K_(2)CO_(3)改性类水滑石衍生复合金属氧化物吸附剂脱除HCl(g)性能

HCl(g)REMOVAL PERFORMANCE OF K_(2)CO_(3)-MODIFIED CAMGAL MIXED METAL OXIDES DERIVED FROM HYDROTALCITE-LIKE

采用浸渍法对钙镁铝类水滑石进行K_(2)CO_(3)改性,并进一步焙烧获得复合金属氧化物吸附剂。在固定床实验系统上对K_(2)CO_(3)改性类水滑石吸附剂的高温脱除HCl(g)性能进行了研究,探究了K_(2)CO_(3)负载量、反应温度和初始HCl(g)浓度对其高温脱除HCl(g)性能的影响,通过X射线衍射(XRD)、比表面积及孔隙分析(BET)、扫描电镜(SEM)及热重分析(TG)对改性前后的类水滑石吸附剂进行了表征。结果表明:1)K_(2)CO_(3)改性后类水滑石吸附剂的脱除HCl(g)性能显著提高,K_(2)CO_(3)的最佳负载量为30%,过高的负载量会导致吸附剂的孔隙堵塞,吸附能力下降;2)在400~800℃的反应温度范围内,吸附剂的HCl(g)吸附容量在600℃时达到最高,为0.289 g/g;3)在不同HCl(g)浓度下吸附剂的脱除HCl(g)性能保持稳定;4)经500℃煅烧后吸附剂的比表面积和孔体积增大,平均孔径减小,吸附能力增强;负载K_(2)CO_(3)后类水滑石吸附剂的热稳定性有所增强。K_(2)CO_(3)改性后的类水滑石衍生吸附剂具有优良的高温脱除HCl(g)性能,为选择高效实用的高温HCl(g)吸附剂提供了参考。

In this paper,the Ca-Mg-Al hydrotalcite-like was impregnated by K_(2)CO_(3),and the derived mixed metal oxide adsorbent was obtained by further calcination.The fixed-bed experimental system was used to study the HCl(g)removal performance of K_(2)CO_(3) modified hydrotalcite-like adsorbent at high temperature.The effects of K_(2)CO_(3) content,reaction temperature and HCl(g)concentration on the removal of HCl(g)were investigated.The adsorbents were characterized by X-ray diffraction,specific surface area and pore analysis,scanning electron microscopy and thermogravimetric analysis.The results showed that:HCl(g)removal performance of hydrotalcite-like adsorbent modified by K_(2)CO_(3)was significantly improved,and the optimum K_(2)CO_(3)content was 30%.When the K_(2)CO_(3)content exceeded 30%,the pore of adsorbent was blocked and the adsorption capacity was decreased.In the reaction temperature range of 400~800℃,the HCl(g)adsorption capacity of the adsorbent reached the maximum value of 0.289 g/g adsorbent at 600℃.After being calcined at 500℃,the specific surface area and pore volume of the adsorbent increased,the average pore size decreased,and the adsorption capacity was enhanced.The thermal stability of the hydrotalcite-like adsorbent was improved after impregnated by K_(2)CO_(3).The high-temperature HCl(g)removal performance of K_(2)CO_(3)modified hydrotalcite-like adsorbent was excellent,providing research directions for finding efficient and practical high-temperature HCl(g)removal adsorbents.