PHOTOCATALYTIC SYSTEM: FATE, REMOVAL AND MINERALIZATION Authored by - PowerPoint PPT Presentation

METRONIDAZOLE IN A UV-TIO 2 PHOTOCATALYTIC SYSTEM: FATE, REMOVAL AND MINERALIZATION Authored by Neghi. N & Mathava Kumar * *Associate Professor Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, Tamilnadu – 600 036, India Tel: +91-44-2257 4267; E-mail: mathav@iitm.ac.in

I NTRODUCTION - ANTIBIOTICS  Antibiotics - treat/prevent bacterial infections  Increasing trend in the consumption of antibiotics 2000- 2010:- Brazil - 68%, Russia -19%, India - 66%,China - 37%, South Africa - 219%( CDDEP,2015) US  10% of the world’s antibiotic consumption  Global antibiotic use by class  Broad spectrum penicillins  Cephalosporins  Macrolides  Trimethoprim and combinations  Quinolones  Aminoglycosides 2  Nitroimidazoles ( Metronidazole falls under this class)

ANTIBIOTICS IN THE ENVIRONMENT PPCP in Consumers PPCP into sludge Ecosystem Excretion & DOC removal other activities PPCP in by biological Centralized effluent process PPCP along Wastewater PPCP into with treatment units SW Wastewater Removal by PPCP into De-Centralized biological Soil 3 process PPCP into GW

ANTIBIOTICS IN THE ENVIRONMENT 4 Reference: www.saveantibiotics.org

ANTIBIOTICS IN THE ENVIRONMENT  Industrial wastewaters (Formulation)  Hospital Wastewaters  Aqua culture wastewaters  Meat processing units  Live-stock units  Feed manufacturing/growth supplement producing units 5

ANTIBIOTICS IN THE ENVIRONMENT  Vanishing Vulture’s  Poisoned animal carcass feeding with Diclofenac 6

ANTIBIOTICS IN THE ENVIRONMENT  Develop antibiotic resistance in aquatic environments  Affect building blocks of the ecosystem processes  WHO report - different antibacterial resistant strains - FS 194 -Updated April 2015 http://www.who.int/mediacentre/factsheets/fs194/en/  Detection range observed to be more in pharmaceutical production plant effluents 7

A NTIBIOTICS IN WATER AND WASTEWATER Source/Point of Origin Sampling Collection System Increase in antibiotics concentration Wastewater treatment units Point of Disposal Sampling Away from disposal points 8

W HY TO REMOVE ANTIBIOTICS ..???? Close the Loop in water use pattern Wastewater Treatment Water Recharge Wastewater into Ground Collection Water Water 9 Supply withdrawl

M ETRONIDAZOLE (MNZ) 2-(2-methyl-5-nitroimidazol-1-yl)ethanol, (C 6 H 9 N 3 O 3 )  Water Solubility  10 mg/mL  Log K ow  0.1 (hydrophilic)  Vapor pressure  3.1 x 10 -7 mm Hg at 25 o C  18% of drug excreted unchanged from human body  10

I NTRODUCTION - PHOTOCATALYSIS  Photocatalysis  One of the AOP’s O 2 + e − → . O 2 −  H 2 O 2 + e − → HO• + OH -  h + + H 2 O → H + + OH −  h + + OH − → HO•  11

A TTRIBUTES OF PHOTOCATALYTIC SYSTEM  Ideal photocatalyst -TiO 2  HO · generated in the system - non-selective- high oxidation potential (E 0 = 2.8V/SHE)  UV-C band of light - ability to handle the antibiotic resistant genes in real time wastewater  Difficulties  Post separation of the catalyst  Operation under continuous-mode  Support catalyst - overcome the difficulties  Support medium - Activated charcoal, Stainless steel 12 plate, Alumina.

