1. AdOxTM --a Kinetic Model for the Hydrogen Peroxide / UV Process
Ke Li
Shumin Hu
John C. Crittenden
David W. Hand
David R. Hokanson
Portions Presented at AOTs-6 The Sixth Annual Conference on
Advanced Oxidation Technologies for Water and Air Remediation
London, Ontario Canada, June 26-30, 2000
Copyright © Michigan Technological University. All Rights Reserved.

2. Outline
Objectives of AdOxTM
AOP Mechanism Behind the Model
Model Validation
Some Important Features
Example Applications
Conclusions
Looking Forward ...

3. Objectives of AdOxTM Understand the chemistry of AOP process
Assess the preliminary design and feasibility of using advanced oxidation processes
Plan pilot plant studies and interpret the results
Predict the effect of operational parameters and provide key parameters for process design
Trace the destruction of contaminants and the formation of byproducts, provide valuable information for mechanism study of AOP

4. Outline
Objectives of AdOxTM
AOP Mechanism Behind the Model
Model Validation
Some Important Features
Example Applications
Conclusions
Looking Forward ...

5. AOP Mechanism Behind The Model
The 44 reactions considered in the model include the most comprehensive mechanism:
Photolysis of H2O2:
Initiation:
H2O2 / HO2- + hv  2HO
Propagation:
H2O2 / HO2- + HO  H2O / OH- + HO2
H2O2 + HO2 / O2-  HO + H2O / OH- + O2
Termination:
HO + HO  H2O2
HO + HO2 / O2-  H2O / OH- + O2
HO2 + HO2 / O2-  H2O2 / HO2- + O2

6. AOP Mechanism Behind The Model
Reactions of organic compound R:
R + hv  Products
R+ HO  Products
Inorganic Scavengers:
HO  + CO32- / HCO3-  CO3  -+OH- / H2O
HO  + HPO42-  HPO4  - + OH-
Direct photolysis of target compound
rUV, R1 = -R1I0 fR1(1-e-A)
A=2.303b ( H2O2 CH2O2 + R1 CR1 + R2 CR2 + S CS + HO2- CHO2-)
fR1 = b R1 cR1 /A

7. AOP Mechanism Behind The Model
Pseudo-steady-state is not assumed
pH variation is considered
The influence of Background Organic Matter is considered:
absorption of UV light (es) and its influence on the photolysis of target compound and H2O2
BOM + hv 
scavenging of hydroxyl radicals
HO + BOM 

8. Outline
Objectives of AdOxTM
AOP Mechanism Behind the Model
Model Validation
Some Important Features
Example Applications
Conclusions
Looking Forward ...

9. Model Validation
The model was validated by comparing model predictions to the following experiments:
1,2-dibromo-3-chloropropane (DBCP) in a complete mixed batch reactor (CMBR) (Glaze and Kang, 1989)
1-chlorobutane (BuCl) in complete mixed flow reactor (CMFR)
(Liao and Gurol, 1995)

10. Model Validation - Relationship between [H2O2]0 and DBCP pseudo-first-order rate constant in a CMBR, CT=4 mM, I0=1.04E-6 einsteins/L-s
120
100 ) -1 s 80 -5
, (10 60
0, DBCP 40
experimental result k
AdOx prediction 20
Glaze et al.'s model prediction 1 2 3 4 5 6 7 [H O ]
, mM 2 2

11. Model Validation - Effect of Humic Acid on BuCl degradation in a CMFR ( [H2O2]0 = 284 mM, [BuCl]0 = 8 mM, t = 7.76 min, CT,CO3 = 4 mM, pH=7.6, I0 = einsteins/L-min
0.2
0.4
0.6
0.8 1 2 4 6 8 10 12 14
H2O2 , experimental result
BuCl, experimental result
AdOx prediction
Liao et al. 's model prediction o /C
Normalized Concentration, e C
Fluka Humic Acid as DOC, mg/L

12. Outline
Objectives of AdOxTM
AOP Mechanism Behind the Model
Model Validation
Some Important Features
Example Applications
Conclusions
Looking Forward ...

13. Important Features of AdOxTM 1.0
Model Various Reactor Configurations:
Completely Mixed Batch Reactor (CMBR)
Completely Mixed Flow Reactor (CMFR)
Completely Mixed Batch Reactor (CMBR) V R C e dC a dt r =
(Governing Equation)
Completely Mixed Flow Reactor (CMFR) Q, C in VR e dC dt ao a + 1 (C r - t = )
(Governing Equation)

14. Features of Current Version AdOxTM 1.0
Tanks-In-Series (TIS or CMFRs)
Plug Flow Reactor (PFR)
Real Reactor (Describe non-ideal mixing with a tanks-in-series model.)
n-CMFR: Q, C in V R n 1
n-1
n-2

15. Important Features of AdOxTM 1.0
Determine Optimum Operational Parameters:
Optimum H2O2 Dosage
UV Light Intensity
Hydraulic Retention Time
Dynamically model multi-component contaminant mixtures (up to 10).
Model multi-chromatic light sources
(up to 100 wavelength)

16. Important Features of AdOxTM 1.0
Includes a database of more than 600 compounds including second-order hydroxyl-radical rate constants
Determine the influence of water quality :
Alkalinity (Total Inorganic Carbon) pH

