二次回归正交旋转组合优化麦麸渣吸附铅离子(Pb^(2+))

Quadratic Rotation-Orthogonal Composite Experimental Design for the Optimization of Experimental Conditions for Pb^(2+) Adsorption by Wheat Bran Dietary Fiber

采用二次回归正交旋转组合设计方法对麦麸渣吸附Pb^(2+)条件进行优化,建立pH值(X_1)、温度(X_2)、时间(X_3)、质量浓度(X_4)、加入量(X_5)5个因素与吸附率Y的回归模型。在pH8、温度100℃、时间1h、Pb^(2+)质量浓度20mg/L、加入量1.6g/100mL条件下,麦麸渣对Pb^(2+)吸附率最高可达98.91%。麦麸渣对Pb^(2+)的吸附以单分子层的物理吸附为主,Freundlich吸附等温式能较好地描述其吸附热力学情况;麦麸渣对Pb^(2+)吸附先是快速吸附,吸附时间超过60min后为慢速吸附;麦麸渣对低质量浓度Pb^(2+)溶液的吸附效果好于活性炭。

Experimental conditions for the adsorption of Pb2＋ by wheat bran dietary fiber （WBDF） were optimized using a quadratic rotation-orthogonal composite experimental design. A regression model for adsorption rate （Y） as function of five independent variables including pH （X1）, temperature （X2）, time （X3）, Pb2＋ concentration （X4）, and adsorbent dose （X5） was established. Maximum adsorption rate （98.91%） was obtained when 1.6 g/100 mL of WBDF was added to 20 mg/L Pb2＋ solution （pH 8） and hold at 100℃ for 1 h. Single molecule layer absorption was dominant during the adsorption process. The adsorption thermodynamics of Pb2＋ could be well described using Freundlich isotherm equation. Moreover, the adsorption process was fast in the first 60 min and then slowed down. WBDF had better adsorption efficiency for Pb2＋ at low concentrations than activated carbon.