Preparation of SiO2/g-C3N4 composite material by 3D printing and its treatment properties for wastewater containing dyes

Abstract

SiO2/g-C3N4 composite aerogel material with high specific surface area and porous structure was prepared by direct ink writing 3D printing. The micro morphology and porous structure of the material were characterized，and its adsorption and catalytic degradation properties for high concentration Rhodamine B（RhB） in wastewater were tested. The research results showed that the 3D-printed SiO2 aerogel has a specific surface area of 482.1 m2/g，a nano porous structure with a pore volume of 1.195 cm3/g，and a good adsorption performance for RhB. The porous structure of SiO2/g-C3N4 composite aerogel prepared by modifying with g-C3N4 had little change and maintained high adsorption performance，and the removal rate of RhB（100 mg/L） by 3D-printed composite under UV could reach more than 99%. After five cycles of testing，the removal rate of RhB by SiO2/g-C3N4 composite aerogel was still 92.98%，compared with 55.75% for 3D-printed SiO2 aerogel. According to the mechanism analysis，g-C3N4 in the composite could absorb light energy and generate photogenerated electron-hole pairs ，the electron-hole pairs could react with H2O and O2 to produce oxidizing active substances superoxide radicals，and finally participated in the photocatalytic oxidation and reduction reaction to catalyze the degradation of RhB macromolecules. The high specific surface area of the 3D printing structure realized the large reaction contact area between the catalyst and RhB，and improved the photocatalytic degradation efficiency and cycle stability of the composite.

Keywords

• 3d printing
• sio2/g-c3n4 composite aerogel
• adsorption
• degradation