Abstract:

Fly ash is the main solid waste of coal combustion, and its large accumulation poses a serious threat to human health and the environment. Due to the porous structure and adsorption performance of fly ash, it can play a role in dispersing and stabilizing photocatalyst, and thus significantly improve the photocatalytic activity, achieving a synergistic effect between adsorption and photocatalysis. This article provides a brief overview of the preparation methods and applications of fly ash loaded photocatalytic materials both domestically and internationally in recent years, focusing on the aggregation issue of semiconductor photocatalytic materials. Firstly, the properties and modification methods of fly ash are introduced, and the advantages and disadvantages of the preparation of fly ash photocatalytic composites by sol-gel method, hydrothermal method and liquid phase precipitation method are compared. In addition, fly ash composite photocatalyst are analyzed from the performance and the positive influence in degradation of water pollutants, NO _x and VOCs gas pollutants, self-cleaning ability, and CO₂ reduction, which show that fly ash mainly participates as adsorbent and carrier. However, as a carrier, fly ash has insufficient active sites, the modification technology was not mature enough, and the research was still at the laboratory scale, making it difficult to achieve large scale industrial applications. Therefore, it is necessary to improve the modification technology of fly ash, and the functional building materials with fly-ash supported photocatalytic materials will be further studied to improve their practicability.

Key words: fly ash, adsorption, photocatalysis, support, composites, degradation

摘要：

粉煤灰是煤炭燃烧最主要的固体废弃物，大量的堆积对人类身体健康及环境均造成了严重的威胁。基于粉煤灰的多孔结构和吸附性能，将其与纳米光催化材料复合可以达到分散和稳定光催化剂的效果，显著提高光催化活性，同时实现吸附与光催化的协同作用。本文主要围绕半导体光催化材料易团聚的问题，对近几年来国内外粉煤灰负载光催化材料的制备方法及应用进行了简要概述。首先，分析了粉煤灰的性质及改性方法，重点介绍了溶胶-凝胶法、水热法、液相沉淀法三种制备粉煤灰光催化复合材料的方法，并对比分析三种方法的优缺点，从水中污染物的降解，NO _x 、VOCs气体污染物的降解以及自清洁性能，CO₂还原性能等几方面的应用，分析了材料的性能和粉煤灰复合光催化剂的积极影响，表明粉煤灰主要作为吸附剂与载体参与其中。但是粉煤灰作为载体，其活性位点少，改性技术不够成熟，且研究还处于实验阶段，未能进行工程化生产，因此还需要不断完善粉煤灰改性技术，同时进一步研究附加粉煤灰负载光催化材料的功能性建筑材料，提高其实用性。

关键词: 粉煤灰, 吸附, 光催化, 载体, 复合材料, 降解