【摘要】 粉煤灰的资源化利用对社会和环境的可持续发展具有重要意义。本文以粉煤灰基硅渣为原料，采用NaOH碱熔法提取SiO₂，在碱熔温度为300℃、碱与灰质量比为2∶1、反应时间为2h的条件下，SiO₂的提取率达到72.26%；进而以提硅得到的Na₂SiO₃溶液和MgO为原料，通过水热反应制备硅酸镁纳米片，考察了Na₂SiO₃溶液浓度、Si与Mg摩尔比、反应温度及反应时间对硅酸镁纳米片的组成、晶相结构和孔道结构的影响规律。结果表明，在Na₂SiO₃浓度为0.50mol/L、Si与Mg摩尔比为1.25∶1、反应温度为220℃和反应时间为10h的条件下制备了结晶度较好、比表面积达240.6m²/g的介孔硅酸镁纳米片；其对亚甲基蓝（MB）具有较快的吸附速率，吸附量达285.0mg/g，对MB的吸附行为符合准二级动力学模型和Langmuir等温吸附模型。更多还原

【Abstract】 The utilization of fly ash is of great significance to the sustainable development of society and environment. NaOH alkali fusion method was adopted to extract SiO₂ from the silicon slag derived from fly ash after extraction of alumina. It was found that the SiO₂ extraction rate reached 72.26% after reaction at 300℃ for 2h with the NaOH and ash mass ratio of 2∶1. Subsequently, MgSiO₃ nanosheets were prepared by hydrothermal reaction using the obtained Na₂ SiO₃ solution and MgO as raw materials. The effects of Na₂ SiO₃ concentration, Si and Mg molar ratio, reaction temperature and time on the MgSiO₃ product were investigated. XRD, SEM and low temperature N₂ adsorption desorption instrument were used to analyze the composition and structure of the prepared MgSiO₃, and its adsorption performance towards methylene blue（MB） was investigated. MgSiO₃ with high purity, preferable crystallinity and a specific surface area of 240.6m²/g was prepared by reacting at 220℃ for 10h with Na₂ SiO₃ concentration of 0.50 mol/L and Si and Mg molar ratio of 1.25∶1. The as-prepared MgSiO₃ nanosheets showed fast adsorption rate towards MB with an adsorption capacity of 285.0 mg/g. Its adsorption behavior towards MB conformed to the quasisecond-order kinetic model and Langmuir isothermal adsorption model.更多还原