A novel composite membrane of fly ash/polyurethane and its performance in organic wastewater treatment

The cost, flux and rejection rate of the membrane are the main factors in the process of water reclamation and reuse. A new type of composite membrane can be prepared by using fly ash (FA) and polyurethane (PU). The structure and properties of composite membrane can be adjusted by the theory of pigment volume concentration (PVC) to treat wastewater containing methylene blue (MB). The morphology, FT-IR spectroscopy, wettability, diffusivity, flux and rejection rate of the composite membrane were studied. The results showed that when PVC was close to the critical pigment volume concentration (CPVC), the performances of the 3# (PVC = 40.03%) composite membrane, the mass ratio of FA to PU was 1.44: 1, were the best. The flux and rejection rate for MB solution of the 3# membrane were 66.52 L·m−2·h−1 and 96.77%, respectively. At the same time, there was no serious pollution on the membrane with a long-term application. In addition, several typical organic wastewaters were treated by this composite membrane. The rejection rates for organic pollutants such as Rhodamine B, phenol and actual industrial wastewater were 96.12%, 96.48%, and 97.58%, respectively. The sustainable technology for the recovery and reuse of water by using solid waste in wastewater treatment has good environmental and social benefits.