R2>0.90) and the pseudo-second order model (R2>0.98) could better explain humic acid adsorption. Conclusion: Having high number of active surface sites, magnetic properties, easily separation using magnetic field, and its cost-effectiveness, the Fe3O4/SiO2 nanoparticles could be used as an efficient adsorbent in removal of humic acid from water.

Background: Fluoride is a pollutant that entered to the environment through Glass, Fertilizer and Semiconductor Material industries and cause problems such as Alzheimer's and brain injuries. Adsorption with using inexpensive materials like zeolite is the best options to remove this pollutant. The main problem of absorption method is its low speed. So the aim of present study is investigated the effect of Fe0/Ag nanoparticles as catalyst in performance of zeolite for removal of fluoride. Methods: In this study were used reduction method for converting Fe2+ to Fe0 and co-precipitation method for coating of Fe0 on Zeolite. For depositing silver on nano zero valent iron the rapid mixing along with the high temperature were used. Absorbent characteristics were analyzed with using SEM, TEM and XRD techniques. Then effect of pH, contact time, stirring speed, temperature, amount of adsorbent and Fluoride concentration were evaluated and optimized. Results: pH=3, 60 min contact time, 200 rpm stirring speed and adsorbent concentration equal to 10g/l were obtained as the optimum conditions for Fluoride removal. Investigating the isotherms and kinetics relationships showed that the experimental data correlate to the Langmuir adsorption isotherm model (R2>0.991) and pseudo-second order kinetics (R2>0.933). The reaction thermodynamic study also expressed that process is endothermic and non-spontaneous Conclusion: According on the obtained results can be stated This Absorbent has appropriate efficiency in fluoride removal, But the catalytic properties of zero valent iron and silver was rejected in relation to removal this contaminants.

Background and Objectives: Nitrate is one of the most groundwater pollutants in world. Reduction of nitrate to nitrite by microorganisms cause serious health hazards. Nitrate can be eliminated using either adsorbtion or reduction. In this study, we investigated the adsorption of nitate on zeolite and the feasibility of removal improvement using supported zero valent nano iron on zeolite via the reduction process. Materials and Methods: The study was done in two phases; investigation the zeolite and modified zeolite with zero valent nano iron in nitrate removal from water. First, we determined the optimum pH and time then the effect of adsorbent and nitrate concentration was investigated in one factor at the time. The adsorption isotherm was calculated according to the optimum condition. The physical characteristics of adsorbents were determined using SEM and TEM. Results: The morphology investigation of adsorbent showed that the particle size of supported zero valent nano iron on zeolite was approximately 30-50 nm in diameter. The best conditions were; pH 5, contact time of 120 min and 15 g/L for zeolite, while pH 3, contact time of 50 min and 7.5 g/L for supported zero valent nano iron on zeolite. The isotherm equations revealed that nitrate adsorption follows Langmiur in both cases.Conclusion: The supported zero valent nano iron on zeolite could be considered as a high potential adsorbent for nitrate because it has several adsorbent sites, and Fe0 as a function for nitrate reduction.

Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background and Objectives: Aniline has been used in different processes of chemical industries, however due to its side effects on the environment, several methods have been considered for its removal. In this study, we evaluated the performance of photocatalytic process using ZnO nanoparticles (nZnO) and ultraviolet (UV) irradiation for removal of Aniline from a synthetic effluent.Materials and Methods: A 5L photocatalytic reactor made from Plexiglas, which the UV lamp (20w) installed in the center of that (inside a quartz jacket), was designed and nZnO (0.2-0.5 g/l) was being added into synthetic effluent with Aniline concentration of 250 ppm. After retention times of 30, 60, and 90 min, samples were centrifuged and supernatant was filtered using a 0.2 µ PTFE filter. The liquid-liquid method and Gas Chromatography instrument was used for extraction and analysis respectively.Results: Results showed that the photocatalytic process of nZnO+UV could effectively remove Aniline from effluent. Increasing trend in the removal efficiency of Aniline using nZnO = 0.5 g/l was slower in comparison with other nZnO concentrations and the ANOVA analysis shows no significant difference between removal efficiency of Aniline in different concentrations of nZnO. The most removal efficiency of Aniline (76.3%) was observed in alkaline pH, retention time of 90 min and nZnO of 0.5 g/l. Conclusion: It could be concluded that the photocatalytic process of nZnO+UV could be suitable technique for Aniline removal from effluents. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;}

Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background and Objectives: Phenols in trace quantities are usually present in the treated effluent of many wastewater-treatment plants. Phenol compounds even at low concentration can cause toxicity, health and significant taste and odor problem in drinking waters. This research focuses on understanding the sorption process and developing a cost-effective technology for the treatment of water contaminated with phenolic compounds, which are discharged into the aquatic environment from a variety of sources. In order to remove phenolic compounds from water, a new natural sorbent, rice husk ash, was developed.Materials and Methods: Removal of phenol, 2-chlorophenol and 4-chlorophenol were characterized by spectrophotometric technique at wavelengths of 269.5, 274 and 280 nm, respectively, under batch equilibrium conditions and via changing the parameters of contact time, initial pH, and initial concentration of adsorbates and dosages of sorbent. Finally, the results were analyzed by the kinetic and isotherm models.Results: in this study, the equilibrium time was found to be 240 min for full equilibration of adsorbates. Removal percent of 2-chlorophenol was lower than two others. The maximum removal of phenol, 2-CP and 4-CP was observed at an initial pH of 5. The percentage removal of these phenolic compounds increased with increasing adsorbent dose and decreasing initial concentration. In kinetics studies, correlation coefficient and ARE factor showed that the sorption of phenol (R2=0.9999), 2-chlorophenol (R2=0.9992) and 4-chlorophenol (R2=1) fitted by pseudo second order model. Isotherm studies also revealed that, Langmuirmodel for phenol (R2=0.9499), Freundlich model for 2-chlorophenol (R2=0.9659) and 4-chlorophenol (R2=0.9542) were the best choices to describe the sorption behaviors.Conclusion: Sorption process is highly dependent on the pH and it affects adsorbent surface characteristics, the degree of ionization and removal efficiency. At high pH hydroxide ions (OH-) compete for adsorption sites with phenol molecules. The sorption was done rapidly and a plateau was reached indicating the sorption sites occuupied till they were saturated. Since the increasing sorbent dose would improve sorption site, its increasing enhances phenolic compounds removal. st1":*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;}

BACKGROUND AND OBJECTIVE: The BTX compounds consist of benzene, toluene and xylenes are volatile organic compounds and are present in fuels and industrial solvents. Its emission to air and exposure to these compounds threats human health. Thus, it is necessary to control these compounds concentration in acceptable limit. Therefore, the purpose of this research was to survey BTX removal ability of a compound of iron and copper oxide metallic nanoparticles which have catalytic properties and also Zeolite as a sorbent and media for nanoparticles.METHODS: In this experimental study, samples were taken from inlet and outlet airflow of reactor for BTX and CO2 concentration determination. Zeolite filters without nanoparticle and a compound of zeolite with zero valence iron and copper oxide nanoparticles which contains 4.5% of nanoparticles and with 1-2mm of zeolite grains size as much as 200g were prepared and the BTX removal by each filter in a 30cm in length and 4.5 cm in diameter column as reactor determined. FINDINGS: The removal efficiency of benzene in the filter without nanoparticle (78.30±5.37%) was more than Iron and copper oxide nanoparticles (49.64±4.19%). But, for the toluene (67.09±4.23%) and xylenes (39.86±2.04%, 47.59±3.24% and 80.73±5.98%, respectively for p, m and o-xylenes) in iron and copper oxide nanoparticles filter it was further than the filter without nanoparticles (toluene 62.10±3.25% and xylenes respectively 30.20±1.84%, 32.15±3.39% and 18.80±3.39%). Also, the pollutant complete decomposition was higher in the filter containing nanoparticles (82.78% versus 16.44%). Average removal efficiency of BTX in the filter without nanoparticle was 43.31% and in the filter with iron and copper oxide nanoparticles was as much as 56.98%. CONCLUSION: As the obtained results the filter of zeolite without nanoparticle mainly removes the BTX compounds by absorption or incomplete decomposition. While, the zeolite filter with iron and copper oxide nanoparticles performs decomposition of the BTX more completely to CO2.

