Degradation and mineralization of the emerging pharmaceutical pollutant Sildenafil by ozone and UV radiation using Response Surface Methodology

ABRILE, MARIANA GUADALUPE; BONO, VIRGINIA MARIEL; CIUCIO, MARÍA MICHELA; FIASCONARO, MARÍA LAURA; DEMARCHI, LOURDES MARLÉN; LOVATO, MARÍA EUGENIA

ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2020

0944-1344

Pharmaceuticals and their degradation products which are present in wastewater andsuperficial waters are becoming an ecological issue. This research investigated thedegradation and mineralization of synthetic solutions of the pharmaceutical compoundSildenafil Citrate (SC) by single ozonation and ozonation jointed with UV radiation (O 3/UV). The effects of initial drug concentration (50 ? 125 mg L -1 ), inlet ozoneconcentration (35-125 g Nm -3 ) and UV radiation on SC degradation and decrease oftotal organic carbon (TOC) were investigated using Response Surface Methodologybased on a central composite experimental design. Through the RSM analysis, it waspossible to confirm the removal of SC for the entire experimental range. Majorintermediates of SC degradation were identified and a degradation pathway wasproposed. The kinetics of SC degradation was modeled as a pseudo first-orderreaction with a rate constant ranging between 0.072 and 1.250 min -1 . The SCdegradation and TOC removal were strongly enhanced by increasing the concentrationof gaseous ozone at the inlet and incorporating UV radiation. The highest TOC removalreached at 60 minutes was 75%, in the O 3 /UV system, with initial SC content of 50mg L -1 and inlet ozone concentration of 125 g Nm -3 . The degradation rate of SCwas increased 3 to 9 times in the presence of UV radiation. Ozone-based advancedoxidation processes appear as a suitable alternative for treatment of the emergingpollutant SC.