固废基ZSM-5合成及其改性研究进展

Research progress on synthesis and modification of solid waste-based ZSM-5

工业生产过程中产生大量粉煤灰、赤泥和煤气化渣,其堆积不仅侵占土地,还会严重破坏生态环境,危及人类健康。这3种固废均含有硅铝元素,且含量较高,硅铝比(氧化硅和氧化铝物质的量比)波动幅度较大。ZSM-5(Zeolite Socony Mobil 5)是一类硅铝比范围较宽的沸石分子筛,具有独特的孔道结构和良好的稳定性,在吸附和催化方面应用广泛。利用富含硅铝的固废制备ZSM-5是其高值化和资源化利用的重要途径之一。系统总结了富含硅铝的固废的活化除杂预处理通用方法,并且基于粉煤灰、赤泥和煤气化渣的理化性质特点,综述了固废基ZSM-5的合成及金属改性、磷改性、水热改性和酸碱改性4种方法的研究进展。分析固废作为硅铝源对ZSM-5合成、结构和性能的影响,指出固废在活化除杂过程中硅铝比的调控、杂质元素的去除转化、及主要元素的迁移转化规律是研究重点;讨论不同改性方法对ZSM-5结构和性能的影响机制,提出固废基ZSM-5中硅铝在骨架和非骨架中的分布、铁钙等杂元素的含量和存在形态、孔结构对改性效果起到非常重要的作用。通过对典型富含硅铝元素的固废基ZSM-5合成及其改性过程中存在问题和研究现状的分析和讨论,提出了粉煤灰、赤泥和煤气化渣多源固废复配,在无机模板剂或无模板剂条件下水热晶化制备ZSM-5,对固废基ZSM-5高效精准改性是未来发展方向。

In the industrial production process,a large amount of fly ash,red mud,and coal gasification slag is generated.The accumula-tion of these wastes not only occupies land but also severely damages the ecological environment and endangers human health.These three types of solid waste all contain silicon and aluminum elements,with relatively high contents and significant fluctuations in the silicon-to-aluminum ratio(molar ratio of silicon dioxide to aluminum oxide).ZSM-5(Zeolite Socony Mobil 5)is a type of zeolite molecular sieve with a wide range of silicon-to-aluminum ratios,featuring a unique pore structure and good stability,widely used in adsorption and catal-ysis.Utilizing silicon-aluminum-rich solid waste to prepare ZSM-5 is one of the important ways to achieve high-value and resource-effi-cient utilization.The general methods for activation and impurity removal pretreatment of silicon-aluminum-rich solid waste were systemat-ically summarized.Based on the physical and chemical properties of fly ash,red mud,and coal gasification slag,the research progress on the synthesis of solid waste-based ZSM-5 and its metal modification,phosphorus modification,hydrothermal modification,and acid-base modification were reviewed.The effects of using solid waste as a silicon-aluminum source on the synthesis,structure,and perform-ance of ZSM-5 were analyzed,highlighting the importance of regulating the silicon-to-aluminum ratio,removing and transforming impuri-ty elements,and understanding the migration and transformation rules of major elements during the activation and impurity removal process.The impact mechanisms of different modification methods on the structure and performance of ZSM-5 were discussed.The distri-bution of silicon and aluminum in the framework and non-framework,the content and forms of impurity elements like iron and calcium,and the pore structure were emphasized as crucial factors influencing the modification outcomes.Through analyzing and discussing the ex-isting problems and research status in the synthesis and modification of typical silicon-aluminum-rich solid waste-based ZSM-5,the fu-ture development should focus on the co-utilization of multiple sources of solid waste such as fly ash,red mud,and coal gasification slag,and the hydrothermal crystallization preparation of ZSM-5 under conditions without inorganic or no template agents.Efficient and pre-cise modification of solid waste-based ZSM-5 is highlighted as the future direction.