Subject : Chemical Engineering Project. bachelor degree of chemical engineering This project aims to study the efficiency of Eliminate Escherichia coli (E.Coli) bacteria by using the Photocatalytic Sterilization of titanium dioxide (TiO2) and silicon dioxide (SiO2) with different proportions In this project, the experiments were divided into 2 experiments, which were the experiment using the Degradation of Methylene blue method and the E.Coli eradication experiment using culture medium. solid culture and 3M Petrifilm E.Coli count plates to measure results and also invent a prototype (Prototype).

1. Disinfection of E.coli using Photocatalytic Sterilization
of TiO2 and SiO2 films coated on polyethylene sheet
Presented by
Thiwa Wadprom
Thanyarath Nueangchamnong
Adviser : Dr. Supunnee Junpirom
School of Chemical Engineering,
Institute of Engineering,
Suranaree University of Technology
1

2. • Motivation
• Introduction and Theory
• Objective
• Experiment
• Result and Discussion
• Conclusion and Suggestion
2/25

3. • 700 species of bacteria in your mouth and teeth
• Bacteria in oral cavity
• Oral health problems
3/25
https://www.facebook.com/bookup.asia/posts/229473433908908?pnref=story
https://www.adentalsolution.com/blog/is-sugar-free-gum-bad-for-your-teeth/

4. The 60–90% of school children and nearly
100% of adults have dental cavities.
Severe periodontal (gum) disease, which may
result in tooth loss, is found in 15–20% of middle-
aged (35-44 years) adults.
Globally, about 30% of people aged 65–74 have
no natural teeth.
Higher among poor and disadvantaged population groups.
4/25
2014
http://www.who.int/publications/en/

5. 5/25
The 60–90% of school children and nearly 100% of
adults have dental cavities.
Severe periodontal (gum) disease, which may result in
tooth loss, is found in 15–20% of middle-aged (35-44
years) adults.
Globally, about 30% of people aged 65–74 have no
natural teeth.
Higher among poor and disadvantaged population
groups.
The most common oral diseases are dental
cavities is
• Periodontal (gum) disease
• Oral Cancer
• Oral Infectious diseases
• Trauma from injuries
2014
http://www.who.int/publications/en/

6. https://www.google.com/patents/US6902397
https://www.youtube.com/watch?v=tgyCb-CGrJA&feature=youtu.be 6/25
6

7. • E. coli (Escherichia coli)
• Worldwide used in biological test
• Caused to diseases
7/25
7

8. Method of
sterilization/Disinfection
Physical
Sunlight Heat
Dry heat
Red heat
Flaming
Incineration
Hot air oven
Infra red
Moist heat
Below 100°C
At 100°C
Above 100°C
Vibration Radiation
Non-Ionizing Ionizing
Electromagnetic
Particulate
Filtration
Earthenware
Asbestos
Sintered glass
Membrane
Chemical
Liquid
Alcohols
Aldehydes
Phenolic
Halogen
Heavy metal
Surface active
agent
Dyes
Gaseous
Peroxide
Plasma
Formaldehyde
• Types of sterilization
8/25
8

9. • Photocatalytic mechanism of TiO₂
9/25
Removal of Air Pollutants by Photocatalytic Process Using TiO2-SiO2 Coated Dan-Kwian Pottery.
Mr. Rachanon Klondon
)
e
(h
TiO
h
TiO CB
VB
2
2




 
TiO2 surface
UV light
Electron
Energy
excitation
recombination
VB
CB
TiO2 surface
h
v
≥
E
g
h
v
<
E
g
UV
e-
h+
O2
O2
-
OH- or H2O
OH• and H+
Reduction:
Oxidation:
VB = Valence band
CB = Conduction band




 (ads)
VB
(ads) OH
h
OH





 H
OH
h
O
H (ads)
VB
2



 2(ads)
CB
2(ads) O
e
O
2
2
2
2
2 O
2OH
O
H
O
2H
2O 


 





 OH
OH
e
O
H -
CB
2
2
heat
)
e
(h
TiO CB
VB
2 
 

e- : electrum in conduction band
h+ : hole in valance band
O-
2 : Superoxide anions
OH- : Hydroxide ion
OH• : Hydroxyl radical
H+ : Hydrogen ion

