Passive photo-catalytic destruction of air-borne VOCs in high traffic areas using TiO2-coated flexible PVC sheet

Photo-catalytic oxidation (PCO) of VOCs in high traffic regions can be achieved by providing optimum catalyst coating on large surface areas of advertising boards. Nine different sol-gel preparation techniques were attempted for coating TiO2 on flexible PVC sheet used for advertising boards. These coatings were characterized for structural continuity, surface roughness, surface impurities, strong surface attachment and particle size using AFM, XRD, FESEM, and EDX analyzers and optimum sol preparation technique for coating was adopted. Several sets of experiments were conducted for oxidation of benzene and toluene in a batch reactor (having optimum coating on PVC sheet) and parameters like reaction rate constant, order of reaction and removal efficiency etc. were evaluated. The reactions followed 1st order reaction rate model with rate constants for benzene 1.65 × 10−5 min−1 cm−2 and toluene 1.07 × 10−4 min−1 cm−2. The oxidation rate achieved on PVC sheet using natural sunlight for benzene and toluene was around 50% and 68% of that achieved for artificially controlled UV light. This study proposes a novel method of ambient air VOC destruction using PCO technique under natural sunlight in high traffic areas having large advertisement boards that can provide surface for catalytic coating.