响应曲面法优化MBfR中PVDF/pDOPA改性膜的表面改性条件

Optimization of PVDF/pDOPA Membrane Surface Modification by Response Surface Methodology for MBfR

膜生物膜反应器研究中,常用疏水性微孔膜存在氧传质性能、耐污染性能较差等问题,论文以课题组自制疏水性PVDF中空纤维膜为原膜,采用自聚合法以左旋多巴为单体对原膜进行表面改性,采用响应曲面法针对左旋多巴浓度、自聚合时间及热处理温度对于改性膜性能的影响进行系统研究,模拟得到改性膜氧传质性能参数K_(La)的二次回归方程模型,结果表明:最佳表面改性条件(L-DOPA质量浓度1.54 g/L、自聚合时间3.0 h、热处理温度37.0℃)下,改性膜K_(La)的实测结果(1.61×10^(-2 )min^(-1))与响应曲面拟合所得模型的预测值(1.60×10^(-2 )min^(-1))基本吻合,该模型可用于优化PVDF/p DOPA改性膜的表面改性条件。最佳表面改性条件下,PVDF/p DOPA改性膜与原膜机械性能相近,氧气传质性能显著优于原膜,K_(La)自原膜0.95×10^(-2 )min^(-1)提高至1.61×10^(-2 )min^(-1),为原膜的1.70倍,改性膜表面亲水性提高(接触角自原膜75.2°降至41.4°)。

Aiming at the insufficient oxygen supply capacity and poor antifouling properties of hydrophobic microporous membrane in membrane biofilm reactor（MBf R）,surface modified composite membrane was prepared by self-made hydrophobic PVDF hollow fiber membrane with self-polymerization of L-DOPA.The response surface methodology（RSM）was adopted to explore the influence of L-DOPA concentration,polymerization time and heat treatment temperature on modified composite membrane properties.Quadratic regression of oxygen mass transfer performance coefficient KLaof modified membrane was simulated.The results showed that,under the optimum conditions of surface modification（L-DOPA concentration,polymerization time and heat treatment temperature was 1.54 g/L,3.0 h and 37.0℃respectively）,the measured value of KLa of the modified membrane was 1.61×10^-2min^-1,which was in good agreement with the predicted value of 1.60×10^-2min^-1,the model could be used to optimize the surface modification of PVDF/p DOPA modified membrane.The PVDF/p DOPA modified membrane had similar mechanical strength compared with the original membrane,and its oxygen transfer coefficient K_（La）improved from 0.95×10^-2min^-1to 1.61×10^-2min^-1,1.70 times as much as the original.The surface hydrophilic of the modified membrane was improved（contact angle decreased from 75.4°to 41.4°）.