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: Thepresence of light and PMShighly enhanced herbicides removal rate: 3.5-5 times increaseswere obtained withUVA light. Oxidant concentration, catalyst load, pHand temperaturewere assessed. Herbicideswere completely oxidized depending on their recalcitrant nature and the operational variables. 55% TOC conversion was reached using Oxone (R) 5x10(-4) mol L-1. Phytotoxicity assays denoted no inhibition after 180 min of photocatalytic treatment (similar to 80% initial inhibition). Solid properties of Co/Ti = 0.1:1 ratiowere studied by means ofSEM(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 amoderate conversion of TOC and elimination of toxicity. (C) 2017 Society of Chemical Industry