基于XRF和XRD的热闷渣改性活性炭降解甲醛机理分析

Mechanism Analysis of Formaldehyde Degradation by Hot Braised Slag Modified Activated Carbon Based on XRF and XRD

活性炭具有发达多孔结构与丰富比表面积是一种高效的去除室内空气中甲醛的吸附性物质,但是其存在生产成本较高、不利于生态环境的可持续发展、使用寿命短和失效后容易造成室内环境二次污染的问题。钢渣是冶金工业中产生的主要固体废弃物,其产量约为每年粗钢产量的15%~20%。由于技术的局限,导致我国钢渣利用率较低,仅为年钢渣产量的10%,同时加之管理制度的不健全,导致钢渣大量露天堆放,对土地资源、地下水源,以及空气质量的严重影响。针对上述问题,利用钢渣改性活性炭开发一种价格低廉且性能优异的改性活性炭,既是冶金固体废弃物的高附加值利用与资源可持续发展的重要途径之一,同时也大幅降低改性活性炭生产成本并提高经济效益。以热闷渣超细粉作为研究对象,利用X射线荧光光谱仪(XRF)与X射线衍射仪(XRD)对热闷渣的化学成分和热闷渣的矿物组成进行测试与分析,针对热闷渣中主要的化学成分与主要的矿物组成,制备热闷渣化学成分改性活性炭与热闷渣矿物组成改性活性炭,依据《室内装饰装修材料人造板及其制品中甲醛释放限量》(GB 18580-2017)对热闷渣化学成分改性活性炭与热闷渣矿物组成改性活性炭的性能进行测试,以研究热闷渣中主要的化学成分与主要的矿物组成对改性活性炭降解甲醛性能的影响,以揭示热闷渣改性活性炭降解甲醛的作用机理。结果表明:热闷渣中主要化学成分为CaO,Fe2O3,SiO2,P2O5,MgO,MnO和Al2O3,其中Fe2O3与MnO对活性炭进行改性可以提高降解甲醛性能。热闷渣中主要矿物组成为Fe3O4,3CaO·SiO2,2CaO·SiO2和RO相,其中Fe3O4与MnO对活性炭进行改性可以提高降解甲醛性能。热闷渣中Fe元素为Fe2O3与Fe3O4,是RO相的矿物组成形式,热闷渣中Mn元素以MnO的化学成分与RO相的矿物组成形式存在,Fe元素与Mn元素协同作用提高热闷渣改性活性炭的降解甲醛性能。热闷渣改性活性炭不仅实现了冶金固体废弃物的高附加值的利用,而且创新出"以废治危"的新室内空气甲醛治理技术。

Activated carbon with developed porous structure and abundant specific surface area was an efficient technical means to remove formaldehyde from indoor air,but it exists the problems of high production cost,unfavorable to the sustainable development of the ecological environment,short service life and easy to cause secondary pollution of indoor environment after failure.Steel slag tailings are the main solid waste in metallurgical industry,with the production of 15%~20%of crude steel.The utilization ratio is quite low and only reaches 10%of steel slag tailings production due to limited technology.Meanwhile,steel slag tailings are disposed in direct stacking and landfill in general since the management system is not perfect,which pollutes land source,underground water source and air quality.In the face of the above problems,the development of low price and superior performance of modified activated carbon has become not only one of the main methods to achieve the high value-added utilization of metallurgical solid waste and the sustainable development of resources,but also one of the main methods to achieve the greatly reduce the production cost of modified activated carbon and improve economic benefits.In this paper,with superfine powder of hot braised slag as the research object,chemical composition of hot braised slag and mineral composition of hot braised slag were characterized by X-ray fluorescence spectrometer(XRF)and X-ray diffractometer(XRD),respectively.According to the main chemical composition and main mineral composition of hot braised slag,hot braised slag chemical composition modified activated carbon and hot braised slag mineral composition modified activated carbon was prepared.Performance of hot braised slag chemical composition modified activated carbon and hot braised slag minerals composition modified activated carbon were tested by referring to Indoor decorating and refurbishing materials-Limit of formaldehyde emission of wood-based panels and finishing products(GB 18580-2017),in order to the influences of main chemical composition and main mineral composition on formaldehyde degradation performance of modified activated carbon.The results show that the main chemical composition of hot braised slag are CaO,Fe2O3,SiO2,P2O5,MgO,MnO and Al2O3,among Fe2O3 and MnO modified activated carbon can improve the formaldehyde degradation performance.The main mineral composition of hot braised slag are Fe3O4,3 CaO·SiO2,2 CaO·SiO2 and RO phase,among Fe3O4 and RO phase modified activated carbon can improve the formaldehyde degradation performance.The element Fe exists as the chemical composition of Fe2O3 and mineral composition of Fe3O4,RO phase in hot braised slag,the element Mn exists as the chemical composition of MnO and mineral composition of RO phase in hot braised slag,the synergistic effect of Fe element and Mn element can improve the formaldehyde degradation performance of hot braised slag modified activated carbon.Hot braised slag modified activated carbon not only realized the high value-added utilization of metallurgical solid waste,but also put forward the new indoor air formaldehyde management technique of"treating danger by waste".