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4.2 Design of Adsorption and Ion-Exchange Processes 307

A f e w comments on copper : Copper is an element that has found man y uses in the man-
ufacture of electrical equipment due to its high electrical and thermal conducti . vity
v
Copper salts hae also been used eely as fungicides, in ceramics and p v xtensi yrotech-
nics, and in many other industrial applications. Ob the utilization of copper by viously ,
man has led to the reinforcement of its presence in the environment, with mining oper-
aste,
ations, solid w agriculture, and sludge from seage-treatment plants being its pri- w
mary anthropogenic releases.
Gastrointestinal, hepatic, and renal effects with symptoms such as se v ere abdominal
pain, v diarrhea, hemolysis, hepatic necrosis, hematuria, proteinuria, h ypoten-
omiting,
sion, tachycardia, con coma, and finally death, may result from the ingestion
vulsions,
of grams of copper salts.

4.2.2 Fixed-bed operations for ion exchange and adsorption

Introduction
In the design of a sorption system, the knowledge of the main principles is important and
v
.
T
many practical aspects hae to be dealt with adequatelygin with, the suitable sor-
o be
bent material for our application has to be selected. It is highly desirable that its equilib-
er
,
v
rium properties such as capacity and selectivity are well known. Moreo their
dependence on temperature and component concentration has to be also understood. In
addition, time and space hae to be included in our design, since sorption operations are
v
held in batch or fixed beds and exhibit a dynamic behavior. It means that steady-state oper-
ation is not the case in sorption systems in contrast to many other chemical operations that
ix
are independent of time. The fed-bed performance has to be well related to adsorption
equilibrium and rate behavior in a successful design. Many practical aspects hae to be v
taken into account so that the process can be properly carried out. Fxample, dispersi or e v e
phenomena at the bed scale as well as the aging mechanism have to be known and included
in our design so that the behavior of the sorption system is controlled.
Fixed bed is the most frequently used operation for ion exchange and adsorption, as
v
it is the predominant way of conducting such sorption separations. Moreo ion
er
,
exchange and adsorption are common operations used for wasteater treatment. For w
example, in ion-exchange processes, zeolites and resins are used for the remoal of v
heavy metals such as Pb 2 ,Cr 3 ,Fe 3 ,Cu 2 , and ammonia (Baycal et al ., 1996;
Blanchard et al ., 1984; Inglezakis et al ., 2002; Cincotti et al ., 2001; Babel and
v
w
Kurniaan, 2003), while in adsorption processes, actiated carbon, peat, iron oxide,
v
kaolin, and fly ash are used for the remoal of heavy metals and seeral organic sub- v
w
stances from wasteaters, such as benzene, phenolic compounds, carbon tetrachloride,
nitrophenol, acid dyes, and p -dichlorobenzene (Weber and Pirbazari, 1082; Chern and
Chien, 2002; Babel and Kurniaan, 2003; Gupta w et al ., 1997, 2000; K o et al ., 2002; Sen
et al ., 2002). Furthermore, adsorption is frequently used for the remoal of toxic com- v
pounds from gas streams, and some examples are the remoal of phenanthrene (P v AH)
using coke (Murillo et al ., 2004), the remoal of sulfur dioxide and hydrogen sulfide
v
using zeolites (Gupta et al ., 2004; Y asyerli et al ., 2002), and the remoal of toluene v
(VOC) from a gas stream using actiated carbon (Cheng v et al ., 2004).