Showing 9 results for Fat
M.t Samadi, M. H Saghi, M. Shirzad, J. Hasanvand, S. Rahimi,
Volume 3, Issue 1 (4-2010)
Abstract
Backgrounds and Objectives:In Iran , indicated that the municipal landfill leachate has been one of the major problem for environment. In the operations, leachate treatment is a very difficult and expensive process. Although, young leachate can be treated easily by biological treatment, COD removal efficiency are usually low due to high ammonium ion content and the presence of toxic compounds such as metal ions. Treatment of leachate is necessary.The aim of this study is reduction of Chemical Oxygen Demond (COD) and Total Suspended Solids (TSS) from hamedan city sanitary landfill leachate by three coagulants: alum, PAC and ferrous sulfate.
Materials and Methods: This experimental study was conducted to investigate the effect of treatment of landfill leachate by a coagulation-flocculation process. The effects of different amounts of coagulant and different pH values on the coagulation processes were compared.
Results:Result shown the high efficiency for reduction of CODby PAC in pH=12 and concentration of 2500(mg/l (62.66%), and by alum in pH=12 and concentration of 1000 (mg/l) (60%) , by ferrous sulfate in pH=2 and concentration of 1000 (mg/l) (70.62%). Also result shown the high efficiency for TSS removal by PAC in pH=12 and 2500(mg/l) concentration of PAC was 58.37%, with alum in pH=2 and 1500 (mg/l) concentration of alum was39.14% , by ferrous sulfate in pH=7 and 2500(mg/l) concentration of ferrous sulfate was 35.58%.
Conclusion:The best coagulant for COD removal is ferrous sulfate.The physico-chemical process may be used as a useful pretreatment step, especially for fresh leachates, prior to post-treatment (polishing) step for partially stabilized leachates.
M.t Ghaneian, M.h Ehrampoush, Gh Ghanizadeh, M Dehvary, M Abootoraby, T Jasemizad,
Volume 3, Issue 2 (7-2010)
Abstract
BackgroundandObjectives: Dyes are organic compoundswith complex structures,which due to toxicity, carcinogenicity and nonbiodegredabity, this type of pollutants is one of the most important pollutants of the environment. The goal of this researchwas to study the feasibility of the application of solar irradiation in presence of potassium persulfate (K2S2O8) for the removal of Reactive blue19 (RB19) from synthetic wastewater.
Materials and Methods:This research wascarri edoutin laboratory scalewith using of 200ml volume of batchphotoreactor.The effectsofoperatingparameters suchas concentrationofK2S2O8,pH,photoexposure time and preliminary concentrations of dye on decolorization have been evaluated.Different concentrations of pollutant inwastewaterwere prepared by solution of variousmasses of RB19 on tapwater. The reactors were exposedwith natural solar irradiation as aUVAsource from11 amto 14 pm.Themaximumabsorbtion wave length of this dye (!max) was determined by spectrophotometer (Unico, 2100). The measurement of dye concentrations was determined with using of standard curve and its best line equation
Results:Analysis of absorbtion spectra showed that the !max of RB19 is 592 nm. The average intensity of the UVA irradiated from solar system was 54.6 µW/Cm2. The results of decolorization process showed that 38.2%of this dye can be removed within 3 hr in the presence of potassium persulfate and decreasing of pH leads to the elevation of dye removal efficiency. Based on these findings, the efficiency of dye removal with 3h photoexposure time and pH ranges of 4,6 and 8 were found to be 98.2 88.5 and 78.5%, respectively.Also, the results showed that increasing of K2S2O8 dosage leads to elevation of dye removal efficiency in 3h photoexposure time and K2S2O8 dosages within 1-5mmol/L, with the removal efficiency of 75,86,92,95 and 98.5%, respectively.Analysis of data indicates that the kinetic of the removal of RB19 with this process is a first order reaction which its rate constant is 0.01min-1.
Conclusion: Due to the operation problems presented in heterogeneous photocatalitical processes such as catalysts separation and high costs of operation and maintenance of these processes caused by manmade sources of irradiations homogeneous photocatalitical process with using of potassium persulfate associated with natural solar irradiation can be used as a suitable process for the removal of dyes from textile industries wastewaters.
B Mortazavi, B Barikbin, Gh.r Moussavi,
Volume 3, Issue 3 (10-2010)
Abstract
Backgrounds and Objectives: Geological situation and/or anthropogenic contamination contain an increased concentration of ions such as hexavalent chromium as well as some other dissolved components such as sulfate in the upper of the establishedMCLs (50µg/L). In this paper, simultaneous removal of Cr (VI) and sulfate from water was investigated using nanofiltration as a promising method for reaching drinking water standards.
