贾里,李泽鹏,郭晋荣,张永强,秦舒宁,王碧茹,樊保国,金燕.多元金属定向修饰的改性生物焦微观特性及单质汞脱除性能研究[J].环境科学学报,2021,41(8):3100-3111
多元金属定向修饰的改性生物焦微观特性及单质汞脱除性能研究
- Study on the micro-characteristics and elemental mercury removal performance of biochar doped by multi-metal directional modification
- 基金项目：国家自然科学基金资助项目（No.U1510135，U1810126，U1910214）；山西省高等学校科技创新项目（No.2020L0073）
- 贾里
- 太原理工大学, 电气与动力工程学院, 太原 030024
- 李泽鹏
- 太原理工大学, 电气与动力工程学院, 太原 030024
- 郭晋荣
- 太原理工大学, 电气与动力工程学院, 太原 030024
- 张永强
- 太原理工大学, 电气与动力工程学院, 太原 030024
- 秦舒宁
- 太原理工大学, 电气与动力工程学院, 太原 030024
- 王碧茹
- 太原理工大学, 电气与动力工程学院, 太原 030024
- 樊保国
- 太原理工大学, 电气与动力工程学院, 太原 030024
- 金燕
- 太原理工大学, 电气与动力工程学院, 太原 030024
- 摘要：针对通过热解直接获得的生物焦汞吸附效率较低的问题，将常规化学沉淀法、溶胶凝胶法、多元金属多层负载与生物质热解制焦过程进行整合，在选择特定组分进行结构设计的基础上，获得了经济高效的掺杂多元金属铁基改性生物焦烟气脱汞剂，为最终实现"以废脱毒"提供关键参数与理论依据.在获得改性生物焦Hg0脱除特性的基础上，针对生物质基础特性，利用多种表征分析手段研究改性样品的微观特性，建立了改性生物焦理化性质与脱汞性能之间的构效关系.研究发现：相比未改性生物焦，以生物焦为载体的铁基复合吸附剂的脱汞性能显著提升，其中掺杂双金属改性样品汞脱除性能的提升程度整体优于掺杂单金属的改性样品；改性生物质的热解过程变得更加剧烈和充分；改性导致生物焦的晶体结构向无序方向演变，所对应的芳香结构单元排列有序度和石墨化程度减弱；所负载或掺杂的多元金属对生物焦物理吸附性能的提升主要体现在对孔隙结构参数的改善方面，同时多元金属的掺杂还可以增强─COOH和C＝O官能团对电子的迁移作用，进而提升生物焦对有机汞Hg-OM的结合能力；不同负载金属自身之间在汞脱除过程中可以起到协同促进的作用，进而大幅提高改性生物焦的脱汞性能.
- Abstract：In this paper, aiming at the problem of low mercury adsorption efficiency of biochar directly obtained by pyrolysis, the conventional chemical coprecipitation method, sol-gel method, multi-metal multilayer loading and biomass pyrolysis coking process were integrated. Based on the selection of specific components for structural design, the low-cost and efficient modified biochar adsorbent doped with multiple metals was obtained, providing key parameters and theoretical basis for the final realization of "demercuration by waste". Based on the Hg0 removal characteristics of modified biochar, according to the basic characteristics of biomass, the micro-characteristics of modified samples were obtained by various characterization methods, establishing the structure-activity relationship between physicochemical properties and mercury removal performance of modified biochar. It was found that compared with the unmodified biochar, the mercury removal performances of Fe-based composite adsorbent with biochar as carrier were significantly improved. The improvement extents of Hg0 removal performance of the samples doped with bimetallic were overall better than those of the samples doped with single metal. The pyrolysis process of modified biomass became more intense and sufficient. The crystal structure of modified biochar evolved to disorder direction, and the arrangement order of corresponding aromatic structural units decreased, leading to the weakening of graphitization degree of the samples. The improvement of the physical adsorption performance of the samples doped different metals was mainly reflected in the development of pore structure parameters. Meanwhile, the doped multi-metals could enhance the electron migration of ─COOH and C＝O functional groups, thus improving the binding ability of biochar to Hg-OM. Different doped metals could play a synergistic role in the mercury removal process, thereby greatly improving the mercury removal performance of modified biochar.
