Characterization of polylactic acid films for food packaging as affected by dielectric barrier discharge atmospheric plasma

Dielectric barrier discharge (DBD) air plasma is a novel technique for in-package decontamination of food, but it has not been yet applied to the packaging material. Characterization of commercial polylactic acid (PLA) films was done after in-package DBD plasma treatment at different voltages and treatment times to evaluate its suitability as food packaging material. DBD plasma increased the roughness of PLA film mainly at the site in contact with high voltage electrode at both the voltage levels of 70 and 80 kV. DBD plasma treatments did not induce any change in the glass transition temperature, but significant increase in the initial degradation temperature and maximum degradation temperature was observed. DBD plasma treatment did not adversely affect the oxygen and water vapor permeability of PLA. A very limited overall migration was observed in different food simulants and was much below the regulatory limits. Industrial relevance: In-package DBD plasma is a novel and innovative approach for the decontamination of foods with potential industrial application. This paper assesses the suitability of PLA as food packaging material for cold plasma treatment. It characterizes the effect of DBD plasma on the packaging material when used for in-package decontamination of food. The work described in this research offers a promising alternative to classical methods used in fruit and vegetable industries where in-package DBD plasma can serve as an effective decontamination process and avoids any post-process recontamination or hazards from the package itself.

Post-combustion CO2 adsorption on activated carbons with different textural properties

Fixed bed CO2 adsorption tests were carried out in model flue-gas streams onto two commercial activated carbons, namely Filtrasorb 400 and Nuchar RGC30, at 303 K, 323 K and 353 K. Thermodynamic adsorption results highlighted that the presence of a narrower micropore size distribution with a prevailing contribution of very small pore diameters, observed for Filtrasorb 400, is a key factor in determining a higher CO2 capture capacity, mostly at low temperature. These experimental evidences were also corroborated by the higher value of the isosteric heat derived for Filtrasorb 400, testifying stronger interactions with CO2 molecules with respect to Nuchar RGC30. Dynamic adsorption results on the investigated sorbents highlighted the important role played by both a greater contribution of mesopores and the presence of wider micropores for Nuchar RGC30 in establishing faster capture kinetics with respect to Filtrasorb 400, in particular at 303 K. Furthermore, the modeling analysis of 15% CO2 breakthrough curves allowed identifying intraparticle diffusion as the rate-determining step of the process.