Abstract:
Synthesis of a material with a bifunctional catalytic property that tends to efficiently detoxify the two major chemical warfare agents (CWAs), nerve agents and mustard gas (HD) simultaneously is highly desirable. Detoxification of mustard gas simulant through partial oxidation without the formation of over-oxidized sulfone is efficient yet challenging. Additionally, efficient hydrolysis of Nerve agents through the same material is quite difficult to achieve. In this research, I synthesized a series of highly photoactive composite materials (CB-Ns), utilizing protonated imidazolium-based porous organic polymer and UiO-66-NH2 having Zr6-SBU, illustrating a promising route for simultaneous detoxification of the two most deadly chemical warfare agents. The imidazolium moiety present in CB-Ns, known for the formation of singlet oxygen, acts as a promising mild oxidizing agent for CEES, and the Zr-OH-Zr moiety acts as an efficient Lewis acidic site for the hydrolysis of the nerve agent simulant, respectively. For the detoxification of CEES, CB-0 displayed an excellent performance with ultrafast kinetics in O2-saturated and under ambient conditions, utilizing MeCN as the suitable solvent. However, CB-100 also shows a satisfactory conversion rate. Furthermore, the detoxification of DENP (ethyl paraoxon, diethyl (4-nitrophenyl) phosphate), a surrogate of the nerve agent, ultrafast kinetic can be seen in CB-250 under 450 nm light irradiation and under ambient conditions, utilizing a basic buffer solution of NEM (N-ethyl morpholine). This work demonstrates developing the Zr6-MOF@Imidazoline porous organic polymer opens a new direction for the photocatalytic degradation of CWAs.
Description:
I have successfully synthesized a series of robust photo-catalytically active Zr-based MOF and imidazoline-based Porous organic polymer composite materials (CB-Ns). The highly conjugated CB-Ns with the spatial distribution of Zr-OH-Zr moiety act as Lewis acid which is responsible for the decontamination of the G-agent simulant (ethyl Paraoxon). Additionally, Imidazoline, known to produce type II reactive oxygen species (singlet oxygen), is mainly responsible for partially oxidizing the mustard gas simulant 2-chloroethyl ethyl sulfide (CEES) in oxygen-saturated and ambient conditions. Surprisingly, CB-250 showed the ultrafast photocatalytic hydrolysis of the nerve agents which is even faster than the previously reported MOFs including UiO-66, UiO-67, MOF808, NU-1000, UiO-66-NH2 and many more indicating the role of Zr-SBU units as well as the importance of Imidazoline moiety which increases the light-harvesting property of the material. Furthermore, CB-0 shows the maximum detoxification of HD agents simulant however, CB-100 and CB-250 also show a satisfactory amount of detoxification indicating that the composite materials (CB-Ns) tend to act as an excellent photocatalytic material that can efficiently perform the detoxification of the two most deadliest chemical warfare agents simultaneously under ambient conditions.
