Recent Advances in Photocatalytic Reactors.
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Recent advances in photocatalytic reactors were summarized in 3 sentences or less: The document reviewed various photocatalytic reactor designs used to degrade organic pollutants like pesticides and dyes, as well as microorganisms, using different catalysts like TiO2 and light sources like sunlight and UV lamps. Reactors included batch, continuous flow, and thin film designs. Degradation rates of over 90% were typically achieved for various contaminants like monocrotophos, acetamiprid, thiabendazole, methyl orange, and rhodamine B.
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Recent Advances in Photocatalytic Reactors.
- 1. RECENT ADVANCES IN PHOTOCATALYTIC REACTORS Submitted by: Madhura N. Chincholi Guided by: Dr. PRG
- 2. INTRODUCTION • Background • Photocatalysis? • Catalysts • Light sources • Reactors • Applications 5/24/2015 2
- 3. LITERATURE REVIEW • Organics and microorganisms • Dyes • Drugs • Toxic components 5/24/2015 3
- 4. ORGANICS & MICROORGANISMS 5/24/2015 4 •Sraw et al. (2013) degraded monocrotophos (MCP), an organophosphorous insecticide •Catalysts- Aeroxide P-25 and LR grade TiO2 •UV (8 blue black UV florescent lamps (Philips, 20W)) and sunlight •Ambient T & P, t = 3 h •84% degradation • Degradation rate increased by 15 % by H2O2 addition with LR TiO2 Fig. 1. Skurry batch photocatalytic reactor setup (Sraw et al. 2013)
- 5. • Grcic et al.(2015) • Household greywater (GW) • Solar photocatalysis • Followed by flocculation by chitosan • TiO2-coated textile fibers by applying TiO2– chitosan pasteous dispersion on polyester/wool blend textile • The reactor assembled mostly from waste materials • Results showed significant decrease in organic content (50.8%), COD and toxicity over a period of 4 h. 5/24/2015 5
- 6. 5/24/2015 6 • Complete degradation of dye molecules and certain aromatic compounds. •The chitosan dissolved at certain extent during photocatalytic treatment •An efficient flocculant in treated wastewater. • Flocs observed shortly after treatment, complete sedimentation 12 h in dark. Fig.2 Schematics of reactor for solar photocatalysis (a) front view, (b) top view (c) side view. (Grcic et al. 2015)
- 7. • Carra et al. (2015) • Acetamiprid (ACTM), thiabendazole (TBZ) and their transformation products (TPs) in an agro-food industry effluent • Solar photo-Fenton treatment. • Novel 5/24/2015 7 Fig. 3 Scheme of the raceway pond reactor (RPR) used in the experiments. (Carra et al. 2015)
- 8. • Avg. UV irradiance of 15 ± 1Wm-2 (winter conditions) measured by a global UV radiometer • Avg. wastewater T: 26 ± 2 °C. • High degradation achieved (>99% TBZ and 91% ACTM in 240 min). • Analyses indicated that after the treatment only three TPs from ACTM were still present in the effluent, while the others had been removed. 5/24/2015 8
- 9. • García-Fernández et al. (2015) • Disinfection of urban effluents using solar TiO2 photocatalysis • E. coli and F.solani spores • Compound parabolic collectors (CPC) reactor • Two CPC mirror titled at 37◦ • T= 45 °C • Qair= 60 L/h • TiO2= 100 mg/L • ~99.9 5/24/2015 9 Fig.4 The 60 L-CPC reactor . Front view (4.5 m2of collector mirrors) with air injection points indicated (a), side view: air injection and DO probe (b), and cooling and heating systems (c)(García-Fernández et al. 2015)
- 10. DYES • Esparza et al. (2011) • Methylene blue (MB) • Natural volcanic ashes (VA) particles and nanostructured titania supported on volcanic ashes (TVA) • High-pressure Na vapour lamp (Philips, model 400-W G/92/2) placed 50 cm far from thereactor • Fixed-bed photocatalytic reactor. (designed and built in the lab) 5/24/2015 10
- 11. • Easy and efficient method to carry out photocatalytic reactions without requiring water filtration post-processing • Conversions in case of TVA, independent of the flow rate were about 90.3% for 3 h reaction time • 96.4%. 5/24/2015 11 Fig. 5. Schematic view of experimental setup (Esparza et al. 2011)
