Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, People's Republic of China.
College of Chemical Engineering and Environment, China University of Petroleum, Beijing 102249, People's Republic of China.
Waste Manag. 2020 Mar 15;105:8-17. doi: 10.1016/j.wasman.2020.01.033. Epub 2020 Jan 31.
When it comes to the combustion of biomass, per ton of solid biofuel will generate 70 kg ash on average. Additionally, these ashes have a high specific surface area, especially fly ash, which may adsorb harmful substances and damage to human health. This work was aimed to reutilize biomass power plant fly ash to produce silica material, to reduce the hazard of ash landfill for environment. The ash underwent acid leaching with 1.5 M HCl after proper heating pre-treatment. Then, 2 M NaOH was direct to react with residue to obtain sodium silicate. Finally, acid titration of solution was used to precipitate silica. The results showed that the amorphous silica has been produced from fly ash successfully with the purity from 44.41% to 93.63% and yield of 20.45%, and the optimal calcination conditions for amorphous transformation of silica in fly ash were temperature of 611 °C with time of 5 h and the minimum crystallinity was 17.41%, modeled with response surface methodology. Spectroscopy analysis revealed that the three-dimensional network silica was hydroxylated to form the linear structure. Thermal analysis indicated that the decomposition of silanol groups tend to be stable at 400 °C, but the ash was decomposing up to 1000 °C. Morphological analysis demonstrated that BET surface area ranged from 24 m/g to 115 m/g, agglomerate particle size from 380.9 nm to 178.8 nm, when the ash was conversion to spherical silica. Consequently, it is possible to turn blend biomass fly ash into amorphous silica nanoparticles.
当涉及生物质燃烧时，每吨固体生物燃料平均会产生 70 公斤的灰分。此外，这些灰分具有很高的比表面积，特别是飞灰，它可能会吸附有害物质并对人体健康造成损害。这项工作旨在将生物质发电厂的飞灰重新利用来生产硅质材料，以减少灰分填埋对环境的危害。灰分经过适当加热预处理后，用 1.5M HCl 进行酸浸。然后，直接用 2M NaOH 与残渣反应得到硅酸钠。最后，用酸滴定溶液来沉淀硅。结果表明，成功地从飞灰中制备出了纯度为 44.41%至 93.63%、产率为 20.45%的无定形硅，并且最佳的硅灰非晶态转化的煅烧条件为温度 611°C、时间 5h，最小结晶度为 17.41%，采用响应面法建模。光谱分析表明，三维网络硅被羟基化形成线性结构。热分析表明，硅醇基团的分解在 400°C 时趋于稳定，但灰分在 1000°C 时仍在分解。形态分析表明，BET 表面积在 24m/g 到 115m/g 之间，团聚颗粒尺寸在 380.9nm 到 178.8nm 之间，当灰分转化为球形硅时。因此，有可能将混合生物质飞灰转化为无定形硅纳米颗粒。
