Abstract
A huge variety of benefits are expected from the application of carbon based
nanomaterials. Currently, the nanoproducts that can be found on the market can
be classified as consumer products whereas future applications are presumed to
encompass areas such as medicine, water purification and industrial
applications. Nanomaterials are used mainly for their unique physicochemical
properties which are known to improve products’ characteristics. Contrary to the
physicochemical goodness, it is these very unique properties that have since
raised health and the environmental concerns for. For the sustainability of this
innovation and protection of the environment as well as human health, pro-active
effort to understand and alleviate potential risks is vital. Current knowledge on
nanoecotoxicology is clouded by uncertainties pertaining their fate and behaviour
in the environment. With the increase in nanotechnology, carbon-based
nanomaterials’ (CBN) have been earmarked for water purification. Their (CBN)
behaviour in the aquatic environment, their biovailability in aquatic systems,
interaction with and internalization by living organisms and their sub-lethal effects
to aquatic organisms are key-determinates to their toxicity, yet they have only
just began to emerge. The overarching aim of this thesis therefore was to
address the existing gap in knowledge and further bring understanding of fate
and behaviour of multi-walled carbon nanotubes (MWCNT) and fullerenes (C60)
and their acute and sub-lethal toxicity to algae (Pseudokirchneriella subcapitata),
daphnia (Daphnia magna) and fish (Poecilia reticulata) in simulated fresh water
systems of varied salinity.
The MWCNT and C60 were successfully synthesized using nebulized spray
pyrolysis and chemical vapour deposition, respectively, as evidenced by
characteristic peaks (D and G bands) identified using Raman spectroscopy. Acid
oxidation of p-MWCNT and p-C60 yielded o-MWCNT and o-C60 respectively...
Ph.D. (Chemistry)