Application of Grey Relational Analysis to the Preparation of Porous Ceramic Dynamic Membrane

This paper deals with optimizing the preparation process of the precoated dynamic membrane (PDM) by grey relational analysis (GRA) method. Various operation parameters which can affect the separate characteristics of the membrane were considered, such as trans-membrane pressure, dipping time, crossflow velocity and kaolin suspension concentration. With GRA, the degree of influence that the controllable process factors (dipping time, crossflow velocity, trans-membrane pressure and kaolin suspension concentration) exert on the indicators can be concluded as follows: crossflow velocity > trans-membrane pressure > kaolin suspension concentration > dipping time. The optimum process parameters to obtain the highest COD removal rate of printing wastewater are also found. The best factor combination is as follows: dipping time is 15 min; crossflow velocity is 0.75 m/s; trans-membrane pressure is 0.2 MPa; kaolin suspension concentration is 0.5 g/L.