- 12. • Lin et al. (2012) • Methyl orange(MO) • A novel multi-layer rotating disk reactor(600 rpm) • Four stacked cells • Eight UV-light lamps (4 W each) and an Al disk (dia. 12 cm) • TiO2 nano-particles coated • Inlet 4×10−5 M MO • At 5 ml/min conversion >95% • High conversion at high flow rate 5/24/2015 12 Fig.6. Schematic diagram of the MLRDR system (Lin et al. 2012)
- 13. • Byberg & Cobb (2012) • Direct Red 23, 80, and 81, Direct Yellow 27 and 50, and Direct Violet 51 • 25 mg/L • Paper embedded TiO2 • Equalized for 30 min, run for 24 h • Complete color removal • 80% TOC reduction, toxicity increased 5/24/2015 13 Fig. 7. Photo and sketch of reactor used at ENSIC. (Byberg & Cobb 2012)
- 14. • Pastrana-Martínez et al. (2013) • TiO2 catalysts: large titania sol–gel nanoparticles (ECT), surface modified titania nanoparticles (m- TiO2) and graphene oxide-TiO2 composite (GOT-3.3) • Under near-UV/Vis and visible light. • Methyl orange (MO) • Quartz cylindrical reactor(7.5 mL solution) • A Heraeus TQ 150 medium pressure Hg vapor lamp (visible light a cut-off long pass filter) • pH 4.4, catalyst loading 0.5 mg/L • Composite (GOT-3.3) quite active, (m-TiO2) visible light 5/24/2015 14
- 15. 5/24/2015 15 • Rasoulifard et al. (2014) • Direct Red 23 (DR23) • UV-LED/S2O8 2- • Continuous photoreactor (octagonal cylindrical ) • 72 UV-LEDs (1 W each) • S2O8 2- (12.5 mM), dye conc. (20 ppm), current intensity (80%) Fig. 8 Schematic representation of continuous photoreactor (3.6 W)( Rasoulifard et al. 2014)
- 16. • Li et al. (2014) • Rhodamine B (RhB) • Novel double-cylindrical-shell (DCS) photoreactor • Monolyer TiO2-coated silica gel beads • An UV black light lamp (Tokyo Metal BM-10BLB) • t= 12h, RhB= 10 mg/L • 49.6% and 90.4% in dark and in UV, resp. 5/24/2015 16
- 17. 5/24/2015 17 • Higher efficiency, lower energy consumption and better repetitive operation performance • Promising alternative for recalcitrant decomposition Fig. 9. Schematic of the TiO2-coated silica gel beads immobilized double-cylindrical- shell (DCS) photoreactor and the photocatalytic system.( Li et al. 2014)
- 18. DRUGS • Wang et al. (2012) • 17-ethinylestradiol(EE2) • Modified flat plate serpentine reactor (MFPSR) • TiO2 • Three lamps (Philips TUV8W) • t= 120 min, TiO2 =0.04 g/L, u= 0.03 m/s, • 98 % 5/24/2015 18 Fig.10. Geometry of MFPSR and flow sheet of the experimental setup (Wang et al. (2012)
- 19. 5/24/2015 19 • Pastrana-Martínez et al. (2013) • Diphenhydramine (DP) • ECT, m-TiO2 and GOT-3.3 • Quartz cylindrical reactor • Heraeus TQ 150 medium pressure Hg vapor lamp • T= 25 °C, pH 5.9, 1 g/L catalyst • Under near-UV/Vis irradiation, ECT most active for the degradation of DP.
- 20. • Rodríguez et al. (2013) • Atenolol (ATL), hydrochlorothiazide (HCT), ofloxacin (OFX) and trimethoprim (TMP) • Photocatalytic oxidation, ozonation and photocatalytic ozonation • Borosilicate cylindrical reactor • A porous plate for gas • Black wooden box (50x30x30 cm) • Two 15 W black light lamps • TiO2 ,pH 4, t= 2 h • TPC and TOC removal of 80% and 60% 5/24/2015 20
- 21. 5/24/2015 21 TOXIC • Abhang et al. (2011) • Phenol • Three phase fluidized bed type of reactor (TPFBR) • TiO2 coated on solid silica gel particles • Four lamps of 8 W • P = 1 atm, T = 25 °C • W/o aeration only 50% • 95.27% within 1.5 h Fig.11 .Schematics of TPFBR Abhang et al. (2011)
- 22. 5/24/2015 22 • Shengyong et al. (2012) • Hexachlorobenzene • Quartz photocatalytic reactor • Nano-TiO2 catalyst film on a glass plate • Two 8W UV lamps • 50-mL ice-bathed hexane and acetone mixture • T=25 to 35 °C, t= 9.5 h, 12 µg , 5 mW/cm2 • ~99% Fig. 12 .Schematic diagram of the photocatalysis reactor. (Shengyong et al. 2012)
- 23. 5/24/2015 23 • Tang et al. (2012) • Perfluorooctanoic acid (PFOA) • Water-jacketed cylindrical quartz photoreactor • Ferrous sulfate and H2O2 • 9W UV lamp • PFOA 20.0 _M, H2O2 30.0 mM, Fe2+ 2.0 mM, pH 3.0 • 95% Fig. 13. A diagram of the experimental set-up for photodegradation of PFOA. (Tang et al. 2012)
- 24. 5/24/2015 24 • Choi et al. (2012) • Anodized nano-structured TiO2 membrane • N-nitrosodimethylamine (NDMA) under UV • Micro-porous tubular-type pure Ti (12-mm inner dia., 100-mm length) was prepared for anode materials. • 99.9 % pure Ta (thickness 0.25 mm, surface area of 50x50 mm2) as a counter electrode.
