XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1357
Surface Functional Groups Studies
The FTIR spectrums of the biochar samples before and
after adsorption were carried out in the wavelength range
of 450 to 4000 cm–1 and the results are shown in Figure 6.
The peaks observed between 2500 cm–1 and 3500 cm–1 for
both samples could be attributed to O-H stretch relating
to carboxylic acid and O-H alcohol functional groups, but
a sharp peak at approximately 3200 cm–1 indicates that it
is likely an O-H alcohol (hydroxyl) functional group. The
hydroxyl functional group in alcohols carries a reactive
O-H bond such that the oxygen is loaded with electrons
while the carbon and hydrogen exhibit electrophile prop-
erties. Functional groups that contain oxygen contributes
more to reactions at the adsorbent surface (Xiaodong Yang
et al, 2019). A sharp peak observed around 1655 cm–1 indi-
cates a likely C=O functional group and in the fingerprint
zone Benzene (C-H) functional group can be detected at
700 cm–1 for the biochar sample after adsorption while the
same peak shifted to the left for the sample before adsorp-
tion. It can be observed from the FTIR spectra results that
there was a vertical shift in the peaks regarding both sam-
ples, this can be attributed to reduction in biochar sample.
The result suggests that there have been no changes in the
chemical structure of the biochar before and after adsorp-
tion process.
Surface Area Analysis
The Figures 8a and 8b shows the nitrogen adsorption-
desorption isotherm curves of biochar samples before and
after adsorption of rare earth elements from aqueous solu-
tions in the relative pressure range (P/P0) of 0.0–1.0.
According to IUPAC classification, the adsorption-
desorption isotherm of the biochar sample before adsorp-
tion in Figure 8a depict a type III isotherm (Qinyuan Xu
et al 2019). In this case, the curve shows that the relation-
ship between the adsorbate and adsorbent is less than the
Figure 5. Surface morphology of biochar sample before rare earth elements adsorption
Surface Functional Groups Studies
The FTIR spectrums of the biochar samples before and
after adsorption were carried out in the wavelength range
of 450 to 4000 cm–1 and the results are shown in Figure 6.
The peaks observed between 2500 cm–1 and 3500 cm–1 for
both samples could be attributed to O-H stretch relating
to carboxylic acid and O-H alcohol functional groups, but
a sharp peak at approximately 3200 cm–1 indicates that it
is likely an O-H alcohol (hydroxyl) functional group. The
hydroxyl functional group in alcohols carries a reactive
O-H bond such that the oxygen is loaded with electrons
while the carbon and hydrogen exhibit electrophile prop-
erties. Functional groups that contain oxygen contributes
more to reactions at the adsorbent surface (Xiaodong Yang
et al, 2019). A sharp peak observed around 1655 cm–1 indi-
cates a likely C=O functional group and in the fingerprint
zone Benzene (C-H) functional group can be detected at
700 cm–1 for the biochar sample after adsorption while the
same peak shifted to the left for the sample before adsorp-
tion. It can be observed from the FTIR spectra results that
there was a vertical shift in the peaks regarding both sam-
ples, this can be attributed to reduction in biochar sample.
The result suggests that there have been no changes in the
chemical structure of the biochar before and after adsorp-
tion process.
Surface Area Analysis
The Figures 8a and 8b shows the nitrogen adsorption-
desorption isotherm curves of biochar samples before and
after adsorption of rare earth elements from aqueous solu-
tions in the relative pressure range (P/P0) of 0.0–1.0.
According to IUPAC classification, the adsorption-
desorption isotherm of the biochar sample before adsorp-
tion in Figure 8a depict a type III isotherm (Qinyuan Xu
et al 2019). In this case, the curve shows that the relation-
ship between the adsorbate and adsorbent is less than the
Figure 5. Surface morphology of biochar sample before rare earth elements adsorption