Oxidation of Pharmaceuticals and Personal-Care Products in Water using Hydrodynamic Cavitation

Transcription

1 Oxidation of Pharmaceuticals and Personal-Care Products in Water using Hydrodynamic Cavitation 245 th American Chemical Society Meeting April 10, 2013 Authors Greg Loraine and Georges L. Chahine Dynaflow, Inc J Iron Bridge Road Jessup, MD U.S.A. ACS 245 th

2 Outline Cavitation and Formation of Free Radicals Acoustic (Ultrasonic) Cavitation vs. Hydrodynamic Cavitation Hydrodynamic Cavitating Jets Chloramphenicol Pharmaceuticals and Personal-Care-Products in Wastewater Conclusions 6000 V spark. Collapse is analogous to cavitation

3 Cavitation Bubble nuclei in water expand & collapse when the local pressure changes very quickly. Collapsing bubbles produce tremendous pressures & temperatures in localized area (~5,200 K, ~200 Atm). Water vapor dissociates into OH and H H 2 O OH + H Volatile compounds can also dissociate into radicals CCl 4 Cl + Cl 3 C Pressure Radius of Bubble

4 Concentration Reaction Location Reactions occur inside collapsing bubble or at interface OH and H concentrations highest in center, decrease toward bubble wall Hydrophobic compounds partition to air-water interface Local depletion of starting compound and build up of products Volatile compounds enter the expanding bubble and decompose during collapse OH H Collapsing Bubble Parent Products Products

5 Hydrodynamic & Ultrasonic Cavitation Ultrasonic (US) cavitation produced by mechanical vibration in a liquid localized at the face of the probe. US- high intensity, localized cavitation, energy intensive, scaling up difficult Hydrodynamic Cavitation (HD) is produced by motion of fluid. All liquid is forced through cavitation region Large pressure fluctuations in shear layer of the liquid cause cavitation. HD wider area of cavitation, 1/10 1/100 energy required, easy to scale US HD

6 DYNAJETS Cavitating Jets Specially designed nozzles intensify cavitation and generate cavitation at lower pump pressures This is achieved through: Bluff body Swirling the flow Passive acoustic excitation Enhance vorticity and reduce pressure in the vortices DYNASwirl Area of Cavitation Centerbody CAVIJET

7 Hydrodynamic Cavitation for Oxidation Hydrodynamic cavitation can be times more energy efficient than acoustic cavitation No addition of oxidizer Optical opacity or particulates are no problem Other than nozzle no special equipment required Specially designed submerged nozzles (DYNAJETS ) Cavitation at lower pressures Lower pressures lower electrical requirements Hydraulic Energy = Flow Rate x Pressure Change x Time Cavitation in wider area Easier to scale up than US

8 C/C0 P-Nitrophe nol Oxidation Efficency, mg/mj Energy: Acoustic & Hydrodynamic Note Much More Rapid Concentration Drop with the DYNAJETS. ULTRASONIC 10 1 DYNAJETS Note High Oxidation Efficency and Short Oxidation Time for DYNAJETS. 0.4 DYNAJETS Time, Hours ULTRASONIC Time, Hours 25 ppm p-nitrophenol Hydrodynamic cavitation can be times more energy efficient than acoustic cavitation* *K.Kalumuck, G. Chahine, J. Fluids Eng., 122,(2000) 465. S. Majumdar, P. S. Kumar, A. Pandit, Ultra. Sonochem., 5 (1998) 113. K. Jyoti, A. Pandit, Water Res., 38 (2004), 2249.

