Immobilizing nitrifying bacteria with Fe₂O₃‐CaO‐SiO₂ porous glass‐ceramics

Abstract

Nitrifying bacteria immobilized on Fe 2 O 3 -CaO-SiO 2 porous glass-ceramics have extensive application prospects for wastewater treatment. To study the effect of the pore structure on the immobilization, Fe 2 O 3 -CaO-SiO 2 porous glass-ceramics with different porosities and pore sizes were prepared by sintering and the addition of pore-forming agent. The pore size and apparent porosity can be controlled by the pore-forming agent content and their sizes. Appropriate amount of the pore-forming agent can promote the apparent porosity and increase the amount of immobilized nitrifying bacteria. The excess of the pore-forming agent can cause the formation of the new crystalline phases and reduce the amount of immobilized nitrifying bacteria. In this study, we demonstrate that Fe 2 O 3 -CaO-SiO 2 porous glass-ceramics with 30% pore-forming agent exhibit a moderate apparent porosity and good immobilization. This combination has good application prospects in the field of ammonia treatment in wastewater. K E Y W O R D Smicroorganism immobilization, nitrifying bacteria, pore-forming agent, porous glass-ceramics