High-value Utilization Of Waste Incineration Fly Ash To Prepare Zeolite-like Hydrogenation Catalyst

The waste incineration fly ash is rich in a considerable amount of toxic substances such as dioxins and heavy metals,which is extremely harmful.The existing solid waste treatment technologies mainly aim at reducing the leachability of heavy metals and decomposing toxic and harmful pollutants,and most of them only aim at one of them.The silicon,aluminum and carbon components in waste incineration fly ash are good catalyst carriers.Therefore,waste incineration fly ash has the potential and advantages to prepare environmental catalysts.In addition,waste incineration fly ash also contains a large amount of valuable heavy metals,such as iron,copper,etc.The rational development and utilization of waste incineration fly ash components and the preparation of high-performance catalysts are one of the important development directions of waste incineration fly ash resource utilization.Biomass-based compounds are an important sustainable resource with great potential in energy production,chemical and material preparation,etc.Hydrogenation catalysts are widely used in high-value catalytic conversion of biomass to synthesize important platform molecular compounds such asγ-valerolactone,for the synthesis ofγ-valerolactone,furfuryl alcohol and 2-methylfuran,the catalyst systems currently developed for the above-mentioned synthesis reactions have problems such as high catalyst prices,and the acidity of the reaction solvent may cause environmental pollution.Therefore,the development of inexpensive,efficient and green catalysts and catalytic systems is a hot issue in the field of high-value biomass conversion.On the basis of fully analyzing the characteristics of heavy metals,silicon and aluminum components in waste incineration fly ash,this topic proposes to prepare waste incineration fly ash-derived zeolite by alkali activation and direct foaming method using waste incineration fly ash as raw material.Two kinds of zeolite-like hydrogenation catalysts derived from waste incineration fly ash were prepared by two functionalization methods,and they were applied to the hydrogenation of levulinic acid toγ-valerolactone and the hydrogenation of furfural to prepare furfuryl alcohol and 2-methyl methacrylate,respectively.In the reaction of zeolite-based furan,the catalytic performance of the zeolite-like hydrogenation catalyst derived from waste incineration fly ash was deeply explored through hydrogenation catalytic experiments combined with microstructure characterization.The main conclusions are as follows:（1）High-performance zeolite was prepared using waste incineration fly ash as raw material.The optimal synthesis scheme is:silicon content≥8wt%,aluminum content≥3wt%,potassium hydroxide content≥25wt%,water content The component content is about 50～60wt%,and the foamed porous material is obtained by direct foaming,wherein the mixing ratio of the foaming agent hydrogen peroxide solution（concentration is 3%）and the foam stabilizer pure oleic acid solution is about 6.5:1（w/w）,the total amount of foaming reagents accounts for about 350%of the total inorganic solid waste.The zeolite-like hydrogenation catalyst derived from waste incineration fly ash was prepared by supporting nickel by the traditional ultra-wet impregnation method and applied to the hydrogenation reaction of levulinic acid.The materials were characterized by SEM,FTIR,XRD,physical adsorption analysis,ICP and other characterization methods.The structural characteristics and leaching properties of heavy metals under high temperature and high pressure were analyzed.Under the typical hydrogenation reaction conditions of levulinic acid hydrogenation to prepareγ-valerolactone,the yield ofγ-valerolactone is up to 94%（comparable to the performance of commercial support materials）.（2）Using waste incineration fly ash as raw material,a three-step method is used to prepare a zeolite-like-based bifunctional hydrogenation catalyst derived from waste incineration fly ash,which realizes the separation,purification and catalytic performance of active metal iron and the regeneration of silicon,aluminum and iron components.The catalytic activity of the bifunctional hydrogenation catalyst was tested and analyzed by SEM,FTIR,XRD,XPS,NH₃-TPD and other characterizations.The results show that the three-step synthesis of waste incineration fly ash-derived zeolite-like-based hydrogenation catalyst（ML-BSA-PW40）has excellent catalytic activity.The selectivity of base furan was 32.21%,64.13%and 67.79%,35.87%,respectively.It is proved that the three-step method for synthesizing bifunctional catalysts is feasible.