9 Previous Work using DYNAJETS Oxidation Pharmaceuticals and Personal Care Products Chlorinated solvents Toluene, Acetone Pesticides: Malathion, Carbaryl, 2,4-D Disinfection Water Wastewater Storm water Recovery of Cellular Matter Algae Pretreatment of lignocellulose biomass Biodiesel production

10 Selectivity of HD Cavitation Oxidation Volatile (high vapor pressure) can be oxidized easily Hydrophobic compounds (high octanol-water partition coefficient log K OW ) oxidize faster than hydrophilic compounds ph can be used to adjust degree of ionization of weak acids and bases Reaction intermediates are formed in regions of high radical concentrations, lower by-product concentrations Operating parameters (pump pressure, jet velocity, etc.), and nozzle design can be varied to improve oxidation performance

11 Chloroamphenicol 2,2-dichloro-N-[1,3-dihydroxy-1-(4-nitrophenyl) propan-2-yl acetamide Broad spectrum antibiotic Log K OW = 1.14, pk a = 9.61 Experimental Oxidized using two types of nozzles Pressure drops across nozzle psi (2 6.2 bar) [CA] 0 = 30 mg/l in DI water (10 L) Analytical Extracted using SDB solid phase extraction disks GC/MS analysis LOD 2.4 mg/l & 95% recovery

12 Chloramphenicol mg/l Effects of Operating Pressure - DYNASWIRL Operating pressure had a large effect on the removal rate, Nozzle design and geometry also affect performance. 30 DYNASWIRL psi 90 psi 60 psi Oxidation Time, mins.

13 Chloramphenicol, mg/l Effects of Operating Pressure Centerbody CAVIJET Operating pressure again affected the removal rate, 91% removal 30 centerbody-cavijet psi 45 psi Oxidation Time, mins.

14 Chloramphenicol Removal per kilojoule 1.2 CAVIJET65 PSI Chloramphenicol [C]/[C] CAVIJET45 PSI DYNASWIRL 30 PSI DYNASWIRL 60 PSI DYNASWIRL 90 PSI kj

15 Concentration, mm Chloramphenicol: Product Formation and Mass Balance Mass Balance Mass Balance Chloramphenicol Nitrobenzaldehyde Dichloromethyl Oxazoline Time (mins.)

16 Proposed Mechanism of Chloramphenicol Oxidation NO 2 N C C Cl Cl + OH NO 2 N C C Cl Cl OH O OH O NO 2 4-Nitrobenzaldehyde + OH N C O C Cl Cl C N Cl H 2 O + C C C O Cl 2-dichloromethyl oxazoline N O C Cl C Cl OH

17 Selective Oxidation of Mixtures: log K OW Seven PPCP spiked into filtered wastewater TP effluent Oxidized using a DYNASWIRL nozzle Range of Log K OW Compound Primary Use Spiked concentration g/l MDL g/l * Concentration Range in Wastewater Effluent ug/l Ibuprofen Pharmaceutic al Triclosan Anti-microbial Chloroxylenol Anti-microbial Galaxolide Fragrance Musk Ketone Fragrance Oxybenzone Sun-screen Log K OW Tris (2- chloroethyl) Phosphate Flame retardant

18 Oxidation of Mixture of PPCP in Wastewater Log K OW C/C Chloroxylenol Tris(2-chloroethyl)Phosphate Galaxolide Musk Ketone Oxybenzone Triclosan Ibuprofen Time (mins.) DYNASWIRL nozzle at 60 psi

19 (1-C/C0) Log K OW and Reaction Extent y = 0.05x R 2 = log K ow In a mixture more hydrophobic compounds react faster

20 Conclusions Cavitation initiated reactions are similar regardless of how the cavitation is initiated Hydrodynamic cavitation can be more energy efficient and easier to scale up than ultrasonic devices Selective removal of volatile and hydrophobic compounds can be accomplished Oxidation rates have non-linear dependence on pump pressure Nozzle geometry can affect oxidation rates

21 Acknowledgements & Contact Information US Environmental Protection Agency NASA Office Naval Research NOAA NIEHS DYNAFLOW, INC J Iron Bridge Road, Jessup, MD USA Dr. Greg Loraine Sr. Research Scientist (301) Dr. Georges L. Chahine President (301) Business POC: Dr. Jin-Keun Choi Principal Research Scientist (301)