Brunel University School of Engineering and Design PhD Theses
Abstract
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This research study addresses a problem of water pollution caused by heavy and toxic
metals Cd, Cr, Cu and Pb. The thesis proposes the use of the technique of
phytoremediation using Phragmites australis (PA) plants that have the capacity to
absorb and to accumulate such metals in their roots and leaves. The metal uptake and
their location of accumulation in the PA plants were determined using flame atomic
absorption spectroscopy (FAAS) and transmission electron microscopy (TEM)
respectively. Leachates from contaminated plant biomass were mixed with silver
nitrate to assess the manufacture of metal nanoparticles as an added value step in the
process from remediation to biomass disposal. Silver nanoparticles were readily
manufactured by the leachates without, with the exception of copper, any
incorporation of the pollutant metal. The presence of copper in the manufactured
silver nanoparticles may be of some commercial use. The results obtained show that PA plants will accumulate toxic metals when in
hydroponic culture and that the majority of the accumulated metals are sequestered in
the roots and do not enter the aerial parts of the plants in significant amounts. Silver
nanoparticles were manufactured from the biomass using a low energy route with no
additional chemicals, apart from silver nitrate thus reducing the environmental load
that would otherwise be present if a chemical means of nanoparticle production was
used