• diatomite;
  • catalyst;
  • porous ceramics;
  • compressive strength;
  • humidity

This study examines potential waste diatomite and catalyst reuse to prepare water absorption and retain porous ceramics. The operating conditions are constant pressure (5 MPa), sintering temperature (1000–1270°C), sintering time (2 h), waste diatomite containing waste catalyst at different proportions (0–20%), respectively. The porous ceramic samples containing waste catalyst show low thermal conductivity properties (0.278–0.349 W/mK), probably owing to the more pores than those in the concrete (1.458 W/mK). Water release (t1/2 value) by the porous ceramic samples is decelerated by porous ceramic samples containing waste catalyst, due to the synergy effect of high water absorption by the waste catalyst and better than in the foamed glass material (4 h). Porous ceramic samples containing waste catalyst is highly promising for use in water absorption and retention applications. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 640–648, 2013