Elham Asrari; Negar Daneshi
Abstract
Background: In recent years, the need for new methods of water treatment on an industrial scale in order to compensate the shortage of water resources has become imperative. Among different methods, the use of adsorption in order to remove aqueous contaminates, including synthetic dyes, has been so effective. ...
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Background: In recent years, the need for new methods of water treatment on an industrial scale in order to compensate the shortage of water resources has become imperative. Among different methods, the use of adsorption in order to remove aqueous contaminates, including synthetic dyes, has been so effective. Methods: In this research, removal of malachite green from aqueous solution by concrete modified with rubber powder has been studied. In order to achieve the maximum efficiency of malachite green removal, the impact of different parameters such as initial concentration of malachite green, pH, adsorbent dosage and contact time was studied using batch experimental method. Results: According to the results, optimum conditions of MG removal were pH of 9, initial concentration of 30 ppm, rubber powder dosage of 35% of sand weight, and contact time of 90 min. Results of compressive strength test have shown that compressive strength of concrete with 35 wt.% of rubber powder reduced 84.13% compared to simple concrete. The removal percentage of MG is 98.33% when the surface of concrete is covered by rubber powder. Experimental data corresponded with pseudo-first order equation with R2= 0.93, Langmuir and Freundlich adsorption isotherms with R2= 0.85 and 0.84, respectively. Real waste sample was used to confirm the application of concrete in ordinary conditions of wastewater basin in accordance with optimum conditions of kinetics wastewater. Elimination rate of MG happened in an optimum condition with real samples taken from industrial factory. Conclusion: Concrete modified with rubber powder has potentials for removal of MG dye from wastewater. Covering the concrete surface with rubber powder can be an innovative and useful solution for increasing the rate of elimination of pollutants and contaminants, cost reduction and accelerating the absorption process. Actually, it could be considered as one solution for managing waste rubber.
Elham Asrari; Esmail Izadi Navan
Abstract
Background: The presence of quantities of dye chemicals in the textile industry effluent is clearly visible and harmful environmental impacts caused by chemical compounds are also as a noticeable challenge. Regarding this issue, control of the pollution has been considered. Methods: In this study, an ...
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Background: The presence of quantities of dye chemicals in the textile industry effluent is clearly visible and harmful environmental impacts caused by chemical compounds are also as a noticeable challenge. Regarding this issue, control of the pollution has been considered. Methods: In this study, an absorbent of Sodium Montmorillonite modified by Methylene Blue dye was used to remove Brilliant Red dye from the textile effluent. All batch experiments were carried out in 250mL of solution of 640 mg/L Methylene Blue with 2g of adsorbent and performed on a shaker with a shaking of 120 rpm; the precipitate was placed in an oven at 60◦C for 24 hours. The effective parameters on the adsorption including: pH, absorbance dose, dye concentration and contact time were optimized by using both one factor at a time technique and Central Composite Design method by designing 30 experiments with four variables (n= 4) and two levels (low (-) and high (+)). Results: The optimal values of the influencing parameters such as pH, absorbance dose, dye concentration and contact time were determined at 6, 0.3 g, 80 mg/L and 60 min with an approximate 92% removal percentage, respectively. The results illustrated that the process was more consistent with Langmuir adsorption isotherm and pseudo-second kinetics equation. Conclusion: The adsorption behaviors of the modified absorbent showed that the adsorption kinetics and isotherms were in good agreement with pseudo-second-order equation and the Langmuir equation, respectively. The potential for regeneration and reuse of the modified absorbent was proved by the desorption studies.
Elham Asrari; Masoud Faraji
Volume 5, Issue 4 , October 2017, , Pages 164-168
Abstract
AbstractBackground: The AERMOD is one of the EPA preferred and recommended air quality dispersion models. The AERMOD is a steady state dispersion model for estimating the concentration of pollutants in urban, rural, flat and elevated, ground level and elevated receptors from different volumes, areas ...
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AbstractBackground: The AERMOD is one of the EPA preferred and recommended air quality dispersion models. The AERMOD is a steady state dispersion model for estimating the concentration of pollutants in urban, rural, flat and elevated, ground level and elevated receptors from different volumes, areas or point sources.Methods: In this study, in order to evaluate the accuracy of software results, the AERMOD was used for estimating the air pollution concentrations at different locations in Emam Hossein Square and Darvazeh Kazeroun Square of Shiraz City, where there are two DOE air quality monitoring stations. The modeling was performed based on hourly annual metrological data of Shiraz airport. The variable air pollutants’ emission rates were used based on different traffic loads at different hours at night and during the day.Results: The modeling results are compared with the values measured at DOE air quality monitoring stations. The results showed that for the maximum daily concentration of pollutants, the AERMOD estimated values were about 5 and 20 percent higher than the values measured for SO2 and CO; also, the estimated values were two times higher than the measured values for NOx and PM10. Furthermore for the average daily concentration of pollutants, the AERMOD estimated values were about 17, 41, 42 and 38 percent lower than the values measured for NOx, CO, SO2 and PM10, respectively.Conclusions: The quality of ambient air in Shiraz City seems to be good since, except for the PM10, the concentrations of CO, NOx and SO2 were in the range of clean air standard. The maximum daily concentrations of PM10, CO, NOx and SO2 were reported as 0.497 mg/m3, 4246 mg/m3, 0.206 mg/m3and 0.037 mg/m3, respectively.