688 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
in Figure 10. Figure 10a shows the real-time absorbance
change of SIPX by using TC. Two evident peaks around
301 and 226 nm can be observed, which correspond to the
characteristic absorbance peaks of SIPX. In the initial dark
adsorption stage, the peak intensity of SIPX declines obvi-
ously and then has little change owing to the achievement
of absorption-desorption equilibrium of xanthate molecules
over the TC photocatalyst surface. Interestingly, the charac-
teristic absorbance peak of CS2 located at 205 nm appears
during the dark adsorption process, demonstrating that
the SIPX molecules start to decompose after adding TC to
the solution. Subsequently, the absorbance intensity of all
peaks reduces gradually with the extending of irradiation
time. About 91.2% of SIPX can be removed thoroughly
since no obvious intermediate residues are found after 30
min UV irradiation. In addition, Figure 10b-d exhibit the
real-time absorbance change of SIPX when adding ATC,
MTC, and BTC composites. The variation trend of absor-
bance curves is similar to that of TC except for the increase
of dark adsorption time and irradiation time.
To determine the reactive species types in the photodeg-
radation system, the trapping experiment was conducted
by using edentate disodium (EDTA-2Na), silver nitrate
(AgNO3), isopropanol (IPA), and 1,4-benzoquinone (BQ)
as scavengers to trap h+, e−,·OH, and · O−2, respectively. As
displayed in Figure 11a, the SIPX degradation efficiency
of TC composites decreases lightly after the addition of
AgNO3 and IPA, suggesting that a very small amount of e−
and ·OH is involved in the degradation system. While the
SIPX degradation efficiency declines obviously after adding
BQ and EDTA-2Na, which demonstrates that · O2− and
h+ play a vital role during the photocatalytic reaction pro-
cess. Figure 11b–d show the influence of active species on
degrading SIPX in the presence of ATC, MTC and BTC
composites. It can be found that the SIPX degradation
efficiencies for three ternary composites decrease after the
addition of BQ, which indicates that · O−2 is the primary
active speci.e., under the visible light irradiation. Besides,
the addition of IPA also causes the decline of SIPX degra-
dation efficiency for ATC and MTC, which highlights the
important role of ·OH. However, h+ is considered to play a
secondary role for BTC system by analyzing the influence
of EDTA-2Na.
Based on the characterization analysis of composite
photocatalysts and the xanthates degradation process, a pos-
sible SIPX degradation mechanism over the photocatalysts
surface is proposed. Initially, the xanthate molecules adsorb
on the surface of photocatalysts due to excellent adsorp-
tion capacity after the introduction of clinoptilolite. Then,
photocatalysts are excited and numerous photogenerated
e−/h+ pairs are produced under UV or visible light irradia-
tion. The e−/h+ pairs can be effectively separated because
of the effect of clinoptilolite support and the construction
of heterojunction. The adsorbed O2 on the surface of pho-
tocatalyst can capture photoinduced e− to generate · O2−,
which is the major active radical in the degradation process.
Meanwhile, the ionized OH– and absorbed H2O react with
h+ to produce ·OH. At last, these active substances with
strong oxidizing ability can thoroughly degrade the xanthate
molecules into non-toxic and harmless substances such as
CO2 and H2O. It should be pointed out that the clinopti-
lolite undoubtedly plays a crucial role in the synthesis of
Figure 9. (a, c, e, g) Degradation efficiency curves and (b, d, f, h) inetic curves of TC, ATC, MTC and BTC composite
photocatalysts to different inds of xanthates
in Figure 10. Figure 10a shows the real-time absorbance
change of SIPX by using TC. Two evident peaks around
301 and 226 nm can be observed, which correspond to the
characteristic absorbance peaks of SIPX. In the initial dark
adsorption stage, the peak intensity of SIPX declines obvi-
ously and then has little change owing to the achievement
of absorption-desorption equilibrium of xanthate molecules
over the TC photocatalyst surface. Interestingly, the charac-
teristic absorbance peak of CS2 located at 205 nm appears
during the dark adsorption process, demonstrating that
the SIPX molecules start to decompose after adding TC to
the solution. Subsequently, the absorbance intensity of all
peaks reduces gradually with the extending of irradiation
time. About 91.2% of SIPX can be removed thoroughly
since no obvious intermediate residues are found after 30
min UV irradiation. In addition, Figure 10b-d exhibit the
real-time absorbance change of SIPX when adding ATC,
MTC, and BTC composites. The variation trend of absor-
bance curves is similar to that of TC except for the increase
of dark adsorption time and irradiation time.
To determine the reactive species types in the photodeg-
radation system, the trapping experiment was conducted
by using edentate disodium (EDTA-2Na), silver nitrate
(AgNO3), isopropanol (IPA), and 1,4-benzoquinone (BQ)
as scavengers to trap h+, e−,·OH, and · O−2, respectively. As
displayed in Figure 11a, the SIPX degradation efficiency
of TC composites decreases lightly after the addition of
AgNO3 and IPA, suggesting that a very small amount of e−
and ·OH is involved in the degradation system. While the
SIPX degradation efficiency declines obviously after adding
BQ and EDTA-2Na, which demonstrates that · O2− and
h+ play a vital role during the photocatalytic reaction pro-
cess. Figure 11b–d show the influence of active species on
degrading SIPX in the presence of ATC, MTC and BTC
composites. It can be found that the SIPX degradation
efficiencies for three ternary composites decrease after the
addition of BQ, which indicates that · O−2 is the primary
active speci.e., under the visible light irradiation. Besides,
the addition of IPA also causes the decline of SIPX degra-
dation efficiency for ATC and MTC, which highlights the
important role of ·OH. However, h+ is considered to play a
secondary role for BTC system by analyzing the influence
of EDTA-2Na.
Based on the characterization analysis of composite
photocatalysts and the xanthates degradation process, a pos-
sible SIPX degradation mechanism over the photocatalysts
surface is proposed. Initially, the xanthate molecules adsorb
on the surface of photocatalysts due to excellent adsorp-
tion capacity after the introduction of clinoptilolite. Then,
photocatalysts are excited and numerous photogenerated
e−/h+ pairs are produced under UV or visible light irradia-
tion. The e−/h+ pairs can be effectively separated because
of the effect of clinoptilolite support and the construction
of heterojunction. The adsorbed O2 on the surface of pho-
tocatalyst can capture photoinduced e− to generate · O2−,
which is the major active radical in the degradation process.
Meanwhile, the ionized OH– and absorbed H2O react with
h+ to produce ·OH. At last, these active substances with
strong oxidizing ability can thoroughly degrade the xanthate
molecules into non-toxic and harmless substances such as
CO2 and H2O. It should be pointed out that the clinopti-
lolite undoubtedly plays a crucial role in the synthesis of
Figure 9. (a, c, e, g) Degradation efficiency curves and (b, d, f, h) inetic curves of TC, ATC, MTC and BTC composite
photocatalysts to different inds of xanthates