Introduction
Biomass is one of the world’s most important renewable energy
sources. It has been reported that the sustainable production of
1.3 Pg of biomass per year can be achieved without significant
changes in agricultural practices or food supplies.1–3 Since annually
renewable biomass contains 75% carbohydrates, converting these
carbohydrates into organic chemicals to ultimately replace those
derived from petrochemical resources is a major challenge for
green chemistry.4
Furfural is produced from the hemicellulosic fraction of biomass,5
and has been identified as one of the top 30 high-value,
bio-based chemicals. Furfural is a versatile furan platform compound
comprised of a heteroaromatic furan ring and an aldehyde
functional group.6 Commercial furfural production is currently carried
out by acid catalytic dehydration of pentosan-containing lignocellulosic
materials in a batch or continuous reactor.
Lignocellulose materials from agricultural waste that are rich in
pentosans, such as rice husks, oat hulls, cottonseed hull bran, almond
husks, and bagasse, have generally been preferred for the
commercial production of furfural.7–13 Rice husk is a renewable,
cheap, and widely available biomass. The majority of rice husk is
burnt in China, resulting in severe environmental pollution. To enhance
the value of rice husk and to decrease pollution, new indus