biosorbent by FTIR, the functional groups in the material can be revealed. The free
functional groups in the adsorbent before treatment and after treatment and the
functional groups after adsorption can also be studied using FTIR to elucidate the
mechanism of biosorption [25].
X-ray photon spectroscopy is used to find the elemental composition of the
biosorbents present. It is also helpful in deducing the empirical formula, electronic
state and chemical state [19]. Energy dispersive X-ray spectroscopy (EDX or
EDAX) is also used for elemental analysis of the material. EDS when used along
with SEM gives the quantitative estimation of the metal adsorbed into the surface of
the adsorbate.
X-ray fluorescence (XRF) spectroscopy and energy dispersive X-ray fluorescence
(EDXRF) spectroscopy are also used to determine the elemental composition of the
biosorbents. The secondary X-rays emitted from the sample when excited by a
primary X-Ray are measured to determine the elemental composition. The metals
adsorbed on the surface of the adsorbent are revealed by XRF and EDXRF
spectroscopy.
Another technique used for elemental analysis is inductively coupled plasma
atomic/optical emission spectroscopy (ICP-AES/ICP-OES). The inductively
coupled plasma produces excited atoms that emit characteristic electromagnetic
radiation which is used to determine the presence of the element.
4.3 Surface Area and Pore Size
Surface area (m
2 /g) is determined by nitrogen adsorption-desorption studies at
77.3 K by Brunauer, Emmett and Teller method (BET analysis) [38], density
function theory (DFT) methods and BJH methods [39]. BET analysis is the common
method for determining the porosity and surface area of a material, while DFT and
BJH methods are used to determine the pore volume (cm
3 /g) of a material.
Micrometrics
® is one of the leading manufacturers of machines that can be used
for BET analysis.
4.4 Thermal Stability
Thermal stability of the material is generally analysed by thermogravimetric analysis
(TGA) and differential scanning calorimetry (DSC). In TGA, the sample is heated
with a programmed heating rate, and the weight of the sample is monitored from
time to time. Graph is plotted between temperature and weight loss. The sample is
thermally stable till the temperature at which the weight loss begins.
Material and Process Selection for Biosorption
249
functional groups in the adsorbent before treatment and after treatment and the
functional groups after adsorption can also be studied using FTIR to elucidate the
mechanism of biosorption [25].
X-ray photon spectroscopy is used to find the elemental composition of the
biosorbents present. It is also helpful in deducing the empirical formula, electronic
state and chemical state [19]. Energy dispersive X-ray spectroscopy (EDX or
EDAX) is also used for elemental analysis of the material. EDS when used along
with SEM gives the quantitative estimation of the metal adsorbed into the surface of
the adsorbate.
X-ray fluorescence (XRF) spectroscopy and energy dispersive X-ray fluorescence
(EDXRF) spectroscopy are also used to determine the elemental composition of the
biosorbents. The secondary X-rays emitted from the sample when excited by a
primary X-Ray are measured to determine the elemental composition. The metals
adsorbed on the surface of the adsorbent are revealed by XRF and EDXRF
spectroscopy.
Another technique used for elemental analysis is inductively coupled plasma
atomic/optical emission spectroscopy (ICP-AES/ICP-OES). The inductively
coupled plasma produces excited atoms that emit characteristic electromagnetic
radiation which is used to determine the presence of the element.
4.3 Surface Area and Pore Size
Surface area (m
2 /g) is determined by nitrogen adsorption-desorption studies at
77.3 K by Brunauer, Emmett and Teller method (BET analysis) [38], density
function theory (DFT) methods and BJH methods [39]. BET analysis is the common
method for determining the porosity and surface area of a material, while DFT and
BJH methods are used to determine the pore volume (cm
3 /g) of a material.
Micrometrics
® is one of the leading manufacturers of machines that can be used
for BET analysis.
4.4 Thermal Stability
Thermal stability of the material is generally analysed by thermogravimetric analysis
(TGA) and differential scanning calorimetry (DSC). In TGA, the sample is heated
with a programmed heating rate, and the weight of the sample is monitored from
time to time. Graph is plotted between temperature and weight loss. The sample is
thermally stable till the temperature at which the weight loss begins.
Material and Process Selection for Biosorption
249