Computer Simulation Study Of CO₂Incorporation Into Pyrophyllite At Elevated Temperatures

Since the industrial revolution, people burn a vast amount of fossil fuels. Inproduction and living, men redundantly exhaust greenhouse gas. Influence thatgreenhouse gas give rise to global warming is increasing. Wang ling etc. found CO2characteristic peak in a series of layer clay of infrared spectroscopy(IR) on sometemperatures. Pyrophyllite, as a sort of layer aluminosilicate clay, widely distributethe three main rock on earth(sedimentary rock, igneous rock and metamorphic rock).On account of CO2incorporation into some clay mineral, for example pyrophyllitte,this type of mineral can be used as CO2storage medium. Through using classicaldynamics(LAMMPS) and quantum chemistry(DMol3), we studied themechanism,which CO2incorporate into pyrophyllite and metapyrophyllite. Our studyfound:1. Classic dynamics simulation of interaction of metapyrophyllite and CO2(1) On (001) surface of metapyrophyllite, CO2molecular is physically attracted.the closest distance between CO2and (001) surface is at2.5, and it isn’t sensitive totemperature.(2) When CO2moleculars are approach to gaseous state, linear CO2molecularsare inclined to vertical (001) surface. With the increase of CO2molecuars’ amount,linear CO2moleculars are inclined to parallel (001) surface.(3) When the system reach equilibrium states, on metapyrophyllite (010) surface,there are some lattice distortion between layer and layer, which lead to close theinterlamination’s entrance. The probability that CO2enter metapyrophylliteinterlamination.(4) On metapyrophyllite (010) surface, bare aluminum atoms attract CO2molecular strongly. There may be chemisorption.2. computer simulation of CO2incorporation into pyrophyllite andmetapyrophyllite with DMol3approach(1) The adjacent OH and H O perssads may be form hydrogen bond onedge surface of pyrophyllite and metapyrophyllite. And some particular position ofH O perssads may be transfer to OH to lower the system enegery. (2) On (110)surface and (001) surface of pyrophyllite, Activation barrier ofdehydration and CO2incorporation process are relatively high from studying andanalyzing the change in energy during reacting. Dehydration and CO2incorporationprocess of metapyrophyllite are the rate-determining step in the overall reaction. On(110)surface and (010) surface of metapyrophyllite, only activation barrier ofdehydration process is relatively high. With CO2incorporating into metapyrophyllite,the system energy is greatly lowered. Dehydration process is the rate-determining stepto metapyrophyllite in the overall reaction.(3) The possibility of CO2incorporation into metapyrophyllite (110) surface and(010) surface is more likely. In addition, the possibility of CO2incorporation intometapyrophyllite (110) surface is more likely to metapyrophyllite (010) surface. Andthe possibility of CO2incorporation into pyrophyllite (110) surface and (010) surfaceis less likely.