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Homogeneous Photocatalytic Degradation of Acid Alizarin Black Using Hydrogen Peroxide
(Advanced Oxidation Processes)
Mr Haydar A.M.SBSc, MSc
Faculty of ScienceChemistry Department
Email: [email protected]
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Outline Aim of the research
Introduction
Experimental
Results and Discussion
Conclusion
Textile industries AOPs How AOPs work UV/H2O2
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Aim of Research
Degradation of Acid Alizarin Black dye using UV/H2O2 under different operating conditions:
Effect of dye concentration
Effect of H2O2 concentration
Effect of pH
Before reaction After reaction20 min
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Introduction
Textile Industries
Is one of the largest polluters in the world.
WB: 20 % of Industrial water pollution comes from textile industries
The textile dyeing industry use large quantities of water
10 % of the dye is lost during the process
Cause pollution of water and serious environmental problems
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Introduction
Textile Industries
Dye molecules, mostly, have a polyaromatic structure.
Contain atoms of nitrogen, sulfur and metals.
The AOPs usage is expanding as water quality requirement
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Introduction
Advanced Oxidation Processes (AOPs)
- Produce highly reactive species, hydroxyl radicals (HO•) using oxidizing agents and catalysts.
- The most common processes are:• O3/H2O2
• H2O2/UV
• O3/UV
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Introduction
AOPs
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Introduction
Reactivity of hydroxyl radical (•OH)Oxidizing species
Relative oxidation power (V)
•OH 2.80
O3 2.07
H2O2 1.78
HO2• 1.70
ClO2 1.57
HOCl 1.49
Cl2 1.36
Compoundsrate constants
(O3)rate constants
(•OH)
Chlorinated alkenes
103-104 109-1011
Phenols 103 109-1010
N-containing organics
10-102 108-1010
Aromatics 1-102 108-1010
Ketons 1 109-1010
Alcohols 10-2-1 108-109
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Introduction
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Introduction
UV/H2O2
●OH generated by direct photolysis of H2O2
H2O2 in ionised form (HO2‾) decomposes to generate ●OH
O●‾ with water can produce another ●OH
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Experimental
Acid Alizarin was used as a model compound.
30 % of H2O2 was used as a initiator
UV lamp (12 watt) with 254 nm was used
Jenway 6800 was used for the analysis.
Materials
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System setup
Experimental
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Experimental
Safety
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Results and Discussion
Effect of initial H2O2 concentration
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Results and Discussion
Effect of initial H2O2 concentration
Removal percentage after 5 min
0 5 10 15 20 25 30 350
20
40
60
80
100
120
H2O2 = 0.1 mLH2O2 = 0.2 mLH2O2 = 0.3 mL
Reaction time (min)
% R
emov
al
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Results and Discussion
Effect of initial AAB concentration
0 5 10 15 20 25 30 350
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
AAB 100 mg/L
AAB 150 mg/L
AAB 200 mg/L
Reaction time (min)
C/C
o
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Results and Discussion
Effect of initial AAB concentration
Removal percentage after 5 min
0 5 10 15 20 25 30 350
20
40
60
80
100
120
AAB = 100 mg/LAAB = 150 mg/LAAB = 200 mg/L
Reaction time (min)
% R
emov
al
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Results and Discussion
Effect of pH
Removal percentage after 30 min
0 5 10 15 20 25 30 350
20
40
60
80
100
120
pH = 3pH = 7pH = 11
Reaction time (min)
% R
emov
al
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Results and Discussion
Effect of H2O2 amount on a pseudo-first order kinetic
H2O2 Volume (mL) k' (min-1) R2
0.1 0.1953 0.984
0.2 0.2327 0.9608
0.3 0.3052 0.9865
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Results and Discussion
Effect of AAB concentration on a pseudo-first order kinetic
[AAB] (mg/L) k' (min-1) R2
100 0.2483 0.9608
150 0.1511 0.9808
200 0.0844 0.994
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Conclusions
Photocatalytic degradation, in the presence of H2O2, of AAB was studied in this research.
The most effective improvements on the degradation of AAB were recorded with initial AAB concentration of 100 mg/L.
It was also found that the increasing of H2O2 quantity enhance the reaction rate of AAB decolourisation.
The removal efficiency of AAB was favourable in the neutral medium more than the acidic and basic medium.
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Further analysis would be to find the impact of temperature on AAB removal using the thermostatic bath.
Additional analysis using (GC), (MS) or (NMR) would be made to identify the molecular structure of the oxidation products.
Future Work
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Thanks for your attention
