Modulating the bactericidal activity and corrosion resistance of Al2O3 porous ceramics through Cu and Fe co-introduction for membrane support application

Abstract

Ceramic membrane-based filtration is perceived as an energy-saving and chemical-less solution to the wastewater problem. In this work, Cu- and/or Fe-containing Al2O3 porous ceramics were fabricated by powder metallurgy, with Cu and Fe introduction for bactericidal functionalization and Cu stabilization, respectively. The Cu- and Fe-free Al2O3 porous ceramics were composed of irregular α- Al2O3 particles and inter-particle NaAlSiO4 phase. The introduction of Cu resulted in the formation of band-shaped CuO and particle-shaped CuAl2O4 spinel phase in Al2O3 matrix. Further introducing Fe into Cu-containing Al2O3 increased the fraction of particle-shaped CuM2O4 (M=Al/Fe) spinel phase, while decreased that of band-shaped CuO. Without Cu incorporation, Fe reacted with Al2O3 to form Al3Fe5O12 phase. The introduction of Cu resulted in increased linear shrinkage and bending strength, while decreased porosity of Al2O3 porous ceramics. However, the effects of Fe were the opposite. The Cu-containing Al2O3 ceramics exhibited excellent bactericidal activity, but poor acidic corrosion resistance. The co-introduction of Cu and Fe enhanced the acidic corrosion resistance due to Cu stabilization from CuO to spinel phase, while compromised the bactericidal activity to some extent. Together, the results indicate that Cu- and Fe-containing Al2O3 porous ceramics are promising candidate materials for ceramic membrane support application.