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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: TiO2,Photocatalytic degradation,Azo dyes,Reactive Red 198,UV-light
- چکیده:
- چکیده انگلیسی: Dye-containing wastewater generated from textile industries is a major source of environmental pollution. Azo dyes, which are the largest group of coloring agents, are widely used in industries.
This research investigated the photocatalytic decolorization and degradation of an azo dye Reactive Red 198 (RR198) in aqueous solution with TiO2-P25 (Degussa) as photocatalyst in slurry form using UV light. There is a significant difference in adsorption of dye on TiO2 surface with the change in the solution pH. The effect of various parameters such as catalyst loading, pH and initial concentration of the dye on decolorization and degradation have been determined. The optimum conditions of the reactor were acquired at dye concentration = 62 ppm, pH = 3.7, catalyst concentration = 2.25 g.L-1, in which dye removal efficiency was 98%. Catalyst loading (relevant coefficient = 19.25) and pH (relevant coefficient = −2.62) were resulted respectively as the most and less effective parameters on dye removal- انتشار مقاله: 26-10-1395
- نویسندگان: Farzaneh Asvadi,Narges Fallah,Shilan Elyasi,Farnaz Mohseni
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Photocatalytic wastewater treatment,Spent Caustic wastewater,Titanium dioxide,Artificial neural networks(ANN),Design of experiment (DOE)
- چکیده:
- چکیده انگلیسی: In this study, the photocatalytic method was used for treating the spent caustic in the wastewater of Olefin units used in petrochemical industries which contain large amounts of total dissolved solids (TDS). By using the synthetic photocatalyst of suspended titanium dioxide and measuring the chemical oxygen demand (COD) which was reduced in the photocatalyst (lbc) process, the values of COD were modeled and evaluated by means of the Box-Behnken (BBD) and the artificial neural network (ANN) using experimental tests in a double-cylindrical-shell photo reactor. According to the applied calculations, it was found that the artificial neural network was a more suitable method than the experimental design in modeling and forecasting the amount of COD removal. The modeling employed in this research showed that increasing the concentration of the photocatalyst in a state of neutral pH enhanced the COD removal up to the optimal amount of 1.31 g/L without restrictions and 2 g/L with restrictions at the rate of 81% and 79%, respectively. In addition, the study of the parameter effects including oxidizer amount, aeration rate, pH, and the amount of loaded catalyst indicated that all factors except pH had a positive effect on the model; furthermore, if the interactions were neglected, the COD removal efficiency would increase by increasing each of these factors (except pH). In addition, there was no interaction between the aeration and the concentration of the photocatalyst, and the acidic pH was more suitable at low concentrations of the photocatalyst. Besides that, by increasing the pH, the efficiency of removal was reduced when the oxidant was at its low level. The results showed that photolysis and adsorption adoptions had a very small effect on the efficiency of the removal of COD compared to the photocatalyst adoptions, and it was insignificant. In addition, the photocatalytic method had an acceptable capacity for removing the phenol in the wastewater sample, whereas it was inefficient in reducing the sulfide solution in the wastewater.
- انتشار مقاله: 23-03-1394
- نویسندگان: Aَli Haghighi Asl,Amin Ahmadpour,Narges Fallah
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Biosorption,Bagasse,Isotherm,kinetic,Styrene
- چکیده:
- چکیده انگلیسی: In this work, styrene removal from wastewater by using sugarcane waste (bagasse) as an adsorbent was studied. Equilibrium isotherms and kinetics were determined; the effects of bagasse particle size and concentration, solutions pH, and temperature on the biosorption of styrene were studied in batch experiments. Adsorption equilibrium data was successfully fitted to Langmuir isotherms (R2=0.986) and Freundlich isotherms (R2=0.96). Also, the kinetics of biosorption was fitted to pseudo-second order equations (K2=0.00146 g mg-1 min-1, qe=24.5 mg g-1 for particle size range of 88-105 μm).
According to the obtained results, an empirical equation was presented that could be used to calculate the percentage of styrene adsorption. The results showed that an increase in temperature caused a decrease in styrene removal. Moreover, maximum uptake was observed with NaOH-treated bagasse. It was found that an increase in average particle size decreased the biosorption rate. According to the calculated heat of adsorption, this sorption can be classified as a chemical biosorption. The optimum uptake was determined to be 88% at a pH equal to 12.1, a temperature of 35 oC, a particle size of 420-500 μm, and a bagasse concentration of 1 g L-1.- انتشار مقاله: 11-07-1393
- نویسندگان: Mehdi Hassanzadeh,Narges Fallah,Bahram Nasernejad,Rouein Halladj
- مشاهده