Synthesis and Environmental Applications of Nanoporous Materials Derived from Coal Fly Ash

Abstract

Coal fly ash (CFA) is the primary solid waste generated by the coal-fired industry, and the predominant treatment methods include accumulation, landfill, and the production of cement-based building materials. However, the availability of these methods is relatively limited, and there is a need for technological upgrades. The extensive accumulation not only leads to environmental pollution but also has detrimental effects on human health. With its loose structure and main chemical components of Al2O3 and SiO2, CFA is conducive to the synthesis of promising nanoporous materials for applications in adsorption. The use of CFA as a raw material can significantly reduce preparation costs, improve comprehensive utilization efficiency, and manufacture more valuable products, aligning with the current strategy of sustainable development. Currently, the most widely used synthesis method is hydrothermal synthesis. This review focuses on the principles, methods, and influencing factors of synthesis, with particular emphasis on CFA-based mesoporous silica, zeolites, and metal–organic frameworks (MOFs), which have not been systematically reviewed previously. The quality of these synthesized nanoporous materials can be finely adjusted through the synthesis process. A comparison of the advantages and disadvantages of each process will be made, and the impact of the synthesis conditions on the synthetic products will be analyzed. Additionally, a brief discussion on the latest research advances in their applications in adsorption will be provided. Finally, relevant challenges and issues have been proposed.

Physicochemical Properties and Planting Performance of Artificial Soil Developed from Multiple Coal-Based Solid Waste Materials

“…It is evident that CG contains significant amounts of organic matter and humus, which are highly beneficial for plant growth. However, FA and GG contain high concentrations of soluble salts, primarily Ca 2+ and SO 4 2− , which may potentially have adverse effects on plant growth. The grading curves of the three raw materials are depicted in Figure 1.…”

“…These materials include coal gangue (CG), fly ash (FA), desulfurization gypsum (DG), gasification slag, and bottom ash [2]. The issues associated with the disposal of these CSWM remain severe; the majority of the remaining CSWM is directly deposited and landfilled, resulting in serious environmental contamination [3,4]. Further improving the resource utilization efficiency of CSWM has become an urgent need for the development of a low-carbon society.…”

Temperature-Driven Structural Evolution during Preparation of MCM−41 Mesoporous Silica

“…Since the seminal discovery of MCM−41 (the 41st in Mobil Composition of Matter) type mesoporous silica by Kresge and colleagues [1] from Mobil Oil Corporation in 1992, this material has captivated the materials science and chemical engineering communities due to its distinctive pore architecture, extensive surface area, adjustable pore diameters, and rich surface hydroxyl groups. Researchers have employed synthesis methods such as sol-gel [2,3], hydrothermal [4], and microwave-assisted [5] techniques to extensively explore various factors affecting the pore size, wall stability, and surface properties of MCM−41 materials [6][7][8][9]. By adjusting synthesis conditions, researchers have successfully tailored the mesoporous structure and chemical properties of MCM−41, unlocking its vast potential in diverse fields like adsorption [10,11], catalysis [12][13][14][15], drug delivery [16], and environmental remediation [17].…”