Dual-loading strategy to construct Au-BiOBr-TiO₂ photocatalysts for fast and efficient degradation of xanthates under visible light

Abstract

With the advancement of mining operations, xanthate as an essential flotation reagent is unavoidably released into natural water bodies through flotation effluent. To protect the surrounding environment of mines, Au-BiOBr-TiO₂ (AuBT) ternary composites were constructed and utilized as an optimal photocatalyst in the degradation process of xanthates. AuBT with high purity was prepared by the integrated techniques of hydrothermal, water bath precipitation, and photodeposition. BiOBr nanosheets and Au nanoparticles were uniformly distributed on the surface of TiO₂ particles in the composites. In simulated mineral flotation effluents, AuBT showed excellent degradation performance in the catalytic oxidation of 20 mg/L xanthate under visible light irradiation, achieving 95.2% removal rate in 20 min. The experiments and characterization results revealed that the dual-loading strategy to construct AuBT photocatalysts effectively decreased the band gap and broadened the photoresponse range of pristine TiO₂, which was significant for the improvement of the photocatalytic activity. DFT calculations demonstrated that partial electrons were transferred around the sodium ethyl xanthate (SEX) molecule and the accumulated charge contributed to the oxidation process. Experimental results of free radical scavenging indicate that the main active species in the reaction system are photogenerated holes (h⁺), followed by superoxide radicals (•O₂). This work indicates that AuBT composites can be used as an efficient photocatalyst to completely degrade various types of xanthates under visible light, which exhibits great potential in flotation wastewater treatment.

Keywords

Au-BiOBr-TiO₂ / ternary composites / photocatalysis / visible light / xanthates

References

[1] JiaY, ZhangY, ZhangX, et al. . Novel CdS/PANI/MWCNTs photocatalysts for photocatalytic degradation of xanthate in wastewater [J]. Separation and Purification Technology, 2023, 309: 123022

[2] ZhouP-f, ShenY-b, ZhaoS-k, et al. . Synthesis of clinoptilolite-supported BiOCl/TiO₂ heterojunction nanocomposites with highly-enhanced photocatalytic activity for the complete degradation of xanthates under visible light [J]. Chemical Engineering Journal, 2021, 407126697

[3] AmrollahiA, MassinaeiM, ZeraatkarM A. Removal of the residual xanthate from flotation plant tailings using bentonite modified by magnetic nano-particles [J]. Minerals Engineering, 2019, 134142-155

[4] JiangM, ZhangM-h, WangL-z, et al. . Photocatalytic degradation of xanthate in flotation plant tailings by TiO₂/graphene nanocomposites [J]. Chemical Engineering Journal, 2022, 431: 134104

[5] TanY, ChenT, ZhengS-l, et al. . Adsorptive and photocatalytic behaviour of PANI/TiO₂/metakaolin composites for the removal of xanthate from aqueous solution [J]. Minerals Engineering, 2021, 171107129

[6] ZhangM-h, HanN, FeiY-w, et al. . TiO₂/g-C₃N₄ photocatalyst for the purification of potassium butyl xanthate in mineral processing wastewater [J]. Journal of Environmental Management, 2021, 297113311

[7] ChenX-h, HuY-h, PengH, et al. . Degradation of ethyl xanthate in flotation residues by hydrogen peroxide [J]. Journal of Central South University, 2015, 22(2): 495-501

[8] ShenM-w, ZhangG-q, LiuJ-y, et al. . Visible-light-driven photodegradation of xanthate in a continuous fixed-bed photoreactor: Experimental study and modeling [J]. Chemical Engineering Journal, 2023, 461141833

[9] LiM-k, ZhongH, HeZ-g, et al. . Degradation of various thiol collectors in simulated and real mineral processing wastewater of sulfide ore in heterogeneous modified manganese slag/PMS system [J]. Chemical Engineering Journal, 2021, 413127478

[10] YuanF, ZhengY-f, GaoD-z, et al. . Facile assembly and enhanced visible-light-driven photocatalytic activity of S-scheme BiOBr/g-C₃N₄ heterojunction for degrading xanthate in wastewater [J]. Journal of Molecular Liquids, 2022, 366120279

[11] García-LeivaB, TeixeiraL A C, ToremM L. Degradation of xanthate in waters by hydrogen peroxide, Fenton and simulated solar photo-Fenton processes [J]. Journal of Materials Research and Technology, 2019, 8(6): 5698-5706

[12] YangS-z, SunH-n, SuS-p, et al. . Fabrication, characterizations and performance of a high-efficiency micro-electrolysis filler for isobutyl xanthate (IBX) degradation [J]. Journal of Hazardous Materials, 2021, 403123640

[13] FangL-m, ZengY, EkholmM, et al. . Field controllable electronic properties of MnPSe₃/WS₂ heterojunction for photocatalysis [J]. Journal of Central South University, 2021, 28(12): 3728-3736

[14] ZhuJ-f, XiaoQi. Meso-macroporous Fe-doped CuO: Synthesis, characterization, and structurally enhanced adsorption and visible-light photocatalytic activity [J]. Journal of Central South University, 2015, 22(11): 4105-4111

[15] ZouheirM, TanjiK, NavioJ A, et al. . Effective photocatalytic conversion of formic acid using iron, copper and sulphate doped TiO₂ [J]. Journal of Central South University, 2022, 29(11): 3592-3607

