3934
Ind. Eng. Chem. Res. 2006, 45, 3934-3943
Removal of Pyridine from Aqueous Solution by Adsorption on Bagasse Fly Ash Dilip H. Lataye, Indra M. Mishra,* and Indra D. Mall
Ind. Eng. Chem. Res. 2006.45:3934-3943. Downloaded from pubs.acs.org by EASTERN KENTUCKY UNIV on 01/24/19. For personal use only.
Department of Chemical Engineering, Indian Institute of Technology, Roorkee-247 667, India
The present study examines the adsorption of pyridine (Py) from aqueous solutions, using bagasse fly ash (BFA), which is a solid waste that is generated from bagasse-fired boilers, as an adsorbent. Batch adsorption studies have been performed to evaluate the influence of various parameters, such as initial pH (pH0), adsorbent dose (m), contact time (t), initial concentration (C0), and temperature (T), on the removal of Py from the aqueous solutions. The maximum removal of Py is determined to be 99% at lower concentrations (93% at the highest initial concentration (C0 ) 600 mg dm-3) and at the lowest temperature (10 °C). Py removal is not affected much by an increase in either temperature or initial concentration. However, note that, as C0 and/or T increases, the Py loading onto BFA (i.e., qe) increases. This means that the Py sorption capacity of the BFA increases significantly with an increase in C0, but only weakly with an increase in the temperature of the solution. This is due to the increase in the mass-transfer driving force, because of the increase in C0.19 It also reflects that the diffusion of Py molecules into the pores is very fast and that the increase in temperature does not enhance the diffusion rate significantly. 3.5. Effect of Contact Time. The effect of contact time on the removal of Py by BFA for m ) 20 g dm-3 and C0 ) 50, 100, and 150 mg dm-3 is shown in Figure 7. This figure showed rapid adsorption of Py in the first 15 min, and thereafter, the
T ) 283 K T ) 293 K T ) 303 K T ) 313 K T ) 323 K
Redlich-Peterson Isotherm 0.69 0.28 4.43 3.63 0.57 0.75 0.98 0.99 0.99 0.99 -0.43 -0.22 16.99 11.63
R2 represents the goodness of fit.
adsorption rate decreased gradually. The adsorptive uptake of Py by BFA is almost instantaneous: ∼86.5% of Py from an aqueous solution of C0 ) 300 mg dm-3 is adsorbed within 1 min of contact. Thereafter, the Py removal is low. The residual Py concentration is 6.78% after 1 h, 3.37% after 6 h, 3.35% after 24 h, and 3.13% after 72 h of contact time. Because the difference in Py removal at 6 and 72 h is
