680
Modification and Regulation of Clinoptilolite-Supported
Composite Photocatalysts for High-Performance
Xanthate Degradation
Yanbai Shen, Sikai Zhao, Dezhou Wei, Zichuan Guan
School of Resources and Civil Engineering, Northeastern University, Shenyang, China
ABSTRACT: The residual xanthate in flotation effluent is difficult to be decomposed under natural conditions,
causing serious damage to ecosystems. In this work, TiO2/clinoptilolite binary composites was firstly used as
photocatalyst, and xanthate could be removed rapidly under UV light by photocatalytic degradation process.
Then, TiO2/clinoptilolite ternary composites decorated by Ag, MoS2, and BiOCl were separately prepared,
and the effective degradation of xanthates under visible light was achieved. The degradation products were
determined by analyzing the instantaneous absorbance during the degradation process, and the radical scavenger
tests were performed to confirm the dominated active substances of different types of composite photocatalysts.
Keywords: Clinoptilolite Composites Photodegradation Xanthate Flotation wastewater
INTRODUCTION
Mineral processing industry consumes billions of cubic
meters of water annually. As a critical step in mineral pro-
cessing operations, froth flotation is considered the most
versatile mineral separation technique, which needs to
use huge amounts of water to achieve the goal of valuable
minerals concentration. In the flotation process, collector
surfactants such as xanthates are the most widely applied
chemicals, which mainly focus on the concentration of
sulfide minerals [1]. It is reported that over 2 billion tons
of ores are processed via flotation per year and the global
xanthates consumption is supposed to exceed 370,000
tons in 2025 annually [2]. Although most of the xanthates
will be consumed by the target minerals, the low-concen-
tration residual xanthates in the flotation wastewater may
pose a severe threat to the ecological environment around
the mine. Xanthates show high toxicity to aquatic organ-
isms owing to their intermediates such as CS2, which can
cause fatal injury to the plankton community and fish [3].
Therefore, from the viewpoint of water reuse and environ-
mental protection, the treatment of flotation wastewater is
very necessary.
In the past few decades, various technologies including
adsorption, ozonation, Fenton reaction, and photocataly-
sis have been intensively investigated to remove remaining
xanthates. Considering the stateof-the-art methods, TiO2-
based photocatalysis attracts widespread attention and
is still one of the most popular techniques in the field of
effluent treatment because of its unique advantages of eco-
friendliness, low cost, high efficiency, and stable chemical
properties [4]. However, the drawbacks of pristine TiO2
photocatalysts are also noticeable. TiO2 can only absorb
UV light to be excited owing to its relatively wide band-
gap energy (~3.2 eV), and the fast recombination of pho-
toinduced carriers (e−/h+) affects the photocatalysis activity
of TiO2, which strongly limits its practical application.
Modification and Regulation of Clinoptilolite-Supported
Composite Photocatalysts for High-Performance
Xanthate Degradation
Yanbai Shen, Sikai Zhao, Dezhou Wei, Zichuan Guan
School of Resources and Civil Engineering, Northeastern University, Shenyang, China
ABSTRACT: The residual xanthate in flotation effluent is difficult to be decomposed under natural conditions,
causing serious damage to ecosystems. In this work, TiO2/clinoptilolite binary composites was firstly used as
photocatalyst, and xanthate could be removed rapidly under UV light by photocatalytic degradation process.
Then, TiO2/clinoptilolite ternary composites decorated by Ag, MoS2, and BiOCl were separately prepared,
and the effective degradation of xanthates under visible light was achieved. The degradation products were
determined by analyzing the instantaneous absorbance during the degradation process, and the radical scavenger
tests were performed to confirm the dominated active substances of different types of composite photocatalysts.
Keywords: Clinoptilolite Composites Photodegradation Xanthate Flotation wastewater
INTRODUCTION
Mineral processing industry consumes billions of cubic
meters of water annually. As a critical step in mineral pro-
cessing operations, froth flotation is considered the most
versatile mineral separation technique, which needs to
use huge amounts of water to achieve the goal of valuable
minerals concentration. In the flotation process, collector
surfactants such as xanthates are the most widely applied
chemicals, which mainly focus on the concentration of
sulfide minerals [1]. It is reported that over 2 billion tons
of ores are processed via flotation per year and the global
xanthates consumption is supposed to exceed 370,000
tons in 2025 annually [2]. Although most of the xanthates
will be consumed by the target minerals, the low-concen-
tration residual xanthates in the flotation wastewater may
pose a severe threat to the ecological environment around
the mine. Xanthates show high toxicity to aquatic organ-
isms owing to their intermediates such as CS2, which can
cause fatal injury to the plankton community and fish [3].
Therefore, from the viewpoint of water reuse and environ-
mental protection, the treatment of flotation wastewater is
very necessary.
In the past few decades, various technologies including
adsorption, ozonation, Fenton reaction, and photocataly-
sis have been intensively investigated to remove remaining
xanthates. Considering the stateof-the-art methods, TiO2-
based photocatalysis attracts widespread attention and
is still one of the most popular techniques in the field of
effluent treatment because of its unique advantages of eco-
friendliness, low cost, high efficiency, and stable chemical
properties [4]. However, the drawbacks of pristine TiO2
photocatalysts are also noticeable. TiO2 can only absorb
UV light to be excited owing to its relatively wide band-
gap energy (~3.2 eV), and the fast recombination of pho-
toinduced carriers (e−/h+) affects the photocatalysis activity
of TiO2, which strongly limits its practical application.