Direct ink writing of porous SiC ceramics with geopolymer as binder

We herein report a novel strategy for direct ink writing of porous SiC parts by using geopolymers (GP) as binders and sintering SiC/GP composites at high temperatures via carbothermal reduction. The effects of treatment temperatures on the microstructure, pore size distribution and compressive strength of SiC/GP composites were systematically investigated. The total porosity of porous SiC carriers was as high as 76.4 vol% after being sintered at 1800 degrees C and exhibited a much broader pore size distribution (pore volumes) between 39 nm and 13.951 mu m (-1.68 mL/g) accompanied by an interconnected hierarchical porous structure. After loading lamellar graphene oxide into the porous SiC carrier to form GO/SiC adsorbents, they exhibited fast and near-unity removal of methylene blue, and the adsorption efficiency still exceeded 82.0% after multiple times usage. These results prove that it is possible to remove hazardous materials from wastewater using reusable porous SiC ceramics as reusable adsorbent carriers.