Synthesis and characterization of silver-loaded mesoporous alumina antibacterial agents by hydrothermal and adsorption methods

Abstract

In view of the compatibility between carriers of antimicrobial agents and ceramic glaze, mesoporous alumina was employed as the carrier of silver ions and silver-loaded mesoporous alumina was synthesized by hydrothermal and adsorption methods. The liquid medium microdilution method and the spread plate methods were studied to evaluate antimicrobial efficiency of silver-loaded mesoporous alumina. \(\hbox {N}_{2}\) adsorption/desorption, HRTEM images and low-angle X-ray diffraction experiment prove the existence of fine mesoporous structure of mesoporous alumina and silver-loaded mesoporous alumina. The chelation of ammonia can improve the adsorption capacity of silver nitrate on mesoporous alumina and adsorption capacity increases by 18 times in the presence of ammonia. The adsorption behaviour of silver nitrate can be described by a multilayer adsorption isotherm of BET and the adsorption principle of silver nitrate on mesoporous alumina is multilayer adsorption in the presence of ammonia. The surface area, pore volume and pore-size distribution of silver-loaded mesoporous alumina are obviously smaller than those of mesoporous alumina due to the blockage of channel by silver-ammonia complex. The antibacterial test results indicate that silver-loaded mesoporous alumina have favourable antibiotic property and MIC \(\le \) 240 \(\upmu \hbox {g}\) \(\hbox {ml}^{-1}\) against Escherichia coli, Staphylococcus aureus and Salmonella. The diameter of inhibition zone of silver-loaded mesoporous alumina is 26 mm against Escherichia coli, 24 mm against Staphylococcus aureus and 22 mm against Salmonella enterica.