重金属在炭质微反应器上的电化学气态脱附行为及其调控机制

In this project, we proposed a new idea that the effective gaseous desorption of heavy metal will be achieved through the use of the electrochemical vapor generation technique based on the carbonaceous micro-reactor. Realization of this working assumption can not only establish a new gaseous desorption technique for utilization of adsorbed heavy metal and the regeneration of activated carbon, but also understand some basic scientific questions deeply through the research the relationship between the activated carbon pore structure and surface functional groups and the electrochemical vapor generation of the adsorbed heavy metal, especially the electron transfer pathways. In this project, we will study from four aspects. Firstly, the batch-type and flow-type electrochemical gaseous desorption-regeneration systems will be established and a series of activated carbon will also be prepared based on different kinds of coal and activation methods. Then we will deeply study on the relationship between the gaseous desorption behavior of different heavy metal elements and the structure of coal-based activated carbon to find its intrinsic law. Secondly, the adsorption and the gaseous desorption conditions of heavy metal elements, including As, Hg and Cd, will be optimized with the different functional carbonaceous adsorbents. The conversion process of heavy metals in gas, liquid and adsorbent will be studied through different analytical technologies. Thirdly, the desorption efficiency of adsorbed heavy metal, the recovery of the gaseous products and the regeneration performance of activated carbon will also be researched under the different adsorbed conditions. The relationship between the electrolyte systems and the component of products will be analyzed be various analytic technologies to deduce the reaction process of the electrochemical vapor generation of heavy metal elements. At the same time, the change degree of the structure and functionalization of carbonaceous adsorbents after regeneration are summarized. Lastly, the electrochemical reduction mechanism and electron migration pathway will be studied by using spectroelectrochemical methods and isotope labeling. The kinetic and thermodynamic data of reaction will also be studied. This work maybe has important scientific significance and theoretical guidance value for improving resource utilization and reducing pollutant emissions.

针对吸附重金属的资源回收与活性炭的循环利用，从炭质微反应器的角度，探索活性炭孔结构和表面官能团对吸附重金属的电化学蒸气发生过程、特别是对电子传递途径的影响，进而建立全新的电化学气态脱附再生方法加以解决。为此项目将构建间歇式和流动式反应系统并制备系列煤基活性炭，深入探讨重金属元素的电化学气态脱附行为与活性炭孔结构的关联；重点考察表面官能团对砷、镉、汞等元素吸附和气态脱附的影响，利用各种检测与表征手段，研究重金属在气、液、固相的转化过程；测试不同吸附条件下，重金属的电化学气态脱附率、回收率以及煤基活性炭的再生性能，对比脱附前后材料孔结构与表面官能团的变化；根据光谱电化学与同位素标记结果，结合动力学和热力学数据，阐述重金属元素在炭质微反应器上的电化学还原历程与迁移途径，并揭示其界面反应与调控机制。此项工作的开展，将为提高资源有效利用率、减少污染物排放等研究工作，提供必要的理论依据与技术支持。

低浓度重金属污染物的精准分析与低成本处理、尤其是吸附重金属的炭质材料再生与资源循环利用，是当前环境化工领域研究的热点和难点问题之一。本项目将电化学蒸气发生技术与固液界面调控相结合，测试吸附态砷、汞等元素高效气态脱附与活性炭直接再生方法；同时利用砷、汞、铬等元素的界面还原及脱附行为，探讨在功能材料及外场辅助下的重金属元素富集与光/电还原可行性，并据此构建系列元素及其形态的光谱直接超灵敏分析技术。具体包括：系统研究了砷在碳与金属材质上的电化学气态还原行为，实现了mg L-1级别含砷废水的直接气相脱砷；通过贵金属沉积物调节电极/电解质界面区分了元素形态电化学行为差异，实现了μg L-1级别无机汞和甲基汞的高效气态转化，并据此建立了一种精准且简单的元素形态光谱直接分析方法；系统考察了砷饱和活性炭的电化学脱附行为，达成了吸附砷的高效气态转化脱附与再生活性炭孔隙结构的保留，提出了吸附-解析-转化机制；测试了铁改性对砷脱附的抑制行为，建立了重金属气相回收与炭再生新方法；此外还对g L-1级别铬的界面还原机理进行了研究，明确了产物脱附控制的光催化、电催化汞蒸气的高效发生与共存组分界面竞争反应等系列元素还原行为历程。.作为项目研究成果，共计发表标注本项目资助SCI收录论文12篇。