1. ICAME-2017 Yildiz University
PHOTODEGRADATİON OF WATER-ORGANİC CONTAMİNANTS WİTH SAFE SENSİTİZED ZnO NANOPARTİCLES: A GREEN SUSTAİNABLE METHOD FOR WATER PURİFİCATİON Presented by: Amani Zu’bi Coauthors: Ahed Zyoud & Hikmat Hilal Chemistry Department / An-Najah N. University, Palestien1
ICAME-2017 Yildiz University

2. ICAME-2017 Yildiz University
The problem to solve
Palestine suffers serious shortages in pure water supplies.
Due to the abuse of ground water resources practiced by settlers. They also dispose their sewage randomly into Palestinian areas
Most commonly: (Industrial dyes, phenolderivatives herbicides, pesticides, insecticides, drugs … ec) and heavy metals.
Contaminants reach ground & surface water
Severe pollution occurs.
Purification & recycling of water is needed.
ICAME-2017 Yildiz University

3. ICAME-2017 Yildiz University
Different types strategies are used to remove contaminants. But expensive or not efficient.
Recently: Natural solar energy has been examined for complete mineralization.
Core issue is developing light-sensitive semiconducting materials to catalyze photo-degradation
ICAME-2017 Yildiz University

4. The Idea of Semiconductors
Band Diagram: Semiconductor with Non Doping
T > 0
Conduction band
(Partially Filled) EC EF EV
Valence band
(Partially Empty)
ICAME-2017 Yildiz University

5. ICAME-2017 Yildiz University
How Semiconductors catalyze photodegradation:
Semiconductor absorbs photon with (hν > Eg), electron is excited to conduction band, & positive hole remains valence band. electron-hole formation.
ICAME-2017 Yildiz University

6. ICAME-2017 Yildiz University
UV Irradiation Experiments Using ZnO Schematic Mechanism of Photo-Excitation ZnO (Semiconductor) by UV Light
ICAME-2017 Yildiz University

7. ICAME-2017 Yildiz University
The purpose: Using lab prepared ZnO nano-powder and using it in degrading organic contaminants (Methyle Orange) under solar simulator light using the UV fraction (~4%), taking into account:
1- efficiency
2- recyclability
3- cost
4- environmental safety
5- working under natural conditions.
ICAME-2017 Yildiz University

8. ICAME-2017 Yildiz University
ZnO Characterization
ICAME-2017 Yildiz University

9. ICAME-2017 Yildiz University
Electronic absorption spectrum for lab-prepared ZnO powder (aqueous suspension).
ICAME-2017 Yildiz University

10. ICAME-2017 Yildiz University
Photoluminescence Spectra
Photoluminescence emission spectrum measured for ZnO powder (in suspension).
ICAME-2017 Yildiz University

11. X-ray Diffraction (XRD) of ZnO
ICAME-2017 Yildiz University

12. ICAME-2017 Yildiz University
Scaning Electron Micrograph images for ZnO
17 nm
ICAME-2017 Yildiz University

13. Solar Simulator Photodegradation Experiments Measuring
The %degradation
Turn over number
Quantum yeild
underdifferent Experiment conditions
ICAME-2017 Yildiz University

14. ICAME-2017 Yildiz University
Methyl Orange
ICAME-2017 Yildiz University

15. Effect of pH on photo-degradation process
intensity 19.0 mW/cm Profiles of photo-degradation reaction for aqueous methyl orange (100 mL, 10 ppm) at different pH values, using ZnO catalyst (0.1g) at room temperature with total radiation
Effect of pH of the photo-degradation rate under 19.0 mW/cm2 irradiation pH
~ 7
~ 5
~ 2.5
~ 9
~ 11
T.N.
1.62 X 10-3
1.94 X 10-3
1.17 X 10-3
8.42 X 10-4
6.71 X 10-4
Q.Y.
4.36X 10-4
4.28 X 10-4
2.92 X 10-4
2.12 X 10-4
1.74 X 10-4
% Degradation
100%
73%
60%
48%
ICAME-2017 Yildiz University

