Study on Catalytic Combustion of Dioxins From Iron Ore Sintering Flue Gas Over Ce-V-Ti Catalysts by XRD and FTIR
SHI Qi1, DING Long1, LONG Hong-ming1,2*, CHUN Tie-jun1
1. School of Metallurgical Engineering, Anhui University of Technology, Ma’anshan 243032, China
2. Anhui Province Key Laboratory of Metallurgy Engineering & Resources Recycling (Anhui University of Technology), Ma’anshan 243002, China
Abstract：Dioxins are a group of chlorinated volatile organic pollutants (VOCs) with environmental persistence, biological accumulation and long-term residual properties. It can cause teratogenic, carcinogenic and mutagenic hazards. During the iron ore sintering process, dioxins can be catalytically synthesized from chlorine-containing precursors by Ullman reaction in the alkaline environment or by some catalytic components on the surface of fly ash. Besides, dioxins can be synthesized by de novo through elementary reaction. Iron ore sintering process is one of the most emission sources of dioxins. Physical adsorption technology can only remove pollutants from gas phase to the solid phase and increase the aftertreatment problem of fly ash. Besides, there is a risk of dioxins regeneration under 250～350 ℃. Catalytic combustion can be completely degradation dioxins into CO2，H2O and HCl/Cl2 over catalysts. It is an efficient, energy conservation and low-cost method to avoid secondary pollution. However, the working temperature of traditional catalysts is too high to the end temperature of the sintering flue gas. It is important to improve the catalytic activity at low temperature to achieve high efficiency catalytic combustion of VOCs from iron ore sintering flue gas. As Ce has the 4f orbital coordination effect and Lewis acid site, which plays a crucial role in the activation of C—H and C—Cl bonds in organic pollutants, the anti-chlorine toxicity and combustion activity of the catalystcan be improved by doping transition metal or adjusting the proportion of active components of catalysts. Hence, the effect of different Ce/V weight ratio of Ce-V-Ti catalysts prepared by sol-gel method were studied in this paper. Chlorobenzene was used as the model molecule of dioxins. The phase, specific area, molecular structure and functional groups of Ce-V-Ti catalysts were characterized by XRD, BET,XPS and FTIR. The results show that the catalytic activity of chlorobenzene over Ce-V-Ti catalysts with 15 Wt% Ce and 2.5 Wt% V can achieve CB conversion of 60% at 150 ℃ and 95% at 300 ℃ under the reaction conditions of GHSV=30 000 h-1, 20% O2 and 100 ppm CB. The chemical interaction between the barrier and the active component affected the catalytic activity of catalysts. According to the spectroscopic analysis, the XRD pattern of Ce-V-Ti catalysts was mainly anatase TiO2. The specific surface area was 95.53 m2·g-1, the volume of the pore was 0.29 cm3·g-1，and DBJH was 6.5 nm. Most of the functional groups on the Ce-V-Ti catalysts were C—H groups and O—H, which was expedited the adsorption and desorption of CB. The introduction of V as co-catalytic compositioninto Ce-Ti catalyst promoted the solid solution reaction of Ce element and increased the oxygen vacancy on the surface of the catalyst, which was conducive to improving the catalytic activity of the catalyst. Meanwhile, the oxidation reaction of V in low-price promotes the reduction reaction of Ce.
Key words：Catalytic combustion; Dioxins; Ce-V-Ti catalysts; Spectral analysis; Iron ore sintering flue gas
收稿日期: 2019-11-23
修订日期: 2020-04-11
基金资助: General Program of National Nature Science Foundation of China (51674002) and the Key Project of National Nature Science Foundation of China (U1660206)
通讯作者:
龙红明
E-mail: yaflhm@126.com
作者简介: SHI Qi, female, (1988—), lecturer, School of Metallurgical Engineering, Anhui University of Technology
e-mail: 13615556646@163.com
引用本文:
施 琦，丁 龙，龙红明，春铁军. 基于XRD和FITR的Ce-V-Ti催化剂减排烧结烟气二噁英的活性分析[J]. 光谱学与光谱分析, 2021, 41(01): 327-332.
SHI Qi, DING Long, LONG Hong-ming, CHUN Tie-jun. Study on Catalytic Combustion of Dioxins From Iron Ore Sintering Flue Gas Over Ce-V-Ti Catalysts by XRD and FTIR. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2021, 41(01): 327-332.
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