Clopyralid degradation using solar-photocatalytic/ozone process with olive stone activated carbon

Publication date: February 2019Source: Journal of Environmental Chemical Engineering, Volume 7, Issue 1Author(s): Zouhour Rajah, Monia Guiza, Rafael R. Solís, Nidhal Becheikh, F. Javier Rivas, Abdelmottaleb OuederniAbstractClopyralid degradation in ultrapure water was investigated by homogeneous ozonation (O3), catalytic ozonation with Olive Stone Activated Carbon (O3/OSAC), under simulated sunlight radiation by photolytic ozonation (O3/Daylight) and photocatalytic ozonation (O3/OSAC/Daylight). The OSAC was characterized by several analytical techniques, such as Nitrogen adsorption desorption at 77 K, Scanning Electron Microscopy (SEM-EDX), determination of pHpzc and X-ray Photoelectron Spectroscopy (XPS). This herbicide exhibited a rapid oxidation rate in the simultaneous presence of ozone, activated carbon and simulated sunlight. The combined process led to a complete removal of clopyralid in less than 30 min. Solar-photocatalytic ozonation was the most efficient process both in terms of clopyralid elimination rate and mineralization. Clopyralid degradation mainly occurs through hydroxyl radical in those systems involving ozone. For comparison purposes, the different processes can be modelled by simple first-order kinetics in clopyralid concentration (rate constants khomo = 0.0159 min−1, homogeneous ozonation; kO3/Daylight = 0.0410 min−1, kO3/OSAC = 0.0705 min−1, kO3/OSAC/Daylight = 0.1433 min−1). 90% of Total Organic Carbon (TOC) remova...
Source: Journal of Environmental Chemical Engineering - Category: Chemistry Source Type: research