16. ICAME-2017 Yildiz University
Effect of temperature
Profiles of photo-degradation reaction of methyl orange solution (100 mL, 20 ppm) at different temperatures, using ZnO catalyst (0.1 g) and total irradiation intensity of 19.0 mW/cm2 at pH ~7
Temp.
10 oC
20 oC
30 oC
45 oC
T.N.
1.86 X 10-3
2.38 X 10-3
2.87 X 10-3
2.80 X 10-3
Q.Y.
3.52 X10-4
4.28 X10-4
5.44 X 10-4
5.29 X 10-4
% Degradation
62%
70%
84%
81%
ICAME-2017 Yildiz University

17. ICAME-2017 Yildiz University
Effect of CO2 and other gas flows
Effect of gas streams on methyl orange photo-degradation. Reactions were conducted using methyl orange solution (100 mL, 20 ppm) under 19.0 mW/cm2 irradiation using ZnO (0.1 g) with continuous stirring at 20oC with different gas flows: (a) exposed to air only
(b) air flow
(c) N2 flow open system
(d) CO2 and air flows together (e) CO2 flow
(f) closed system with nitrogen flow
(g) N2 and CO2 flows together.
exposed to air only
air flow
N2 flow open system
CO2 and air flows together
CO2 flow
T.N.
2.87 X 10-3
1.72 X 10-3
1.44 X 10-3
0.75 X 10-3
1.03 X 10-3
Q.Y.
5.44 X 10-4
3.25 X 10-4
2.72 X 10-4
1.42 X 10-4
1.95 X10-4
% Degradation
84%
52%
50%
25%
19%
ICAME-2017 Yildiz University

18. ICAME-2017 Yildiz University
Effect of contaminant concentration
Effect of contaminant concentration under 19.0 mW/cm2 irradiation
10 ppm
20 ppm
30 ppm
40 ppm
T.N.
1.73 X 10-3
2.38 X 10-3
2.37 X 10-3
2.29 X 10-3
Q.Y.
3.07 X 10-4
4.28 X 10-4
4.48 X 10-4
4.17 X 10-4
% Degradation
100%
70%
66%
45%
ICAME-2017 Yildiz University

19. ICAME-2017 Yildiz University
Effect of catalyst nominal amount on photo-degradation process
Effect of catalyst amount on the photo-degradation rate under 19.0 mW/cm2 irradiation
0.05 g
0.10 g
0.20 g
0.3 g
T.N.
3.10 X 10-3
1.68 X 10-3
9.82 X 10-4
9.57 X 10-4
Q.Y.
2.93 X 10-4
3.19 X 10-4
3.72 X 10-4
3.62 X 19-4
% Degradation
95%
100%
ICAME-2017 Yildiz University

20. Effect of light intensity on the photodegraation process
Effect of radiation intensity on the photo-degradation rate on 10 ppm contaminant
1.90 mW/cm2
5.12 mW/cm2
8.78 mW/cm2
19.0 mW/cm2
T.N.
6.96 X 10-4
1.5 X 10-3
1.58 X 10-3
1.73 X 10-3
Q.Y.
1.42 X 10-3
1.35 X 10-3
6.57 X 10 -4
3.07 X 10-4
% Degradation
54%
95%
96%
100%
Effect of radiation intensity on the photo-degradation rate on 20 ppm contaminant
7.96 X 10-4
1.86 X 10-3
1.99 X 10-3
2.38 X 10-3
1.62 X 10-3
1.41 X 10-3
8.76 X 10-4
4.28 X 10-4
34%
58%
65%
70%
ICAME-2017 Yildiz University

21. ICAME-2017 Yildiz University
Catalyst re-use experiments
Fresh ZnO
1st re-use
2nd re-use
T.N.
2.87 X 10-3
2.60 X 10-3
2.44 X 10-3
Q.Y.
5.44 X 10-4
4.90 X 10-4
% Degradation
84%
82%
78%
ICAME-2017 Yildiz University

22. Complete mineralization
ICAME-2017 Yildiz University

23. ICAME-2017 Yildiz University
Thank You
ICAME-2017 Yildiz University