改性豆渣对酸性品红的吸附力学研究

Study on Adsorption Thermodynamics and Kinetics of Acid Fuchsin on Modified Soybean Dreg

通过环氧氯丙烷和二甲胺化学改性豆渣,SEM表征其结构,进而对改性豆渣吸附酸性品红的过程进行动力学与热力学的研究,并采用吸附等温模型对吸附过程进行拟合.结果表明,二级动力学方程能更好地描述改性豆渣对酸性品红的吸附过程(r=0.999,p<0.01),吸附速率常数k2随着温度的升高而增大,故温度升高有利于吸附的进行;Langmuir模型能很好地拟合改性豆渣对酸性品红的吸附过程(r=0.999,p<0.01),符合单分子层吸附理论,随着温度的升高,最大吸附量由217.39mg/g升高至303.03mg/g.热力学研究表明,改性豆渣吸附酸性品红是自发的、吸热的、熵增加的过程.

Soybean dreg was chemically modified with epichlorohydrin and dimethylamine and characterized with scanning electron microscopy (SEM).The kinetics and thermodynamics of adsorption of acid fuchsin on the modified soybean dreg were studied,and the adsorption process was fitted by adsorption isotherm models.The results indicated that the adsorption of acid fuchsin on modified soybean dreg followed the second-order kinetic model (r=0.9 9 9 ,p<0.0 1 )and the adsorption rate constant k2 increased with in-creasing temperature,indicating that high temperature favors the adsorption.The adsorption process could well be fitted by the Langmuir adsorption isotherm (r=0.999,p<0.01),which fitted with a mono-layer adsorption.The maximum adsorption capacity rose from 217.39 mg/g to 303.03 mg/g with increas-ing temperature.Thermodynamical study showed that the adsorption process was a spontaneous,endo-thermic and entropy-increasing process.