Ju Tongyao,Han Siyu,Meng Fanzhi,Lin Li,Li Jinglin,Chen Kailun,Jiang Jianguo
Ordered mesoporous silica materials exhibit enormous potential in industrial production. Since coal fly ash (CFA) is abundant in Si, it has become a green and promising way to utilize CFA by synthesizing porous silica materials. However, the stable crystalline structure of CFA limits the extraction of Si, and the residue is generated during the process of extracting Si. In this work, we proposed a no-residue method to synthesize ordered mesoporous silica out of CFA. Sodium carbonate (Na 2 CO 3 ) was used to reconstruct the crystals of the CFA, and the calcined mixture then directly reacted with the precipitators. This method combined the process of Si extraction and porous material synthesis. In this method, no residue was generated and the silicon in both amorphous and crystalline phases of CFA was fully utilized. By this method, the extraction efficiency of Si was increased from 31.75% to nearly 100%. The as-synthesized mesoporous silica had a highly-ordered pore structure with a space group of la-3d , a surface area of 663.87 m 2 /g, a pore volume of 0.41 cm 3 /g, and an average pore diameter of 2.73 nm. The mechanism of crystalline transformation and material structure formation were systematically studied. This method provides a new idea to dispose of CFA and synthesize porous silica materials.
Chen Zhang,Duoyong Zhang,Xinqi Zhang,Xiaoou Chen,Linrui Chen,Yongqiang Tian,Liwei Wang
Materials with tunable properties are crucial for mitigating CO 2 emissions. Here, uniform and well-structured porous Rubik’s cube-shaped Linde type A (LTA) zeolites are synthesized for CO 2 capture, representing advancement in eco-friendly and cost-effective materials. The synthesis procedure extracts melting silicon from silicon-rich biomass ashes, followed by template-free hydrothermal synthesis. The melting approach is proposed to collect silicon for high hydroxide anion concentration and outstanding flowability, accelerating reaction kinetics and yielding alkaline silicon-containing solutions to promote crystallization of zeolites. These zeolites possess CO 2 sorption capacity (2.97 mmol/g at 1 bar and 298 K) and selectivity for CO 2 /N 2 (around 255.1), influenced by ultramicropores with heterogeneous surfaces containing metal ions. Cyclic robustness during vacuum temperature swing cycles displays a low attenuation rate (approximately 7.7% over 20 cycles). Thus, Rubik’s cube-shaped LTA zeolites are a promising and cost-effective approach to addressing CO 2 capture challenges by leveraging readily available biomass materials.
Coal fly ash, a waste byproduct of coal-fired power plants rich in silica, is produced in vast quantities, exceeding 750 million tons annually. This abundance underscores the importance of finding sustainable and value-added applications for its reuse. Silver nanoparticle–silica composites represent a class of inorganically hybrid antimicrobial agents as the protection layer of cotton fabrics. However, prior work has seldom involved in the recycling of waste silica sources or in situ incorporation of well-defined and hierarchical Ag nanostructure. In this study, a new type of hydrophobic and antimicrobial fabric layer composed of silver-doped silicate nanomembrane was fabricated with the extraction of silica particles from waste coal fly ash by physicochemical and hydrothermal method for dual applications in personal protection and oil–water separation. The results from detailed material synthesis, soft flakes of silica extraction and formation of silver nanoparticle-based silicate revealed correlations between SiO 2 and Ag having featured surface morphology and antimicrobial activity without any toxic effect to cells with polydimethoxysilane coatings. The developed fabric shows the satisfactory antimicrobial property increased up to 100% and oil–water separation performance was increased more than 90%, excellent selectivity, reversibility, reusability and stability. The compiled results have great implications for the management of solid waste like coal fly ash to biomedical and textile industry toward the production of personal protective equipment and high-performance nanomembrane for the treatment of contaminated water with oil.
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