PHOTO PRODUCTION OF HYDROGEN FROM HYDROGEN SULFIDE IN AQUEOUS SOLUTIONS OF MONOETHANOLAMINE USING TITANIUM DIOXIDE AS PHOTOCATALYST

number: 
1112
English
department: 
Degree: 
Author: 
INAM HUSSEIN ALI MOHMMED AL-MOSAWI
Supervisor: 
Dr.Salah Al-Deen Naman
Dr. Safa Salih Al-Omer
year: 
2005

        In the present work, the production of hydrogen fuel from photodecomposition of hydrogen sulfide in aqueous solution of monoethanolamine, using titanium dioxide as photocatalyst has been investigated. The influence of various parameters such as the percentage of monoethanolamine, the load of the catalyst, the effect of addition of sensitizer, the effect of addition of an oxidant and the increase of temperature is also studied.  Al photochemical experiments have been carried out in a Pyrex cylinder cell of capacity 35mL. The volume of hydrogen produced is measured using U- tube.The blank experiments for either illuminated aqueous solutions of monoethanolamine and hydrogen sulfide or the suspension containing titanium dioxide have showed that both illumination and the catalyst are necessary for the decomposition of hydrogen sulfide.The photochemical processes are monitored at different percentages of monoethanolamine (10%, 15%, 20%, 25%, 30%, 35%), different sources of light (1000W, 500W) Tungsten-Halogen lamp, different temperatures (278.15, 283.15, 293.15, 298.15, 303.15)K and different load of titanium dioxide photocatalyst (0.5mg, 1mg, 1.5mg, 2mg, 2.5mg)/35ml of photocell. The results have shown that higher hydrogen production was achieved using 20% MEA at 278 K using 1000W Tungsten-Halogen lamp with 2mg load of TiO2.The effect of passing oxygen gas was investigated and no significant effect was shown. The addition of an oxidant using hydrogen peroxide was studied and the volume of hydrogen produced is increased.The organic sensitizer (Riboflavin) can be sensitized the photocatalytic decomposition of hydrogen sulfide. It is generally found that the volume of hydrogen produced is increased and at maximum using 2.5 mg of sensitizer in 35 mL of photocell. U.V visible and IR spectra analysis was investigated and no significant effect was shown. According to the kinetic results, the reaction is first-order, with activation energy of 25.32 kJ /mole.Reaction mechanism has been suggested for this reaction in absence and presence of titanium dioxide photocatalyst.