Novel Sorbents of Non-Metal-Doped Spinel Co sub(3)O sub(4) for the Removal of Gas-Phase Elemental Mercury

• Published in: Environmental science & technology Vol. 42; no. 2; pp. 590 - 595
• Main Authors: Mei, Zhijian, Shen, Zhemin, Wang, Wenhua, Zhang, Yejian
• Format: Journal Article
• Language: English
• Published: 01.01.2008
• DOI: 10.1021/es071145+
• ISSN: 0013-936X

N-doping technology is introduced to improve Co sub(3)O sub(4)'s Hg super(0) removal ability and anion activation ability for the first time. The adsorption tests show that N-doped Co sub(3)O sub(4) has a higher S sub(BET) and greater Hg super(0) removal ability. The reaction mechanism has been carefully studied using a number of different analyses methods such as X-ray diffraction, Brunauer-Emmett-Teller, and X-ray photoelectron spectroscopy. The analysis results illustrate that N atoms have been doped into a Co sub(3)O sub(4) matrix as anions and are thought to substitute for O atoms. Anions, such as Cl super(-) and Br super(-), can be activated by N-doped Co sub(3)O sub(4) and then oxidize Hg super(0). It is considered that nitrogen atoms in polycrystalline N-doped Co sub(3)O sub(4) are responsible for the significant enhancement of Hg super(0) removal ability. Different NH sub(4)Cl or NH sub(4)Br adulteration values have been tested, and the results show that 50 mol % NH sub(4)Cl or 40 mol % NH sub(4)Br doped Co sub(3)O sub(4) have the highest Hg super(0) removal ability. Compared with Co sub(3)O sub(4), N-doped Co sub(3)O sub(4) has a longer breakthrough time and better SO sub(2) antipoisoning ability. On the basis of the above analyses, possible Hg super(0) oxidation mechanisms of N-doped Co sub(3)O sub(4) are provided.