| 引用本文: | 王美霞,熊晓虎,孙悦,胡神涛,李璇,许东东,张银,周卫健.2026.粉煤灰基多级孔结构X型分子筛的常压制备及其对金属离子的吸附机制研究[J].地球环境学报,17(4):1067-1076 |
| WANG Meixia,XIONG Xiaohu,SUN Yue,HU Shentao,LI Xuan,XU Dongdong,ZHANG Yin,ZHOU Weijian.2026.Preparation of coal fly ash-based X-type zeolite with hierarchical porous structure at ambient pressure and its adsorption mechanism for metal ions[J].Journal of Earth Environment,17(4):1067-1076 |
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| 摘要: |
| 我国粉煤灰（CFA）年排放量位居世界首位，其大量排放与堆存带来了显著的生态环境污染风险。粉煤灰的资源化利用是发展循环经济的必然要求。文章提出了一种新的粉煤灰基分子筛制备方法：通过常压下碱熔和两步老化法，将粉煤灰制备成具有微孔-介孔复合结构的X型分子筛（ZX-CFA）。通过X射线衍射、扫描电子显微镜、傅里叶变换红外光谱及X射线光电子能谱分析，发现了微孔-介孔结构的存在，并且铁原子部分取代铝原子进入沸石X骨架中。吸附实验结果表明，ZX-CFA对Sr2+的单离子吸附容量达108.8 mg/g，对Cu2+达102.5 mg/g；当吸附Cu2+后再吸附Sr2+时，两种离子可达的最大吸附容量为134.0 mg/g。吸附机制研究表明，ZX-CFA存在-Al-O-和-Fe-O-双活性吸附位点，微孔-介孔复合结构和沸石骨架中Fe3+部分替代Al3+对污染物捕获具有增强作用，且Cu2+相较于Sr2+优先选择性地吸附于ZX-CFA的-Fe-O-活性位点。研究基于“以废治废”思路，提出了一种经济型的粉煤灰基分子筛合成方法，所制备分子筛对典型重金属及放射性离子表现出良好的吸附性能，为粉煤灰的高值资源化利用提供了一种新方案。 |
| 关键词: 粉煤灰 X型分子筛 多级孔结构 离子交换机制 双活性位点 |
| DOI：10.7515/JEE2025025 |
| CSTR：32259.14.JEE2025025 |
| 分类号: |
| 基金项目:陕西省科技发展计划项目（2024QY-SZX-31）；黄土与第四纪地质国家重点实验室重点项目（SKLLQGZD2101）；西安地球环境创新研究院院级科研基金项目（XAIIEER2309） |
| 英文基金项目: |
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| Preparation of coal fly ash-based X-type zeolite with hierarchical porous structure at ambient pressure and its adsorption mechanism for metal ions |
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WANG Meixia1，2，3，4，XIONG Xiaohu1，3，SUN Yue1，3，HU Shentao1，2，3，LI Xuan1，2，3，XU Dongdong4，ZHANG Yin1，2，3，ZHOU Weijian1，2，3，4
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1.State Key Laboratory of Loess Science, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061 , China ；2.University of Chinese Academy of Sciences, Beijing 100049 , China ；3.Shaanxi Provincial Key Laboratory of Accelerator Mass Spectrometry Technology and Applications, Xi’an AMS Center, Xi’an 710061 , China ；4.Xi’an Institute for Innovative Earth Environment Research, Xi’an 710061 , China
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| Abstract: |
| Background, aim, and scope Global coal fly ash (CFA) production has reached 1.63 billion tons, with China contributing 899 million tons. Yet the large amount of CFA leads to both environmental pollution risk and resource waste. Concurrently, hydrosphere faces unprecedented pressures from dual contamination sources that industrial wastewater discharges contain heavy metals and radionuclides from nuclear facilities. Conventional remediation approaches include chemical precipitation, membrane filtration, etc., failing to achieve sustainable resource circularity. This study aims to develop an integrated technological route that simultaneously realize the resource utilization of CFA and multi-pollutant wastewater treatment through designing hierarchical porous adsorbents derived from CFA. This study covers the following aspects: systematic optimization of CFA conversion parameters, multi-scale characterizations of synthesized zeolite, and adsorption studies targeting Cu2+ and Sr2+. Materials and methods We proposed an ambient-pressure hydrothermal synthesis route that integrates alkali fusion with an optimized dynamic and static two-step aging process to convert CFA into X-type zeolite (ZX-CFA). The synthesized ZX-CFA was characterized by using X-ray diffraction (XRD), scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and N2 adsorption and desorption analysis. Results The synthesized ZX-CFA exhibits: (1) successful crystallization of X-type zeolite; (2) hierarchical porosity: a surface area of 273.6 m2/g, a microporous volume of 0.09 cm3/g and a mesoporous volume of 0.23 cm3/g; (3) a strong association between Al and Fe by SEM-EDS, a decreased 2θ value on the (111) crystal plane, a new band in the range of 1340 cm-1 to 1559 cm-1, and a weaker Al 2p peak along with new Fe 2p peaks at approximately 711.9 eV and 725.5 eV; and (4) large adsorption capacities with 108.8 mg/g for Sr2+ and 102.5 mg/g for Cu2+ in single-ion systems, when Sr2+ was adsorbed after the initial adsorption of Cu2+, the maximum adsorption capacity for both ions can reach 134.0 mg/g. Moreover, SEM-EDS mapping demonstrated that both Cu and Sr were uniformly distributed throughout the adsorbed sample, while the Na signal was significantly weaker in the single-ion adsorption system. In the simultaneous adsorption of Cu2+ and Sr2+, the areas with a stronger Fe signal corresponded to a heightened Cu2+ signal whereas the Sr2+ signal was more closely aligned with the Al signal. Discussion The multi-factorial characterization data suggests that Fe is likely incorporated into the zeolite framework through an isomorphic replacement mechanism. The radius of the Fe3+ (0.064 nm) is larger than that of Al3+(0.054 nm), leading to an increased lattice distance upon incorporation of Fe into the X type zeolite lattice. According to the Bragg equation (2d sin θ=nλ), an increase in the d value results in a decrease in the 2θ value. The new band observed in the FTIR spectrum is associated with the presence of surface Fe hydroxide groups. Based on the NIST binding energy database, the binding energies of Fe oxides typically range from 710.9 eV to 724.0 eV; however, when Fe incorporates into the zeolite structure as Fe-O-Si, the higher electronegativity of Si (1.90) compared to Fe results in elevated binding energies of the Fe 2p orbitals within the zeolite framework. SEM-EDS mapping suggests a process of ion-exchange-driven adsorption that there are dual active sites in ZX-CFA. The active sites associated with Fe, preferentially selective adsorbs Cu2+ in the binary-ion adsorption system. Conclusions This study establishes an energy-efficient circular economy paradigm by proposing a waste-to-resource strategy that converts CFA into a low-cost, high-efficiency adsorbent. The ambient-pressure synthesis method not only offers scalability and energy efficiency but also addresses urgent needs for treating complex wastewater systems contaminated with heavy metals and radionuclides. Recommendations and perspectives Our findings present a timely solution to pressing environmental and regulatory challenges, including nuclear wastewater management and coal waste utilization. Future study should focus on pilot-scale applications and lifecycle analysis for industrial implementation. |
| Key words: coal fly ash X-type zeolite hierarchical porosity ion exchange mechanism dual active sites |
