Preparation of controlled nano-MgO and investigation of its bactericidal properties

Nano-Mg is a good bactericide but with strong alkalinity in water due to its rapid hydrolysis. To control its hydrolysis rate and keep its bactericidal properties, we synthesized nano-MgO microspheres using chitosan-alginate system in this study. The synthesized nano-MgO release-controlled microspheres (nMgO-RCM) were with 0.98-1.20 mm of particle sizes. Also, their embedding ratio and loading percentage was 63.52% and 12.27%, respectively. Based on the characterization results, nano-MgO was only observed on surface of the nMgO-RCM. Its release rate from the nMgO-RCM could be controlled by the chitosan-alginate system, and the observed rate constant (k(obs)) increased from 0.0289 h(-1) to 0.0358 h(-1) with the increment of the dosage from 10 mg L-1 to 80 mg L-1. Furthermore, the nMgO-RCM could maintain pH value lower than 8.5 and colony counts less than 20 CFU mL(-1) for at least 120 h. (C) 2012 Elsevier Ltd. All rights reserved.