Materials and Methods: For varying pressure, pH , anion and cation solution effect, Sulfate and Cr (VI) concentration which have chosen were levels found in drinking water sources (Cr=0.1- 0.5mg/L) and (SO4-2= 100-800mg/L).Experiments were performed using NaCl, Na2SO4,K2 Cr2O7and anhydrous CrCl3. 6H2O which prepared with de mineralized water on procedure detailed in standard methods. All salts were purchased from Merck Corporation with purity over 99'.
Results: The results for hexavalent chromium experiments showed that when the concentration decreases, the chromate anions were given a better retention to 4 bars (96'). But when the concentration increases, concentration polarization led to increased removal of Cr (VI) (98'). For Cr (III) the influences of the ionic strength as well as the concentrations were strongly dependant on rejection but operating pressure were found weak. In addition, with increasing total dissolved solids, perfect rejection of chromium was seen. The effect of pH showed that better retention was obtained at natural and basic pH.
Conclusion: This study indicates that the nature of anions and cations, driven pressure and pH have significant effect on nano filtration operation. Research findings show that it seems nano filtration is a very good promising method of simultaneous removal of Cr (VI) and sulfate from water.
Z Rahmani, M Harati, Mr Rahmani, Y Poureshgh, Mt Samadi,
Volume 9, Issue 2 (9-2016)
Abstract
Background and Objective: Surfactants can be found in soaps, detergents, pharmaceutical products, personal care products, as well as in leather industries. In this study, adsorption of Sodium Dodecyl Sulfate (SDS) on magnetic multi-walled carbon nanotubes in the aqueous solutions was investigated.
Materials and methods: Surfactant concentration, adsorbent dosage, and pH values were considered as variables. Residual surfactant was measured using methylene blue method and adsorbent characteristic was determined by X-Ray diffraction and Fourier transform infrared spectroscopic analysis. Adsorption capacity, adsorption isotherm, and kinetic reaction were also investigated.
Results: Adsorption investigations demonstrated that the increase in initial SDS concentration or pH values, led to the decrease in SDS adsorption. Conversely, the same result was achieved by decreasing adsorbent dosage. After 120 min SDS adsorption became stable. By increasing in SDS concentration from 15 to 150 mg/L, adsorption capacity improved from 8 to 61 mg/g. Isotherm and kinetic data demonstrated that experimental data pursued Langmuir isotherm (R2=0.993) and pseudo-second order equation (R2=0.992).
Conclusion: Magnetic multiwall carbon nanotubes can be used as an effective and useful sorbent for SDS removal due to several advantages including: high adsorption capacity, relatively low equilibrium time, and easy separation of magnetic multiwall carbon nanotubes from aqueous solutions.
R Shokohi, A Shabanloo, F Zamani,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: Nitrophenols are among the most common and toxic compounds in industrial effluents that 2, 4 dinitrophenol (2, 4-DNP) is the most toxic compound in this group. The object of this study was to optimize the removal of 2, 4-DNP by thermally activated persulfate using a central composite design.
Materials and Methods: This study was performed on a batch thermal reactor with a volume of 4 L. In this study, a central composite design (CCD) with RSM method was used for designing and optimizing the operation parameters such as initial pH of solution, potassium persulfate concentration and temperature. The effect of 2, 4-DNP concentration and reaction time at optimum conditions were also investigated.
Results: The results indicated that the degradation rate of 2, 4-DNP was enhanced by increasing the concentration of persulfate and reducing temperature and pH. The optimum conditions for the highest degradation efficiency (99%) were as initial concentration 10 mg/L, reaction time 30 min, temperature 60 °C, Potassium persulfate concentration 10 mmol/L, and pH 5. At the optimum conditions, when 2, 4-DNP concentration was increased to 50 mg /L, the 2, 4-DNP degradation rate decreased to 73%.
Conclusion: This study indicated that the heat-activated PS oxidation could be an efficient approach for decomposition of 2, 4-DNP. Temperature was the most influential variable in this regard (p<0.0001).
