关键词: 汞, 竹炭, 改性, 机理分析

Abstract:

Elemental mercury from coal combustion has become an increasingly environmental concern due to its high volatility and toxicity，and it has been found that activated carbon adsorption is an effective mercury-control method，but there exists high-cost limit. An important precursor for activated carbon is bamboo，a renewable bioresource，and bamboo charcoal(BC)may act as a low-cost sorbent used for mercury controlling. In this paper，the adsorptive potential of modified BC using ZnCl₂(Cl-BC)for elemental mercury was investigated in a bench-scale bed. Their pore structure and surface chemical properties were characterized by BET and XPS. The results suggested that Cl-BC had excellent adsorption potential for elemental mercury even at a relative higher temperature，and the enhancing-effect was more obvious with increasing Cl content. There was an optimum ZnCl₂ concentration for impregnation. The increase of performance of Cl-BC is probably due to the increase of active sites for mercury adsorption. The kind of Cl functional groups on the original and ZnCl₂-modified BC was found to be different，the latter is of the active site for mercury adsorption and oxidation，and for the former it is negligible. There is an optimum Cl content on the ZnCl₂-modified BC for elemental mercury removal，and mercuric chloride could be formed during mercury sorption.

Key words: 汞, 竹炭, 改性, 机理分析