Background and aimsFluoride is released to environment naturally and via Industrial effluents. According to concentration of fluoride in potable water and its total uptake rate, can bebeneficial or harmful. Due to simplicity of operation, easy access to the coagulants of alum and poly aluminum chloride and low cost, coagulation was selected for fluoride removal from water. The purpose of this study was to comparison the efficiency of alum and commercial polyaluminum chloride for fluoride removal from water.MethodsLab scale experiments were carried out via Jar apparatus. Variations of this study, including pH, coagulant dosage and fluoride concentration were experimented in defined conditions.ResultsResults indicate that optimum pH for both of coagulants was equal to 4. Concentrations of alum and poly Aluminum chloride for fluoride removal were 240 and 160 mg/L respectively and removal efficiency in optimum pH and dosage of coagulant were 84.2 and 84 % respectively.ConclusionAccording to data obtained from this study, it can be stated that coagulation is a suitable method for removal of fluoride from water and poly Aluminum chloride is compatible with alum.

Background and Objective: Double-glazing is one of the methods of sound control. The use of materials other than gas inside double-glazing can develop sound transmission loss. The present study aims to make a double-glazing filled with A200 hydrogel at different ratios and measure the sound transmission loss. Materials and Methods: In the present study, 4 samples of double-glazing were made with water and A200 hydrogel. The mixing ratios of hydrogel with water were 1:20, 1:75, and 1: 150. The sound transmission loss of each sample was measured three times by AvaSina impedance tube using the sound pressure level through two microphones installed on both sides of the sample according to ISO 10534-1. Then, the results were analyzed by SPSS software (version 24) and repeated measures test. Results: According to the results, the highest amount of sound transmission loss was related to the water sample at 250 and 500 Hz and the A200-1:20 sample at 1000 and 2000 Hz. Meanwhile, the A200-1:75 sample had the lowest sound transmission loss at 250, 500, and 1000 Hz, and the water sample at 2000 Hz. Conclusion: The present study indicated that filling empty space of doubleglazing with hydrogel increases transmission loss in high frequencies and decreases it in low frequencies compared to that of the water sample. Also, transmission loss of the air sample was found significantly different from all other samples except the A200-1:150 sample by comparing the water and hydrogel samples with the air sample as a control. [ABSTRACT FROM AUTHOR]

Background and Objectives: Phenols in trace quantities are usually present in the treated effluent of many wastewater-treatment plants. Phenol compounds even at low concentration can cause toxicity, health and significant taste and odor problem in drinking waters. This research focuses on understanding the sorption process and developing a cost-effective technology for the treatment of water contaminated with phenolic compounds, which are discharged into the aquatic environment from a variety of sources. In order to remove phenolic compounds from water, a new natural sorbent, rice husk ash, was developed. Materials and Methods: Removal of phenol, 2-chlorophenol and 4-chlorophenol were characterized by spectrophotometric technique at wavelengths of 269.5, 274 and 280 nm, respectively, under batch equilibrium conditions and via changing the parameters of contact time, initial pH, and initial concentration of adsorbates and dosages of sorbent. Finally, the results were analyzed by the kinetic and isotherm models. Results: in this study, the equilibrium time was found to be 240 min for full equilibration of adsorbates. Removal percent of 2-chlorophenol was lower than two others. The maximum removal of phenol, 2-CP and 4-CP was observed at an initial pH of 5. The percentage removal of these phenolic compounds increased with increasing adsorbent dose and decreasing initial concentration. In kinetics studies, correlation coefficient and ARE factor showed that the sorption of phenol (R2=0.9999), 2-chlorophenol (R2 =0.9992) and 4-chlorophenol (R2 =1) fitted by pseudo second order model. Isotherm studies also revealed that, Langmuirmodel for phenol (R2 =0.9499), Freundlich model for 2-chlorophenol (R2 =0.9659) and 4-chlorophenol (R2 =0.9542) were the best choices to describe the sorption behaviors. Conclusion: Sorption process is highly dependent on the pH and it affects adsorbent surface characteristics, the degree of ionization and removal efficiency. At high pH hydroxide ions (OH-) compete for adsorption sites with phenol molecules. The sorption was done rapidly and a plateau was reached indicating the sorption sites occuupied till they were saturated. Since the increasing sorbent dose would improve sorption site, its increasing enhances phenolic compounds removal. [ABSTRACT FROM AUTHOR]

