Controlled release of fertilizers from Ca(II)-alginate matrix modified by yerba mate (Ilex paraguariensis) waste

LENIN LLIVE; MERCEDES PERULLINI; PATRICIO R. SANTAGAPITA; SCHNEIDER-TEIXEIRA ALINE; DELADINO LORENA

EUROPEAN POLYMER JOURNAL

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2020

0014-3057

Yerba mate (Ilex paraguariensis) is an infusion traditionally drunk in many countries of SouthAmerica. Along its industrial manufacture, a fine yerba mate powder represents a considerableproportion of the total production, consisting of an industrial by-product not safe for humanconsumption, rich in minerals, that could be useful as organic compost. In line with currentbioeconomic trends, here we present the recycling of yerba mate industrial by-products into urea,potassium and phosphate-containing capsules as an environmentally friendly strategy for thedesign of controlled-release fertilizers. The capsule matrix is based on Ca(II)-alginate with a finalyerba mate powder (YMP) content of 83% w/w. The aim of this work was to study the kinetics ofmineral fertilizers release both in soil and water, along with an exhaustive macro andmicrostructural characterization (PIM, DSC, TGA, SEM-EDX, X ray scan tomography andSAXS) to allow the analysis of structure/function relationships. The encapsulation efficiency andrelease in water of phosphorous were affected, being significantly lower than urea and potassiumand releasing under different mechanism. Retention and degradation in soil was mainly related tocapsule structure, as well as their thermal properties. The incorporation of different fertilizerinduced structural changes in Ca(II)-alginate network as assessed by SAXS.