B ACKGROUND 13

O BJECTIVES  Feasibility of MNZ removal by photocatalytic system with TiO 2 and GAC  Quantify the roles of catalysts and UV power on MNZ removal  Correlate MNZ removal with economic analysis to identify best suitable experimental condition  Long term goal  Create a system for continuous- mode photocatalysis for antibiotics removal 14

B ATCH PHOTOCATALYTIC REACTOR ELECTRONIC STIRRER UV POWER PROBES SUPPLY CONNECTED TO pH/ORP/Temp METER DOUBLE WALLED CYLINDRICAL GLASS REACTOR WITH WORKING VOLUME OF 1.9 L METRONIDAZOLE AND TiO 2 IN SUSPENSION 15

P HOTOGRAPHIC VIEW OF THE REACTOR 16

E XPERIMENTAL CONDITION Initial MNZ Catalyst Type of Comments UV Power concentration dosage catalyst (W) (mg/L) (g/L) - Blank 16 Photolytic 15 - - studies 32 - Photocatalytic 15 16 2.5 TiO 2 studies 32 - Adsorption 15 2.5 GAC 32 studies 17

A NALYTICAL TECHNIQUES MNZ and its metabolites - HPLC/ LC-MS I. Organic carbon constituents of samples - TOC II. Surface morphology of the catalyst and the support III. chosen – SEM Elemental composition of the catalyst/ adsorbent – IV. EDS pH/Temperature/Oxidation-Reduction Potential of the V. system - Benchtop multi-parameter analyzer COD analysis - Standard Methods (APHA, 2002) VI. 18

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MNZ REMOVAL BY CHOSEN PROCESSES 1,2 16W 1,0 32W TiO2 adsorption 0,8 TiO2+16W TiO2+32W 0,6 C/C 0 GAC adsorption 0,4 GAC+32W 0,2 0,0 0 20 40 60 80 100 120 20 Time(min)

ORP T REND 400 16W 32W 300 TiO2+16W ORP (mV)) TiO2+32W 200 GAC+32W 100 0 0 20 40 60 80 100 120 Time (min) 21

C OMPARISON OF MNZ REMOVAL 96,4 100 At 60 min 94,1 At 120 min 77,5 80 61,1 62,4 60 52,9 42,4 40 33,8 32,5 23,9 23,6 21,7 18,7 20 15,6 0 16W 32W TiO2+ TiO2 + GAC + GAC TiO2 16W 32W 32W adsorption adsorption 22

E NERGY CONSUMPTION ANALYSIS Rate of Reaction: Energy Consumption: 23

E NERGY CONSUMPTION OF THE SYSTEM FOR DIFFERENT PROCESS 1 Energy Consumed* (KWh) 0,9 EEO (KWh m-3 order-1) 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0 16W 32 W TiO2+16W TiO2+32W GAC+32W GAC TiO2 24 adsorption adsorption

R ESULTS OF B ATCH ANALYSIS Removal Removal (%) Rate constant Energy E EO (KWh Comments (%) after 60 after 120 min ‘k 1 ’ Consumed* m -3 min (min -1 ) (KWh) order -1 ) MNZ COD MNZ COD 1.4 4.0 1.4 4.0 0.000 0.000 0.000 Blank 23.6 15.3 23.9 17.5 0.002 0.032 0.144 16W 32W 33.8 16.9 42.4 31.1 0.004 0.064 0.141 TiO 2 +16W 61.1 56.3 94.1 72.2 0.022 0.172 0.077 TiO 2 +32W 62.4 60.0 96.4 80.7 0.026 0.204 0.080 GAC+ 32W 52.9 - 77.5 - 0.012 0.214 0.129 GAC 21.7 - 32.5 - 0.002 0.096 0.296 adsorption TiO 2 15.6 48.8 18.7 61.2 0.001 0.150 0.877 adsorption 25 Energy consumed by (a) electronic overhead stirrer - 70/42 W (I/O), (b) UV Lamps - 16 W each, and (c) orbital shaker for adsorption studies - 48 W were included for energy consumption analysis.

D EGRADATION OF 15 PPM OF MNZ IN P HOTOCATALYTIC S YSTEM Removal in percent 96,4 80,7 66,5 MNZ COD TOC removal reduction removal Series1 96,4 80,7 66,5 26

SEM ANALYSIS OF ADSORPTION OF MNZ ONTO T I O 2 & GAC (a) TiO 2 before treatment (b) TiO 2 after treatment GAC before (c) treatment (d) GAC after treatment 27

LC-MS A NALYSIS 28

LC-MS A NALYSIS 29

C ONCLUSIONS  Highest MNZ removal  with 32 W UV power and 2.5 g L -1 TiO 2 in 120 min.  Removal of MNZ using GAC as a photocatalyst was remarkably higher than that of GAC used as an adsorbent.  The concept of electrical energy consumed per order, i.e. E EO - ideal parameter for the economic analysis. 30

Upgraded-Setup for PPCP Removal Research 31

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