**9. References**


The BET equation developed originally by Brunauer et al. (1938) is able to describe type I to type III. The type III isotherm can be produced from the BET equation when the forces between adsorbate and adsorbent are smaller than that between adsorbate molecules in the liquid state (i.e. E, < EL). Fig. 20 shows such plots for the cases of C = 0.1 and 0.9 to illustrate

The BET equation does not cover the last two types (IV and V) because one of the assumptions of the BET theory is the allowance for infinite layers of molecules to build up on top of the surface. To consider the last two types, we have to limit the number of layers which can be formed above a solid surface. (Foo K.Y., Hameed B.H., 2009), (Moradi O. , et

In following chapter thermodynamics of interface is frequently applied to derive relations between macroscopic parameters. Nevertheless, this chapter is included as a reminder. It presents a consist summary of thermodynamics principles that are relevant to interfaces in view of the topics discussed such as thermodynamics for open and close systems, Equilibrium between phases, Physical description of a real liquid interface, Surface free energy and surface tension of liquids, Surface equation of state, Relation of van der Waals constants with molecular pair potentials and etc in forthcoming and special attention is paid

Adamson, A.W. and Gast, A.P. (1997) *Physical Chemistry of Surfaces* (6th edn).Wiley, New

Abdullah M.A., Chiang L., Nadeem M., Comparative evaluation of adsorption kinetics and

Ahmaruzzaman M. d., Adsorption of phenolic compounds on low-cost adsorbents: a

Aveyard, R. and Haydon, D.A. (1973) *An Introduction to the Principles of Surface Chemistry*.

Dabrowski A., Adsorption—from theory to practice, Adv. Colloid Interface Sci. 93 (2001)

Dubinin M. M., Radushkevich L.V., The equation of the characteristic curve of the activated charcoal, Proc. Acad. Sci. USSR Phys. Chem. Sect. 55 (1947) 331–337. Erbil, H.Y. (1997) Interfacial Interactions of Liquids. In Birdi, K.S. (ed.). *Handbook of Surface* 

Foo K.Y., Hameed B.H., Recent developments in the preparation and regeneration of activated carbons by microwaves, Adv. Colloid Interface Sci. 149 (2009) 19–27.

review, Adv. Colloid Interface Sci. 143 (1–2) (2008) 48–67. Adam, N.K. (1968) *The Physics and Chemistry of Surfaces*. Dover, New York.

Atkins, P.W. (1998) *Physical Chemistry* (6th edn). Oxford University Press, Oxford.

isotherms of a natural product removal by Amberlite polymeric adsorbents, Chem.

type III isotherm.

**8. Conclusion** 

**9. References** 

York, USA.

135–224.

al. 2003). (Hirschfelder, and et al. 1954).

to heterogeneous systems that contain phase boundaries.

Cambridge University Press, Cambridge.

*and Colloid Chemistry*. CRC Press, Boca Raton.

Eng. J. 146 (3) (2009) 370–376.


**9** 

*Iran* 

**Exergy, the Potential Work** 

The exergy method is an alternative, relatively new technique based on the concept of exergy, loosely defined as a universal measure of the work potential or quality of different forms of energy in relation to a given environment. An exergy balance applied to a process or a whole plant tells us how much of the usable work potential, or exergy, supplied as the input to the system under consideration has been consumed (irretrievably lost) by the process. The loss of exergy, or irreversibility, provides a generally applicable quantitative measure of process inefficiency. Analyzing a multi component plant indicates the total plant irreversibility distribution among the plant components, pinpointing those contributing most to overall plant

Unlike the traditional criteria of performance, the concept of irreversibility is firmly based on the two main laws of thermodynamics. The exergy balance for a control region, from which the irreversibility rate of a steady flow process can be calculated, can be derived by combining the steady flow energy equation (First Law) with the expression for the entropy

Exergy analysis of the systems, which analyses the processes and functioning of systems, is based on the second law of thermodynamics. In this analysis, the efficiency of the second law which states the exact functionality of a system and depicts the irreversible factors which result in exergy loss and efficiency decrease, is mentioned. Therefore, solutions to reduce exergy loss will be identified for optimization of engineering installations (Ebadi&Gorji-Bandpy, 2005). Considering exergy as the amount of useful work which is brought about, as the system and the environment reach a balance due to irreversible process, we can say that the exergy efficiency is a criterion for the assessment of the systems. Because of the irreversibility of the heating processes, the resulting work is usually less than the maximum amount and by analyzing the work losses of the system, system problems are consequently defined. Grossman diagrams, in which any single flow is defined by its own exergy, are used to determine the flow exergy in the system (Bejan, 1988). The other famous flow exergy diagrams have been published by Keenan (1932), Reisttad (1972) and Thirumaleshwar (1979). The famous diagrams of air exergy were published by Moran (1982) and Brodianskii (1973). Brodianskii (1973), Kotas (1995) and Szargut et al. (1988) have used the exergy method for thermal, chemical and metallurgical analysis of plants. Analysis of the technical chains of processes and the life-cycle of a product were respectively done by Szargut et al. (1988) and Comelissen and Hirs (1999). The thermoeconomy field, or in other words, interference of economical affairs in analyzing exergy, has been studied by Bejan

inefficiency (Gorji-Bandpy&Ebrahimian, 2007; Gorji-Bandpy et al., 2011)

**1. Introduction** 

production rate (Second Law).

(1982).

Mofid Gorji-Bandpy

*Noshirvani University of Technology* 

