mass transfer mechanism and mathematical model for extraction process of l-theanine across bulk liquid membrane

this paper deals with the extraction of l-theanine containing aliquat 336 as a carrier and cyclohexane as solvent across bulk liquid membrane. the optimum operation condition are as follows: extraction time of 150 min, initial concentration of theanine in the feed phase is 1.8 g/l, the carrier concentration is 0.5 m, the ion of the receiving phase is 0.2 m nacl of na2hpo4-nah2po4 buffer solution. a mathematical model of transport process was deduced, the forward interfacial reaction rate constants and the backward interfacial reaction rate constants between the feed phase and the membrane phase, the receiving phase and the membrane phase were taken into account in the model equations. using the experimental results, several parameters of the proposed model have been achieved by a nonlinear fitting method.