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Introduction: Colored compounds which often are toxic and carcinogen is one of the environmental pollutants. These pollutants should be removed prior than discharge to the environment. The aim of this study was the evaluation of maize tassel powder efficiency for the removal of Reactive Red 198 dye from synthetic textile wastewater. Materials & Methods: This experimental study was performed in laboratory scale by using of batch reactors. In this study, the effect of adsorbent dose, contact time, initial dye concentration and pH had been evaluated. Maximum adsorption wavelength (λmax) and the concentration of dye were determined by UV/Vis spectrophotometer. The adsorbent was prepared in laboratory condition and pulverized by standard ASTM sieves with the range of 40-60 mesh. The data were analyzed with Langmuir and Freundlich isotherm models. Results: The result showed that increasing of adsorbent dose led to increasing of the adsorption efficiency but adsorption efficiency was decreased with an elevation of pH from 3 to 9 and increasing of dye concentration from 25 to 50 mg/l. With increasing reaction time, adsorption efficiency increased and the most adsorption occurred in first 30 min of reaction. Obtained data were in good concordance with both Langmuir and Freundlich isotherm models. The adsorption kinetics followed the pseudo-second-order equation. Conclusion: Maize tassel powder is a natural and cheap adsorbent that can be used for the removal of contaminants in the environment.

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Introduction: Dyes have complicated structures, they are usually toxic and resistant to biological treatment and enter the environment through industrial waste streams. The aim of this study was to review the isotherm and kinetic adsorption studies of Reactive Blue 19 (RB19) dye onto Jujube stems powder from synthetic textile wastewater. Materials and Methods: This study was conducted in laboratory scale. Synthetic wastewater was prepared with dissolving RB19 in distilled water. The dye concentration was determined by using the UV/Vis spectrophotometer at 592 nm. In this study, we investigated the effects of initial dye concentration, pH, adsorbent dose and contact time. For better understanding of the adsorption process, the experimental data were analysed with Langmuir and Freundlich isotherm models and kinetic studies. Results: The results showed that removing RB19 dye with Jujube stems powder as a natural biosorbent had the best efficiency in alkaline condition (pH=10) and by increasing the pH from 3 to 10, the dye removal efficiency increased. By decreasing of initial dye concentration and increasing the time and adsorbent dose, dye removal efficiency increased. In this study, the best fit of the adsorption isotherm data was obtained using the Langmuir model. Kinetic analysis of our results showed that the results well fitted by pseudo-second-order reaction. Conclusion: We can conclude that Jujube stems powder could be used as a biosorbent for dye removal from aqueous solutions.

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Abstract

Introduction: Dyes are among the most hazardous chemicals in industrial wastesdue to their toxicity for aquaculture, reduction of light permeability, and in turn development of disorders in photosynthesis process. The current study aimed to investigate the efficiency of coral in removing red reactive 198 from textile dye wastewater was investigated.

Materials & Methods: In this experimental study, the adsorption process was completedperformed on a synthetic sample in a batch systemOptimal conditions was also performed on the real wastewater of Yazdbaf textile factory. The effects of such parameters as the pH, dye's concentration, contact time, sorbent's dose, and temperature were investigated, following this, adsorption isotherms were determined and then the process was examined kinetically and thermodynamically. Next, the study data was analyzed by SPSS (ver,21), EXCEL 2007, applying Pearson correlation coefficient.

Results: The optimal conditions in removing the dye included pH=3, an equilibrium contact time of 120 min, 25 mg/L of the dye's concentration, and 3g/100mg of the sorbent's initial value. Underthe optimal conditions, the dye's removal efficiency and the maximum adsorption capacity in the synthetic and real wastewater sample of Yazdbaf Company were 97.63%, 8.14 mg/g and 67.78%, 5mg/g respectively.The equilibrium data followed the Langmuir adsorption isotherm with a correlation coefficient of R²=0.96 and the adsorption's kinetics followed pseudo-second-order model with a correlation coefficient of 1 (R²=1). The thermodynamic investigations also indicated that the adsorption is of physical process an endothermic.

Conclusion: Asthe results revealed, the good performance of the coral sorbent in removing dyes in aquatic environments, enjoying suitable density, havingquick precipitation properties, not needing activation, and environmental safety of the process can encourage the efficiency of this adsorbent in treatment of dye-containing wastewaters.