新型改性吸附剂制备、表征及脱除单质汞的实验研究

摘要/Abstract

摘要：

采用KBr和KI对高岭土、沸石、膨润土和壳聚糖进行改性，利用VM3000在线测汞仪作为检测手段，在固定床台架上进行脱Hg⁰实验。采用N2吸附/脱附、X射线荧光探针(XRF)和傅里叶变换红外光谱(FTIR)等分析仪对吸附剂进行表征。分析发现改性后吸附剂的孔隙和比表面积降低;碘离子进入了膨润土的内部，碘、硫酸和壳聚糖中的氨基发生了化学反应。脱汞实验表明，与高岭土和沸石相比，膨润土因其独特结构而具有良好的脱汞效果。适量硫酸的加入可以极大地提高壳聚糖类吸附剂的脱汞效率;与溴改性吸附剂相比，碘改性吸附剂更能够大大提高吸附剂的脱汞效率;适当提高吸附温度可以提高其脱汞效率;因改性膨润土和壳聚糖不同的物理化学特性，水蒸气的加入使得它们的脱汞效率出现相反的趋势。

关键词:

壳聚糖, 膨润土, 脱汞, 碘, 改性

Abstract:

Adsorption experiments of vapor-phase elemental mercury were carried out by using bromine (Br) - and iodine (I)-modified kaolin, zeolite, bentonite and chitosan (CTS) in a laboratory-scale fixed-bed reactor.VM3000 online mercury analyzer was used to detect the inlet and outlet Hg0 concentrations.The characterizations of the sorbents were analyzed by using the method of nitrogen (N₂₎ adsorption/desorption, X-ray fluorescence (XRF) technique and Fourier transform infra-red spectroscopy (FTIR).It was observed that the porosity and specific surface area decreased after modification.The FTIR spectra demonstrated that iodine was found in the internal layer of bentonite, and the chemical reactions of iodine and sulfate ion with the amide of CTS occurred.Fixed-bed adsorber tests showed that compared with kaolin and zeolite, the modified bentonite exhibited excellent mercury capture because of its unique structure.Mercury removal efficiency of CTS sorbents could be significantly enhanced when an appropriate amount of H₂SO₄ was added.Generally, the iodine-modified sorbents demonstrated higher mercury capture efficiency than that of bromine-modified sorbents.The mercury removal efficiencies ofthese sorbents increased with temperature.Bentonite’s capacity for mercury uptake decreased with the presence of moisture while chitosan’s capacity for mercury uptake exhibited an opposite tendency due to their absolutely different physicochemical properties.

Key words:

壳聚糖, 膨润土, 脱汞, 碘, 改性

张安超, 向军, 孙路石, 胡松, 付鹏, 程伟, 邱建荣. 新型改性吸附剂制备、表征及脱除单质汞的实验研究 [J]. 化工学报, 2009, 60(6): 1546-1553.

ZHANG Anchao, XIANG Jun, SUN Lushi, HU Song, FU Peng, CHENG Wei, QIU Jianrong. Synthesis and characterization of novel modified sorbents 
and their performance for elemental mercury removal
[J]. CIESC Journal, 2009, 60(6): 1546-1553.

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