A green approach to DDT degradation and metabolite monitoring in water comparing the hydrodechlorination efficiency of Pd, Au-on-Pd and Cu-on-Pd nanoparticle catalysis.

ABSTRACT

DDT (1,1,1-trichloro-2,2-bi(p-chlorophenyl)-ethane) and its metabolites (DDD, 1,1-dichloro-2,2-bis-(4'-chlorophenyl)ethane, and DDE, 1,1-dichloro-2,2-bis-(4'-chlorophenyl)ethylene) are persistent organic pollutants that can be catalytically degraded into a less toxic and less persistent compound. In this work, ecofriendly methodologies for catalyst synthesis, catalytic degradation of DDT and reaction monitoring have been proposed. Three types of Pd-based nanoparticles, NPs, (Pd, Au-on-Pd and Cu-on-Pd) were synthesized and used for catalytic hydrodechlorination of DDT and its metabolites. The structural and electronic properties of NPs were investigated using TEM and XAS spectroscopy. Au-on-Pd showed the highest hydrodechlorination efficiency within 1 h of reaction. To obtain the best reaction conditions, the effects of H2 flow and base addition Au-on-Pd NPs activity were investigated. To study the effectiveness of the different NPs, a solvent-free analytical method was optimized to detect and measure DDT and its by-products. The SPME-GC-MS method provided low detection limits (0.03 µg L-1) and high recovery (≥88.75%) and was a valuable tool for the NP degradation study. In this way, a green method for degradation and monitoring of DDT and its by-products in water was achieved.