- 25. 5/24/2015 25 Graph. 1 Removal of NDMA using RO membrane (conditions: contact time 100 min, temperature 20 ± 1 C, NDMA 1 mg L-1, initial pH 6 ± 0.2, UV intensity 64 W and ozone concentration 9.0 mg L-1). Here, anodized Ti membrane and reverse osmosis are denoted as A-Ti-M and RO, • Electrolyte, 1 M KH2PO4 solutions with 0.35 wt% NH4F. •Electrolyte stirred continuously and anodization was conducted at a constant potential with a DC power supply. •Lead to the formation of distinct array of TiO2 nanotubes
- 26. 5/24/2015 26 • Souzanchi et al. (2013) • Phenol • Annular sieve-plate column photoreactor • Two concentric columns • TiO2 immobilized on a stainless steel sieve plate • 15W UV-A lamp • t= 6 h, T=35 °C, 0.5 mM phenol • ~100% • COD lowered by 95%
- 27. 5/24/2015 27 Fig. 14. Details of size and dimensions of the ASCP photoreactor used in the present study in two sections: vertical (a), and horizontal (b). (1) Inner quartz tube; (2) outer Pyrex tube; (3) 15WUV- A lamp; (4) stainless steel sieve plate rings (i.e., TiO2 immobilized support); (5) inlet; (6) outlet.
- 28. 5/24/2015 28 Paper Degradation of Reactor Catalyst Light source Operating Conditions Result Sraw et al (2013) Monocrotophos (MCP) Slurry batch reactor Aeroxide P-25 and LR grade TiO2 Blue black UV florescent lamps (Philips, 20W) t= 3 h MCP= 25 ppm P25= 0.5 g/L, pH = 5 84% García- Fernández et al. (2015) Escherichia coli and Fusarium solani spores Compound parabolic collectors (CPC) reactor Suspended TiO2 Sunlight T= 45 °C Qair= 60 L/h TiO2= 100 mg/L ~99.9 Grcic et al.(2015) Household greywater Thin film reactor TiO2 coated textile fibre Sunlight t= 4 h 50% organics, significant reduction in other ingredients Carra et al.(2015) Acetamiprid(AC TM), thiabendazole(T BZ) and their transformation products(TPs) Raceway pond reactor Fenton (Ferrous iron) Sunlight, UV irradiance of 15 ± 1Wm-2 pH= 2.8 ± 0.1 T=26 ± 2 °C t= 240 min >99% TBZ, 91% ACTM,. only 3 TPs remained PESTICIDES AND OTHER ORGANICS
- 29. 5/24/2015 29 Paper Degradation of Reactor Catalyst Light source Operating Conditions Result Esparza et al. (2011) Methylene blue Fixed-bed reactor Natural volcanic ashes (VA), nano- titania supported on volcanic ashes (TVA) High-pressure Na vapour lamp (Philips, 400-W G/92/2) pH =7 T= 20 °C Degradation 85.6% with VA, 96.4% with TVA Lin et al. (2012) Methyl orange Multi-layer Rotating disk reactor Nano-sized tio2 particles 8 UV-light lamps (4 W each; Winstar Lighting Co., Ltd) Ambient temperature, 600 rpm Within s of residence time 95% conversion Byberg & Cobb (2012) Direct Red 23, 80, and 81, Direct Yellow 27 and 50, and Direct Violet 51 Thin film reactor TiO2 paper substrate UV lamp Dye 25 mg/L t= 24 h TOC ~80% 100 % color removal Pastrana-Martínez et al. (2013) Methyl orange Quartz cylindrical reactor ECT, m-TiO2 and GOT-3.3 Heraeus TQ 150 medium pressure Hg vapor lamp T= 25 °C, 0.5 g/L catalyst pH 4.4 ~99% Li et al. (2014) Rhodamine B (RhB) Novel double- cylindrical-shell (DCS) photoreactor Monolyer TiO2-coated silica gel beads An UV black light lamp (Tokyo Metal BM- 10BLB) t= 12h RhB= 10 mg/L 49.6% and 90.4% in dark aad in UV, resp. Rasoulifard et al. (2014) Direct Red 23 (DR23) Continuous photoreactor (octagonal cylindrical) Potassium peroxydisulfate 72 UV-LEDs of 1 W each S2O8 2- (12.5 mM), DR23 (20 ppm), current I.(80%) 90% DYES
