wastewater treatment using nanocatalyst employing the photocatalysis mechanism has been discussed

1. Industrial wastewater treatment via
photocatalysis
Category: nanofiltration
Team name : innovations
Team ID : RA-0006
User ID: FP-0100

2. Index
1. Nanomaterials
2. Catalyst
3. Nanocatalyst
4. Wastewater treatment
5. Photocatalysis
6. Applications of ZnO
7. Parameters affecting the wastewater treatment
8. Conclusion
9. References

3. keyconcepts
Nanomaterials and its synthesis
Catalyst and its applications
Homogeneous vs heterogeneous catalyst along with mechanism

4. nanocatalyst
nanocatalyst are usually heterogeneous catalyst broken up into
metallic nanomaterial size in order to speed up the catalytic
process[2].

5. heterogeneous catalyst nanocatalyst homogeneous catalyst
excellent stability high activity high activity
easily accessible high selectivity high selectivity
easily separable excellent stability
demerits: easily separable demerits:
more reaction time energy efficient difficult in catalyst recovery
less catalytic activity
compared to homogeneous
economical

6. why nanocatalyst?
● it has combined advantages of homogeneous and
heterogeneous catalyst
● high surface to volume ratio
● high reactivity
● selective chemical transformation with high yield
● easily recoverable[1]

7. nanocatalyst : an emerging
technology
● Catalysis is old, nanocatalyst emerge since 1950s.
● Can be recovered easily
● an important both in academic as well as industrial research
and development[1].

8. potential benefits of nanocatalyst
● energy efficient
● minimum chemical waste
● super catalysts and reagents
● reduce global warming
● improved economy
● water remediation

9. Industrial wastewater
● wastewater discharged from industries to water stream has
become a major environmental issue.
● lack of availability of pure water resources
● deterioration of water resources.
● serious environmental threats
● The effluent contains wide range of chemicals.
● dyes - highly structured organic compounds
● difficult to be broken down biologically.

10. ● Experiments to reduce
● total suspended solids (TSS),
● chemical oxygen demand (COD),
● total dissolved solids (TDS) and turbidity.
● Coagulation and flocculation methods- effective
● But costlier
● Also generate high amount of mud

11. Conventional treatment methods
❖ Use of naturally available adsorbents like
● Natural clay
● Bagasse pith
● Maize cob
Etc.
❖ But this method have comparatively higher cost[4].

12. One such innovative idea………..
● Semiconductor nanoparticles having bandgap (< 3eV) can
easily get converted into holes and electrons.
● This combination pair is highly reactive in nature and can
degrade organic molecules into simpler inorganic molecules
like carbon dioxide and water.
● For e.g. ZnO, TiO2, Ag2CO3 , etc.
● It occurs via mechanism called photocatalysis.

13. Photocatalysis

14. For continuing the discussion let us actually begin with review of
this research paper!
Shamsa Al Sadi, Geetha Devi.M, Murtuza Ali SyedFeroz.S
and Varghese. M.J
Treatment of textile Industry Waste water using Solar photo
Catalysis
Research Journal of Chemical Sciences
ISSN 2231-606X Vol. 5(10), 20-27, October (2015)

15. Typical textile industry wastewater
composition in Oman.
Parameters Range of Values
pH 7-9
Biochemical Oxygen Demand (mg/L) 80 – 6,000
Chemical Oxygen Demand (mg/L) 150 – 12,000
Total Suspended Solids (mg/L) 15 – 8,000
Total Dissolved Solids (mg/L) 2,900 -3,100
Chloride (mg/L) 1000 – 1600
Total Kjeldahl Nitrogen (mg/L) 70 – 80
Colour (Pt-Co) 50-2500

16. Experimental setup
Photocatalytic experiments:
9 AM to 3 PM in the month of March - April.
maximum UV-index of 11 was selected for the solar radiation.
The first set of experiments was carried out with
1.5 litre of wastewater using ZnO catalyst coated reactor.
The discharge - re-circulated through the reactor system for a
period of 4 hours.

17. The samples were collected every 1 hour
filtered for further parametric analysis[4].
The schematic representation of the experimental set up is
shown in next slide

18. Experimental setup

19. Characteristics of pretreated Textile Mills
wastewater
Parameters (unit) Value
pH 8.71
Conductivity (µS) 4.847
TDS (ppm) 3.1
COD (ppm) 2780
TOC (ppm) 119.4
DO (ppm) 0.16
Turbidity (NTU) 26

20. Preparation of coating solution
● Coating solution:
● 2 g of chitosan powder was dissolved in 100 ml of 1% acetic
acid
● stirred until the polymer dissolved completely
● 0.2 g of ZnO catalyst added to the prepared solution
● stirred for 5 hours with constant heating at 60°C[4].

21. Justification of setup
● We can use ZnO nanoparticles suspended in wastewater
● Hence coating the surface with ZnO nanoparticles can
become an alternate and efficient solution.
● However, we can also apply carbon porous material as a
supporter to catalyst[5].

22. Reactions involved:
Photocatalysts (TiO2/ZnO) + hν→ e- + h+
h+ + H2O→ H+ + OH•
h+ + OH-→ OH•
e- + O2→O2
-
2e- + O2 + 2H+→H2O2
e- + H2O2→ OH• + OH-
Organic + •OH十O2→CO2+H2O+other degradation products

23. Now we will study various parameters
affecting the treatment:
● Temperature
● Concentration of dye
● Time provided for the reaction
● Variation of pH and TOC with time
● Also comparison between ZnO and TiO2

24. Effect of time provided for reaction[6]

25. Effect of temperature[6]

26. Variation of pH with time

27. Variation of TOC with time

28. Effect of concentration of dye[6]

29. shortcomings:
Photocorrosion of ZnO
difficulty in recovery of ZnO nanoparticles
Can’t take risk to remain suspended in water
harmness is still unknown.[4]

30. conclusion
Author finally concluded that ZnO is more reactive and efficient
compared to TiO2.
Also ZnO cost around 1Rs./gram
TiO2 cost around 300 Rs./gram.
Both TiO2 and ZnO have their merits and demerits.
a future of treating industrial wastewater in this era.

31. References:
[1] santosh bahadur singh, praveen k. Tandon
catalysis: a brief review on nano-catalyst
Journal of energy and chemical engineering Aug. 2014, Vol. 2
Iss. 3, PP. 106-115
[2] https://en.wikipedia.org/wiki/Nanomaterial-based_catalyst

32. [3] Leena V. Bora, Rajubhai K. Mewada
Visible/solar light active photocatalysts for organic effluent
treatment:Fundamentals, mechanisms and parametric review
Renewable and Sustainable Energy Reviews 76 (2017) 1393–
1421
[4] Shamsa Al Sadi, Geetha Devi.M, Murtuza Ali SyedFeroz.S
and Varghese. M.J.
Treatment of textile Industry Waste water using Solar photo
Catalysis
Research Journal of Chemical Sciences ISSN 2231-606X Vol.
5(10), 1-10, October (2015)

33. [5] KUNAL MONDAL, and ASHUTOSH SHARMA
Photocatalytic Oxidation of Pollutant Dyes in Wastewater by
TiO2 and ZnO nano-materials – A Mini-review
[6] FALAH H. HUSSEIN and THEKRA A. ABASS
SOLAR PHOTOLYSIS AND PHOTOCATALYTIC
TREATMENT OF TEXTILE INDUSTRIAL WASTEWATER
Int. J. Chem. Sci.: 8(3), 2010, 1409-1420

34. Thank you!
Any queries?