removal of wastewater pharmaceutical chemical contaminants
TRANSCRIPT
Removal of Wastewater Pharmaceutical Chemical Contaminants Using AOPs
Stephen P. MezykDepartment of Chemistry and Biochemistry
California State University at Long BeachLong Beach, CA, 90840, USA
HN
NO
O
S
OOH
It’s all about potable water!
▪ Current lack of potable water▪ Human population increasing
▪ Water pollution increasing▪ Climate change occurring
▪ Increased water demand:▪ Human consumption▪ Agricultural needs
• Desalination? – Costly, but getting better – Environmental problems (retentate)
• Conservation? YES of course!
• Reusing our wastewater?– ~1012 litres wastewater/day in US!
• Direct toilet to tap – Public perception is bad– Costs????
Where can we get more water?
What’s in our wastewater?PathogensPesticides
Carcinogens
Pharmaceuticals
Industrial chemicals
NH
N
O
F
OH
OOHOHNH
N
O
F
OH
OOHOH
NH
N
NN
NH
Cl
HO
HO
R
N N
O
R'
H3C
CO
CH3
CH3
H3C
HN
NO
O
S
OOH
DOM HCO3-
NO3-/NO2
-
How do we clean wastewater?
▪ More than current 1o and 2o wastewater
treatment!
▪ Use ionizing radiation radical based treatment?
▪ Orange County Water District CA!
▪ Advanced Oxidation Processes (AOPs)
▪ Most work on ●OH, can maybe use SO4-●?
▪●OH radicals (Eo = 2.8V), SO4
-● (Eo = 2.4V)
▪ What is the cost of using AOPs?
An •OH radical is an •OH radical!
•OH
Electron beam
Beams
Gamma Radiation
Non-thermal
Plasmas
Electrohydraulic
Cavitation &
Sonolysis
O3/UV
H2O2/O3
H2O2/UV
H2O2/O3/UV
Supercritical Water
Oxidation
H2O -/\/\ 0.28 •OH + 0.27e-aq +0.06H•
+ 0.07H2O2 + 0.05H2 + 0.27H+
Orange County Water CA District approach:
Why Do We Care?• Trace antibiotic levels can cause
major health problems
• Unnecessary environmental exposure causes development of dangerous resistant strains MRSA, NDM-1, CRE of bacteria
• Allergies and sensitivities• Public concern over detection
of estrogenic chemicals in waterHO
HO
What do we need to understand the chemistry?
▪ Computer models that accurately predicts chemistry
of removal for quantifying costs of AOPs
▪ Contaminants minor wastewater constituents (< 0.1%)
▪ Kinetic computer models combine engineering and
chemistry:
▪ Rate constants for all relevant radical reactions
▪ Mechanisms of reactions
▪ Efficiencies of contaminant removal (impact of
wastewater matrix)
b-lactam antibiotics:
▪ Rate constants for ●OH and SO4-● radical in pure water
well established.
