A novel way to design suitable inorganic material from the smectite familyfor sorption of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin

The activities of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (2,3,7,8-TCDD), a highly toxic pollutant, and its suitable sorbent from the dioctahedral s mectite family are investigated using a range of reactivity indexes using d ensity functional theory (DFT). From the values of the local softness and t he charge on the hydrogen atom of the bridging hydroxyl attached to the oct ahedral metal site present in smectite, used as a first approximation to th e local hardness, it is concluded that the local acidities of the inorganic material systems are dependent on several characteristics which are of imp ortance within the framework of the hard and soft acids and bases principle . We first rationalized an understanding of the electronic structure of 7,3 ,7,8-TCDD, followed by the local softness calculation, to locate its active site. We compared its activity with that of the OH group of the isomorphou sly substituted (Fe3+, Mg2+, Fe2+, and Li+) dioctahedral smectite family. T he recently proposed local hard-soft acid-base principle characterizes the reactive centers of two systems on the basis of equal local softness. We va lidate the proposition by considering the interaction between systems with different global softnesses, which further paves the way for proposing a no vel qualitative way to choose the best sorption material. The results were compared with the interaction energy calculations using DFT. The ordering f or best sorption follows the order Mg2+ > Fe2+ > Fe3+ > Li+.