Removal of Wastewater Pharmaceutical Chemical Contaminants

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??