From fruit waste to hydrogels for agricultural applications

Abstract

Here, we describe and assess a method for reusing specific food waste to make hydrogels, which can be employed to improve the efficacy of agrochemicals and water. It represents an approach for tackling current challenges, such as food waste, water management, and pesticide optimization. Depending on the formulation, the hydrogels were created by crosslinking pectin and starch with CaCl2 or sodium trimetaphosphate. FTIR and SEM were employed to investigate the methylation degree of the extracted pectin, as well as the surface morphology and interior structure of the hydrogels. The swelling behavior and water retention in sandy soil have been investigated. In addition to the hydrogels’ potential to control and reduce pesticide loss, the herbicide Picloram is a model compound. The results show that the hydrogels have important swelling, up to 300%, and a capacity to retain water, preserve, and increase the water content in sandy soil up to 12 days. Picloram experiments show that hydrogels can limit herbicide mobility for up to 30 days under controlled conditions. The conversion of food wastes to highly valuable materials is a promising approach to optimize the water consumption and the loss of agrochemicals regarding sustainable agriculture.