A new approach to evaluate kinetic parameters and mass transfer coefficients stirred tank reactors.Application to antibiotic separation

Abstract

A new method is proposed to evaluate kinetic parameters and mass transfer cofficient for adsorption processes carried out in continuous stirred tank reactors.This method,employing a biphasic mode,does not lincarize nonlinear solute consertraion versus time data,not does it assume the existence of equlibirium in a typical nonequlibirium situation as is currently done. For a nonlinear adsorption isotherum the coupled differintal equation need to be solved numerically,but using an elegant analytical solution it is possible to determine rate constants and mass transfer coefficient in the case of nonlinear kinetic with a linear adsorption isotherum.This solution(biphasic model, linear isotherum)is obtaind and compared with solution incorporating(i)a linear model(linear isotherum)and(ii)a numerical solution(nonlinear isotherum)for recovery of the antibiotic novobiocin in stirred tank reactor.For novobiocin adsorption versus time data,use of the biphasic model result in a lower mean presentage error then either the linear model or the numerical simulation, futher.It provide a far superior fit of short-time adsorption behavior.Hence, we strongly advocate that the biphasic model be routinely employed along with linear models and numerical simulations of Langmuir/Freundlich isotherums for interpretation of adsorption data.