Synergism between peroxymonosulfate and LaCoO3-TiO2 photocatalysis for oxidation of herbicides. Operational variables and catalyst characterization assessment
Metadatos
Afficher la notice complèteMateria
Photocatalysis Advanced oxidation Environmental remediation Heterogeneous catalysis Decontamination
Date
2016Referencia bibliográfica
Published version: Rodríguez Solís, R. et al. Synergism between peroxymonosulfate and LaCoO3-TiO2 photocatalysis for oxidation of herbicides. Operational variables and catalyst characterization assessment. Journal of Chemical Technology and Biotechnology 92(8), 2017, 2159-2170. [https://doi.org/10.1002/jctb.5228]
Patrocinador
Junta de Extremadura GR15033; CICYT of Spain CTQ2015/64944-R; FEDER founds; Gobierno de Extremadura; FSE Funds (PD12058); University of Extremadura; Junta de Extremadura; MICINN; FSERésumé
BACKGROUND. This paper reports the use of novel coupled LaCoO3-TiO2 as photocatalyst with double route of peroxymonosulfate (PMS) activation. First, as a photocatalyst due to titania; and second, through PMS heterogeneous decomposition onto LaCoO3 particles. Thus, photocatalytical activity was tested for removing a mixture of four herbicides of different recalcitrance (metazachlor, tembotrione, tritosulfuron and ethofumesate). RESULTS. The presence of light and PMS highly enhanced herbicides removal rate: 3.5–5 times increases were obtained with UVA light. Oxidant concentration, catalyst load, pH and temperature were assessed. Herbicides were completely oxidized depending on their recalcitrant nature and the operational variables. 55% TOC conversion was reached using Oxone® 5 × 10−4 mol L−1. Phytotoxicity assays denoted no inhibition after 180 min of photocatalytic treatment (∼80% initial inhibition). Solid properties of Co/Ti = 0.1:1 ratio were studied by means of SEM (LaCoO3 aggregates linked to a variety of shapes and sizes of TiO2), XRF (6.1% of LaCoO3), XPS (superficial Co3+, La3+ and Ti4+), XRD (anatase, rutile and rhombohedral LaCoO3) and UV–vis diffuse reflectance (visible range absorption and bandgap of 2.88 eV for TiO2). CONCLUSION. Catalysts based on LaCoO3-TiO2 combined with peroxymonosulfate seem to be suitable for removing organic pollutants, with a moderate conversion of TOC and elimination of toxicity.