Efficient degradation of clofibric acid by heterogeneous photocatalytic oxidation process
1 Univ. Rennes, Ecole Nationale Sup rieure de Chimie de Rennes, CNRS, ISCR UMR6226, F-35000 Rennes, France, 11 All e de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France
2 Vasile Alecsandri University of Bacau, Faculty of Engineering, Department of Chemical and Food Engineering, 157 Calea Marasesti, 600115 Bacau, Romania
3 Ion Ionescu de la Brad University of Agricultural Sciences and Veterinary Medicine of Iasi, Faculty of Horticulture, Department of Horticultural Technologies, 3 Mihail Sadoveanu Alley, 700490 Iasi, Romania
4 Gheorghe Asachi Technical University of Iasi, Cristofor Simionescu Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, 73 Prof. Dr. Docent D. Mangeron Str., 700050 Iasi, Romania
5 Lucian Blaga University of Sibiu, Faculty of Agricultural Science, Food Industry and Environmental Protection, 7-9 Dr. I. Ratiu St., 550012 Sibiu, Romania
6 West Pomeranian University of Technology Dept. of Immunology, Microbiology, and Physiological Chemistry, Szczecin, Poland
2 Vasile Alecsandri University of Bacau, Faculty of Engineering, Department of Chemical and Food Engineering, 157 Calea Marasesti, 600115 Bacau, Romania
3 Ion Ionescu de la Brad University of Agricultural Sciences and Veterinary Medicine of Iasi, Faculty of Horticulture, Department of Horticultural Technologies, 3 Mihail Sadoveanu Alley, 700490 Iasi, Romania
4 Gheorghe Asachi Technical University of Iasi, Cristofor Simionescu Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, 73 Prof. Dr. Docent D. Mangeron Str., 700050 Iasi, Romania
5 Lucian Blaga University of Sibiu, Faculty of Agricultural Science, Food Industry and Environmental Protection, 7-9 Dr. I. Ratiu St., 550012 Sibiu, Romania
6 West Pomeranian University of Technology Dept. of Immunology, Microbiology, and Physiological Chemistry, Szczecin, Poland
Abstract
Emerging pollutants such as pharmaceutical active compounds were detected worldwide in different environmental compartments. Nowadays, multiple studies are focused on the investigation of their environmental fate, as well as to find new, efficient and sustainable removal technologies. Several studies demonstrated that heterogeneous photocatalysis is one of the most promising techniques used for water purification. Thus, the aim of our work was to evaluate the photodegradation efficiency of a refractory emergent compound, named clofibric acid, under UV light in aqueous solution. We report that photodegradation and mineralization efficiency are strongly dependent of the catalyst used. Results showed that the photodegradation was enhanced in the presence of TiO2 Aeroxide. The complete elimination was achieved for an initial pollutant concentration of 1.5 mg/L after 30 min of irradiation, the degradation rate following the pseudo-first order kinetics. It was also observed that the rate constant for the photodegradation process is affected by the concentration of catalyst. Process efficiency is enhanced by increasing the light intensity. The simultaneous reduction of pollutant concentration and dissolved organic carbon demonstrates the mineralization of the target molecule. Furthermore, it was demonstrated that the addition of nitrate to the system increases the pollutant degradation rate, while the carbonate reduces its removal, suggesting that this last ion can act as a hydroxyl scavenger. Preliminary phytotoxicity tests were also carried out and showed the capacity of the heterogeneous photocatalysis to reduce the toxicity of reaction intermediates generated during the photocatalytic reaction.
Keywords
degradation; kinetics; mineralization; nanosized catalysts; persistent micropollutant; photocatalysis