Abstract:
In the present study, nickel loaded activated carbon (Ni/AC) was synthesized and
characterized by various techniques. It was further used for the adsorption of nitrogenous
compound (N) (represented by quinoline) and sulfur compound (S) (represented by
dibenzothiophene (DBT)).
Various methods like X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy,
energy dispersive and scanning electron microscopy, thermo-gravimetric analysis etc. were used
for physico-chemical characterization of Ni/AC before and after the adsorption of N and S. FTIR
spectra of Ni/AC indicated the presence of various types functional groups on its surface.
Thermo-gravimetric analysis exhibited the thermal stability of Ni/AC up to 400 oC temperature.
The influence of various factors like loading, adsorbent dose, time and temperature on
the adsorption of N and S from model fuel by Ni/AC were investigated. Equilibrium time for N
and S was found to be 6 h and 9 h, respectively. The optimum adsorbent dose was found to be 20
g/l. It was found that adsorption of N and S followed pseudo-second-order kinetics. The
adsorption of N and S was best represented by Redlich-Peterson isotherm.
Taguchi’s method (L27 orthogonal array) was used to optimize various parameters for
the removal of N and S simultaneously from model fuel using Ni/AC. The effect of various
parameters like initial adsorbate concentration (Co,i), adsorbent dose, temperature and contact time
on the adsorption of N and S has been studied at three levels to see their effect on qN, qS and qtot.
It was found that the adsorbent dose is the most significant factor while the interaction between
Co,i’s is also significant.
For the binary system containing both S and N, equilibrium adsorption data was
obtained (Co,S = 1.56-23.43 mmol/l, Co,N = 3.57-53.57 mmol/l, T= 303 K, t = 9 h, m = 20g/l). It
was found that the adsorption capacity of Ni/AC was higher for N than that for S. For binary
component system containing S and N, extended Freundlich isotherm best represented the
isotherm data at 30 oC.
