Regenerable antimicrobial silica gel with quaternarized N-halamine

A novel regenerable antimicrobial silica gel was prepared by a dehydration between silanols of silica gel and hydrolyzed 3-chloropropyltrimethoxysilane, a quaternization between grafted hydrolyzed 3-chloropropyltrimethoxysilane and (5,5-dimethylhydantoinyl-3-ylethyl)-dimethylamine (DHEDA), and a chlorination of amide groups of DHEDA. The as-prepared antimicrobial silica gel was characterized by FT-IR and X-ray photoelectron spectroscopy. Antimicrobial tests showed that the as-prepared antimicrobial silica gel was capable of about a 6-log inactivation of Staphylococcus aureus and Escherichia coli O157:H7 within 10 min of contact. Interestingly, more than 2 × 10 4  CFU/mL of Escherichia coli O157:H7 could be almost inactivated under flowing water condition. Furthermore, the as-prepared antimicrobial silica gel exhibits good regenerability and storage stability.