Absorption and photocatalytic degradation of VOCs by perfluorinated ionomeric coating with TiO2 nanopowders for air purification

Abstract

In this work, we propose a transparent multilayered perfluoropolymeric coating as immobilization method for TiO2 nanoparticles, and evaluate its suitability in the gas phase photocatalytic degradation of six different volatile organic compounds. The coating was made of a layer of TiO2containing perfluorosulfonic acid polymer on a layer of perfluorinated amorphous polymer. The chemical stability of perfluoropolymeric materials to UV radiation and UV-activated TiO2 overcomes the possible degradation of the polymeric immobilization system which is typical of more traditional polymeric coatings. Moreover, the TiO2-containing ionomeric perfluorosulfonic layer worked as selective membrane for pollutants absorption and catalyst preservation, depending on the interactions between the superacidic polar heads of the ionomer and the pollutants, in particular those capable of hydrogen bonding. Gas-phase photocatalytic degradation tests were performed using pentane, methanol, 2-propanol, toluene, dichloromethane and pyridine as reference volatile organic pollutants, thus ranging on different polarity properties. Results indicate performances comparable to other approaches reported in the literature and show a strong influence of both atmospheric conditions (namely, humidity) and pollutant nature-polarity, proticity-on the actual kinetics of photodegradation, also depending on the interactions regulating the affinity between the ionomeric layer of the coating and pollutants. The high potential of the coating in the photodegradation was confirmed by the observed values of the photoabatement rates: all approximatively above 10-5 s-1 and maximum for alcohols (1.4 × 10-4 and 1.7 × 10-4 s-1 in dry and humid conditions, respectively).

Photocatalytic inactivation of airborne bacteria in a polyurethane foam reactor loaded with a hybrid of MXene and anatase TiO2 exposing {0 0 1} facets

“…Sansotera et al’s study [53] revealed that the increase in atmospheric humidity progressively increased the photodegradation rates of VOCs given that water vapors can be adsorbed on the TiO 2 active sites as resources for • OH, and therefore the enhancement of inactivation performance may result from the promoted generation of ·OH under high humidity [54] . Fig.…”

The Sonophotocatalytic Degradation of Pharmaceuticals in Water by MnOx-TiO2 Systems with Tuned Band-Gaps

“…TiO 2 is one the most employed semiconductors. It has found applications in water and air purification [16][17][18], sterilization [19], self-cleaning building materials [20], defogging [21], and H 2 generation from water splitting [22]. TiO 2 is cheaper and more photo-chemically and chemically stable than other semiconductors [13].…”

Antimicrobial TiO2 nanocomposite coatings for surfaces, dental and orthopaedic implants

“…Consequently, the cell membrane of B. subtilis and its spore could protect them from the attack of ROSs during photocatalysis. The Log inactivation efficiency of the photocatalyst was increased with respect to the humidity from 30 to 95 %, indicating that the high humid conditions stimulate the photo-generation of ROSs [80] , [81] . The reactivation of microbes was tested after the treatment of photolysis and photocatalysis.…”