XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 681
Moreover, nanostructured TiO2 has poor adsorption abil-
ity and tends to agglomerate into large particles due to its
high surface energy [5]. It remains challenging to overcome
the inherent defects of nanoscale TiO2.
Fortunately, it has been confirmed that the poor adsorp-
tion capacity and dispersity of nano-TiO2 can be compen-
sated via the introduction of clay minerals acting as support
[6]. Clinoptilolite, one of the most common aluminosili-
cate minerals, has great potential to be used as a photo-
catalyst carrier since it is widely distributed on earth and
has abundant pores and channels [7, 8]. Coupling nano-
TiO2 onto the surface of clinoptilolite can significantly
enhance the dispersity and bring the TiO2/clinoptilolite
(TC) composite photocatalysts with excellent adsorption
performance. Besides, considerable efforts have been car-
ried out to enlarge the light response range of TiO2 through
element doping, noble metal decoration, and heterojunc-
tion construction [9].
Herein, TC binary composites were first prepared via
a one-step hydrothermal method, and their photocatalytic
activity towards xanthates was determined under UV light
irradiation. On this basis, Ag nanoparticles (ANPs), MoS2
nanosheets (MNSs), and BiOCl nanosheets (BNSs) were
separately synthesized to decorate TiO2 via in-situ
reduction, secondary hydrothermal and water bath pre-
cipitation, and the obtained Ag/TiO2/clinoptilolite, MoS2/
TiO2/clinoptilolite and BiOCl/TiO2/clinoptilolite ter-
nary composites were denoted as ATC, MTC, and BTC,
respectively. The xanthate photodegradation performance
of three ternary composite photocatalysts was compara-
tively investigated under visible light irradiation. A series
of modern characterization techniques were conducted to
analyze the physicochemical properties of all samples.
EXPERIMENTAL SECTION
Synthesis of Composite Photocatalysts
Before using the clinoptilolite as support, wet grinding and
acid-leaching treatment were performed to reduce the par-
ticle size and purify the powder. The corresponding grain
size characteristic curves after ball-milling are displayed in
Figure 1. It indicates that the average size of clinoptilolite
particle reduces from 48 to 1 μm. Besides, the chemical
compositions of natural clinoptilolite (NC) and acid-leach-
ing clinoptilolite (ALC) are shown in Table 1.
For the synthesis of TC, 1.5 g of (NH4)2TiF6 and
1.0 g of ALC were added into 50 mL of deionized water,
respectively. Then, 4 mL of H2O2 was added dropwise into
the slurry with 5 min intense stirring. NH3·H2O was put
into the suspension drop by drop along with another 20
min continuous stirring. Next, the mixture was moved
to an autoclave and kept at 160 °C for 12 h in a drying
oven. TC composites were obtained after the procedure
of being washed, dried and calcination at 400 °C for 2 h.
For the synthesis of ternary composites, the processes are
briefly described as follows. (1) ATC synthesis: 4.0 mL
of AgNO3 solution (0.02 M) was added into 20 mL of
Figure 1. Grain size characteristic curves of clinoptilolite (a) before and (b) after ball milling
Table 1. Main chemical compositions of NC and ALC (wt. %)
Samples SiO2 Al2O3 CaO K2O Fe2O3 MgO Na2O TiO2 L.O.I
NC 73.00 14.70 4.50 2.58 2.07 1.57 0.98 0.35 0.25
ALC 83.10 9.52 1.46 2.51 1.75 0.77 0.46 0.34 0.09
Moreover, nanostructured TiO2 has poor adsorption abil-
ity and tends to agglomerate into large particles due to its
high surface energy [5]. It remains challenging to overcome
the inherent defects of nanoscale TiO2.
Fortunately, it has been confirmed that the poor adsorp-
tion capacity and dispersity of nano-TiO2 can be compen-
sated via the introduction of clay minerals acting as support
[6]. Clinoptilolite, one of the most common aluminosili-
cate minerals, has great potential to be used as a photo-
catalyst carrier since it is widely distributed on earth and
has abundant pores and channels [7, 8]. Coupling nano-
TiO2 onto the surface of clinoptilolite can significantly
enhance the dispersity and bring the TiO2/clinoptilolite
(TC) composite photocatalysts with excellent adsorption
performance. Besides, considerable efforts have been car-
ried out to enlarge the light response range of TiO2 through
element doping, noble metal decoration, and heterojunc-
tion construction [9].
Herein, TC binary composites were first prepared via
a one-step hydrothermal method, and their photocatalytic
activity towards xanthates was determined under UV light
irradiation. On this basis, Ag nanoparticles (ANPs), MoS2
nanosheets (MNSs), and BiOCl nanosheets (BNSs) were
separately synthesized to decorate TiO2 via in-situ
reduction, secondary hydrothermal and water bath pre-
cipitation, and the obtained Ag/TiO2/clinoptilolite, MoS2/
TiO2/clinoptilolite and BiOCl/TiO2/clinoptilolite ter-
nary composites were denoted as ATC, MTC, and BTC,
respectively. The xanthate photodegradation performance
of three ternary composite photocatalysts was compara-
tively investigated under visible light irradiation. A series
of modern characterization techniques were conducted to
analyze the physicochemical properties of all samples.
EXPERIMENTAL SECTION
Synthesis of Composite Photocatalysts
Before using the clinoptilolite as support, wet grinding and
acid-leaching treatment were performed to reduce the par-
ticle size and purify the powder. The corresponding grain
size characteristic curves after ball-milling are displayed in
Figure 1. It indicates that the average size of clinoptilolite
particle reduces from 48 to 1 μm. Besides, the chemical
compositions of natural clinoptilolite (NC) and acid-leach-
ing clinoptilolite (ALC) are shown in Table 1.
For the synthesis of TC, 1.5 g of (NH4)2TiF6 and
1.0 g of ALC were added into 50 mL of deionized water,
respectively. Then, 4 mL of H2O2 was added dropwise into
the slurry with 5 min intense stirring. NH3·H2O was put
into the suspension drop by drop along with another 20
min continuous stirring. Next, the mixture was moved
to an autoclave and kept at 160 °C for 12 h in a drying
oven. TC composites were obtained after the procedure
of being washed, dried and calcination at 400 °C for 2 h.
For the synthesis of ternary composites, the processes are
briefly described as follows. (1) ATC synthesis: 4.0 mL
of AgNO3 solution (0.02 M) was added into 20 mL of
Figure 1. Grain size characteristic curves of clinoptilolite (a) before and (b) after ball milling
Table 1. Main chemical compositions of NC and ALC (wt. %)
Samples SiO2 Al2O3 CaO K2O Fe2O3 MgO Na2O TiO2 L.O.I
NC 73.00 14.70 4.50 2.58 2.07 1.57 0.98 0.35 0.25
ALC 83.10 9.52 1.46 2.51 1.75 0.77 0.46 0.34 0.09