10. • Photocatalytic Process e.g. Photocatalytic of TiO₂
10/25
TiO₂
TiO₂ adsorbs UV Destroy germ
cells
Harmless
H₂O
H₂O
H₂O
CO₂
H₂O and CO₂
released
CO₂
CO₂
Strong oxidizing
agent is produced
OH•
O -
2
H₂O₂
OH•
Germ Cells
H₂O₂
H₂O₂
O -
2

11. • General properties of TiO2
11/25
1. Large surface area
2. Generate superoxide anions radical (O2
−) and hydroxyl radicals (OH•)
3. Semi conductor, Cheap, Non-toxic
4. Pure phase titanium dioxide nanoparticles : Anatase, Rutile, Brookite
Anatase Rutile Brookite
Titanium Dioxide powder

12. • General properties of SiO2
1. Also known as silica.
2. Most commonly found in nature as quartz and in various living organisms.
3. Semi conductor, Cheap, Non-toxic.
4. To improve efficiency for photocatalytic process
Silicon Dioxide powder Silicon Dioxide quartz
12/25
12

13. • Procedure
Titanium
Dioxide
Silicon Dioxide
Catalyst Results
Coated on PE sheet Prototype
Rise husk
Sol-Gel Method
Characterization
XRD
Bacteria
Testing
E.Coli
13/25

14. • SiO₂ Preparation
Rice husk
Impregnating in acid 2.5 hr.
Washing by water
Drying in oven 100ºC 24 hr.
Rice Husk
Burning at 600ºC 2 hr.
Silicon dioxide powders
Mixing with TiO2
14/25
14

15. Titanium (IV) n-butoxide + Ethanol absolute
Gel
Drying in oven 110ºC 12 hr.
Mixing
Calcination at 600ºC 6 hr.
Titanium dioxide powders
HNO3 +
DI water +
Ethanol absolute
Silicon dioxide
powders
Titanium dioxide
coated on Silicon
dioxide powders
Characterization
Solution A
Solution B
X %w/w
TiO2 : SiO2
• TiO₂ Preparation by Sol-Gel method
15/25

16. • Ratios of TiO₂ : SiO₂
16/25
No. sample test Ratio ( TiO₂ : SiO₂ )
1 Control : none
2 Pure TiO₂
3 1:1
4 1:2
5 1:3

17. • Bacteria Testing
TiO2
SiO2
• Assumption
• Isothermal, Isobaric, Perfect mixed
• Condition
• Dark zone
• 0.1 %wt. of catalyst
• 10 ml. of solution
• 10 min. UV-light
UV Lamp
culture medium
3M™ Petrifilm™ E. coli/Coliform Count Plates
• Dropping 100 μL of E.coli in LB at
initial condition = 106 CFU/ml in
solution
• Serial dilution to 10-5 and 10-6 time.
• Take a sample.
E.Coli
https://th.wikipedia.org/wiki
http://il-biosystems.com/dk/microbiology/3mtm-petrifilmtm/3mtm-petrifilmtm-ecolicoliform-count-plates/ 17/25
17

18. UV-VIS Spectrophotometer
• Methylene Blue Testing
• Assumption
• Isothermal, Isobaric,
Perfect mixed
• Condition
• Dark zone
• 0.1 %wt. of catalyst
• 10 ml. of solution
• 10 min. UV-light
• 0.01mg MB/L is initial
concentration
UV Lamp
TiO2
SiO2
Methylene blue
18/25
18

19. • XRD Pattern
10 15 20 25 30 35 40 45
2Thata Scale
1:1 1:2 1:3
Standard pattern of Anatase phase
Standard pattern of Rutile phase
• At 1:1 anatase phase more than
another ratio
• Anatase phase will decrease when
increase SiO₂
• Rutile phase will increase when
increase SiO₂
19/25
3017
870
2927
1337
2127
4378
19

