Novel green chemical technologies will play a key
role helping society move towards the elimination of waste while offering a
wider range of products from biorefineries, according to a Univ. of York
Professor James Clark, Director of the Univ.’s
Green Chemistry Centre of Excellence, will tell a symposium at the Annual
meeting of the American Association for the Advancement of Science (AAAS) that
the use of low environmental impact green chemical technologies will help
ensure that products are genuinely and verifiably green and sustainable.
He says the extraction of valuable chemicals from
biomass could form the initial processing step of many future biorefineries.
“We have shown that wax products with
numerous applications, can be extracted from crop and other by-products
including wheat and barley straws, timber residues and grasses, using
supercritical carbon dioxide—a green chemical technology that allows the
production of products with no solvent residues,” he says.
“The extracted residues can be used in
applications including construction as well as in bioprocessing.”
Low-temperature microwaves can also be used to
pyrolyse biomass, allowing greater control over the heating process. The
process results in significant energy savings and produces high quality oils,
and oils and solids with useful chemical properties.
Professor Clark says that combining continuous
extraction with microwave irradiation, it is possible separate an aqueous phase
leaving the oils cleaner, less acidic and with lower quantities of other
contaminants such as alkali metals. The oils have significant potential as
feedstocks for making chemical products as well as for blending into transport
“Our microwave technology can also be tuned to produce bio-chars with
calorific values and physical properties that make them suitable for co-firing
with coal in power-stations,” he adds.