Preparation and antibacterial activity of Ag-loaded tobermorite derived from coal fly ash

Abstract

Antibacterial materials are increasingly important in inhibiting germs' spread. In this study, tobermorite, hydrothermally synthesized from coal fly ash, is used as an antibacterial material after loading Ag+. A maximum of 130.1 mg/g Ag+ was loaded in tobermorite under optimal conditions at 25 °C for 120 min based on the ion exchange of Na+ and Ca2+. This Ag-loaded tobermorite showed superior antibacterial performance for inhibiting Escherichia coli (E. coli), and Staphylococcus aureus (S. aureus). It inhibited E. coli and S. aureus up to 15.4 mm and 16.5 mm, respectively, and the corresponding inhibition circle diameter remained at 13.9 mm and 14.1 mm, after 30 days. Besides, the minimum inhibitory concentration (MIC) for both bacteria was stable at 150 mg/L and 125 mg/L, respectively, and the minimum bactericidal concentration (MBC) was 250 mg/L and 200 mg/L, respectively. Accordingly, this Ag-loaded tobermorite was of high antibacterial activity and slow Ag+ release rate, which is expected to be used as antibacterial decorative material for public health protection with potential application prospects.