Backgrounds and objectives: Today chr('39')s World is faced with the environmental problems associated with heavy metal contamination as one of the main issues of concern. Mercury, known as one of the most toxic heavy metals, has gained a lot of attention due to its sustainability and bioaccumulation in the food chain as well as having detrimental health problems such as kidney failure and gastrointestinal damages. This study is centered on the removal of Hg (II) ions from aqueous solutions using a magnetite/biosilica/sodium alginate nanocomposite as an efficient adsorbent. Materials and methods: Within this study, the magnetite/biosilica/sodium alginate nanocomposite was successfully synthesized via a co-precipitation method. The structure and morphology of the prepared adsorbent were confirmed by SEM, XRD and VSM analyses. The parameters affecting the adsorption process such as pH, contact time, adsorbent amount, temperature and initial concentration of Hg (II) ions were all evaluated. Findings: The optimum conditions obtained were as follows: pH 5, adsorbent dosage 0.2 g/L, contact time 80 min, temperature 45 °C. The results revealed that the removal efficiency dropped by increasing Hg(II) concentration. The adsorption of Hg (II) obeyed the Langmuir isotherm (R2 0.9998) and pseudo-second kinetic model (R2 0.9997). Additionally, the thermodynamic studies demonstrated that the adsorption process is of endothermic and spontaneous nature. Conclusions: All in all, the synthesized adsorbent was applied for the removal of Hg (II) ions from the aquatic environment. Ease of separation from the aqueous solution due to its magnetic properties as well as high level of Hg (II) recovery are amongst the unique feature of the adsorbent.

Background and Aims: Nowadays, soil pollution with total petroleum hydrocarbons (TPH) is one of the major environmental issues caused serious problems to human and other living organisms. One of the best and most reliable methods of bioremediation is the use of earthworms known as vermin-remediation. In this study, bioremediation of gasoline-contaminated soil using Eisenia Fetida, the mixture of activated sludge and compost was evaluated. Materials and Methods: In order to determine the efficiency of bioremediation to removal gasoline from contaminated soil, cow compost and urban sewage sludge with a weight ratio of 1: 0.35:0.25, was used. Experiments were carried out in 6 reactors with different concentrations of diesel (10 and 30 g / kg soil), a different number of Eisenia Fetida earthworm (10 and 20) at ambient temperature during 90 days. To compare the performance of biodegradation of gasoline using Eisenia Fetida earthworm, two control reactors that contained only contaminated soil with two ratios of gasoline, vermicompost and activated sludge, were used. The (TPH) decomposition rate was measured by GC-FID. Results of this study were analyzed by Minitab version 17 software. Results: Results indicated reactor No.3 has the best removal efficiency of light hydrocarbons during 90 days. the removal efficiency of average hydrocarbons was 70% and heavy hydrocarbons with the highest removal efficiency of 68% in reactor No. 4 with characteristics Soil polluted with 10 g / kg of soil + 20 number of Eisenia Fetida, With a significant difference of other reactors. Conclusion: Based on the results of this study, the degradability of hydrocarbons has increased significantly with the addition of organic modifying materials and the increase in the number of earthworms.

