Several mulberry twig (MT) chars were prepared by conventional pyrolysis

steam activation

and impregnation with H2O2

ZnCl2 and NaCl.Adsorption performance of mercury in a simulated flue gas by MT chars were studied in a bench-scale fixed bed absorber

and the effects of steam activation

impregnation agent

adsorption temperature

and the composition of simulated flue gas

etc.on mercury adsorption performance were analyzed.The results indicated that steam activation could significantly increase surface areas of MT pyrolysis chars.Impregnation with H2O2 can further improve surface areas of steam activated MT chars and its pore structure. However

impregnation with ZnCl2 and NaCl led to decrease of surface areas

D-R micro-pore and total pore volume of MT chars in some extent.The mercury adsorption capacities of MT chars impregnated with 10% and 30% H2O2 were 2.02 and 1.77 times of that for steam activated MT char

respectively

and that of MT char impregnated with ZnCl2 was a little better than that impregnated with NaCl at the same impregnation concentration.The performance of mercury adsorption enhanced with increase of ZnCl2 concentration for modified MT char.The mercury adsorption for MT600-A-ZnCl2(5%) was 29.55 μg·g-1

3.37 times of that for steam activated MT char.At temperature of 60—120℃

the mercury adsorption efficiency and capacity of MT chars impregnated with H2O2 decreased with increase of adsorption temperature. However

the capacity of MT chars impregnated with ZnCl2 showed an increase trend at first and then decrease

and its optimum adsorption temperature was 90℃.SO2 and NO in the simulated flue gas showed adverse effect on mercury adsorption.Both mercury adsorption efficiency and capacity decreased slightly with increase of SO2 and NO concentration.