煤气化渣一步重构碳/P沸石及其吸附结晶紫机制

One step reconstruction of carbon/P zeolite from coal gasification slag and its adsorption mechanism for crystal violet

  • 摘要: 煤气化渣的高效资源化利用是当前能源、环保和可持续发展领域亟待解决的关键问题。作为煤气化过程的主要副产物,煤气化细渣的年排放量巨大。但其传统处理方法存在炭灰分离困难、原子利用率低、二次污染严重等技术瓶颈,严重制约了其资源化利用效率。本研究创新性地开发了一种煤气化细渣原位活化一步法重构技术,成功制备了碳/P型沸石复合材料(CPCMs),实现了温和条件下细渣中硅、铝及碳元素的高效协同活化。复合材料具有花状多级孔结构,比表面积为107 m2/g,以介孔为主。此外,通过调控碱溶出时间与煅烧条件,CPCMs中的P型沸石可定向转化为钠十字沸石。CPCMs对水中结晶紫染料表现出优异吸附性能,在303 K时最大吸附量为454.6 mg/g。其吸附行为符合准二级动力学模型,R2 > 0.995,表明化学吸附主导。等温吸附数据与Langmuir模型高度吻合,证实单层均匀吸附特性。热力学分析显示,吸附过程为自发吸热,ΔG < 0,ΔH=33.92 kJ/mol,ΔS > 0。机理研究表明,吸附作用源于多机制耦合:P型沸石的介孔限域效应和静电吸引,pH > 7时吸附量显著提升;残碳组分的π-π共轭作用;复合材料中金属离子与结晶紫阳离子的离子交换以及络合作用。值得注意的是,CPCMs在宽盐度范围内保持稳定吸附性能,展现出良好的抗干扰能力。该研究不仅实现了煤气化细渣的高值化资源利用,还为工业废水处理提供了经济高效的吸附材料,具有重要的环境与经济效益。

     

    Abstract: The efficient resource utilization of coal gasification slag is a key issue that urgently needs to be addressed in the fields of energy, environmental protection, and sustainable development. As the main byproduct of the coal gasification process, the annual emissions of coal gasification fine slag are enormous. However, its traditional processing methods face technical bottlenecks such as difficulty in separating carbon ash, low atomic utilization rate, and severe secondary pollution, which seriously restrict its resource utilization efficiency. This study innovatively developed a one-step reconstruction technology for in-situ activation of coal gasification fine slag, and successfully prepared carbon/P-type zeolite composite materials (CPCMs), achieving efficient synergistic activation of silicon, aluminum, and carbon elements in fine slag under mild conditions. The composite material has a flower shaped multi-level pore structure with a specific surface area of 107 m2/g, mainly composed of mesopores. In addition, by regulating the alkaline leaching time and calcination conditions, P-type zeolite in CPCMs can be directionally converted into sodium cross zeolite. CPCMs exhibit excellent adsorption performance for crystal violet dye in water, with a maximum adsorption capacity of 454.6 mg/g at 303 K. Its adsorption behavior conforms to a quasi second order kinetic model, R2 > 0.995, Indicating that chemical adsorption is dominant. The isothermal adsorption data is highly consistent with the Langmuir model, confirming the uniform adsorption characteristics of the monolayer. Thermodynamic analysis shows that the adsorption process is spontaneous endothermic, ΔG < 0, ΔH=33.92 kJ/mol, ΔS > 0. Mechanism studies have shown that adsorption is due to multi mechanism coupling: the mesoporous confinement effect and electrostatic attraction of P-type zeolite, and the adsorption capacity is significantly increased when pH > 7; π - π conjugation of residual carbon components; Ionic exchange and complexation between metal ions and crystalline violet cations in composite materials. It is worth noting that CPCMs maintain stable adsorption performance over a wide salinity range and exhibit good anti-interference ability. This study not only achieved high-value resource utilization of coal gasification fine slag, but also provided economically efficient adsorption materials for industrial wastewater treatment, which has important environmental and economic benefits.

     

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