Catalytic Reforming of the Aqueous Phase Derived from Diluted Hydrogen Peroxide Oxidation of Waste Polyethylene for Hydrogen Production.

Abstract

The thermal degradation and conversion of waste polyethylene (PE) using a two-step process including hydrothermal oxidation (HO) and aqueous phase reforming (APR) were investigated. The objective of this study was to achieve efficient disposal of waste PE and generate H2 in a mild and green way. The effects of various HO conditions on both HO and APR processes were studied. A high H2 O2 concentration caused overoxidation of PE resulting in more CO2 . Decreasing the H2 O2 concentration weakened the overoxidation. The process using diluted H2 O2 exhibited the highest selectivity for acetic acid among the produced carboxylic acids. When the HO temperature exceeded 200 °C, there was an increase in the CO2 yield during the HO process and a decrease in the H2 yield during the APR process. In addition, the effects of various monometallic and bimetallic catalysts on the reforming of the aqueous phase from the HO of PE were discussed. The highest H2 mole fraction (51.52 %) in gaseous products from the APR process was obtained with Ru/mesoporous carbon. Nevertheless, Ru-Ni exhibited a higher stability than the monometallic Ru catalyst.