Abstract
M.Tech. (Chemistry)
This study investigated the functionalization of coke particles and their utilization
for the preparation of coke-polymer composite. Looking at the possibility of using it
for the removal of lead and chromium ions from their aqueous solutions. Due to
various inorganic materials in coke, it was treated with acid to demineralize the
ash content. The demineralized coke was further oxidized with hydrogen peroxide
to add functional groups on its surface as well as in the bulk of coke particles
before coating of the polymers. The composite preparation entails modifying the
surface properties of coke with hydrophilic polymers like polyvinyl alcohol (PVA),
poly ethylene glycol (PEG) and poly vinyl pyrrolidone (PVP) followed by the
crosslinking to improve the interfacial interaction between the polymer and coke to
make the synthesized composite stable in water.
The structural composition of coke and modified coke was examined by FT-IR
spectroscopy, X-ray diffraction, X-ray fluorescence, Raman Spectroscopy, thermal
analysis and scanning electron microscopy combined with energy dispersive X-ray
analysis. It was also observed that the modified coke samples have enhanced
carbon reactivity which indicates that the non-carbon phases were removed by the
treatment with acid.
The adsorption studies for the removal of Pb (II) and Cr (III) ions from
contaminated water was done in batch mode using variables such as pH, contact
time and the initial concentration. The synthesized material was found to have
better adsorption capacity as compared to raw coke. To understand the adsorption
isotherm processes, Freundlich and Langmuir isotherms were applied. The
monolayer adsorption capacity for the removal of lead ions was found to be 2.41
mg/g, 2.95 mg/g, 8.32 mg/g, 9.70 mg/g and 9.84 mg/g for raw coke, acid treated
coke, PVA coated coke, PEG coated coke and PVP coated coke, respectively.
The chromium monolayer adsorption capacity was found to be 9.48 mg/g, 9.94
mg/g, 35.84 mg/g, 32.79 mg/g and 34.13 mg/g for the same order of adsorbents
mentioned for lead. Studies were carried out at the optimum pH of 6.0 for both the
metal ions. The adsorption kinetic studies showed that both the metal ions
followed pseudo second order rate equation and the adsorption equilibrium was
attained in 60 minutes and 120 minutes for Pb (II) and Cr (III) ions, respectively.