Adsorption Characteristics of Mercuric Chloride on Sulfur Modification Powdered Activated Carbon

A number of activated carbons had been produced from waste tires by pyrolysis and water activation methods, and they had been modified by sulfur steam at high temperature. Produced sulfur-impregnated activated carbons were examined for their mercuric chloride adsorptive ability by thermal gravimetric analysis. The experiment data show that sulfur should be evenly distributed in the activated carbon surface and pores after sulfur modification, and the sulfur content would obviously be improved from about 2% to 10%~6%. There was efficaciously improvement on mercuric chloride saturated adsorption capacity after sulfur modification, which of high surface area activated carbon reached 1.557 mg/g (above 22 times comparing with un-modifying activated carbon). The mercuric chloride adsorption curves could divide into two adsorption stages: (i) at the first adsorption stage (in 10 min), the adsorption velocity of mercuric chloride kept quickly as the mercuric chloride molecules only entered into macropores and mesopores belonging to surface physical adsorption; (ii) at the second adsorption stage (after 10min), the adsorption velocity of mercuric chloride became slowly and slowly for the mercuric chloride molecules gradually turned into mesopores and micropores. The mercuric chloride adsorption velocities of activated carbons before 10min were all in the range of 0.0089 μg/g · min to 0.0299μg/g · min, and adsorption velocities improved with increasing of the mercuric chloride concentration. The mercuric chloride adsorption velocities of activated carbons between 10min and 60 min were all in the range of 0.0007 μg/g · min to 0.0041μg/g · min, obviously lower than former 10min. There was no penetrating case of mercuric chloride in 1h and the high sulfur activated carbon possessed best adsorption capacity of mercuric chloride. Consequently, it would be quite feasible that sulfur-impregnated activated carbon from waste tires was applied in municipal incinerator to remove mercuric chloride.