Preparation and Adsorption Performance of Fly Ash Based Porous Ceramics

Abstract: The effective utilization of fly ash based porous ceramics can not only reduce the pollution of fly ash to the environment but also show high application value in wastewater treatment and other fields. In this paper, porous ceramics with excellent performance were prepared by direct molding sintering method with fly ash as the main raw material, bentonite as the binder and activated carbon as the pore forming agent. The effects of sintering temperature and activated carbon amount on the structures and properties of porous ceramics were studied. The results show that sintering fly ash and bentonite forms the porous ceramic skeleton, oxidized activated carbon forms the pores, and porous ceramics are formed under their synergetic effects. At the same time, with the increase of sintering temperature and the decrease of activated carbon amount, the apparent porosity and water absorption decrease, the bulk density and compressive strength increase. When the sintering temperature is 1 100 ℃ and the amount of the activated carbon is 60% (mass fraction), the prepared porous ceramics with good comprehensive performance can be prepared. Its apparent porosity is 61.75%, bulk density is 0.93 g·cm^-3, water absorption is 63.48%, compressive strength is 4.29 MPa. Moreover, its removal rate is 98.4% and the saturated adsorption capacity is 45.79 mg·g^-1 in the Pb²⁺ solution of 100 mg·L^-1.

Key words: fly ash, activated carbon, porous ceramics, Pb²⁺, removal rate, adsorption capacity