Solid-Waste-Derived Geopolymer-Type Zeolite-like High Functional Catalytic Materials Catalyze Efficient Hydrogenation of Levulinic Acid

Three common solid wastes (waste incineration fly ash, sewage sludge, and polluted soil) were the raw materials used in the synthesis of a geopolymer-type zeolite-like product, which was then used as a catalyst carrier to prepare a nickel hydrogenation catalyst for the catalytic hydrogenation of levulinic acid to gamma-valerolactone. Under optimum synthesis conditions, the synthesized geopolymer zeolite has excellent structure and performance. The characterization results show that the composites have a three-dimensional network structure, and the pore structure is homogeneous mesoporous or microporous. In this work, the results of catalytic hydrogenation show that the yield of gamma-valerolactone can achieve up to 94% using the synthesized catalyst, which is comparable to that of commercial catalysts and the concentrations of typical polluting heavy metals of Cu, Zn, Pb, and Cd in the reaction solution were all below the emission concentration limit (Class I standard) after five cycles of reaction. In summary, this geopolymer-type zeolite-like catalyst is cheap and has excellent performance; it is, therefore, expected to be widely used in catalysis instead of commercial carriers.