The Synthesis of FeCl3-Modified Char from Phoenix Tree Fruit and Its Application for Hg0 Adsorption in Flue Gas

A sample of FeCl3-modified phoenix tree fruit char (MPTFC) was prepared using pyrolysis and a facile chemical immersion method; it was proposed as an effective sorbent for Hg-0 adsorption in flue gas. The BET, SEM, FTIR, and XPS methods were adopted for the characterizations of the sorbents, and a series of Hg-0 adsorption tests were conducted on a bench-scale Hg-0 removal setup in the lab. The morphological analysis of the sorbent indicated that the hollow fiber in phoenix tree fruit (PTF) shifted to organized directional porous tubular columns in phoenix tree fruit char (PTFC) after pyrolysis. The surface area of MPTFC increased slightly in comparison with PTF and PTFC. The MPTFC showed excellent performance for Hg-0 adsorption at 200 degrees C in flue gas ambiance, and the Hg-0 removal efficiency approached 95% with 5% (wt.%) FeCl3 modification. The presence of O-2 may help to activate the MPTFC for Hg-0 adsorption in flue gas, thus greatly promoting Hg-0 adsorption capability. NO had a positive effect on Hg-0 adsorption, while the presence of SO2 in flue gas restrained Hg-0 adsorption by MPTFC. Functional groups, such as C-Cl and Fe-O, were successfully decorated on the surface of PTFC by FeCl3 modification, which contributed greatly to Hg-0 adsorption. In addition, C=O, lattice oxygen (O-alpha), and adsorbed oxygen (O-beta) also contributed to Hg-0 adsorption and oxidization.

Automated summary

A modified phoenix tree fruit char prepared by pyrolysis and chemical immersion method showed excellent adsorption performance for Hg-0 in flue gas, with significant enhancement by FeCl3 modification. The morphology, surface area, and functional group modification of the char, as well as the composition of the flue gas, played important roles in Hg-0 adsorption.