Espumas sustentáveis de poliuretano incorporadas com diferentes cargas: adsorção de Cr(III) e SARS-CoV-2 em soluções aquosas

Abstract

Due to the contamination of water resources by the discharge of industrial, municipal, agricultural, and hospital wastewater containing heavy metals and pathogenic microorganisms, it is indispensable, to implement cost-effective, efficacious, and environmentally-friendly treatment procedures to eliminate these contaminants. In this sense, adsorption is an alternative, as it is considered to be effective in removing a variety of pollutants from aqueous media. The aim of this study was to synthesize and characterize polyurethane (PU) foams with added vegetable fillers for the adsorption of Cr(III) and SARS-CoV-2 in synthetic aqueous. To accomplish this objective, the foams were impregnated with commercial activated carbon (CAC) and vegetable biomass (derived from peach stone and its activated biochar). The results showed high percentages of SARS-CoV-2 removal, above 98%, for all the foams, and the presence of the fillers (peach stone and its activated biochar) in them enhanced the Cr(III) adsorption capacity. The Sips isotherm and Elovich kinetic models showed the best fit for Cr(III) adsorption, while the thermodynamic studies revealed that the adsorption process was endothermic, spontaneous, and favorable for Cr(III) adsorption for the foams with fillers. In addition, increasing the pH (4 – 6.5) increased the Cr(III) adsorption capacity of the foams, reaching maximum removal levels of 42.6% and 62.2% at pH 6.5, mass concentration 0.6 g L-1, for the foams containing the peach stone and its activated biochar. Moreover, the incorporation of fillers into polyurethane foams resulted in a reduction of their apparent density and an enhancement of their water absorption capacity. In short, this study provides relevant information on the potential use of functionalized polyurethane foams as a plant-based adsorbent for the removal of SARS-CoV-2 and Cr(III) from water. This work opens up space for the development of new research analyzing the removal capacity of other contaminants by the polyurethane foams mentioned above, as well as encouraging the use of agro-industrial waste, ensuring environmental sustainability.