• 关键词：金属氧化物  六氯苯  低温热降解  脱氯加氢  脱氯缩合

• 基金项目：重庆交通大学研究生创新项目（No.20160113）；国家自然科学基金（No.21377121）

• 吉冰静
• 1 重庆交通大学河海学院, 重庆 400074;2 中国环境科学研究院, 北京 100012

• 高兴保
• 中国环境科学研究院, 北京 100012

• 黄启飞
• 中国环境科学研究院, 北京 100012

• 杨延梅
• 重庆交通大学河海学院, 重庆 400074

• 摘要：以氧化铝（α-Al₂O₃、γ-Al₂O₃）、氧化钙（CaO）、过渡金属氧化物（MnO₂、α-Fe₂O₃、γ-Fe₂O₃、Ni₂O₃、CuO）为催化剂,考察了催化剂种类、添加比例等因素对六氯苯（Hexachlorobenzene,HCB）降解效果和产物组分的影响.结果表明,催化效果随催化剂添加比例的提高显著增加.在反应温度为350 ℃,反应时间1 h,金属氧化物添加比例为100∶1的条件下,碱土金属氧化物CaO及过渡金属氧化物中的α-Fe₂O₃和Ni₂O₃降解活性较好,这3种氧化物对HCB的降解率分别达到65.5%、100.0%和100.0%,脱氯率D₁分别为54.4%、81.9%和77.5%.HCB降解有机产物分析结果显示,8种金属氧化物与HCB样品反应产物中均存在低氯代苯,在α-Fe₂O₃和Ni₂O₃的催化作用下有2~4氯代低氯苯检出,说明在降解过程中存在明显的逐级脱氯/加氢反应；与CaO反应后的产物中低氯代苯较少,经拉曼光谱定性分析,有无序碳的检出,说明除了脱氯/加氢还存在脱氯缩合反应.

• Abstract：Different metal oxides such as α-Al₂O₃, γ-Al₂O₃, CaO, MnO₂, α-Fe₂O₃,γ-Fe₂O₃, Ni₂O₃ and CuO were used for hexachlorobenzene (HCB) degradation in sealed systems at temperature of 350 ℃ for 1 h. The results indicated that the dechlorination activity was related to the type and dosage of metal oxides. HCB dechlorination rate increased significantly with dosage. When mass ratio of metal oxide to HCB was 100:1, CaO, α-Fe₂O₃ and Ni₂O₃ were much more effective than other metal oxides with HCB degradation of 65.5%, 100.0% and 100.0%, respectively, while the dechlorination rate reached 54.4%, 81.9% and 77.5%, respectively. According to the quantitative analysis of residual HCB and intermediates, lower chlorinated chlorobenzenes were detected. By the catalysis of α-Fe₂O₃ and Ni₂O₃, DCB-, TrCB-and TeCB-were all detected, indicating that a sequential dechlorination/hydrogenation pathway of HCB existed obviously. By the catalysis of CaO, dechlorinated products barely existed. However, amorphous carbon was detected, explaining the phenomenon of discrepancy in chlorine balance and indicating the presence of dechlorination/polymerization pathway.

• Key words：metal oxide  hexachlorobenzene (HCB)  low-temperature thermal dechlorination  dechlorination/hydrogenation  dechlorination/polymerization

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