20. sample
no.
ratio
wave
length (nm)
Adsorption %Degradation
1 MB 662 3.337 0.00%
2 pure TiO₂ 662 1.003 69.94%
3 1:1 648 0.057 98.29%
4 1:2 612 0.081 97.57%
5 1:3 657 0.098 97.06%
• Degradation of Methylene blue
• 1 : 1 the best result.
• 1 : 1, 1:2, 1:3 the same result.
• SiO₂ can improve photocatalytic process.
• Use TiO2 : SiO₂ at 1:1 is enough for improve
photocatalytic process.
20/25
Where
Ani = Adsorption at previous ration
AMB = Adsorption of Methylene Blue

21. sample
no.
ratio
wave
length (nm)
Adsorption %Degradation
1 MB 662 3.337 0.00%
2 pure TiO₂ 662 1.003 69.94%
3 1:1 648 0.057 98.29%
4 1:2 612 0.081 97.57%
5 1:3 657 0.098 97.06%
• Degradation of Methylene blue
• 1 : 1 the best result.
• 1 : 1, 1:2, 1:3 the same result.
• SiO₂ can improve photocatalytic process.
• Use TiO2 : SiO₂ at 1:1 is enough for improve
photocatalytic process.
21/25
Where
Ani = Adsorption at previous ration
AMB = Adsorption of Methylene Blue
MB none 1:1 1:2 1:3
0.00%
69.94%
98.29% 97.57% 97.06%
MB pure TiO2 1:1 1:2 1:3
%Degradation
Ratio
% Degradation of methylene Blue

22. E.Coli = 5 CFU/ml
How to count amount of E.Coli by using culture medium
E.Coli = Contaminate
22/25
• E.Coli disinfection measure by culture medium

23. Ratio
No. of E.Coli (CFU/ml)
% degradation
Run 1 Run 2 Average
None 6 5 5.5 0.00%
Pure 4 5 4.5 18.18%
1:1 0 0 0 100.00%
1:2 3 3 3 45.45%
1:3 4 6 5 9.09%
Ratio
No. of E.Coli (CFU/ml)
% degradation
Run 1 Run 2 Average
None 0 4 2 0.00%
Pure 6 con con con
1:1 0 0 0 100.00%
1:2 1 0 0.5 75.00%
1:3 2 1 1.5 25.00%
• E.Coli disinfection measure by culture medium
• At concentration 10-5 CFU/ml • At concentration 10-6 CFU/ml
Where
Ani = Average amount of E.Coli at previous ratio
AMB = Average amount of E.Coli at initial concentration
21/25

24. Ratio
No. of E.Coli (CFU/ml)
% degradation
Run 1 Run 2 Average
None 6 5 5.5 0.00%
Pure 4 5 4.5 18.18%
1:1 0 0 0 100.00%
1:2 3 3 3 45.45%
1:3 4 6 5 9.09%
Ratio
No. of E.Coli (CFU/ml)
% degradation
Run 1 Run 2 Average
None 0 4 2 0.00%
Pure 6 con con con
1:1 0 0 0 100.00%
1:2 1 0 0.5 75.00%
1:3 2 1 1.5 25.00%
• E.Coli disinfection measure by culture medium
• At concentration 10-5 CFU/ml • At concentration 10-6 CFU/ml
Where
Ani = Average amount of E.Coli at previous ratio
AMB = Average amount of E.Coli at initial concentration
0.00% 18.18%
100.00%
45.45%
9.09%
None Pure 1:1 1:2 1:3
%Degradation
Ratio
concentration at 10-5 CFU/ml
21/25
0.00% contaminate
100.00%
75.00%
25.00%
None Pure 1:1 1:2 1:3
%Degradation
Ratio
concentration at 10-6 CFU/ml

25. How to count amount of E.Coli by using 3M Petrifilm E.Coli count plates.
547 CFU/ml
Example at TiO2:SiO2 = 1:1 Example at none cat.
1,102 CFU/ml
25/25
• E.Coli disinfection measure by 3M Petrifilm E.Coli count plates.

26. Ratio
No. of E.Coli (CFU/ml)
% degradation
Run 1 Run 2 average
None 1102 1090 1096.0 0.00%
Pure 785 703 744.0 32.12%
1:1 547 512 529.5 51.69%
1:2 635 616 625.5 42.93%
1:3 764 751 757.5 30.89%
• At TiO2 : SiO2 at 1 : 1 , generated the most
oxidizing agent
26/25
Where
Ani = Average amount of E.Coli at previous ratio
AMB = Average amount of E.Coli at initial concentration
• E.Coli disinfection measure by 3M Petrifilm E.Coli count plates.

