Ministry of Science, Education, Culture and Sport of Ukraine National Aviation University Institute of Ecological Safety Department of Biotechnology

Report
On subject: “Ferment preparations and vitamins technology”
Theme: “Sorption process”

Done by: student of 405 group
Department of Biotechnology
Institute of Ecological Safety
Olga Svyatenko
Approved by Vitryak O. P.

Kyiv 2011
Sorption
Most sorption technologies act like a sponge or a filter, soaking up contaminants until they run out of surface area. Sorption in remediation processes as an add-on to Pump and Treat systems, in spill containment and cleanup, and in the subsurface. Sorption is the common term used for both absorption and adsorption. These terms are often confused. Absorption is the incorporation of a substance in one state into another of a different state (e.g., liquids being absorbed by a solid or gases being absorbed by water). Adsorption is the physical adherence or bonding of ions and molecules onto the surface of another molecule. It is the most common form of sorption used in cleanup. In general, adsorption is a surface phenomenon, where gas or liquid is concentrated on the surface of solid particles or fluid interfaces. There are many adsorption systems. Ion-Exchange Adsorption. Adsorption beds of activated carbon for the purification of citric acid, and adsorption of organic chemicals by charcoal or porous polymers, are good examples of ion-exchange adsorption systems. Synthetic resins such as styrene, divinylbenzene, acrylamide polymers activated carbon are porous media with total surface area of 450–1800m2*g_1. There are a few well-known adsorption systems such as isothermal adsorption systems. The best known adsorption model is Langmuir isotherm adsorption.

FIG.1. Langmuir isotherm adsorption model.
Langmuir Isotherm Adsorption. Adsorption, like extraction, depends on equilibrium relationships. Isothermal adsorption is projected by Langmuir isotherms. The model is shown in Fig. 1, which is based on the linear model of the following equation:
,
where, C*As is equilibrium concentration (kg solute/kg solid) and CASm is the maximum loading of adsobate.
Freundlich Isotherm Adsorption. Another useful model for isothermal adsorption is the Freundlich model, which is presented by the following equation.

where kF and n are constants based on the characteristics of the particular adsorption system. If adsorption is favourable, the value of n is greater than 1. For n less than 1, the adsorption process is not favourable. Fixed-Bed Adsorption. Fixed-bed adsorption may give a higher adsorption area per unit volume than any other type of adsorber. The point of saturation of the bed is called the breakthrough point. By knowing this point one can determine operation schedules. In designing fixed-bed adsorbers, the quantity of resin and the time required for adsorption of a given quantity of solute must be estimated.

Literature list 1. Ghasem D. Najafpour. Biochemical engineering and biotechnology. – Oxford: Elsevier, 2007. – 421 p.