- 30. 5/24/2015 30 Paper Degradation of Reactor Catalyst Light source Operating Conditions Result Wang et al. (2012) 17- ethinylestradiol (EE2) Modified flat plate serpentine reactor TiO2 Three lamps (Philips TUV8W) T=25±2 °C t= 120 min TiO2 =0.04 g/L u= 0.03 m/s, Iw = 282 W/m2 98 % Pastrana- Martínez et al. (2013) Diphenhydramine (DP) Quartz cylindrical reactor Large titania sol– gel nanoparticles, surface modified titania nanoparticles Graphene oxide- tio2 composite Heraeus TQ 150 medium pressure mercury vapor lamp T= 25 °C pH 5.9 1 g/L catalyst t= 240 min DP (3.40x104 mol/L) ~98% Rodríguez et al. (2013) Atenolol (ATL), hydrochlorothiazide (HCT), ofloxacin (OFX) and trimethoprim (TMP) Borosilicate cylindrical reactor TiO2 Two 15 W black light lamps (Lamp 15TBL HQPowerTM Velleman®) pH 4 t= 2 h TPC and TOC removal of 80% and 60% DRUGS
- 31. Paper Degradation of Reactor Catalyst Light source Operating Conditions Result Abhang et al. (2011) Phenol Three phase fluidized bed type of reactor (TPFBR) TiO2 coated on solid silica gel particles Four lamps of 8 W P = 1 atm T = 25 °C t = 2 h 95.27% within 1.5 h Shengyong et al. (2012) Hexachlorobenzene Quartz photocatalytic reactor Nano-TiO2 catalyst films Two 8W UV lamps T=25 to 35 °C t= 9.5 h 12 µg 5 mW/cm2 ~99% Tang et al. (2012) Perfluorooctanoic acid (PFOA) Water-jacketed cylindrical quartz photoreactor Ferrous sulfate and H2O2 9W UV lamp PFOA 20.0 _M, H2O2 30.0 mM, Fe2+ 2.0 mM, pH 3.0, 5 h 95% Choi et al. (2012) N- nitrosodimethyla mine Membrane reactor TiO2 nanotubes UV (64 W) t= 100 min, T= 20 ± 1 °C, NDMA= 1 mg L-1, initial pH= 6 ± 0.2 ~100% Souzanchi et al. (2013) Phenol Annular sieve- plate column photoreactor TiO2 immobilized on a stainless sieve plate 15W UV-A lamp t= 6 h, T=35 °C, 0.5 mM phenol ~100% COD lowered by 95% 5/24/2015 31 TOXIC COMPONENTS
- 32. 5/24/2015 32 PROJECT OUTLINE • Improve cooling tower efficiency • Biological fouling • Disinfection of water • Source • Identify the microorganisms • TiO2 • Reactor type • MOC • Light source
- 33. REFERENCES • Abhang R. M., Kumar D. & Taralkar S. V., “Design of Photocatalytic Reactor for Degradation of Phenol in Wastewater”, Int. J. Chem. Eng. Appl. 2, 337–341 (2011). • Choi W.-Y., Lee Y.-W. & Kim J.-O., “Performance of photocatalytic membrane reactor with dual function of microfiltration and organics removal”, 1517–1522 (2013). • Izadifard M., Achari G. & Langford C. H., “Application of Photocatalysts and LED Light Sources in Drinking Water Treatment”, 726–743 (2013). 5/24/2015 33
- 34. • Lin C.-N., Chang C.-Y., Huang H. J., Tsai D. P. & Wu N.-L., “Photocatalytic degradation of methyl orange by a multi-layer rotating disk reactor”, Environ. Sci. Pollut. Res. 19, 3743– 3750 (2012). • Nakata, K. & Fujishima A., “TiO2 photocatalysis: Design and applications”, J. Photochem. Photobiol. C Photochem. Rev. 13, 169–189 (2012). • Tang H., Xianga Q., Lei M., Yan Zhub L., & Zouc J., “Efficient degradation of perfluorooctanoic acid by UV – Fenton process”, Chem. Eng. J. 184, 156–162 (2012). 5/24/2015 34
Notas del editor
- due to the presence of aromatic amines So further degradation by biological secondary treatment would be necessary.
