Preparation, Properties and Application of Homogeneous Polypropylene Cation Exchange Membrane

Electrodeionisation (EDI) is one of the most important methods for the separation and purification of heavy metal ions from wastewaters. Acrylic acid (AA) and butyl acrylate (BA) were grafted onto polypropylene nonwoven to prepare cation exchange membranes, which were used for EDI treatment of simulated Cu(II) wastewater. The effects of the ratio of two monomers, initiator and crosslinker on the microstructure, mechanical and electrochemical properties of the resultant homogeneous polypropylene membranes were investigated. The experimental results show that at the conditions of AA: BA = 2:1, BPO 3.75%, and PETA 7%, a grafting rate of over 240% is achieved with high IEC, low water permeability and good mechanical properties. However, too much crosslinking makes area resistance high. Compared to commercially available heterogeneous membrane, the resultant membranes have better Cu(II) separation, longer service life but lower current efficiency.