Bioapatite derived from animal bones as support for environmentally concerned catalysts: WGS with suppressed methanation activity

Abstract

The potential of natural apatite derived from pork bones to be used as a support of Ni catalysts for the Water-Gas Shift (WGS) reaction was investigated. Samples of bone char were chemically treated with either K2CO3 or H2SO4 and subsequently heated in inert or oxidizing atmosphere at various temperatures. Catalysts were characterized by ICP-AES, N2 physisorption, XRD, FTIR, TG-DTG, H2-TPR, XPS, H2 chemisorption and NH3-TPD, and tested in the WGS reaction, using both ideal and realistic (mixture of H2O, CO2 and H2) feed streams. Nickel was partly exchanged with Ca2+ ions in the support. Regarding the effect of the atmosphere, an inert atmosphere had a negative effect due to the collapse of the porous structure. On the contrary, the combination of an oxidizing atmosphere and treatment with K2CO3 allowed a superior WGS performance under real reformer conditions, with a substantial decrease in the methane formation (six-fold decrease, compared to the non-activated reference catalyst). The catalytic activity could be related to the apatitic phase growing geometry, which can be tailored by the activation method.