Photo-mineralization of noxious o-toluidine water pollutant by nano-ZnO: The role of the oxide surface texture on the kinetic path

• Commercial and homemade ZnO were adopted to degrade toxic o-toluidine pollutant.
• Best performance achieved by Z_comm sample: 83% degradation and 26% mineralization.
• Intermediate products were identified by coupling LC/MS and ATR-FTIR analyses.
• Two different degradation reaction pathways were described.
• Extensive analyses including photocurrent and ATR confirm the photo-results.

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.

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