Investigation on mercury removal and recovery based on enhanced adsorption by activated coke

This work is to systematically study the mercury-removal behavior of activated coke (AC), regeneration of spent AC by microwave treatment and subsequent recycling of Hg-0. The powdery (AC) was obtained under coal-fired hot gas conditions in a drop-tube reactor. The adsorption mechanism and capacity of the AC for Hg-0 removal in a H2O + SO2 + O-2 atmosphere were investigated. The regeneration of the AC by microwave heating and recovery of Hg0 were studied. The results showed that this AC preparation method can greatly simplify the process, and the AC's large surface area, developed pore structure, and abundant functional groups played a key role in the adsorption of Hg-0. The adsorption mechanism and the optimum reaction conditions were determined, with a highest average Hg-0-adsorption efficiency of 91% obtained at 70 degrees C in 3 h. Desorption of Hg-0 was also studied, in which the alkaline-functional-group content and pore structure were enhanced, and S was detected by X-ray photoelectron spectroscopy in microwave-regenerated AC, which could improve the Hg-0 removal efficiency increased to 96% after five adsorption/desorption cycles. The Hg-0 could subsequently be recovered from the desorbed gas by condensation with an efficiency of 87.4% using ice-water.