concentration gradient between the liquid and the gas ΔC) and is defined by the
following equation (Cozma and Gavrilescu 2010):
OTR ¼ k L a ΔC
ð11:4Þ
11.2.7 Fluidized Bed Reactors (FBRs)
The FBRs can be used as a high-throughput system for treatment of liquid effluent
and discharges from industries. The phenomenon of fluidization leads to suspension
of solid particulates in an upward-flowing stream of liquid. The liquid velocity is
critically optimized to suspend the particulate matters, without expulsion from the
reactor vessel. The solid particles combine to form the loosened bed quickly and also
form a suspension at the top with lesser particle at the top. The fluidized material is
quite often a solid, and the fluidizing medium is either a fluid or a gas. The qualities
and conduct of a fluidized bed are unequivocally subject to both the solid and fluid or
gas properties. Before the reactor has begun, the catalyst pellets lie on a mesh at the
base of the reactor which later in process converts hazardous pollutants to
non-hazardous moiety. Reactants are pumped into the reactor through a distributer
consistently making the bed fluidized. The bed’s conduct after introductory fluidization relies upon the condition of the reactant. In the event that it is a fluid, the bed
grows consistently with expanded upward stream of the reactant (Fig. 11.4).
11.2.8 Packed Bed Bioreactors (PBRs)
The PBRs also known as fixed-bed bioreactors use particulate or immobilized
biocatalysts throughout vertical tube which is completely packed beads of
biocatalysts. Through this packed bed system, the effluents are introduced in through
either the bottom or top of the column, and this creates the continuous liquid
occupancy in PBRs. PBRs have a low attrition and impact on biocatalyst as
compared to STR. PBRs are commercially used for wastewater treatment by using
immobilized enzymes and cells for the production of amino acid and organic acid
and also the transformation of antibiotics such as penicillins. The particles must be
incompressible, and it also has to endure their own weight in PBRs without
deformities or blocking the fluid flow pattern. Between the liquid medium and
solid catalyst, mass transfer is carried out at high liquid flow rates through the bed,
and in order to attain this, the packed beds are frequently operated with liquid recycle
(Warren et al. 1976).
The mass transfer coefficient k s should be known even before an account for
external mass transfer effects can be made. k s is based on the hydrodynamics of the
reactor and properties of liquid state of matter, namely, viscosity, density and
diffusivity. Values of k s can be approximately estimated using correlations from
existing literature (Moo-Young and Blanch 1981):
11 Adsorptive Chromatography: A Sustainable Strategy for Treatment of Food and. . . 303
following equation (Cozma and Gavrilescu 2010):
OTR ¼ k L a ΔC
ð11:4Þ
11.2.7 Fluidized Bed Reactors (FBRs)
The FBRs can be used as a high-throughput system for treatment of liquid effluent
and discharges from industries. The phenomenon of fluidization leads to suspension
of solid particulates in an upward-flowing stream of liquid. The liquid velocity is
critically optimized to suspend the particulate matters, without expulsion from the
reactor vessel. The solid particles combine to form the loosened bed quickly and also
form a suspension at the top with lesser particle at the top. The fluidized material is
quite often a solid, and the fluidizing medium is either a fluid or a gas. The qualities
and conduct of a fluidized bed are unequivocally subject to both the solid and fluid or
gas properties. Before the reactor has begun, the catalyst pellets lie on a mesh at the
base of the reactor which later in process converts hazardous pollutants to
non-hazardous moiety. Reactants are pumped into the reactor through a distributer
consistently making the bed fluidized. The bed’s conduct after introductory fluidization relies upon the condition of the reactant. In the event that it is a fluid, the bed
grows consistently with expanded upward stream of the reactant (Fig. 11.4).
11.2.8 Packed Bed Bioreactors (PBRs)
The PBRs also known as fixed-bed bioreactors use particulate or immobilized
biocatalysts throughout vertical tube which is completely packed beads of
biocatalysts. Through this packed bed system, the effluents are introduced in through
either the bottom or top of the column, and this creates the continuous liquid
occupancy in PBRs. PBRs have a low attrition and impact on biocatalyst as
compared to STR. PBRs are commercially used for wastewater treatment by using
immobilized enzymes and cells for the production of amino acid and organic acid
and also the transformation of antibiotics such as penicillins. The particles must be
incompressible, and it also has to endure their own weight in PBRs without
deformities or blocking the fluid flow pattern. Between the liquid medium and
solid catalyst, mass transfer is carried out at high liquid flow rates through the bed,
and in order to attain this, the packed beds are frequently operated with liquid recycle
(Warren et al. 1976).
The mass transfer coefficient k s should be known even before an account for
external mass transfer effects can be made. k s is based on the hydrodynamics of the
reactor and properties of liquid state of matter, namely, viscosity, density and
diffusivity. Values of k s can be approximately estimated using correlations from
existing literature (Moo-Young and Blanch 1981):
11 Adsorptive Chromatography: A Sustainable Strategy for Treatment of Food and. . . 303