Abstract ZnO-NPs can be obtained through various methods, resulting in nanoparticles with different size and morphology, which directly influences their antimicrobial potential. The objective of this work was to evaluate the antibacterial activity of ZnO-NPs obtained by a solochemical process against important human foodborne pathogens: Staphylococcus aureus, Salmonella Typhimurium, Bacillus cereus and Pseudomonas aeruginosa. ZnO-NPs were identified as nanorods with the length between 90.1 and 100 nm (10.5 % frequency), the diameter between 80.1 and 90 nm (21 % frequency), and wurtzite type crystalline structure. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were equal to 0.05 mg mL-1 and 0.5 mg mL-1 for S. aureus and S. Typhimurium, respectively, lower than previous results related in the literature. ZnO-NPs produced by solochemical method had a superior antibacterial activity. For instance, they can be incorporated in packaging materials for increasing microbial safety and food shelf-life by inhibiting bacterial growth.

The quaternary chitosan was synthesized by reaction of chitosan with glycidyl trimethylammonium chloride. it was characterized by infrared spectra and conductometric titration. Adsorption of reactive blue 4 (RB4) and reactive red 120 (RR120) by quaternary chitosan was studied from aqueous medium. Two kinetic adsorption models were tested: pseudo first-order and pseudo second-order. The experimental data best fitted the pseudo second-order model. The Langmuir isotherm model provided the best fit to the equilibrium data in the concentration range investigated and the maximum adsorption capacity determined was 415 mg (RR120) and 637 mg (RB4) of reactive dye per gram of adsorbent.

Glass-ceramic materials can be produced by the addition of LiO2 to fly ashes disposible in Southern Brazil. These glass-ceramics are based on the Al2O3-SiO2-Li 2O system. The high viscosity of the obtained glasses, however, makes forming useful articles with these materials difficult. In this study we investigate the effect of adding low cost Na2CO3 on the melt viscosity and on the nature of the developed crystalline phases. It was intended that the ultimate crystalline phase (LiAlSi3O8) should not be altered. With additions up to 3 wt. % Na2CO3, the viscosity was apparently lowered and no new crystalline phase were detected.