Condicionador de solo baseado em nanocompósito: TPS/nanoargila

Abstract

Projections indicate continued population growth, increasing food demand and putting pressure on increasingly depleted arable land. Soil conditioners are a good alternative in the search for greater soil efficiency, aiming to increase its productivity to meet the growing global demand for food. In this sense, thermoplastic starch (TPS) presents interesting characteristics for this purpose, while nanoclay (NA) shows potential to reinforce its polymeric mesh, generating new properties. Thus, these low-cost materials were combined to develop optimized formulations of 3%, 5% and 7% (w/w) of NA to TPS. FTIR experiments demonstrate that structural modifications occurred in the material when the two components were mixed, with greater intensity in TPS/NA7%, being visible in the SEM images. The TPS/NA7% sample was the one that swollen the most to TPS, with emphasis on slightly acidic and neutral media, being 32%, 39% and 21% at pH's 5, 7 and 9, respectively. The TPS/NA7% sample also had the lowest solubility, mainly in slightly acidic and slightly basic media, 30%, 25.4% and 24.4% for the respective pH's 5, 7 and 9. The neutral pH of the nanocomposites can guarantee their use in a wide variety of soils. The cation exchange capacity (CEC) was also higher in the nanocomposites to TPS, with a higher value in TPS/NA7%, indicating greater availability of nutrients for the medium in which they were found. Showing such superiority, TPS/NA7% was subjected to further experiments. Thus, performance tests of leaching, biodegradability, microbial activity and planting show that TPS/NA7% is the composite that presents a better release of NPK ions, as well as a lower release of CO2 and proliferation of microorganisms, and a higher productivity in seedling growth, reducing the dormancy effect in seeds. Finally, the TPS/NA7% composite stood out from the others and showed a product that not only showed improvement in the physical-chemical properties of the soil, but also economic viability and sustainability. Thus, this work also contributed to more sustainable and efficient agricultural practices