氧化石墨烯制备过程优化及其吸附特性

Optimization of preparation process of graphene oxide and its adsorption properties

为了使改进的Hummers法制备氧化石墨烯(GO)的制备过程更容易控制,以反应温度、KMnO_(4)加入时间、KMnO_(4)全部加入后继续反应时间、超声时间为考察因素,亚甲基蓝(MB)的吸附容量为评价指标,在单因素实验基础上,利用响应曲面法对所制备的氧化石墨烯(CGO)的制备工艺进行优化,建立二次多项式回归模型。结果表明,多项式模型的四因素对MB去除效果的影响顺序为:反应温度>KMnO_(4)加入时间>超声时间>KMnO_(4)全部加入后继续反应的时间。最佳制备条件为反应温度25℃、KMnO_(4)加入时间113.25min、t为25min、超声时间6.21h,MB的吸附容量为150mg·g^(-1)。

In order to make the preparation of GO by the improved Hummers method control easily,based on the single-factor exper-iment,preparation process of graphene oxide(CGO)was optimized by response surface methodology(RSM).Reaction temperature,KMnO_(4)addition time,reaction time after all KMnO_(4)was added,and ultrasonic time were considered operational variables.The ad-sorption capacity of methylene blue(MB)was selected as a response value.The regression model of fiting quadratic polynomial was establelished.The results showed that the degree of influence of four factors on the adsorption capacity of methylene blue was:reac-tion temperature>KMnO_(4)addition time>ultrasonic time>the time of continuing reaction after all KMnO_(4)was added.The adsorption capacity was 150mg·g^(-1)at the optimized conditions when the reaction temperature was 25℃,theaddingtimeofKMnO_(4)was 113.25min,the reaction time after adding all KMn04 was 25min,and the ultrasonic time was 6.21h.The adsorption kinetic could be well simulated by Pseudo-second-order model.The adsorption isotherm was consistent with the Freundlich model and the adsorption was mainly controlled by physical adsorption.