Use of Ni-containing catalysts for synthetic olive mill wastewater steam reforming

Abstract

The olive oil mill wastewater (OMW) is a by-product (with a high organic load) derived from the production of the olive oil. The OMW steam reforming (OMWSR) process was studied herein, aiming to decrease the environmental damage of such effluents; simultaneously, the waste is economically and energetically valorized with the H2 production. Several Ni-containing catalysts were prepared and tested to compare their performances for the OMWSR using a synthetic OMW effluent; still, stability tests were also carried out. The materials were extensively characterized: thermogravimetric analysis, temperature-programmed oxidation/reduction, temperature-programmed desorption of CO2/NH3, chemisorption of H2, inductively coupled plasma optical emission spectrometry and physical adsorption-desorption of N2 at −196 °C. Amongst the materials tested, the Ni–Ru/SiO2 sample stood out, exhibiting high catalytic performance: at 400 °C, the H2 yield (>8 molH2·molOMW-1) and conversion of total organic carbon (≈75%) were high during all the 24 h of the long-term test, with only a small deactivation being noticed.