菠萝蜜果皮吸附亚甲基蓝的研究

以菠萝蜜果皮为原料,经粉碎制成粉末吸附剂。探究了菠萝蜜果皮吸附亚甲基蓝的性能。结果表明,在100 mL 100 mg/L的亚甲基蓝溶液中,菠萝蜜果皮最佳投加量为0.8 g,pH为5、温度为25 ℃、震荡时间为40 min。利用准一级、准二级动力学方程模拟菠萝蜜果皮吸附亚甲基蓝的动力学过程,利用Freundlich和Langmuir方程模拟其热力学行为。结果表明菠萝蜜果皮吸附亚甲基蓝的过程适合于准二级动力学、Freundlich模型。文中计算了焓变(ΔH0)、自由能(ΔG0)、熵变(ΔS0)等热力学参数,菠萝蜜果皮吸附亚甲基蓝的ΔG0小于0,ΔS0小于0、ΔH0小于0,说明菠萝蜜果皮吸附亚甲基蓝的过程是一个自发的趋于有序的放热过程。通过对吸附亚甲基蓝染料前后菠萝蜜果皮材料表面形貌进行分析,发现亚甲基蓝染料填充了菠萝蜜果皮表面的的空隙,导致吸附前后菠萝蜜的表面形貌发生了变化。

Study on Adsorptive Performance of Jackfruit Peel on Methylene Blue

This paper mainly focuses on the absorptive properties of Jackfruit Peel on methylene Blue. The raw jackfruit peel was prepared as adsorbent powder by crush. It showed that the optimal adsorption conditions in 100 mL 100 mg/L methylene solution were as follow:The dosage of jackfruit peel powder at 0.8 g was perfect condition with the pH5, the temperature 25 ℃,and the shaking time 40 minutes. The quasi-first-order and quasi-second-order kinetic equations were used to simulate the kinetics process of the adsorption of methylene blue on the jackfruit peel,and the Freundlich and Langmuir equations were used to simulated the thermodynamic behavior. The results also showed that the pseudo-second kinetic equation and the Freundlich equa-tion were suitable for describing of the whole adsorption process. The thermodynamic parameters of Gibbs free energy(ΔG^0), enthalpy(ΔH^0)and entropy change(ΔS^0)were calculated and results were as follow:In the process of Jackfruit Peel powder adsorption of methylene blue,the value of ΔG^0,ΔS^0,and ΔH^0 were kept as:ΔG^0<0,ΔH^0<0 and ΔS^0<0,which indicated that it was a spontaneous,orderly and exothermic process. The surface of the jackfruit peel were analyzed both before and after the process of adsorption. It found that the surface of the jackfruit peel was filled by methylene blue,which was resulted in the shape changing.