Reza Barati Rashvanlou, Mahdi Farzadkia, Abbas Ali Moserzadeh,
Volume 14, Issue 1 (5-2021)
Abstract
Background and Objective: Hydrolysis of fat, oil and grease by ultrasonic waves is a pre-treatment method before anaerobic digestion which can change their physical, chemical and biological properties. The main purpose of this study was to investigate the efficiency of ultrasonic waves to improve the hydrolysis process and its use as an auxiliary substrate to increase the efficiency of anaerobic digestion process along with municipal sewage sludge.
Materials and Methods: Sampling of fat and oil of the degreasing unit and physical preparation by conducting ultrasonic waves with frequencies of 20 kHz and current density of 0.012-0.14 W/mL within 0-12 min were performed. The efficiency of pretreatment process were performed through tests such as soluble chemical oxygen demand (SCOD), and lipase enzyme activity. In addition, the anaerobic digestion process were evaluated by measuring the TS, VS, VA (volatile acidity), alkalinity, biogas production and biogas methane content.
Results: The results showed that the highest increase in the activity of lipase enzyme under ultrasonic effect with a power of 0.1 w/mL was obtained after 8 minutes. Organic loading with 10%, 20% and 40% FOG/MSS ratios: resulted in 55%, 66% and 64% increase in methane production compared to the control samples, respectively. Organic loading over the 40% FOG/MSS caused a limitation in the simultaneous digestion process.
Conclusion: The results show that ultrasonic wave pretreatment with optimal power and time can improve the hydrolysis of TFOG while increasing the activity of lipase enzyme and also its use as an auxiliary substrate can enhance digestion performance and make digestion more stable.
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.
Samira Sheikhi, Hassan Aslani, Reza Dehghanzadeh, Ammar Maryamabadi,
Volume 15, Issue 1 (4-2022)
Abstract
Background and Objective: Chlorpyrifos (CPF), an organophosphate pesticide, has been widely used in the agricultural industry and may cause environmental damage. The present study aimed to evaluate the potential application of Fe(VI) and Fe(VI)/PMS processes for oxidation of CPF in water after pretreatment with ferric chloride coagulant.
Materials and Methods: This study was performed in two phases including coagulation and flocculation process and advanced oxidation process (AOP). In the first phase, the coagulation process was performed for turbidity removal by ferric chloride (FeCl3). In this phase, using a central composite design (CCD) with R software, the combined effect of four variables including initial turbidity, initial pH, coagulant dose and contact time was investigated. The supernatant from this process was transferred to the next phase for further analysis. In the AOP phase, the effect of Fe(VI) and Fe(VI)/PMS oxidants were investigated separately.
Results: In the first phase (coagulation and flocculation), FeCl3 showed the highest efficiency (95.79%) at alkaline pH (pH=8). In the next phase (AOP), the results showed that the degradation efficiency of Fe(VI)/PMS process was higher compared to sole Fe(VI) process at all pHs. Also, by examining the reaction kinetics, it was found that after the coagulation process by FeCl3, the removal rate in the Fe(VI)/PMS process is 1.5 times higher than the Fe(VI) process.
Conclusion: Due to the high removal efficiency and higher degradation rate of Fe(VI)/PMS process, this technique can be used as a relatively effective method in removing chlorpyrifos from aqueous solution.
Sakine Shekoohiyan, Mojtaba Pourakbar, Asghar Zohdi Shiran, Farshid Ghanbari, Mostafa Mahdavianpour, Ehsan Aghayani,
Volume 16, Issue 4 (3-2024)
Abstract
Background and Objective: The development of the automobile industry has caused various pollutants to enter the environment, one of which is fluoride. Therefore, this study aims to improve the fluoride removal from wastewater pre-paint units of the automotive industry to achieve discharge standards to surface waters.
Materials and Methods: The study is descriptive and on an applied scale, which has been carried out to compare the efficiency of the chemical coagulation process using lime and alum, as well as the electrocoagulation process using aluminum anodes in the presence of lime to remove fluoride.
Results: The results of real wastewater characteristics showed that the pH of wastewater is in the range of 6.1 to 6.3, and its fluoride concentration is in the range of 45 to 55 mg/L. The results of the experiments show that in the most optimal possible state in the chemical coagulation process, it is possible to achieve fluoride removal efficiency in the range of 76 to 81 percent. However, the removal efficiency in the electrocoagulation process using an aluminum anode at a concentration of 5 mol/L of calcium ions, and current density of 20 A/m2 after reaction time of min 20 to 99% can also be achieved.
Conclusion: Considering the high fluoride removal rate (more than 99%) in the electrocoagulation process in the presence of calcium ions, this process can be introduced as an efficient technology for fluoride removal.
