Preparation, characterization and properties study of a superhydrophobic ceramic membrane based on fly ash

With the increasing demand for environmental protection, the recovery and reuse of fly ash has attracted more and more attention. In this paper, the fly ash based porous ceramic membrane is modified from hydrophilic to superhydrophobic successfully. Average contact angle and roll-off angle of the modified superhydrophobic fly ash based ceramic membrane are 151.3° and 11.3°, respectively. Additionally, a variety of performances of the prepared superhydrophobic fly ash based ceramic membrane are characterized. Dynamic process of droplets with different initial velocities impacting on the surface of superhydrophobic fly ash based ceramic membrane is photographed by high-speed camera. It is proved that dynamic process of droplet impacting on superhydrophobic surface includes spreading, retraction and partial rebound. Spreading, retraction and solid-liquid contact time of droplets are about 2.9 ms, 11.5 ms and 14.4 ms, respectively. The above data is almost unaffected by impact velocity of droplets. In addition, experiments show that the prepared superhydrophobic fly ash based ceramic membrane has good acid and alkali corrosion resistance, and self-cleaning performance. In this paper, superhydrophobic ceramic membrane prepared by fly ash shows excellent performance and it can provide guidance for the reuse of fly ash.