TRANSPORT OF ACRIDINE IN SATURATED POROUS-MEDIA

The effects of the aqueous solution pH, temperature, initial solute co ncentration and non-equilibrium processes on the transport of acridine in saturated porous media (silica) were investigated in a series of c ontinuous-flow column experiments. The enthalpy of the adsorption reac tion was more exothermic when the solution pH was above acridine's pK( a) (5.6) than when it was below. The extent of adsorption was greater when the solution pH was below the pK(a) of acridine than when it was above. Non-equilibrium effects on the adsorption reaction were found t o be unimportant at groundwater velocities. The results from this stud y suggest that the mobility of acridine in aquifers, in which adsorpti on to silica edge sites is significant, would increase as the temperat ure of the groundwater increased and the acridine mobility would be gr eatest when the pH of the groundwater is above the pK(a) of acridine. The transport of acridine in such aquifers can be effectively modeled using the local equilibrium assumption.