1. Use Micromath’s
Scientist program to investigate the reactions of chlorine with bromide and
phenol. To help with this, I will
provide you with a “template” model file that includes all of the reactions
between phenolic compounds and active halogens (HOCl and HOBr). You should work with this file, adding
reactions as needed and parameter to solve the problems. Be careful to use “apparent” rate constants (kapp) whenever the reactive species is not the
most abundant one at the particular pH.
Assume you’re adding 1.0 mg/L free chlorine to a water with NOM that consumes free chlorine at a 1st
order rate of 0.1 hr-1. Also
assume that the initial phenol concentration is 0.05 µM. Predict concentrations of phenol, all halophenols and inorganic species for the following
scenarios:
a. No bromide, no ammonia, pH 7
b. No bromide, no ammonia, pH 9
c. 1 µM initial bromide, no
ammonia, pH 7
d. 1 µM initial bromide, 20 µM
initial ammonia, pH 7
e. 1 µM initial bromide, no
ammonia initially, but then 20 µM ammonia is added after 30 seconds; all at pH
7
For each of
the five scenarios above, determine all reactant concentrations with the help
of the Scientist program. Consider reactions times up to 48 hours, but you may
want to focus on the very early stages of the reaction forconditions
that result in complete conversion of chlorine to chloramines. You should present your results in graphical
format with time from chlorine addition on the x-axis, and concentration on one
or more y-axes. You may need several
graphs for each set of conditions.
As mentioned, I am providing you with a model input
file (halophenols 2.eqn) for the complete set of HOCl and phenolic reactions as
well as the HOBr and phenolic
reactions as presented in Acero et al., 2005 (Water Research,
39:2979-2993). This includes 28 separate
reactions. In addition I’ve added the
bromide oxidation reaction and the chlorine decay reaction, making a total of
30. All abbreviations used in this file
are listed on the next page for clarity.
You will need to generate the parameter file and populate it with rate
constants, initial concentrations, time spans, etc. You may also need to add additional reactions
to the model file that I haven’t included (e.g., reactions pertaining to halamine formation and degradation).
Assigned: 5 May 08
Due: 16 May 08
Symbols/Abbreviations used in equation file.
|
Rate Constant |
Reactant #1 |
Reactant #2 |
Product |
|||
|
Symbol |
Name |
Symbol |
Name |
Symbol |
Name |
|
|
k0 |
C |
Hypochlorous Acid |
|
NOM |
|
|
|
k1 |
P |
phenol |
C |
Hypochlorous Acid |
C2CP |
2-chlorophenol |
|
k2 |
P |
phenol |
C |
Hypochlorous Acid |
C4CP |
4-chlorophenol |
|
k3 |
C2CP |
2-chlorophenol |
C |
Hypochlorous Acid |
C24DCP |
2,4-dichlorophenol |
|
k4 |
C2CP |
2-chlorophenol |
C |
Hypochlorous Acid |
C26DCP |
2,6-dichlorophenol |
|
k5 |
C4CP |
4-chlorophenol |
C |
Hypochlorous Acid |
C24DCP |
2,4-dichlorophenol |
|
k6 |
C24DCP |
2,4-dichlorophenol |
C |
Hypochlorous Acid |
C246TCP |
2,4,6-trichlorophenol |
|
k7 |
C26DCP |
2,6-dichlorophenol |
C |
Hypochlorous Acid |
C246TCP |
2,4,6-trichlorophenol |
|
k8 |
C246TCP |
2,4,6-trichlorophenol |
C |
Hypochlorous Acid |
X |
non-phenolics |
|
k9 |
C2BP |
2-bromophenol |
C |
Hypochlorous Acid |
C2B4CP |
2-bromo-4-chlorophenol |
|
k10 |
C2BP |
2-bromophenol |
C |
Hypochlorous Acid |
C2B6CP |
2-bromo-6-chlorophenol |
|
k11 |
C4BP |
4-bromophenol |
C |
Hypochlorous Acid |
C2C4BP |
2-chloro-4-bromophenol |
|
k12 |
C24DBP |
2,4-dibromophenol |
C |
Hypochlorous Acid |
C24DB6CP |
2,4-dibromo-6-chlorophenol |
|
k13 |
C26DBP |
2,6-dibromophenol |
C |
Hypochlorous Acid |
C26DB4CP |
2,6-dibromo-4-chlorophenol |
|
k14 |
C246TBP |
2,4,6-tribromophenol |
C |
Hypochlorous Acid |
C246TB3CP |
2,4,6-tribromo-3-chlorophenol |
|
k15 |
P |
phenol |
B |
Hypobromous Acid |
C2BP |
2-bromophenol |
|
k16 |
P |
phenol |
B |
Hypobromous Acid |
C4BP |
4-bromophenol |
|
k17 |
C2BP |
2-bromophenol |
B |
Hypobromous Acid |
C24DBP |
2,4-dibromophenol |
|
k18 |
C2BP |
2-bromophenol |
B |
Hypobromous Acid |
C26DBP |
2,6-dibromophenol |
|
k19 |
C4BP |
4-bromophenol |
B |
Hypobromous Acid |
C24DBP |
2,4-dibromophenol |
|
k20 |
C24DBP |
2,4-dibromophenol |
B |
Hypobromous Acid |
C246TBP |
2,4,6-tribromophenol |
|
k21 |
C26DBP |
2,6-dibromophenol |
B |
Hypobromous Acid |
C246TBP |
2,4,6-tribromophenol |
|
k22 |
C246TBP |
2,4,6-tribromophenol |
B |
Hypobromous Acid |
X |
non-phenolics |
|
k23 |
C2CP |
2-chlorophenol |
B |
Hypobromous Acid |
C2C4BP |
2-chloro-4-bromophenol |
|
k24 |
C2CP |
2-chlorophenol |
B |
Hypobromous Acid |
C2B6CP |
2-bromo-6-chlorophenol |
|
k25 |
C4CP |
4-chlorophenol |
B |
Hypobromous Acid |
C2B4CP |
2-bromo-4-chlorophenol |
|
k26 |
C24DCP |
2,4-dichlorophenol |
B |
Hypobromous Acid |
C24DC6BP |
2,4-dichloro-6-bromophenol |
|
k27 |
C26DCP |
2,6-dichlorophenol |
B |
Hypobromous Acid |
C26DC4BP |
2,6-dichloro-4-bromophenol |
|
k28 |
C246TCP |
2,4,6-trichlorophenol |
B |
Hypobromous Acid |
C246TC3BP |
2,4,6-trichloro-3-bromophenol |
|
k29 |
Br |
Br- |
C |
Hypochlorous Acid |
B |
Hypobromous Acid |