Background: Laccase enzyme is capable of oxidizing many resistant and non-biodegradable environmental pollutants, so it has been studied frequently in recent years and is widely used in biodegradation of contaminants. Despite its abundant applicability, due to its short life span, nonrecovery, thermal instability and instability in organic environments, its widespread use is very limited. The present study aimed to increase the stability of laccase by immobilizing it on silica coated iron oxide nanoparticles. Materials and Methods: Fe3O4 nanoparticles were synthesized based on the co-precipitation method and after coating with silica, their surface was modified by amine groups. The enzyme was then immobilized by covalent binding using glutaraldehyde. Specifications of synthesized nanoparticles and immobilized enzyme were investigated using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and Energy-dispersive X-ray spectroscopy (EDX). Results: Results of successful laccase immobilization on nanoparticles showed that laccase immobilization significantly increased storage and thermal stability, maintaining activity in a wider range of temperature and pH than free laccase. Conclusion: The immobilization of laccase on silica-coated iron oxide nanoparticles can reduce the barriers and challenges of various enzymes by increasing its efficiency and stability.

Background &Objective: the advantage of choosing Household water treatment over tap water for drinking is based on the human health assurance of health risks with these devices. The Hazard Analysis Critical Control Points system (HACCP) is a framework that identifies and manages significant hazards at the source to point of use in the process of producing drinking water. This study can be aimed at introducing of HACCP systems as a model to identify the most important potential hazards and control these risks in the flow diagram of RO-based Household Water Treatment in Tehran. Methods: The possible hazards identified at each step of water production by household water treatment. According to the principle of Seven HACCP, Critical Control Point (CCP) is selected and determined critical limits, monitoring, and corrective action. Sampling water is taken from each critical control point. Physicochemical and microbiological parameters were measured by standard methods. Results: Results of CCP Risk assessment have confirmed that the parameters of pH, nitrate, total organic carbon, and total coliform and fecal coliform were in the critical limits for defined CCPs. While, the total hardness, fluoride, and HPC were in the critical limit only at the CCP1. Conclusion: The results showed that the HACCP system can be used to reduce the risks, increase the safety of the output water of the household water treatment. To this end, regular monitoring must be carried out in the specified period by the appropriate operator.

Background and purpose: Nitrate is one of the most common chemical pollutants in groundwater in the world. Adsorption has been considered as an effective and efficient method of removing pollutants, particularly nitrate from aqueous solutions and so the aim of this study was to magnetization of the carbon nanotubes with zero-valent iron and using it as an adsorbent for the removal of nitrate from aquatic environments. Materials and methods: In this study, reduction method for converting divalent iron into zero-valent iron and co-precipitation method for iron particles deposition on carbon nanotubes was used. Characteristics of absorbent were analyzed by SEM (Scanning electron microscopy), XRD (X-ray powder diffraction), and VSM (Vibrating Sample Magnetometer) techniques. In this study, the effect of the pH, contact time, mixer speed, temperature, adsorbent dosage and the concentration of nitrate was investigated by one factor at the time method and then was optimized. Results: The pH equal to 3, 60 min contact time, 200 rpm stirring speed and 1 g/l absorbent was obtained as the optimum conditions in the adsorption of nitrate. Investigating the isotherm and kinetic models showed that the experimental data correlate to the Langmuir adsorption isotherm model (R²> 0.997) and pseudo-second order kinetic (R²> 0.993). The reaction thermodynamic study also expressed endothermic and spontaneous reaction. Conclusion: In optimal conditions, carbon nanotubes modified by zero-valent iron has well potential to quickly and effectively remove nitrate and simply be separated from the solution by the magnet due to its magnetic property. [ABSTRACT FROM AUTHOR]