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.

Automated summary

In this study, a novel strategy for direct ink writing of porous SiC parts using geopolymers (GP) as binders and sintering SiC/GP composites at high temperatures via carbothermal reduction was reported. The results showed that porous SiC carriers with high porosity and hierarchical porous structure could be obtained by adjusting the treatment temperatures, which could be used for the removal of hazardous materials from wastewater.