27. Ratio
No. of E.Coli (CFU/ml)
% degradation
Run 1 Run 2 average
None 1102 1090 1096.0 0.00%
Pure 785 703 744.0 32.12%
1:1 547 512 529.5 51.69%
1:2 635 616 625.5 42.93%
1:3 764 751 757.5 30.89%
• At TiO2 : SiO2 at 1 : 1 , generated the most
oxidizing agent
27/25
Where
Ani = Average amount of E.Coli at previous ratio
AMB = Average amount of E.Coli at initial concentration
0.00%
32.12%
51.69%
42.93%
30.89%
None Pure 1:1 1:2 1:3
%DEGRADATION
RATIO
At concentration 10-5 CFU/ml
• E.Coli disinfection measure by 3M Petrifilm E.Coli count plates.

28. • At ratio of TiO₂ and SiO₂ equal to 1 : 1 represent the most anatase phase.
• When increase amount of SiO₂ ,anatase phase will decrease and rutile phase will increase.
• At ratio of TiO₂ and SiO₂ equal to 1 : 1 can degrade the color of methylene blue at the most.
• At ratio of TiO₂ and SiO₂ equal to 1 : 1 can effective to disinfect of E.Coli
• At ratio of TiO₂ and SiO₂ equal to 1 : 1 occur the best performance of photocatalytic process which
the same performance in theory
28/25

29. 29/25
Polyethylene
Sheet
UV Lamp
• Enhanced dental hygiene system with direct UVA photoexcitation. (Patent)
This brush is coated by
catalyst using hot pressing
method.
coated non-coated

30. 30/25
• Enhanced dental hygiene system with direct UVA photoexcitation. (Patent)
This brush is coated by
catalyst using hot pressing
method.
coated non-coated

31. Thank You
31

32. 32
• Serial Dilution

33. • Sterilization e.g. Hydrogen Peroxide Sterilization
33
4) KILL_OVER stage
3) H₂O₂ injection stage
2) H₂O₂ surface reaction stage
1) H₂O₂ contact stage
Vaporized H₂O₂
Micro Organism
http://www.hmmdt.com/img/tec_plasma02_con01.gif

34. • Sol-Gel Process
34
Metal
Alkoxide
Solution
Hydrolysis
Polymerization
Gelation
(Dehydration)
Sol (solution) Wet Gel
https://www.researchgate.net/figure/26548041_fig1_Overview-of-the-sol-gel-process-illustrating-the-differences-between-xerogels
https://en.wikipedia.org/wiki/Sol-gel

35. • How to Disinfection of E.Coli by using Photocatalytic of TiO2
35
• Destroy DNA structure
• Change protein and fat in cell wall
• Generate covalence band with protein or some of
enzyme caused to protein or some enzyme doesn’t
work well
Ref : Reactive Species and Antioxidants. Redox Biology Is
a Fundamental Theme of Aerobic Life, Barry Halliwell 1999

36. 36

37. 37
Research example that use compound of TiO2
can disinfection

38. • Why is anatase a better photocatalyst than rutile.?
• https://www.nature.com/articles/srep04043
• https://pubs.acs.org/doi/10.1021/cs500785z
38

39. http://www.eng.hokudai.ac.jp/labo/crystal/en/research.html
https://www.jeol.co.jp/en/products/list_sem.html
■ Preparation
• X-Ray Diffraction : XRD
(Rint-2000, Cu K⍺ radiation)
Crystalline
Phases
39

40. • 3m
• LA
40

41. • H2o2 ในเฟสอะไร
• ระบบที่ต่างกัน สามารถสร้าง H2O2 ได้หรือไม่
• ช่องปากมีแบคทีเรียอะไร ทาไมใช้ e coli
• มั่นใจได้อย่างไรว่าแปรงฟันกับผู้ปป่วยแบบนีได้
• H2O2 properties
• รูปทรงของ TIO2
41