芥子气模拟剂2-氯乙基乙基硫醚的光催化降解

利用连续流动微反、原位红外和GC/MS等手段考察了芥子气模拟剂2-氯乙基乙基硫醚（2-CEES）在P25 TiO2上的光催化降解反应,证实CO2和H2O是这个反应的最终产物.详细的跟踪分析表明,除了CO2和H2O外,在反应的气相混合物中可检测到C2H4、CH3CHO、CH4、CO、HCl和H2S；少量小分子的羧酸、醚和砜；微量C2H5SC2H5、C2H5S2C2H5、C2H5SC2H4Cl和CH2ClCH2Cl等中间产物;在反应后的催化剂表面可检测到C2H5S2C2H5、C2H5SC2H4OH、C4H9S2C2H5和C2H5S2C2H4OH、等物.根据这些结果提出了2-CEES光催化降解的反应机理,推断2-CEES的光催化降解涉及脱氯、C－S键断裂、有机硫化物光聚合和裂解等复杂过程最终转化为CO2和H2O.认为各种硫物种在表面的积聚引起了催化剂的缓慢失活.

Study on the Photocatalytic Degradation of a Simulate Agent (2-CEES) of Mustard Gas

The Photocatalytic deg radation reaction of 2-chloroethyl ethyl sulfide (2-CEES) on P25 TiO2 was st udied by using flow micro-reaction technique,GC-MS,and in situ FTIR.It was s howed that 2-CEES could be oxidized finally into CO2 and H2O at room temperatu re during the process.Detailed analysis found that C2H4,CH3CHO,CH4,CO,HCl and H2 S;a small quantity of low molecular weight carboxylic acids,ethers and sulphones ;a trace amount of C2H5SC2H5,C2H5S2C2H5,C2H5SC2H4Cl and CH2ClCH2Cl exist in the gaseous product of reaction besides CO2 and H2O,and some species such as C2H5S2C 2H5,C2H5SC2H4OH,C4H9S2C2H5 ,C2H5S2C2H4OH and remain on the surface of the catal yst after reaction.According to the above results,a photocatalytic degradation m echanism of 2-CEES was suggested,deducing that 2-CEES was photocatalytically degraded into CO2 and H2O via a complicated process including dechlorination,C-S bond splitting,photo-polymerization and decompose of organo-sulfur inte rmediates.The accumulation of sulfur-contained species on the surface was thou ght to result in deactivation of the catalyst.