By:

Mr. Gazy Khatmi .R ALBEDRI

Supervisor:

Dr.Nazr Alameain

Co-Supervisor:

Dr.Nashwa aboalhassen

Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Laser physics.

October 2014

Introduction :

• 1.1 Billion people without access to safe water.• water borne diseases kill nearly 12 million people every year (majority under 5 yrs).

The following water treatment methods for the application at household level generally are recommended [WHO, 1997] to reduce feacal contamination of drinking water:

1-WATER STORAGE 2- BOILING OF WATER 3-WATER PASTEURISATION 4- WATER FILTRTION 5- WATER DISINFECTION WITH CHLORINE 6- FLUORIDATION

Introduction :

SODIS is a new water treatment to be applied at household level with a great potential to reduced diarrhea incidence of users.

Solar water disinfection (SODIS)

A graphical description on the solar disinfection (SODIS) household water treatment technique(courtesy of Dr. Kevin McGuigan, Royal College of Surgeons in Ireland, drawn by Maria Boyle).

Test of Bacteria coliforms:

The test coliforms chosen were the Coliform bacteria that include Citrobacter, Enterobacter, K elbsila and Escherichia coli ent (E. coli). Sample from White Nile river -Khartoum

Cont..

Contaminated water Fresh water(uncontaminated)

Result and dissections

The effect SODIS on Bacteria coliform

Zero Time

1 hour 2 hours 3 hours 5 hours 6 hours

NumbrOf coli forms CFU/ 100ml

600 200 160 140 31 Zero

Cont.

Effect of Bacteria coliforms ((N0: 52CFU mL-1) , (N0: 600 CFU mL-1) and (N0: 850 CFU mL-1)

Cont.The inactivation of bacteri produced by light irradiation is used the Gaudy equation N/No = e –KIT

where N is bacterial density after exposure (colony-forming units (CFU) per milliliter of effluent), No is initial bacterial density (CFU per milliliter of influent), N/No is the bacterial survival ratio, K is the inactivation rate constant (squarecentimetres per microwatt minute, cm2/μW min), I is the intensity of received solar UV-A radiation (microwatts per square centimeter), T is time of exposure to solar UV-A radiation (min), and e is equal to 2.7182.Bacteria cannot survive long exposure to solar UV light. The highest bacterial coliform inactivation was obtained at 3 h (99.9%), turbidity value 0NTU. On the contrary, 6hs at turbidity 25NTU. That mean at turbidity high than Zero need 6h to inactivate the total Bacterial coliform. Figure(1)

Comparison between Nanoscale ZnO and Nanoscale TiO2

Effect of solar radiation with ZnO and TiO2 (0.01g/l) on Bacteria coli form disinfection efficiency (N0: 600 CFU mL-1)

Cont. TiO2 is the most widely used photocatalyst due to its high efficiency,

photochemical stability, non- toxic nature and low cost. In contrast, ZnO, a kind of semiconductor that has the similar band gap as TiO2, is not thoroughly studied [13]. TiO2 as a photocatalyst is more effective in the re- moval of Bacteria than ZnO.

The time of inactivation Bacterial coliform is reduced to 5 hours instead of 6 when used ZnO nanoparticls with 0.01g/l and less than four hrs when TiO2 used with same concentration

Mechanism of photocatalytic reactions

The mechanism of charge separation and photocatalytic activity of the TiO2 ZnO nanoparticls

Cont.

Effect of solar radiation with TiO2 with different concentrations on Bacteria coli form disinfection efficiency (N0: 600 CFU mL-1)

Test of Microbial re growth:

Treated Water Treated Water after Four Dyes

Treated Water By Solarphotocatlysis Re growth after Seven day

Cont. The microbial re-growth test results showed that inactivated

coliform bacteria can re-grow at ordinary room conditions after Four days of storage in case of Water trated by solar radiation . Contrarily in Solarphotocatlsis treated results showed that inactivated coliform bacteria failed to re-grow at ordinary room conditions after 7 days of storage in adark place, or indicating that the inactivation process was irreversibl

Photocatalysis materials charactrsicts

XRD pattern of Zno nanoparticle

TEM image of ZnO nanoparticl

Cont.

Cont.

UV.Visible absorption of ZnO

Cont.…

Touc plote of ZnO

TEM image of TiO2 nanoparticle

Cont.

Conclusions:

This thesis research was conducted to study the effects of numerous variables on the disinfection properties of solar radiation and enhancement of solar radiation disinfection by adding ZnO and TiO2 nanoparticls to the water Bottles . The variables tested were turbidity and exposure time. The samples were exposed to sunlight during sunny (September and October OF 2014 ) .Experiments were also conducted in the laboratory to quantify the effect of ZnO and TiO2 nanoparticls . In analyzing the results from these experiments, the following conclusions were drawn:1-The study has the possibility of disinfection microbial contaminated water with low – or non cost technology (SODIS).2-The Bacterial coliform were completely inactivated in sample of no turbidity within 3hours of sunlight exposure time ,where the samples with turbidity 25ntu needs exposure time at least 6hous . The Bacteria coliform re-growth test results showed that inactivated coliform bacteria can re-grow at ordinary room conditions after four days of storage .

Cont.

3-The Bacterial coliform were completely inactivated in sample of turbidity 25 ntu within 3hours of sunlight exposure time ,when the bottles added to the ZnO and less than 3hours when TiO2 added to the sample with o.o1g/l

Bacteria coliforms achieved inactivation in 3hours in photocatalytic bottles whereas standard bottles did not achieve inactivation in the measured time period (6hours). Another remarkable finding is that Bacterial coliforms were incapable of regrowth in the photocatalytic bottles until 7deys.

The significance of this result is two-fold. Firstly, it shows another advantage in the application of photocatalytic in SODIS bottles, namely that photocatalytic bottles are ‘bactericidal’ whereas standard SODIS bottles can be ‘bacterio-static’.

Recommendations

Due to limited resources and time, the following section details recommendations for future research.1- water sample with natural turbidity was tested, yet the turbidity level was lessthan 30 ntu, it is recommended that water samples with higher levels of suspended particles be tested. Bacterial coliform , specially E. coli is a common test organism and inactivation results correlate to the effects of solar disinfection on other organisms such as pathogenic bacteria. However, it is recommended that solar disinfection tests be conducted on other bacteria ,Virus and Fungi . For example, studies are lacking on the effects of solar disinfection on spore-forming organisms and protozoa.

Cont 2- To enhancement of SODIS using nanoparticls

semiconductors ,another particle with different size should be synthesized .

3- Recommendations for future directions is to coatings the PET bottles with TiO2 and ZnO

4- Photo –reactor desine and visible light absorbtion of TiO and ZnO

Clear water = health better This mean life beater

Thank for your time and attention