Kinetics, Thermodynamics and Equilibrium Studies on Adsorption of Reactive Red ۱۹۸ from Textile Wastewater by Coral Limestone as a Natural Sorbent

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 ۱۹۸ 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, dyechr('۳۹')s concentration, contact time, sorbentchr('۳۹')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,۲۱), EXCEL ۲۰۰۷, applying Pearson correlation coefficient. Results: The optimal conditions in removing the dye included pH=۳, an equilibrium contact time of ۱۲۰ min, ۲۵ mg/L of the dyechr('۳۹')s concentration, and ۳g/۱۰۰mg of the sorbentchr('۳۹')s initial value. Underthe optimal conditions, the dyechr('۳۹')s removal efficiency and the maximum adsorption capacity in the synthetic and real wastewater sample of Yazdbaf Company were ۹۷.۶۳%, ۸.۱۴ mg/g and ۶۷.۷۸%, ۵mg/g respectively.The equilibrium data followed the Langmuir adsorption isotherm with a correlation coefficient of R۲=۰.۹۶ and the adsorptionchr('۳۹')s kinetics followed pseudo-second-order model with a correlation coefficient of ۱ (R۲=۱). 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.

کلیدواژه ها:

YAZDBAF factory ، Reactive Red ۱۹۸ ، Adsorption ، Coral Limestone ، Kinetics ، Thermodynamics