New Evidence of the Enhanced Elimination of a Persistent Drug Used as a Lipid Absorption Inhibitor by Advanced Oxidation with UV-A and Nanosized Catalysts

Abstract

This work demonstrates new evidence of the efficient destruction and mineralization of an emergent organic pollutant using UV-A and titanium nanosized catalysts. The target compound considered in this work is the primary metabolite of a lipid regulator drug, clofibrate, identified in many studies as refractory during conventional wastewater treatment. The photocatalytic performance study was carried out in batch mode at laboratory scale, in aqueous suspension. Kinetic data showed that titanium dioxide P25 Aeroxide® exhibits the highest photocatalytic efficiency compared to the other investigated catalysts. Pollutant degradation and mineralization efficiencies strongly increased when decreasing the initial substrate concentration. Target molecules oxidized faster when the catalyst load increased, and the mineralization was enhanced under acidic conditions: 92% of mineralization was achieved at pH 4 after 190 min of reaction. Radical quenching assays confirmed that HO• and (
 
 
 
 
 h
 
 vb
 
 +
 
 )
 
 
 
 were the reactive oxygen species involved in the photocatalytic oxidation of the considered pollutant. In addition, further results revealed that the removal efficiency decreased in real water matrices. Finally, data collected through a series of phytotoxicity tests demonstrated that the photocatalytic process considerably reduces the toxicity of the treated solutions, confirming the process’s effectiveness in the removal of persistent and biorefractory emergent organic water pollutants.

An Eco-Friendly Solution for the Efficient Elimination of Pentoxifylline from Water: An Operational Performance Investigation

“…Under these conditions, the target molecule was completely degraded in approximatively 60 min. Our previous studies conducted on 2,4-diclorophenol [39] and on clofibric acid [40] revealed comparable findings in terms of the reduced efficiency of adsorption and photolysis and of the high utility of combining the effect of catalyst with that of the UV-A irradiation.…”

“…the adsorption of hydroxyl ions. Additionally, the photons are no longer able to reach the catalyst surface [40,46]. Hence, all these aspects have a negative impact on the pollutant elimination.…”

TiO2 Doped with Noble Metals as an Efficient Solution for the Photodegradation of Hazardous Organic Water Pollutants at Ambient Conditions

“…Briefly, in a photocatalytic reaction, a semiconductor interacts with photons that have sufficient energy in order to promote an electron from the valence band to the conduction band, followed by the generation of reactive oxidizing species (often hydroxyl radicals) from water. In many studies, hydroxyl radicals, HO•, are typically reported as very reactive species which are able to degrade and mineralize organic pollutants, transforming them into harmless products, such as CO 2 and H 2 O [5][6][7]. Among these semiconductor materials, titanium dioxide (TiO 2 ) was widely used in many photocatalytic applications because of its low toxicity, chemical stability, availability, convenient physical and optical properties, and low cost [8,9].…”

TiO2/Fly Ash Nanocomposite for Photodegradation of Organic Pollutant

“…OH) and superoxide (O 2À. ) radical species that transform organic compounds into nontoxic anionic byproducts [19]. An essential advantage of TiO 2 is that in specific conditions organic compounds are completely mineralized, and this process has high rates even at ambient temperature.…”