Effects of Ni/Al2O3 catalyst treatment condition on thermocatalytic conversion of spent disposable wipes

Abstract

Municipal solid waste (MSW) management is an essential municipal service. Proper waste treatment is an important part of the waste management. Thermocatalytic waste upcycling has recently gained great interest and attention as a method to extract value from waste, which potentially substitutes traditional waste treatment methods. This study aims at demonstrating the potential for thermocatalytic waste upcycling using spent disposable wipes as an MSW surrogate. Two different Ni/Al 2 O 3 catalysts were prepared, treated under two different atmospheres (N 2 and CO 2 ). The catalyst treated in N 2 (Ni/Al 2 O 3 -N 2 ) exhibited a higher surface metallic Ni site than the catalyst treated in CO 2 (Ni/Al 2 O 3 -CO 2 ). The use of the Ni/Al 2 O 3 -N 2 increased the yield of gas pyrolysate and decreased the yield of byproduct (e.g., wax), compared with no catalyst and the Ni/Al 2 O 3 -CO 2 . In particular, the Ni/Al 2 O 3 -N 2 catalyst affected the generation of gaseous hydrogen (H 2 ) by increasing the H 2 yield by up to 102% in comparison with the other thermocatalytic systems. The highest H 2 yield obtained with the Ni/Al 2 O 3 -N 2 was attributed to the most surface metallic Ni sites. However, the Ni/Al 2 O 3 -N 2 catalyst led to char having a lower higher heating value than the other catalysts due to its lowest carbon content. The results indicated that the reduction treatment environment for Ni/Al 2 O 3 catalyst influences thermocatalytic conversion product yields of spent disposable wipes, including enhanced H 2 production. Electronic Supplementary Material Supplementary material is available in the online version of this article at 10.1007/s11814-023-1461-8.