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1. Treatment Of Waste Water Using Photocatalysis TiO 2 Name-Mithun Jhodia Roll No-CH/10/23 M.Sc. 3 rd semester Dept. Of Chemistry Fakir Mohan University , Balasore

2. Outline Introduction Methodology Discussion Conclusion

3. According to the World Health Organization, more than two million people per year die of water-borne diseases, and one billion people lack access to a source of improved drinking water…

4. What is wastewater ? Water that has been utilized in some capacity that negatively impacts the quality of water. Sewage is a subset of wastewater that is contaminated with feces or urines.

5. Where does wastewater come from? Residences (kitchen, bathroom) Rainfall, Highway drainage Industrial institution

6. Important Contaminants Of Wastewater Treatment Nutrients (P, N2&C) Organic and inorganic compounds Refractory organics Heavy metals Dissolved inorganics

7. What is wastewater treatment? process of removing contaminants from wastewater, both runoff and domestic and making it suitable to discharge back into the environment. Municipal wastewater treatment Industrial wastewater treatment

8. Methods involved in wastewater treatment Wastewater Treatment Mechanical (Physical) Treatment Preliminary Primary Secondary (Biological) Treatment Tertiary (Chemical) Treatment by photocatalysis

9. History of Photocatalysis :- In 1967, professor Fujishima of the University of Tokyo first discovered the Photocatalysis by chance. In 1972, the discovery of Photocatalysis was published in British Science Journal Nature. In 1994, Dr. Ichinose of Saga Ceramics Research Laboratory succeeded in manufacturing water soluble titanium dioxide.

10. Among the many available techniques, Semi-Conductor Photocatalysis is gaining enormous interest in the field of environmental techniques it is because of….. Ambient condition for reaction Use of air as a source of oxygen for oxidation Abundantly available solar energy No Secondary Pollution

11. Why only Semi-conductors? Metals No Band Gap Only oxidation/reduction Non-Metals Wide Band Gap High energy requirement Semi-conductors Excited by UV/Visible light Suitable for redox reactions

12. How photocatalytic degradation (PCD) occur?

13. Mechanism of photocatalytic process: When photocatalyst titanium dioxide absorbs Ultra violet radiation from sun light or illuminated light source, it will produce a pair of electrons and holes. The electron of the valance band titanium dioxide becomes excited when illuminated by light.

14. The excess energy of this excited electron promoted the electron to the conduction band of titanium dioxide therefore creating the negative-electron(e-) and positive-hole(h+) pair. This stage is reffered to as the semiconductors photo-excited state. The energy difference between the valence band and conduction band is known as the “Band Gap”.

15. The positive-hole of titanium dioxide breaks apart the water molecule to form hydrogen gas and hydroxyl radical. The negative-electron reacts with oxygen molecule to form super oxide anion.This cycle continues when light is available.

16. Design Approach

17. Photoreactor during the experimental run

18. Results and discussion (Photocatalytic degradation of S 2 O 3 : Effect of UV light and TiO 2 )

19. Advantage Of TiO 2 TiO 2 is mostly used as a photocatalyst due to its: Provide greater Efficiency. Photochemical stability. Non-toxic in nature. Having low cost.

20. Conclusions Nanotechnology has applications in environmental protections. Nanoengineering can enable practical solutions to unmet needs . Solar light in place of UV light lamp can be used to reduce the pollutant

21. Thank You