H2O -/\/\ 0.28 •OH + 0.27e-aq +0.06H•
+ 0.07H2O2 + 0.05H2 + 0.27H+
N2O saturated soln:
e-aq/H
● + N2O → ●OH
t-BuOH/N2/S2O82-
●OH/H● + t-BuOH → R●
e-aq + S2O8
2- → SO42- + SO4
-●
Compound k•OH (109M-1s-1)
Aminopenicillanic Acid 3.35 ± 0.06
Penicillin G 8.70 ± 0.32
Penicillin V 9.14 ± 0.12
Ampicillin 8.21 ± 0.29
Carbenicillin 7.31 ± 0.11
Cloxacillin 6.27 ± 0.13
Cephalothin 4.93 ± 0.15
Cefotaxime 9.29 ± 0.12
Kinetic data for β-lactams and •OH
Dail and Mezyk, JPCA, 114, 8391-5 (2010)
Average: kav ~
7.15 x 109 M-1 s-1
0.0 2.0 4.0 6.0 8.0-2.0
0.0
2.0
4.0
6.0
8.0
10.0
12.0
10
3 A
bsorb
ance
Time (s)
SO4•- and β-lactams
Compound kSO4• - (109 M-1s-1)
6-amino-
penicillanic acid
2.41 0.08
Amoxicillin 3.48 0.05
Ampicillin 1.87 0.30
Carbenicillin 0.59 0.30
Cloxacillin 0.86 0.13
Penicillin G 1.44 0.04
Penicillin V 2.00 0.05
Piperacillin 1.17 0.11
Ticarcillin 0.80 0.02
kav ~1.6 x 109 M-1 s-1N
S
HN
O
H
COOH
R1
Rickman and Mezyk, Chemosphere, 81, 359-365 (2010)
0.0 5.0 10.0 15.0
0.0
5.0
10.0
15.0
20.0
10
3 A
bsorb
ance
Time (s)
1.80 mM
1.38 mM
1.02 mM
0.61 mM
0.37 mM
0.20 mM
Species k•OH
M-1s-1
kSO4-•
M-1s-1
b-lactamsav 7.2 x 109 1.6 x 109
HCO3- 8.5 x 106 ~ 5 x 106
CO32- 4.0 x 108 4.1 x 106
NO3- ~ 0 5.0 x 104
NO2- 1.1 x 1010 9.0 x 108
DOM 6.27 x 108 3.8 x 107
Sulfate radical may be better choice!
vs
• HPLC measures parent loss
• •OH + β-lactam → β-lactam•
Watch peak area decrease
with degradation of compound
•●OH Efficiency
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0 1 2 3
Ab
so
lute
Dif
fer
en
ce
Dose (kGy)
Cefazolin 60Co
•OH Reaction EfficiencyCompound ●OH Reaction
Efficiency
Ampicillin 49.7 ± 2.5%
Cefaclor 45.6 ± 2.6%
Cefazolin 78.4 ± 4.9%
Penicillin-G 75 ± 10%
• This means that we require 1-2 •OH reactions to
chemically remove one antibiotic molecule
• Have to quantitatively account for radical rate
constant and efficiency
What about biological efficiency?
• One oxidation will change chemical
structure, but may not perturb function.
• Monitor bacterial growth when exposed to
oxidized product. As the dose increases,
growth should increase as well.
Structure/Function Relationships:
Macrolides
prevent protein
elongation
MTS Assay
Metabolically Active Cell
Required Oxidations – β-lactams
Measured Parameters
Compound k•OH
(109 M-1s-1)
•OH
Oxidations
Penicillin 8.70 ± 0.32 5
Penicillin V 9.14 ± 0.12 6
Ampicillin 8.21 ± 0.29 4
Amoxicillin 6.94 ± 0.44 6
Cloxacillin 6.27 ± 0.13 5
Roxithromycin 4.85 ± 0.25 12
Neomycin 4.73 ± 0.12 11
SO4-• + Pen G P1
SO4-• + DOM P2
SO4-• + t-butanol P4
Pen G + DOM = Complex + t-butanol
k1
k4
k3k2
P1 P2P3 P4
K
Pen G + DOM = Complex K = ?SO4
-• + Complex P3
Real world - Interactions of Pen G and DOM
k3 =?
Second order rate constant for Pen G/DOM + SO4
-• was much slower than 2.08 x 109, so there must be an
interaction
Results
K = 130.0 ± 26
LCMS Oxidation productsNH2H
N
HN
SCH3
CH3
OHO
OOOH
NH2HN
N
SCH3
CH3
OHO
OO
HO
NH2HN
N
SCH3
CH3
OHO
OO
O OHN
N
SCH3
CH3
OHO
OO
HN
NO
O
S
OOH
Where are we now?• Understand kinetics, radical reaction efficiencies,
and products of multiple classes of antibiotics
• Initiated estrogenic steroid study• Estrogen-sensitive
MCF-7 human breast cancer cells
• Ultimately studyestrogen mimics
Thanks:• Radiation Laboratory, Univ.
of Notre Dame
• OCWD: Ken Ishida
• Any questions??