Chemistry of wood
Seyed Hassan Sharifi; Saltanat Archin; Leila Aghanaghifar
Abstract
DOR:98.1000/1735-0913.1398.34.16.66.1.1575.1603 One of the most important sources of environmental pollution is dye from industrial wastewater which is harmful for human health and environment. Therefore, the aim of this study was to evaluate removal of Methylene Blue (MB) dye from aqueous solutions ...
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DOR:98.1000/1735-0913.1398.34.16.66.1.1575.1603 One of the most important sources of environmental pollution is dye from industrial wastewater which is harmful for human health and environment. Therefore, the aim of this study was to evaluate removal of Methylene Blue (MB) dye from aqueous solutions by straw using ultrasonic wave with response surface methodology. The batch experiment was conducted to evaluate the effect of dye concentration, contact time, adsorbent dosage and pH on dye removal from aqueous solution. Response surface methodology was applied to appraise the effect of these different variables. The dye concentration in the solutions was measured by spectrophotometer at the wavelength of 664 nm. The results showed that the optimum parameter values for maximum color removal efficiency were: dye concentration 20 mg/L, reaction time 8 min, dose of adsorbent 4 g/L and pH=9. The Maximum and minimum dye removal were obtained 92.29 and 47.5 percent, respectively. Analysis of variances test showed that the quadratic model was the best model to explain the interaction of variables. Based on analysis of variance (ANOVA), the coefficient of determination value (R2 =0.9116) was high, showing that the experimental values fitted well with the predicted values. In addition, the statistical analysis of the results indicated that in the range studied, dose of adsorbent and pH had a significant effect on color removal efficiency. The Gibbs free energy and enthalpy data verified its spontaneous and endothermic nature. In addition, survey of pseudo first and second order kinetics models presented that the adsorption process was compatible to pseudo-second order kinetics equation.
Pulp and paper
Seyed Hassan Sharifi; nouredin Nazarnezhad
Abstract
To reuse recycled cellulosic fibers in paper production, contaminated particles and other impurities of the fibers can be greatly removed using a de-inking stage which is considered as a supplementary step in waste paper recycling technology. The effect of using ultrasonic pretreatment on the deinking ...
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To reuse recycled cellulosic fibers in paper production, contaminated particles and other impurities of the fibers can be greatly removed using a de-inking stage which is considered as a supplementary step in waste paper recycling technology. The effect of using ultrasonic pretreatment on the deinking of old newspapers was investigated utilizing the common conventional chemical method across this research work. Experimental design method was served to optimize the amount of ultrasonic bath temperature and sonication time. Therefore, 13 tests were designed using Response Surface Methodology (RSM) and Central Composite Design with Design Expert 7.0.0 Trial software. Ultrasonic bath temperature and sonication time at three different levels (1, 0 and 1+) and two axial points (α + and α-) were used as independent variables, and the optical and mechanical properties of handsheets were used as dependent variables. Response surfaces and contour plots were served to show the interaction between the independent variables and the response variable. ANOVA test showed that the quadratic model is the best model to explain the interaction among the studied variables. The predicted values of the obtained model had much conformity with the experimental results (R2=0.98). According to ANOVA results, it can be concluded that the effect of each of the variables on the optimal properties is significant and the ultrasonic time is the most effective factor on the response. According to the results, the proposed optimum conditions to achieve the highest amount of mechanical and optical properties (43.43) are the ultrasonic bath temperature 47 oC and the ultrasonic time of 31 min.
