Hydration and bactericidal activity of nanometer- and micrometer-sized particles of rock salt-type Mg1-xCuxO oxides

Copper substitution together with nano-structuring are applied the aim to increase bactericidal performances of rocksalt-type MgO oxide. The partial magnesium ions Cu2+ has been successfully achieved in both micrometer- and nanometer-sized particles up 20 mol% increments 5 mol%. Microstructural analyses using Integral Breadth method revealed that thermal decomposition single source precursor Mg1-xCux(OH)2-2y(CO3)y.zH2O at 400 °C creates numerous defects 10–20 nm-sized Mg1-xCuxO thus obtained. These make surface nanoparticles highly reactive towards sorption water molecules, extent cubic cell a parameter as-prepared expands by +0.24% as soon exposed ambient air (60% RH). hydration liquid is based on conventional dissolution-precipitation mechanism. Particles few microns size dissolve all more slowly higher copper content only Mg(OH)2 starts precipitating after 3 h. In contrast, dissolution complete over h period suspension contains 4–12 Mg1-xCux(OH)2 Thereby, activity reported for depends speed which these precipitate first Only 10 cupric sufficient kill E. coli S. aureus kinetics faster reductions viability (6.5 Log10 2.7 Log10, respectively) than antibacterial agent CuO (4.7 2 under same conditions). EPR spin trapping study reveals “hydroxylated” Mg0.9Cu0.1O well Mg0.9Cu0.1(OH)2 produce spin-adducts toxic hydroxyl radicals their copper-free counterparts. rapid mass adsorption onto envelopes following precipitation ability Reactive Oxygen Species responsible exceptionally high measured course hydroxylation nanoparticles.