Pinewood char templated mordenite/carbon honeycomb composite

Abstract

Biotemplating with carbonized wood is a novel way of zeolite adsorbent and catalyst production, with uniform, hierarchically ordered macro- and micropore structure, having low diffusional resistances against mass transport of adsorptives, reactants and products around the zeolite crystallites. Pinewood (Picea abies) cubes of 1-cm size edges were carbonized at 700 °C in nitrogen flow. The obtained charcoal cubes contain parallel channels of 20–30 μm diameter, separated by about 1–3 μm thick carbon walls. The hydrophobic character of the channel walls was effectively reduced using oxidative treatment with nitric acid. Following saturation with zeolite synthesis solution the carbon cubes were exposed to hydrothermal conditions. Mordenite/carbon composite materials were formed where Na-mordenite microcrystals coated the walls of the carbon macropores. The thickness and density of the zeolite layer was controlled by varying the synthesis conditions. Owing to reduced diffusional resistance, the preparations are favourable adsorbents and catalysts.