Efficient removal of oil pollutant via simultaneous adsorption and photocatalysis using La-N-TiO2-cellulose/SiO2 difunctional aerogel composite

摘要

Nano-TiO2 photocatalysts doped with La-N(La-N-TiO2) were prepared by solgel method. The La-N-TiO2 was loaded on the cellulose/SiO2 composite aerogel (La-N-TiO2-CSA). La-N-TiO2-CSA had both oil absorption and oil degradation functions under the sun. The static state water contact angle is up to 148 degrees close to superhydrophobic surface. An apparent decomposition rate of oil is 92%, which is much higher than 26% of pure TiO2. Under the visible light irradiation, the photocurrent density has increased by 50%. Characterization results show that LaONO3 was uniformly distributed in TiO2 crystal. Compared with pure TiO2, the UV-Vis DRS data showed the absorption band of La-N-TiO2 had extended to 441 nm. The La increased the valence band position and N lowered the conduction band position, which reduced the band gap of TiO2 from 3.59 to 2.81 eV. The formation of LaONO3 reduced carrier transfer resistance, and the migration rate and electron-hole separation efficiency were improved. The possible oil decomposition pathways were proposed.