removing pollutants from environment, adsorption is the most economic and
eco-friendly method. Nowadays, the use of biosorption process for removal of
pollutants has been increased due to its efficiency, reusability of biosorbents and
low cost of operation. The rate and efficiency of biosorption depend on the selection
of suitable biosorbent and the process. To select an effective biosorbent for any
process, the characteristics such as porosity, surface area and other chemical natures
need to be studied. This chapter describes the various types of biosorbents, treatments applied to biosorbents, techniques and methods to study the characteristics of
biosorbents, mechanisms, modes of operation, recovery and regeneration of
biosorbents, kinetics, and modelling studies. Microscopic techniques such as electron microscopy (SEM and TEM) and atomic force microscopy (AFM) can be used
to reveal the surface characteristics of the biosorbents. Pore volume and surface area
of the biosorbent can be determined by Brunauer–Emmett–Teller (BET) analyser.
Other characteristics such as thermal stability and particle size can be measured by
instruments such as thermogravimetric analyser (TGA), differential scanning calorimetry (DSC) and particle size analyser. The mechanisms of biosorption at various
locations (intracellular, cell surface and extracellular) are also discussed in detail in
this chapter. The biosorption process can be performed in a batch and continuous
modes depending on the type of pollutant removed. The selection of suitable mode
of operation for different pollutants is emphasized. This chapter also covers the
different factors influencing the biosorption process.
Keywords Biosorbents, Biosorption, Characterization techniques, Kinetics and
modelling, Process selection
1 Introduction
Release of various pollutants into the water resources has been increased in recent
times as a result of increasing industrialization and globalization. There are several
methods such as precipitation, membrane separation, oxidation and chemical treatments available for removal of pollutants from aqueous solutions. Adsorption is a
simple, eco-friendly and economically feasible method for large-scale removal and
purification of aqueous solvents. According to De Gisi et al. [1], “Adsorption is a
mass transfer process which involves the accumulation of substances at the interface
of two phases, such as, liquid–liquid, gas–liquid, gas–solid or liquid–solid
interface”.
The substance being adsorbed is the adsorbate and the adsorbing material is
termed the adsorbent. If the adsorbate and adsorbent have a physical interaction,
then the adsorption is called as physisorption. If there is a chemical bonding between
the adsorbate and adsorbent, then it is called as chemisorption. Adsorption involving
biological materials as adsorbents is called as biosorption. The adsorbents used in
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eco-friendly method. Nowadays, the use of biosorption process for removal of
pollutants has been increased due to its efficiency, reusability of biosorbents and
low cost of operation. The rate and efficiency of biosorption depend on the selection
of suitable biosorbent and the process. To select an effective biosorbent for any
process, the characteristics such as porosity, surface area and other chemical natures
need to be studied. This chapter describes the various types of biosorbents, treatments applied to biosorbents, techniques and methods to study the characteristics of
biosorbents, mechanisms, modes of operation, recovery and regeneration of
biosorbents, kinetics, and modelling studies. Microscopic techniques such as electron microscopy (SEM and TEM) and atomic force microscopy (AFM) can be used
to reveal the surface characteristics of the biosorbents. Pore volume and surface area
of the biosorbent can be determined by Brunauer–Emmett–Teller (BET) analyser.
Other characteristics such as thermal stability and particle size can be measured by
instruments such as thermogravimetric analyser (TGA), differential scanning calorimetry (DSC) and particle size analyser. The mechanisms of biosorption at various
locations (intracellular, cell surface and extracellular) are also discussed in detail in
this chapter. The biosorption process can be performed in a batch and continuous
modes depending on the type of pollutant removed. The selection of suitable mode
of operation for different pollutants is emphasized. This chapter also covers the
different factors influencing the biosorption process.
Keywords Biosorbents, Biosorption, Characterization techniques, Kinetics and
modelling, Process selection
1 Introduction
Release of various pollutants into the water resources has been increased in recent
times as a result of increasing industrialization and globalization. There are several
methods such as precipitation, membrane separation, oxidation and chemical treatments available for removal of pollutants from aqueous solutions. Adsorption is a
simple, eco-friendly and economically feasible method for large-scale removal and
purification of aqueous solvents. According to De Gisi et al. [1], “Adsorption is a
mass transfer process which involves the accumulation of substances at the interface
of two phases, such as, liquid–liquid, gas–liquid, gas–solid or liquid–solid
interface”.
The substance being adsorbed is the adsorbate and the adsorbing material is
termed the adsorbent. If the adsorbate and adsorbent have a physical interaction,
then the adsorption is called as physisorption. If there is a chemical bonding between
the adsorbate and adsorbent, then it is called as chemisorption. Adsorption involving
biological materials as adsorbents is called as biosorption. The adsorbents used in
242
K. J. Samuel P N et al.