Highly toxic o-toluidine pollutant was photo-degraded in water by using ZnO nanoparticles. The tested powders were both commercial and laboratory-made, the latter obtained by means of two innovative synthetic procedures. The disappearance and the relative mineralization of the molecule were followed by HPLC/UV and TOC determinations, respectively. Intermediate products were identified by coupling LC/MS of the eluate after 3 h of reaction and ATR-FTIR analyses of the used ZnO powders at the end of photocatalytic tests. Selected degradation paths, characterized by different kinetic degradation rates, can be suggested as a function of the different surface texture, the effective photocatalytic active area and the e(-)/h(+) recombination processes of the ZnO particles. (C) 2014 Elsevier B.V. All rights reserved.