Environmental Engineering Reference
In-Depth Information
Diminishing reserves and dramatic fluctuations in the price of oil, the most impor-
tant raw material for chemicals, have been highlighted. However, the wider reality
is of resource depletion of many key minerals and price increases for commodities
affecting almost all chemical manufacturing as well as other important industries,
notably electronics [25]. There has also been an exponential growth in product-
focused legislation and non-governmental organisation (NGO) pressure, threaten-
ing the continued use of countless chemicals. The most important legislative
driver is REACH [26]. This powerful legislation requires the thorough testing of
all chemicals used at quantities of more than 1 tonne per year in Europe (including
those manufactured outside of the EU and imported in). Persistence, bioaccumu-
lation and toxicity (PBT) are the key assessments.
While there has been considerable debate on the impact of REACH on the
European chemical industry due to the high costs of assessment and testing and
the inevitable bureaucracy, the biggest results will ultimately be the identification
of chemicals that require authorisation or restricted use. At the time of writing, the
list of chemicals effectively black-listed or at least highlighted as being of serious
concern (making their use very difficult due to NGO and consumer pressure) is
growing and already causing alarm in industries whose own processes or supply
chains rely on the same chemicals. Solvents are an area of great concern as they
are widely used in many industries; several polar (e.g. N-methylpyrolloidone),
polarisable (e.g. chlorinated aliphatics) and non-polar (e.g. hexane) solvents are
likely to fall foul of REACH. In such cases a critical issue is suitable alternatives.
While replacing some chemicals may not prove too difficult, in many cases there
are no suitable alternatives. This certainly applies to solvents where currently used
compounds may well have a complex set of desirable properties (liquid range,
boiling point, polarity/polarisability, water miscibility, etc.); finding a suitable
alternative that also has better PBT characteristics can be very difficult. This is an
area where renewable products may prove to be very important. New solvents
with a diverse range of properties (e.g. terpenes, esters, polyethers) can be tailored
for some problematic processes, such as limonene as referred to earlier [22].
By using the low-environmental-impact technologies developed in the 1990s to
obtain safe 'REACH-proof' chemicals from large-volume bioresources, we can
take a major step towards the creation of a new generation of green and sustaina-
ble chemicals as well as tackle the escalating waste problems faced by modern
society. Through the use of green chemistry techniques to obtain organic chemi-
cals and materials from biomass and materials and metals from waste electronics
and other consumer waste, we can help establish a life-cycle for many products
that is sustainable on a sensible timescale within the human lifespan.
We must make better use of the primary metabolites in biomass. Cellulose,
starches and chitin need to be used to make new macromolecular materials and not
simply act as a source of small molecules; this can include composites and blends
with synthetic polymers as we move towards a sustainable chemical industry. The
small molecules that we obtain in this way need to become the building blocks of
