基于ICP-MS的特殊钢渣-废弃核桃壳制备钢渣基生物质活性炭机理研究

Study on the Preparation Mechanism of Steel Slag-Based Biomass Activated Carbon by Special Steel Slag-Discard Walnut Shells Based on ICP-MS

氯气泄漏应立即对其进行应急处置,同时日常也要加强对含氯尾气的及时回收和净化处理。目前普遍采用具有发达多孔结构与丰富比表面积的活性炭吸附有害气体,但是目前活性炭的生产普遍需要消耗木材、竹子等自然资源,导致成本高且不利于可持续发展。因此采用生物质废弃材料制备活性炭,同时利用冶金固体废弃物对活性炭进行改性处理,以进一步降低生产、环境成本与提高吸附性能,已经成为活性炭生产领域研究的热点。研究以特殊钢渣与废弃核桃壳为研究对象制备钢渣基生物质活性炭。采用氯气专用P-C-T吸附装置测试吸收氯气的性能,电感耦合等离子体质谱仪(ICP-MS)、X射线荧光光谱仪(XRF)、激光粒度仪(LPSA)、场发射扫描电子显微镜(SEM)分别测试其浸出重金属浓度、化学成分、粒径分布、微观形貌,从微观层面阐述特殊钢渣-废弃核桃壳制备钢渣基生物质活性炭机理。结果表明特殊钢渣超微粉溶液中含有Cd、Cu、Pb、Zn、Ni、Cr、As等重金属,其中Pb、Ni、Cr的浸出毒性含量高于《浸出毒性鉴别标准》(GB 5085.3—2007)中相关重金属的浸出毒性限值。磷酸具有破坏结构特性、无水乙醇具有促进分散特性,有利于消除微粉颗粒间的引力,提高废弃核桃壳超微粉与特殊钢渣超微粉的分散性。特殊钢渣超微粉所含具有磁性的Fe_(2)O_(3)与具有催化性的CuO、MnO形成协同作用,有利于氯气在钢渣基生物质活性炭表面形成富集,提高对氯气吸附能力。钢渣基生物质活性炭对氯气的吸附能力随着吸附环境温度上升呈现先小幅降低后大幅降低的趋势,过高的吸附环境温度会增强氯气分子的活跃性,造成被钢渣基生物质活性炭吸附的氯气出现解析现象。钢渣基生物质活性炭在活化处理与焙烧过程中废弃核桃壳超微粉形成的活性炭不仅包裹特殊钢渣超微粉,而且将特殊钢渣超微粉所含重金属稳定固化于活性炭中。

When chlorine leaks,measures should be taken immediately.Also the recovery and purification of chlorine-containing exhaust gas should be strengthened.At present,activated carbon with a developed porous structure and rich specific surface area is widely used to adsorb harmful gases.However the current production of activated carbon generally requires the consumption of natural resources such as wood and bamboo,resulting in high costs and is not conducive to sustainable development.Therefore,the preparation of activated carbon using biomass waste materials,and the modification of activated carbon by using metallurgical solid waste to reduce production and environmental costs further and improve adsorption properties,have become a hot spot in the field of activated carbon production.This study used special steel slag and discarded walnut shells as research objects to prepare steel slag-based biomass-activated carbon.The property of chlorine absorption was tested by a P-C-T adsorption device,and the inductively coupled plasma mass spectrometer(ICP-MS),X-ray fluorescence spectrometer(XRF),laser particle size meter(LPSA)and field emission scanning electron microscope(SEM)was used to test the concentration of the leached heavy metals,chemical composition,particle size distribution and microscopic morphology,respectively.Moreover,the mechanism of preparing steel slag-based biomass-activated carbon from special steel slag-discard walnut shells was elaborated from the microscopic level.The results show that the special steel slag ultrafine powder solution contains heavy metals such as Cd,Cu,Pb,Zn,Ni,Cr,As,etc.,and the leaching toxicity content of Pb,Ni and Cr is higher than the leaching toxicity limit in the“Leaching Toxicity Identification Standard”(GB 5085.3—2007).Phosphoric acid has destructive structural characteristics,and anhydrous ethanol promotes dispersion,which is conducive to eliminating the gravitational force between the micronized particles and improving the dispersion of the discard walnut shell ultrafine powder and the special steel slag ultrafine powder.The magnetic Fe_(2)O_(3) contained in the special steel slag ultra-fine powder and the catalytic CuO and MnO form a synergistic effect,which is conducive to the formation and enrichment of chlorine gas on the surface of the steel slag-based biomass-activated carbon,and improves the adsorption capacity of chlorine gas.The adsorption capacity of steel slag-based biomass-activated carbon to chlorine gas shows a tendency to decrease slightly and then decrease greatly with the rise of the ambient adsorption temperature.The excessively high adsorption ambient temperature will enhance the activity of chlorine molecules,resulting in the analytical phenomenon of chlorine adsorbed by steel slag-based biomass activated carbon.The activated carbon formed during the activation treatment and roasting process of discarding walnut shell ultrafine powder not only wraps the special steel slag ultrafine powder but also solidifies the heavy metals in the special steel slag ultrafine powder.