Ethylene removal by adsorption and photocatalytic oxidation using biocarbon –TiO2 nanocomposites

Abstract

A series of adsorbents and photocatalysts were developed using agricultural residues (olive stones) as raw materials. Activated carbons (ACs) were synthesized by physical activation and posteriorly, impregnated with TiO2 by a hydrothermal method. Both adsorbents (ACs) and composites (carbon-TiO2) were texturally, morphologically and chemically characterized by using complementary techniques (i.e., SEM, gas adsorption, TG, XRD, pHPZC, and so on) and then, the affinity of these samples for the ethylene molecules was tested in columns under dynamic conditions. The corresponding breakthrough curves were determined obtaining the amounts adsorbed at the breakthrough and saturation points. Finally, the photooxidation of ethylene to CO2 using carbon-TiO2 composites was analysed under UV-Vis and near UV-Vis irradiations. The physicochemical characteristics of supports and composites were correlated with their ability to remove ethylene, looking to identify the parameters allowing to improve the performance of the samples.