(612b) A Dft Study of Mercury Capture on Paper Waste Derived Sorbents

Control of mercury emissions in post-combustion gases from coal-burning power plants and other industrial sources has been investigated over the last several decades. Despite all of the prior work, little is known about the fundamental mechanisms of Hg- species adsorption on sorbents. Current technologies rely on low temperature adsorption. The purpose of our research is to determine the mechanisms of interaction of Hg and HgCl2 with high temperature and efficient mercury capturing sorbents, specifically a paper waste derived (kaolinite and calcium based) sorbents(PWDS).

In this work, density functional theory (DFT) was used to investigate the structure of the PWDS using the DMOL3 program with both the LDA and GGA functional and the DNP basis set. The choice of method and basis set combination was validated through a detailed comparison of theoretical geometry and heats of reaction predictions to experimental data available in the literature. The Hg and HgCl2 adsorption energies on a variety of sorbent surfaces were calculated along with other thermodynamic properties.

In addition, the cluster structure of PWDS was built to simulate the Hg and HgCl2 adsorption process to reproduce experimental data. Meanwhile, the effect of temperature on adsorption was evaluated. This work not only allows for a more thorough understanding of mercury's speciation adsorption on PWDS in the flue gas environment, but also lays a foundation for finding more efficient dry sorbents in the future.