Removal of pyridine from aqueous solution by adsorption on bagasse fly ash

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 (pH(0)), adsorbent dose (m), contact time (t), initial concentration (C-0), 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 (< 50 mg dm(-3)) and 95% at higher concentrations (600 mg dm(-3)), using a BFA dosage of 25 kg m(-3) at normal temperature. Studies on Py adsorption equilibrium and kinetics by BFA also have been conducted. The adsorption equilibrium analyses also are performed, using the Langmuir, Freundlich, Redlich-Peterson, and Temkin isotherm equations. The Langmuir equation is determined to best represent the equilibrium sorption data. Thermodynamic studies revealed that the adsorption of Py on BFA is endothermic in nature and that the isosteric heat of adsorption decreases as the equilibrium uptake of Py on the BFA surface increases. The desorption of Py from Py-loaded BFA with several solvents shows that only 68.70% and 51% of Py could be recovered, using ethyl alcohol and 0.1 N H2SO4, respectively.