Removal of Wastewater Pharmaceutical Chemical Contaminants Using AOPs

Transcription

1 H S H Removal of Wastewater Pharmaceutical Chemical Contaminants Using APs Stephen P. Mezyk Department of Chemistry and Biochemistry California State University at Long Beach Long Beach, CA, 90840, USA

2 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

3 Where can we get more water? Desalination? Costly, but getting better Environmental problems (retentate) Conservation? YES of course! Reusing our wastewater? ~10 12 litres wastewater/day in US! Direct toilet to tap Public perception is bad Costs????

4 Pathogens Carcinogens R R' Industrial chemicals H 3 C H C 3 C CH 3 CH 3 What s in our wastewater? Pesticides H Cl H DM HC 3-3- / 2 - Pharmaceuticals H H H H F H H S H H

5 How do we clean wastewater? More than current 1 o and 2 o wastewater treatment! Use ionizing radiation radical based treatment? range County Water District CA! Advanced xidation Processes (APs) Most work on H, can maybe use S - 4? H radicals (E o = 2.8V), S - 4 (E o = 2.4V) What is the cost of using APs?

6 H 2 -/\/\ 0.28 H e - aq +0.06H H H H + H 2 2 / 3 /UV Supercritical Water xidation Gamma Radiation 3 /UV H 2 2 / 3 H 2 2 /UV H An H radical is an H radical! Electron beam Beams on-thermal Plasmas Electrohydraulic Cavitation & Sonolysis

7 range County Water CA District approach:

8 Why Do We Care? Trace antibiotic levels can cause major health problems Unnecessary environmental exposure causes development of dangerous resistant strains MRSA, DM-1, CRE of bacteria H H Allergies and sensitivities Public concern over detection of estrogenic chemicals in water

9 What do we need to understand the chemistry? Computer models that accurately predicts chemistry of removal for quantifying costs of APs 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)

10 b-lactam antibiotics: Rate constants for H and S 4 - radical in pure water well established. H 2 -/\/\ 0.28 H e - aq +0.06H H H H + 2 saturated soln: e - aq/h + 2 H t-buh/ 2 /S H/H + t-buh R e - aq + S S S 4 -

11 10 3 Absorbance Kinetic data for β-lactams and H Compound k H (10 9 M -1 s -1 ) Aminopenicillanic Acid 3.35 ± 0.06 Penicillin G 8.70 ± 0.32 Penicillin V 9.14 ± 0.12 Ampicillin 8.21 ± 0.29 Average: k av ~ 7.15 x 10 9 M -1 s Carbenicillin 7.31 ± 0.11 Cloxacillin 6.27 ± 0.13 Cephalothin 4.93 ± 0.15 Cefotaxime 9.29 ± 0.12 Dail and Mezyk, JPCA, 114, (2010) Time ( s)

12 10 3 Absorbance R 1 H H S S 4 - and β-lactams CH k av ~1.6 x 10 9 M -1 s -1 Compound k S4 - (10 9 M -1 s -1 ) 6-aminopenicillanic acid Amoxicillin Ampicillin Carbenicillin Cloxacillin Penicillin G Penicillin V Piperacillin Ticarcillin Time ( s) 1.80 mm 1.38 mm 1.02 mm 0.61 mm 0.37 mm 0.20 mm Rickman and Mezyk, Chemosphere, 81, (2010)

13 Sulfate radical may be better choice! Species k H M -1 s -1 vs k S4- M -1 s -1 b-lactams av 7.2 x x 10 9 HC x 10 6 ~ 5 x 10 6 C x x ~ x x x 10 8 DM 6.27 x x 10 7

14 Absolute Difference H Efficiency HPLC measures parent loss H + β-lactam β-lactam 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0 Cefazolin 60 Co Dose (kgy) Watch peak area decrease with degradation of compound

15 H Reaction Efficiency Compound H 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 H reactions to chemically remove one antibiotic molecule Have to quantitatively account for radical rate constant and efficiency What about biological efficiency?

16 Structure/Function Relationships: ne 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. Macrolides prevent protein elongation

17 MTS Assay Metabolically Active Cell

18 Required xidations β-lactams

19 Measured Parameters Compound k H (10 9 M -1 s -1 ) H xidations Penicillin 8.70 ± Penicillin V 9.14 ± Ampicillin 8.21 ± Amoxicillin 6.94 ± Cloxacillin 6.27 ± Roxithromycin 4.85 ± eomycin 4.73 ±

20 S Pen G P 1 S DM P 2 S t-butanol P 4 Real world - Interactions of Pen G and DM Pen G + DM = Complex K =? S Complex P 3 k 3 =? K Pen G + DM = Complex k 1 k 2 k 3 k 4 Second order rate constant for Pen G/DM + S 4 - was much slower than 2.08 x 10 9, so there must be an interaction + t-butanol P 1 P 2 P 3 P 4

21 K = ± 26 Results

22 LCMS xidation products H 2 H SCH 3 H H CH 3 H H H 2 H H S H SCH 3 CH 3 H H 2 H H SCH 3 CH 3 H SCH 3 CH 3 H

23 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 study estrogen mimics

24 Thanks: Radiation Laboratory, Univ. of otre Dame CWD: Ken Ishida Any questions??