17. Some Important Features
Modeling Different Reactor Configurations

18. Some Important Features
Modeling Multi-chromatic (up to 100) Light Sources

19. Some Important Features
Dye Study Analysis for Tanks-In-Series Model

20. Some Important Features
Database of Second-Order Hydroxyl-Radical Rate Constants

21. Selection of Optimum [H2O2]0/[DBCP]0 as a function of Water Quality Parameters

22. Influence of CT,CO3 on the pseudo-first-order rate constant of DBCP and H2O2 ([H2O2]0=1.00 mM, I0 =1.04X10-6 eins./L.s,CTIC=4mM)

23. Impact of CT,CO3 on EE/O for the Degradation of DBCP ([H2O2]0=1
Impact of CT,CO3 on EE/O for the Degradation of DBCP ([H2O2]0=1.00 mM, I0 =1.04X10-6 eins./L.s, CTIC=4mM, pH=7~8.4)

24. Impact of pH on Degradation Rate of DBCP and H2O2 (I0 = 1.0410-6 eins./L-s;[H2O2]0 = 1.00mM; CTIC = 4 mM)

25. Impact of pH on EE/O for the DBCP Degradation (I0 = 1. 0410-6 eins
Impact of pH on EE/O for the DBCP Degradation (I0 = 1.0410-6 eins./L-s; [H2O2]0 = 1.00mM; CTIC = 4 mM)

26. Outline
Background
Objectives of AdOxTM
AOP Mechanism Behind the Model
Model Validation
Some Important Features
Example Applications
Conclusions
Looking Forward ...

27. Example Applications Electrical Energy per Order (EE/O)
The electrical energy (in kilowatt hours) required to reduce the concentration of a pollutant by one order of magnitude for 1000 U.S. gallons of water. For a CMBR:

28. Example Application I - Predicted Energy Requirement for an Influent Vinyl Chloride Concentration of 10 g/L(Treatment Objective=2g/L) 3
0.5 1
1.5 2
2.5 5 10 15 20 [H O ]
, (mg/L)
[H3C2Cl]0=10g/L=1.610-7M=0.16M
TOC = 5 mg/L
TIC = 8.0 mM
pH 7.0
I0 = 1.010-6 eins./L-s
Optical length L = 7.5 cm
K HO and NOM = 2.0104 (mg/L)-1s-1
The UV-light absorption and direct photolysis of vinyl chloride are ignored
(Kw-hour/Kgal-Order)
EE/O

29. Example Application II - Predicted Energy Requirement for an Influent TCE Concentration of 200 g/L (Treatment Objective=5g/L) 3 6 9 20 40 60 80 [H 2 O ]
, (mg/L)
[TCE]0=200g/L=1.52M=1.5210-6 M
TOC = 5 mg/L
TIC = 8.0 mM
pH 7.0
I0 = 1.010-6 eins./L-s
Optical length L = 7.5 cm
K HO and NOM = 2.0104 (mg/L)-1s-1
TCE=10M-1 cm-1, the direct photolysis of TCE is ignored.
(Kw-hour/Kgal-Order)
EE/O

30. Example Application III - Relationship between EE/O and [H2O2]0/[DBCP]0 -- Impact of operational parameters on process efficiency
0.0
1.0
2.0
3.0
4.0
5.0
300
600
900
1200
1500
Io=1.04e-6eins./L-s, Carbonate=0.01mM, pH7.64
Io=1.04e-6eins./L-s, Carbonate=0.1mM, pH8.1
Io=1.04e-6eins./L-s, Carbonate=4mM, pH6.4
Io=1.30e-6eins./L-s, Carbonate=4mM, pH8.4
Io=1.04e-6eins/L-s, Carbonate=4mM, pH8.4
Io=0.52e-6eins./L-s, Carbonate=4mM, pH8.4
EE/O, (Kwh/Kgal-Order)
Molar Ratio: [H 2 O ]
/[DBCP]

31. Outline
Objectives of AdOxTM
AOP Mechanism Behind the Model
Model Validation
Some Important Features
Example Applications
Conclusions
Looking Forward ...

32. CONCLUSIONS
AdOxTM is an easy-to-use tool for the design and mechanistic study of the H2O2/UV process.
AdOxTM is capable of simulating the dynamic behavior of the H2O2/UV process for several reactor configurations.
AdOxTM can evaluate the impact of process variables on process performance.

33. CONCLUSIONS
AdOxTM is a practical model and considers the impact of background components in the water matrix, non-ideal mixing, and multi-chromatic light sources.
AdOxTM is user-friendly with its database, archiving ability and Visual Basic front-end.

34. Looking Forward... More processes options
Models of other AOP technologies such as the H2O2/O3 and UV/O3
Byproduct prediction
Generate the reaction pathway and predict the fate of possible byproducts
More informative database
More compounds
photochemical properties

35. Further Reading
Crittenden, J.C., Hu, Sh., Hand D.W., and Green S.A., "A Kinetic Model for H2O2/UV Process in a Completely Mixed Batch Reactor," Water Research, 33(10), (1999).

36. Contact us...
Prof. John C. Crittenden, CenCITT, Michigan Tech, (906) ,
Prof. David W. Hand, CenCITT, Michigan Tech, (906) ,
Ke Li, CenCITT, Michigan Tech, (906) ,