|
Bitumen, a by-product of oil-refining, is mainly used in paving and roofing. In paving operations,
bitumen is heated and mixed with mineral aggregates. The use of recycled materials and industrial byproducts
in asphalt mixtures is increasing. Hot bitumen (130–200 °C) emits vapours and aerosols
(fumes) that contain various compounds, including polycyclic aromatic hydrocarbons (PAHs) and
sulphur-containing organochemicals. Bitumen fumes contain 1–5-ring unsubstituted PAHs, alkylated
PAHs, heterocyclic PAHs and terpenoids which may have mutagenic and carcinogenic activities.
Additionally some of these compounds are odour causing compounds. One of the effective ways of
biochemical and chemical deactivation of odour causing and carcinogenic compounds is application of
ozone and low temperature plasma environment. In these conditions the most stable organic
compounds including monoaromatic and polyaromatic compounds can be oxidized. In the experiment
degradation of volatile organic compounds from asphalt industry, including odour causing compounds,
was conducted. With this end in view a special plasmachemical reactor was developed. In analytical
part solid phase microextraction and GC-MS was applied for identification and quantitative
measurements. It was observed that compounds containing heteroatoms were easily degradable than
compounds containing condensed rings and aliphatic substituted benzene rings. The preliminary
results of our investigations showed that methods utilizing ozone and/or low temperature plasma
environment could be successfully applied for degradation of odour causing and carcinogenic
compounds emitted in off-gases originating from asphalt industry. These methods can be however
applied in specific conditions, after precise determination of process parameters and identification of
the formed products.
|
