Solar light responsive TiO2-ZnO, modified with graphitic carbon nitride nano-sheet for degradation of AB29

Abstract

BACKGROUND Photodegradation has drawn much attention in recent decades due to the technique’s ability to mineralize nonbiodegradable pollutants. Renewable energy sources, such as solar light energy, can be used to aid the reaction in the present of a solar light-responsive photocatalyst. Mixed metal oxides (TiO2-ZnO) modified with graphitic carbon nitride (gCNS-3TiZn) were synthesized successfully and employed for the degradation of AB29 under artificial solar light. Ultrasonication–hydrothermal treatment was used to develop gCNS-3TiZn.

RESULTS Surface analysis investigation showed that the material is mesoporous with 5 nm pore diameter and 195 m2 g–1 surface area. The optical analysis showed successful reduction in the band gap of the material, making it capable of efficiently absorbing light energy in the visible wave region. The developed gCNS-3TiZn was 3.33-fold faster at AB29 degradation than the unmodified mixed oxides under the same reaction conditions, and this was attributed to the reduction in band-gap energy of the catalyst resulting in a better absorption of solar light. It took 60 min to attain complete degradation of 50 ppm AB29 using 1.25 g L–1 gCNS-3TiZn loading, whereas the AB29 degradation by the unmodified catalyst under the same conditions took 200 min to attain complete degradation. Recyclability study on gCNS-3TiZn revealed that it can be used up to 10 cycles in the degradation of the selected pollutant without diminished performance.

CONCLUSION The synthesized photocatalyst is a potential candidate for real wastewater treatment due to its reusability, stability and ability to utilize solar light as renewable energy source.