6. The Kinetic Studies in the Adsorption of Hazardous Substances Using Clay Minerals

For the design of the adsorption system, reliable adsorption kinetic data are required. Different concepts are employed to develop a reliable adsorption kinetic model. Most of the available models were developed according to mass transfer principles or the concept of chemical reaction occurring on the surface of a solid. The models based on the surface-reaction kinetic step as controlling the sorption rate have also been proposed, these models include pseudo-first order kinetic (also called as Lagergren model), pseudo-second order kinetic, and Elovich equation. This chapter discusses various aspects of pseudo-first order kinetic and pseudo-second order kinetic in representing the adsorption kinetic data of some hazardous compounds onto clay minerals. The pseudo-first order kinetic is the earliest known equation to describe the rate of sorption in the liquid phase system. The behavior of time constant parameters k ₁ and k ₂ of pseudo-first order kinetics and pseudo-second order kinetics as a function of initial concentration as well as the temperature is discussed in this chapter. One of the kinetic models which also widely used to represent the sorption kinetic data is an intraparticle diffusion model also briefly discussed in this chapter.