Co-activation of Martian regolith and hydrochar for enhanced water retention and water holding capacity

Abstract

With the goal of sustainable life on Mars, the importance of maximizing the use of all available materials has become crucial. One such method in which to utilize the available resources is through the synthesis of a carbon-rich, porous material, creating a material fit for a variety of essential applications such as water retention. This study improved the water retention properties of Martian regolith through co-activation with pine, a carbon-rich biomass. To enhance carbon porosity, biomass was first hydrothermally carbonized at 260°C, and combined with Martian regolith (0, 5, 10, 25, 50 % w/w) before being chemically co-activated using potassium hydroxide as an activation agent, for two hours, at 800 °C. The co-activated regolith samples were characterized to quantify surface porosity, morphology appearance analysis by scanning electron microscopy, crystallinity analysis by powder X-ray diffraction, and chemical composition analyses by proximate and ultimate analyses. The results highlight an increased surface porosity of 287 %, with a 50 % addition of hydrochar, and minimized water loss from 24 % to just 4 % as well as an increased water holding capacity of 16 % with an increase in Martian regolith from 50 % to 95 %.