Synthesis of bio-inspired porous silicon carbides using Cortaderia selloana and Equisetum arvense grasses as remarkable sulfur adsorbents

In this paper, we have studied on green synthesis of bio-inspired porous silicon carbides using two types of grasses. The outer layers of these grasses contain significant amounts of silica. Therefore, they were used as the sources of silica in these syntheses. Meanwhile, starch was used as a natural carbon source. For converting herbal precursors to the corresponding silicon carbides without losing their nanostructures, first the silica/starch composites were prepared with treatment of bio-silica with starch solution under ultrasound, then porous SiCs are synthesized at low temperature. Results show that using ultrasound treatment made good penetration of carbon source into the Si skeleton of grasses and can maintain the primitive structure of herbal precursor with their cellular pores, so the porous SiCs with high surface areas were obtained. Then, the synthesized porous SiCs applied as the adsorbents for removing sulfur in model fuel. The results showed that Equisetum-SiC sample achieved higher adsorption capacity of 35.5mgS/g (71% sulfur removal) due to its higher surface area and lower pore size. Also, these porous SiCs were demonstrated to be efficient and stable adsorbents for the removal of S-compounds in the order of DMDBT>DBT>BT.