Preparation of ultrafine fibrous membrane with TiO2/Bi2SiO5 photocatalyst on eggshell and its degradation of organic dye under visible light

This is due to the fact that TiO2 has the wide energy gap and short life and its photocatalytic active only under ultraviolet light, and so its application is greatly limited. TiO2 can form a heterojunction if combined with other semiconductors to enhance its photocatalytic ability under visible light. In this study, a TiO2/Bi2SiO5 photocatalyst with n–n heterojunction was successfully synthesized by the sol–gel method and hydrothermal method. Eggshell waste has long been used as fertilizer to grow plants or food additives for livestock, or as an adsorbent in metal ions and organic dyes. Using eggshell as a carrier of photocatalyst can possibly reduce its cracking of the substrate. The photocatalyst was deposited on eggshell powder by solid state dispersion (SSD). It was analyzed for the adsorption and degradation of methylene blue by various compositions of the photocatalysts and eggshell powder under visible light. The results demonstrated that the ratio of TiO2/Bi2SiO5: eggshell powder at 1:1 could have the best removal ability. To better facilitate the recovery of the photocatalyst from the aqueous solution, we used the techniques of electrostatic spraying and electrospinning to prepare nylon 6,6 nanofiber membranes with various composite photocatalyst (TiO2/Bi2SiO5/Eggshell/Nylon 6,6 NFM). The nanofiber membrane degraded 98% of methylene blue after 30 min of dark adsorption and 1 h of visible light irradiation.