Solar photocatalytic oxidation of Triclosan with TiO_2 immobilized on volcanic porous stones on a CPC pilot scale reactor

摘要

Triclosan (TCS) has been used as an antimicrobial agent for more than 30 years and is present in effluents from wastewater treatment plants, in receiving rivers, in tap water and even in groundwater. This compound is resistant to conventional water treatment processes and has been classified as endocrine disruptor and emerging concern pollutant by several organizations. For this reason it is essential to find an efficient process that allows its degradation to non-toxic substances. In this study, TiO_2 was immobilized by forming thick TiO_2 films on volcanic meso-porous stones, creating a photocatalyst that fills a Pyrex® CPC reactor (packed bed reactor type CPC). This reactor is used to remove aqueous Triclosan from water. Films structure and composition is determined experimentally. Efficiency of the organic molecule removal is being related with initial conditions. Films present a very high mechanical stability, excellent adhesion on stones and photocatalytic activity. Reactor, packed with covered stones, presents a reasonable pressure drop. One of the main goals is to have the reactor in operation without any solid - liquid separation step (which is quite expensive energy - demanding) and to employ locally available and inexpensive packing material for the reactor, reaching high cleaning of polluted water.