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New Route for Valorization of Oil Mill Wastes: Isolation of Humic-Like Substances to be Employed in Solar-Driven Processes for Pollutants Removal

2018; American Chemical Society; Volume: 3; Issue: 10 Linguagem: Inglês

10.1021/acsomega.8b01816

2470-1343

Sara García-Ballesteros, Jaume Grimalt, Silvia Berto, Marco Minella, Enzo Laurenti, R. Vicente, Maria F. López-Pérez, Ana M. Amat, Alessandra Bianco Prevot, Antonio Arques,

Water Quality Monitoring and Analysis

The valorization of olive oil mill solid wastes (OMW) has been addressed by considering it as a possible source of humic-like substances (HLSs), to be used as auxiliary substances for photo-Fenton, employing caffeine as a target pollutant to test the efficiency of this approach. The OMW-HLS isolation encompassed the OMW basic hydrolysis, followed by ultrafiltration and drying. OMW-HLS structural features have been investigated by means of laser light scattering, fluorescence, size exclusion chromatography, and thermogravimetric analysis; moreover, the capability of OMW-HLS to generate reactive species under irradiation has been investigated using spin-trap electronic paramagnetic resonance. The caffeine degradation by means of photo-Fenton process driven at pH = 5 was significantly increased by the addition of 10 mg/L of OMW-HLS. Under the mechanistic point of view, it could be hypothesized that singlet oxygen is not playing a relevant role, whereas other oxidants (mainly OH• radicals) can be considered as the key species in promoting caffeine degradation.