SORPTION OF TRIOCTYL AMINE TO KAOLINITE

Sorption of trioctyl amine onto kaolinite from kerosene was studied using a sorbent with the specific surface area of 18.2 +/- 0.8 m(2) g(-1) and the loss on ignition of 0.009 +/- 0.004 % (w/w). The kaolinite particles were hexagonal in shape and this was not affected by the trioctyl amine sorption. All the major XRD peaks of kaolinite were detected in the region of 1.5405 A regardless of their exposure to kerosene and trioctyl amine. Trioctyl amine sorbed onto the kaolinite surface. This was concluded from the presence of signals from C-H stretching and C-H bending vibrations of trioctyl amine molecules in the infra-red spectra of kaolinite exposed to the trioctyl amine solution in kerosene. Sorption equilibrium for trioctyl amine was reached after 144-168 hours. The equilibrium removal efficiencies of trioctyl amine ranged from 17.5 to 35.8 %, depending on the initial trioctyl amine concentration, its particle size and the solid liquid ratio. The relevant equilibrium sorption capacities for trioctyl amine ranged from 0.88 to 0.93 g/g. The linearised Freundlich isotherms had an R-2 between 0.9719 and 0.9795 and the optimised values of n and K-f ranged from 1.077 to 1.086; and from 2.622 to 2.843, respectively.