This document discusses the removal of heavy metals from water using nano metal oxides. It introduces heavy metals as relatively high density metals that are toxic, like lead, arsenic, cadmium and mercury. Heavy metals accumulate in organisms and can be harmful. Nano metal oxides like ZnO are effective at removing heavy metals from water through adsorption and photocatalysis mechanisms involving the absorption of light and production of electron-hole pairs on the nanoparticle surface. This allows for the reduction of heavy metals or reaction with electron acceptors. Nano metal oxides provide an efficient and low-cost approach for heavy metal removal through these photocatalytic processes.

2. REMOVAL OF
HEAVY METAL BY
NANO METAL
OXIDE

3. Contents
 Introduction
 Effect of heavy metals
 Removal of heavy metals by nano metal oxide
 General mechanism
 conlusion

4. INTRODUICTION TO HEAVY METALS
 Metals with relatively high densities, atomic weights, or atomic
number.
 Most common heavy metal are leads (Pb), arsenic (As), cadmium
(Cd), and mercury (Hg).
 They are highly toxics

5. Why to remove heavy metals
 High demand of water due to increase in population
 High amount of waste water is generated
 They are non-biodegradable and have toxic effect
 They enter into the food chain
 They destablize the ecosystem

6. Effect of heavy metals
 Mercury can build up into the tissues of fishes and may
be harmful to people and other animals that eat them.
 Aluminum accumulate in the gills of fishes and cause
inhalation problem.
 On the accumulation of heavy metals plants
experiences oxidative stretch and cellular damage.

7. Removal of heavy metals by
nano metal oxide
 It is adsorption technique.
 Involve the mechanism of photo catalysis.
 Reduction by nano particles.
 Different metal oxides are used.

8. General mechanism
 Absorb the UV radiation from the sun and produced
the hole and electron pair
 Electron of VB become excited when illuminated by
light.
 Excess energy of this electron promoted them to
conduction band.
 Creation of negative electron and positive hole.

9.  Photo catalytic mechanism is initiated by absorption of photon (hv)
producing electrons and holes on the surface of nanoparticle
 Excited state electron and hole can-
1. Recombine and dissipate heat
2. React with electron donor and electron accepter

10. Photocatalysis

12. Photo catalysis by ZnO

14. Magnetic removal

15. ADVANTAGES
 Convenient approach for separating and removing
contaminants by applying external magnetic fields.
 High efficiency for absorption maintained even after
many absorption cycle
 High surface area
 Low cost

16. Limitation
 Corrosion of metal surface
 UV light is required

17. Conclusion
 Heavy metals are dangerous to health so they should
be remove from water .
 Nano technology is very efficient
 Nano metals are effective in the removal of heavy
metals by their photo catalytic action.

18. References
 M.jamil,M.S.Zia,M.Qasim,Contamination of agro-acho
system and human health hazards from waste water
used for irrigation ,J.Chem.Soc.Pak,32(2010)
 S.H .Peng,W.X.Wang ,X.D.Li,Y.F.Yen metal partitioning
in river sediments measured by sequential extraction
and biometic approaches,chemospheres 57 (2004)

19. THANKYOU