Ni/Mg/Al catalysts with different atomic ratios were synthesized and tested for simultaneous H2-rich syngas recovery and toxic hydrogen cyanide (HCN) removal from polyurethane cushion waste. The waste decomposition products were converted into H2-rich syngas, and toxic HCN was removed using the Ni/Mg/Al catalysts. The catalyst composition drastically affected the ease of reduction to metallic Ni. Easily reduced catalysts effectively increased the syngas yield with redNi1.0Mg2.1Al6.0, giving the maximum syngas yield (1925 mL/g sample). Moreover, smaller Ni particle sizes (high dispersion) resulted in more effective HCN decomposition. Thus, red-Ni1.0Mg4.9Al4.1 gave the lowest HCN yield (0.9 wt %) and concentration (0.5 vol %). Durability testing revealed a decrease in the catalytic activity with repeated use (first cycle, 1497 mL/g sample; fifth cycle, 1148 mL/g sample). However, regeneration improved the gas yield (1515 mL/g sample) owing to the redispersion of the aggregated Ni particles. These results reveal the potential for the continuous use of catalysts, advancing the possibility of recycling polyurethane waste.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering