title: Solar photocatalytic gas-phase degradation of n-decane--a comparative study using cellulose acetate monoliths coated with P25 or sol-gel TiO₂ films.
abstract: Cellulose acetate monoliths (CAM) were used as the substrate for the deposition of TiO2 films to produce honeycombed photoactive structures to fill a tubular photoreactor equipped with a compound parabolic collector. By using such a setup, an efficient single-pass gas-phase conversion was achieved in the degradation of n-decane, a model volatile organic compound. The CAM three-dimensional, gas-permeable transparent structure with a rugged surface enables a good adhesion of the catalytic coating. It also provides a rigid structure for packing the tubular photoreactor, and maximizing the illuminated catalyst surface. The efficiency of the photocatalytic oxidation (PCO) process on n-decane degradation was evaluated under different operating conditions, such as feeding concentration (73 and 146 ppm), gas stream flow rate (73, 150, and 300 mL min(-1)), relative humidity (3 and 25 %), and UV irradiance (18.9, 29.1, and 38.4 WUV m(-2)). The results show that n-decane degradation by neat photolysis is negligible, but mineralization efficiencies of 86 and 82 % were achieved with P25-CAM and SG-CAM, respectively, for parent pollutant conversions above 95 %, under steady-state conditions. A mass transfer model, considering the mass balance to the plug-flow packed photoreactor, and PCO reaction given by a Langmuir-Hinshelwood bimolecular non-competitive two types of sites equation, was able to predict well the PCO kinetics under steady-state conditions, considering all the operational parameters tested. Overall, the performance of P25-CAM was superior taking into account mineralization efficiency, cost of preparation, surface roughness, and robustness of the deposited film.
authors.affiliation: LSRE-Laboratory of Separation and Reaction Engineering, Associate Laboratory LSRE/LCM, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, Porto, 4200-465, Portugal.
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Miranda
authors.forename: Filipe V S
authors.initials: FV
authors.lastname: Lopes
authors.forename: Caio
authors.initials: C
authors.lastname: Rodrigues-Silva
authors.forename: Susana D S
authors.initials: SD
authors.lastname: Martins
authors.forename: Adrián M T
authors.initials: AM
authors.lastname: Silva
authors.forename: Joaquim L
authors.initials: JL
authors.lastname: Faria
authors.forename: Rui A R
authors.initials: RA
authors.lastname: Boaventura
authors.forename: Vítor J P
authors.initials: VJ
authors.lastname: Vilar
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D000473:Alkanes / Q000737:chemistry*; D002384:Catalysis; D002482:Cellulose / Q000031:analogs & derivatives; D007700:Kinetics; D009930:Organic Chemicals; D010084:Oxidation-Reduction; D010782:Photolysis; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D055549:Volatile Organic Compounds / Q000737:chemistry*
chemical_list: D000393:Air Pollutants; D000473:Alkanes; D009930:Organic Chemicals; D055549:Volatile Organic Compounds; C009495:titanium dioxide; C005062:acetylcellulose; D002482:Cellulose; D014025:Titanium; C012867:decane