Active packaging for reducing surrounding ethylene of climacteric produce is becoming more widespread in the global market. Their practical use requires shaping porous materials to confer mechanical strength, structural integrity, and improved handling properties. For this reason, powder materials and composites were studied to determine the evolution of the structure with the chemical composition and its influence on the adsorptive mechanisms. A zeolite NaA and an Ag+/Zn2+-exchanged A were synthesized to provide biocidal and ethylene-scavenging properties. The NaA and exchanged-A were shaped by moulding process using a matrix of poly (lactic acid) to produce a biocomposite leading to a composite with a porous structure in the macro scale with different interphases zeolite/polymer. The zeolite NaA was in close contact with the polymer while the formation of metal and oxide nanoparticles in exchanged-zeolite induced well-defined interphases evidencing a repulsive interaction between the polymer and the crystals.
Powder materials exhibited the highest adsorption capacity. In NaA, physisorption was the primary adsorption mechanism, whereas in exchanged-A, chemisorption played a significant role. NaA is advantageous for recyclability due to the weak bonding of C2H4, allowing for easier regeneration. In contrast, exchanged zeolite demonstrated enhanced sensitivity for scavenging trace amounts of C2H4. The biocomposite containing exchanged-A displayed a distinct behavior, where chemisorption became the dominant adsorption mechanism.
Andrea M. Pereyra, M Sergio Moreno, Cristian M. Piqueras, J. Alejandro Ávila Ramírez