摘要
[Objective] The research aimed to study the adsorption characteristics of the Helianthus tuberosus stems to methylene blue in water. [Method] The optimum condition, adsorption thermodynamic and kinetic characteristics were studied on the methylene blue adsorbed by Helianthus tuberosus stems. [ Result] The equilibrium process was described well by the Langmuir isotherm model. The thermodynamics parameters were enthalpy changes （△H） of -12.147 kJ/mol, Gibb＇S free energy changes （△G） of -25.75 k J/reel, and entropy changes （△S） of 47.21 J/（mol · K）, respectively, at 288 K, indicating that the adsorption thermodynamic of methylene blue adsorbed by helianthus tuberoses stems was a spontaneous and exothermic process. The kinetics of the interactions showed better agreement with the Lagergren second order kinetics. The apparent activation energy （Ea） of adsorption process was 271.7 kJ/mol. [ Conclusion] This study provided the theoretical basis for the development and utilization of low-cost agricultural wastes to remove the hazardous substances in industrial wastewater.
[Objective] The research aimed to study the adsorption characteristics of the Helianthus tuberosus stems to methylene blue in water. [Method] The optimum condition, adsorption thermodynamic and kinetic characteristics were studied on the methylene blue adsorbed by Helianthus tuberosus stems. [ Result] The equilibrium process was described well by the Langmuir isotherm model. The thermodynamics parameters were enthalpy changes （△H） of -12.147 kJ/mol, Gibb＇S free energy changes （△G） of -25.75 k J/reel, and entropy changes （△S） of 47.21 J/（mol · K）, respectively, at 288 K, indicating that the adsorption thermodynamic of methylene blue adsorbed by helianthus tuberoses stems was a spontaneous and exothermic process. The kinetics of the interactions showed better agreement with the Lagergren second order kinetics. The apparent activation energy （Ea） of adsorption process was 271.7 kJ/mol. [ Conclusion] This study provided the theoretical basis for the development and utilization of low-cost agricultural wastes to remove the hazardous substances in industrial wastewater.
基金
Supported by the National Training Programs of Innovation and Entrepreneurship for Undergraduates(201210719011)
the Key Program of Natural Science Foundation of Yan'an University(YDZ2012-09)
