Enhanced mechanical strength and bactericidal activity of macro-porous Al2O3 ceramics through the introduction of Cu for membrane support application

Enhancing the mechanical strength of macro-porous ceramics and simultaneously endowing them with bactericidal activity are considered to be beneficial for their application as membrane support materials for water and wastewater treatment. In this study, Cu-containing Al2O3 porous ceramics were prepared by powder mixing, cold pressing and subsequent sintering. The microstructures of as-fabricated ceramics consisted of large alpha-Al2O3 particles as matrix, as well as inter-particle NaAlSiO4, CuAl2O4 and CuO phase. With increased sintering temperature from 1430 to 1560 degrees C, the proportion of band-shaped CuO phase, which exhibited stronger binding tendency with Al2O3 than NaAlSiO4, gradually increased, while that of particle-shaped CuAl2O4 phase decreased. Increasing the Cu content from 2 to 8 wt% at a fixed sintering temperature of 1500 degrees C resulted in the presence of more band-shaped CuO phase in Al2O3 matrix which tightly bonded Al2O3 particles together. The increase of sintering temperature and Cu content could both lead to enhanced bending strength and reduced porosity, while the later factor showed stronger modulatory effects than the former one. Moreover, the bactericidal rates of Cucontaining Al2O3 porous ceramics towards Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were found to increase with increased Cu content in a Cu content-dependent manner. Together, the Cu-containing Al2O3 porous ceramic added with 8 wt% Cu and sintered at 1500 degrees C exhibited the highest bending strength and strongest bactericidal activity, which could be a promising candidate material for membrane support application.

Automated summary

This study aimed to enhance the mechanical strength and bactericidal activity of macro-porous ceramics by incorporating copper. The results showed that increasing the sintering temperature and copper content led to improved bending strength and reduced porosity. The bactericidal activity against Escherichia coli and Staphylococcus aureus also increased with higher copper content. The Cu-containing Al2O3 porous ceramic with 8 wt% Cu and sintered at 1500 degrees C exhibited the highest performance.