Fabrication and characterization of magnetoresponsive carbon nanotube-infused polysulfone (cnt-ipsf) nanocomposites for water purification
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Date
2017-09
Authors
Shisia, Kuboka Silvanus
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Abstract
The search for materials for purification of polluted water is growing daily with the
advent of nanoparticles. This is particularly important because many populations of
people in the developing countries lack clean water due to water pollution. Water
pollutants such as heavy metals and polycyclic aromatic hydrocarbons (PAHs) are
known to have adverse effects on humans and environment. This work investigated
the potential of synthesized magnetoresponsive CNT-polysulfone infused polymeric
nanocomposites (CNT-IPSF) in water purification against heavy metals and
polycyclic aromatic hydrocarbons (PAHs) pollution. Adsorption mechanism was
studied at constant initial Pb(II) ion concentrations, nanocomposite dosage, contact
time, and pH. Carbon nanotubes (CNTs) with internal diameters in the range of 20-30
nm were prepared via chemical vapour deposition (CVD) process. Magnetite and
silica coated magnetite nanoparticles (NPs) prepared by solvothermal and sol gel
methods respectively exhibited UV-Visible spectrometric spectra at about 395 nm and
396 nm respectively. Successfully synthesized Fe3O4 nanoparticles exhibited FT-IR
absorption bands at 460 and 521 cm-1 which ascribed for the vibrations of Fe-O bond.
X-ray diffraction analysis of core shell NPs showed strongest peak at D(311) plane,
characteristic of a cubic spinel structure. The core shell nanoparticles obtained
displayed a thin hysteresis loop having saturation magnetization of 2.2 emu g-1 with
ferrimagnetic property. Removal efficiency of the synthesized CNT-PSF/Fe3O4
nanocomposite for Pb(II) ions and phenanthrenes was 69 % and 63 % respectively
compared to that for a commercially available activated carbon which recorded 54 %
and 53 % respectively. Adsorption of Pb(II) ions and phenanthrenes followed pseudosecond-
order while Freundlich adsorption isotherm gave the best-fit for the two
pollutants. Regeneration for Pb(II) ions of above 60 % and a gradual decrease in
desorption efficiency for phenanthrenes of up to 50 % after three desorption cycles
confirmed the reusability of the fabricated magnetoresponsive CNT-IPSF/Fe3O4
nanocomposites. This study has developed a novel CNT-IPSF/Fe3O4 nanocomposite
material with higher removal efficiency for water pollutants than commercially
available activated carbon for use in water treatment
Description
A thesis submitted in fulfillment of the requirements for the award of the degree of doctor of philosophy (chemistry) in the school of pure and applied sciences of Kenyatta University, September 2017