Photo-degradation of yperite over V, Fe and Mn-doped titania-silica photocatalysts.
The photocatalytic decomposition of yperite (bis(2-chloroethyl)sulfide), a chemical warfare agent, was achieved by using titania-silica catalysts doped with several transition metal ions. The preparation of these catalysts was achieved by impregnation of a titania-silica mixed oxide previously synthesized using a sol-gel route with salts of the doping elements (vanadium, iron, manganese). The above catalysts were characterized using several spectroscopic techniques: FTIR, Raman, DR-UV-Vis, and XPS. The band gap energy was measured for each photocatalytic system. The reaction was carried out in two different types of reactors, i.e. naturally aerated and a closed quartz tube aerated under a constant flow, and using two types of irradiation, UV-Vis and Vis. The investigated systems proved to be extremely active, leading to an almost complete degradation of yperite in 2 h of irradiation. An excellent correlation between the photocatalytic performances and the band gap has been found. Based on the characterization data and on the temporal evolution of the reaction products, a reaction mechanism has been suggested. This mechanism considers two distinct pathways for the decomposition of yperite, namely the C-S bond cleavage and the S oxidation.
Neaţu
Stefan
S
University of Bucharest, Faculty of Chemistry, Department of Chemical Technology and Catalysis, Bd. Regina Elisabeta 4-12, 030018 Bucharest, Romania.
Pârvulescu
Vasile I
VI
Epure
Gabriel
G
Preda
Emilia
E
Somoghi
Vasile
V
Damin
Alessandro
A
Bordiga
Silvia
S
Zecchina
Adriano
A