Environmentally friendly catalysts for improved cleaning of toluene-containing gaseous effluents

Abstract

This research describes the design of green oxidation catalysts capable of cleaning toxic gaseous effluents using low cost rice production sub-products, iron oxide chosen as the active phase due to its low toxicity and price (ca. 4 orders of magnitude less than noble metals normally utilised in oxidation reactions) and a low cost abundant clay with excellent rheological properties to facilitate the conformation of the catalysts. These catalysts have activities similar to others which often are based on synthetic and/or expensive and hazardous materials. The use of agro-industrial sub-products lowers the production costs, improves the catalytic performance, leading to a sustainable cycle in which waste materials from an industry are used as renewable raw materials for the same or others. Although addition of palladium (taken as an example of an efficient noble metal for catalytic oxidations) to the best iron containing catalyst, improves the oxidation of toluene decreasing energy costs, there are evidences that its presence in particulates and aerosols produced on use, can cause health problems.