Fly ash is waste from thermal power plants that not only has a serious impact on soil and water but also accumulates in landfills and must be treated properly. In addition, plastic waste, especially polyethylene terephthalate bottles, deteriorates for a long time, so there is an urgent need to recycle them into valuable products. To solve the environmental pollution mentioned above, a feasible zero-waste method has been developed that converts 100% of fly ash into a lightweight composite aerogel reinforced with recycled polyethylene terephthalate fiber. In this study, raw fly ash is bound to the skeleton of the fibers by a non-toxic, biodegradable xanthan gum solution as a binder, which is then lyophilized, leaving a hollow porous structure. The obtained composite aerogels display extremely low density of 0.026–0.062 g/cm³, high porosity of 96.59–98.42%, low thermal conductivity of 34–39 mW/(m·K), flexibility with Young's modulus of 3.98–20.61 kPa, and noise reduction coefficient of 0.18–0.31. Adding fly ash to the fiber framework results in a lightweight composite aerogel with higher porosity, heat, and acoustic insulation, as well as impressive compressive modulus, compared to the fly ash-free aerogels. This study provides a safe, environmentally friendly, and cost-effective solution for recycling fly ash into high-value engineering materials.

粉煤灰是火力发电厂产生的废物，不仅对土壤和水产生严重影响，而且会堆积在垃圾填埋场中，必须妥善处理。此外，塑料垃圾，尤其是聚对苯二甲酸乙二醇酯瓶，时间长了会变质，因此迫切需要将其回收成有价值的产品。为解决上述环境污染问题，开发了一种可行的零浪费方法，将 100% 的粉煤灰转化为用回收的聚对苯二甲酸乙二醇酯纤维增强的轻质复合气凝胶。在这项研究中，生粉煤灰通过无毒、可生物降解的黄原胶溶液作为粘合剂与纤维骨架结合，然后将其冻干，留下中空的多孔结构。所得复合气凝胶的密度极低，为 0.026–0.062 g/cm ³, 96.59–98.42% 的高孔隙率，34–39 mW/(m·K) 的低导热率，杨氏模量 3.98–20.61 kPa 的柔韧性，以及 0.18–0.31 的降噪系数。与无粉煤灰气凝胶相比，将粉煤灰添加到纤维框架中会产生具有更高孔隙率、隔热性和隔音性以及令人印象深刻的压缩模量的轻质复合气凝胶。该研究为将粉煤灰回收成高价值工程材料提供了一种安全、环保且具有成本效益的解决方案。