- reactor filled with 7.5 mL . GOT-3.3 composite was quite active in the photodegradation of MO, especially under visible light, where P25 was practically inactive. m-TiO2 displayed a remarkable photocatalytic activity for degradation of MO under visible light irradiation, suggesting promising results for visible light applications.
- Results revealed that UV-LEDs continuous photoreactor could be energy-efficiently applied for the degradation of low-levels of the organic pollutants especially synthetic dyes.
- This photocatalytic reactor, in comparison with reported slurry-suspension and thin film photoreactors, showed higher efficiency, lower energy consumption and better repetitive operation performance for the degradation of RhB and MO. The TiO2-coated silica gel beads immobilized DCS photoreactor was a promising alternative for the decomposition of recalcitrant organic pollutants in wastewater.
- Two poly (methyl methacrylate) baffles separated the whole reactor into three equal channels. Three quartz glass tubes were mounted axially inside the channels and centered with respect to the channels. A suspension of EE2, TiO2 (Degussa P25), and distilled water was magnetically stirred for 30 min in darkness to ensure the adsorption equilibrium was achieved and then transferred to the recirculation feed tank which was fitted with a gas pump. The pump saturated the reaction solution with O2, thus avoiding any complication arising by deficiency in the reacting system and stripe CO2 which was produced by the degradation of the endocrine-disrupting chemicals.
- The higher efficiency of ECT is related to its enhanced availability to originate reactive hydroxyl radicals from photoinduced holes at the catalyst surface.
- It was equipped with bubbling and/or magnetic agitation (depending on the process) and inlets for measuring temperature, feeding the gas (air, O2 or O3-O2 through a porous plate at the reactor bottom), sampling and one outlet for the non absorbed gas. The reactor was situated in the center of a 50x30x30 cm black wooden box. Two 15 W black light lamps (Lamp15TBL HQPowerTM Velleman®) were placed in two opposing corners inside the box, 365 nm being the main emission wavelength. The lamps were chosen in an attempt to simulate the UVA solar radiation.
- The catalysts coated using sodium acetate. Sandwiched chambers to utilize UV light efficiently plexi glass (good pressure durability and optical properties) The two adjacent compartments from the central one were made water proof and sealed from all sides except from the top to house the UV lamps. The central one was the inlet compartment. Remaining two compartments, dimensional half of the width of the central compartment, these compartments acted as fluidized bed column. These also were the outlet section, having two 25 mm outlets drilled. The UV light source and the central compartment had a dimension of 50×200×1000 mm, the other two had 25×50×1000 mm and the bottom compartment had 200×200×50 mm. Drilled plate at the bottom of three horizontal compartments the inlet compartment consists of 4 mm drilled holes and the outlets compartments consists of 2 mm drilled holes. The bottom compartment had an aeration system, which had copper tube with 2 mm holes on the face at distance of 10 mm. The tube length was 190 mm and were four in number. Two situated below the inlet section and other two placed below the outlet section one on each side.
- Two equal volumes of this mixture were used in sequence to wash the glass plate after reaction; the rinses were analyzed for HCBz contents that remained unreacted on the catalyst surface. Hardly any HCBz was detected in the second rinsing liquid, which confirms that almost all remaining HCBz can be absorbed by one rinsing liquid. The temperature of the surface of the reactor slightly raised above the room temperature (25 to 35 °C) during the test.
- The anodized nano-structured TiO2 membrane annealed at 500°C efficiently decompose NDMA under UV light irradiation. This improvement can be attributed to the production of hydroxyl radicals generated by the UV irradiation of anodized TiO2 metal membrane.
- two concentric columns with the quartz and Pyrex glass as the inner and outer tubes, respectively. Fifty sieve plates of stainless steel in ring shape prepared as the supports for the immobilization of TiO2 nanoparticles were installed in the annulus space between the two tubes in parallel layers. The light source consisted of one UV lamp of 15 W emitting UV-A radiation and it was placed within the inner quartz tube. The test liquid was circulated between the photoreactor and a liquid tank equipped with jacket.