[16] YangT, HuX-y, WangJ-t, et al. . Interfacial coupling effects in g-C₃N₄/InxSb₂ − xS₃ heterojunction for enhanced photocatalytic activity under visible light [J]. Journal of Central South University, 2022, 29(5): 1447-1462

[17] YuanH-b, OuyangY-x, WangL-bing. Solgel synthesis of metal ions doped TiO₂ catalyst with efficient photodegradation of dye pollutant [J]. Journal of Central South University, 2023, 30(4): 1086-1094

[18] TongH-x, ChaiL-y, ZhangX-rui. Spectra analysis and O₂ evolution for TiO₂ photocatalyst compounded with indirect transition semiconductors [J]. Journal of Central South University, 2012, 19(9): 2425-2433

[19] MengA-y, ChengB, TanH-y, et al. . TiO₂/polydopamine S-scheme heterojunction photocatalyst with enhanced CO₂-reduction selectivity [J]. Applied Catalysis B: Environmental, 2021, 289120039

[20] HeB-w, LuoC, WangZ-l, et al. . Synergistic enhancement of solar H₂O₂ and HCOOH production over TiO₂ by dual co-catalyst loading in a triphase system [J]. Applied Catalysis B: Environmental, 2023, 323122200

[21] LiG-d, ShenY-b, ZhaoS-k, et al. . Construction of rGO-SnO₂ heterojunction for enhanced hydrogen detection [J]. Applied Surface Science, 2022, 585152623

[22] YinY-y, KangX-c, HanB-xing. Two-dimensional materials: Synthesis and applications in the electro-reduction of carbon dioxide [J]. Chemical Synthesis, 2022, 2(4): 19

[23] GaoM-m, LiW-x, SuX-j, et al. . A regenerable Cu₂O/BiOBr S-scheme heterojunction photocatalysts for efficient photocatalytic degradation of mixed organic pollutants [J]. Separation and Purification Technology, 2023, 313123447

[24] FanG-d, ZhouJ-f, RuanF-y, et al. . The Z-scheme photocatalyst S-BiOBr/Bi₂Sn₂O₇ with 3D/0D interfacial structure for the efficient degradation of organic pollutants [J]. Separation and Purification Technology, 2023, 309123099

[25] LanM, ZhengN, DongX-l, et al. . Application of flexible PAN/BiOBr-Cl microfibers as self-supporting and highly active photocatalysts for nitrogen fixation and dye degradation [J]. Applied Surface Science, 2022, 575151743

[26] GuY-y, ZhaoL, YangM-y, et al. . Preparation and characterization of highly photocatalytic active hierarchical BiOX (X=Cl, Br, I) microflowers for rhodamine B degradation with kinetic modelling studies [J]. Journal of Central South University, 2017, 244754-765

[27] ZhongW-l, WangC, ZhaoH-l, et al. . Synergistic effect of photo-thermal catalytic glycerol reforming hydrogen production over 2D Au/TiO₂ nanoflakes [J]. Chemical Engineering Journal, 2022, 446137063

[28] LunaM, GaticaJ M, VidalH, et al. . Au-TiO₂/SiO₂ photocatalysts with NO_x depolluting activity: Influence of gold particle size and loading [J]. Chemical Engineering Journal, 2019, 368417-427

[29] ZhangY-x, LiuC, ZhouY, et al. . Boosting light harvesting and charge separation over hollow double-shelled Ag@SrTiO₃-TiO₂ with Z-scheme heterostructure for highly efficient photocatalytic reduction of nitrate to N₂ [J]. Chemical Engineering Journal, 2023, 457140992

[30] DangJ-j, ZhangJ-x, ShenY, et al. . Fabrication of magnetically recyclable Fe₃O₄/BiOCl/BiOBr nanocomposite with Z-scheme heterojunction for high-efficiency photocatalytic degradation of tetracycline [J]. Materials Science in Semiconductor Processing, 2023, 158107371

[31] XingY-l, WuD-p, JinX-y, et al. . Enhanced photocatalytic activity of Bi₂₄O₃₁Br₁₀ nanosheets by the photodeposition of Au nanoparticles [J]. Solid State Sciences, 2019, 95105921

[32] ZhangJ-w, CaoG, WangH-y, et al. . Graphene-Bi₂₄O₃₁Br₁₀ composites with tunable architectures for enhanced photocatalytic activity and mechanism [J]. Ceramics International, 2016, 42(10): 11796-11804

[33] XuY-j, WangF, LeiS-l, et al. . In situ grown two-dimensional TiO₂/Ti₃CN MXene heterojunction rich in Ti³⁺ species for highly efficient photoelectrocatalytic CO₂ reduction [J]. Chemical Engineering Journal, 2023, 452139392

[34] HeY, ZhuL-k, HuJ, et al. . Enhanced photoelectrochemical activity of bi-functional photocatalytic fuel cell by a superior heterostructure SnO₂/BiOBr/MoS₂ photoanode [J]. Applied Surface Science, 2023, 622156821

[35] XuL, WuX-q, LiC-y, et al. . Sonocatalytic degradation of tetracycline by BiOBr/FeWO₄ nanomaterials and enhancement of sonocatalytic effect [J]. Journal of Cleaner Production, 2023, 394136275

[36] QinW-b, ZhangR-z, YuanZ-y, et al. . Exposure surface active sites of perovskite-type LaFeO₃ gas sensors by selectively dissolving La cations for enhancing gas sensing properties to acetone [J]. Advanced Materials Technologies, 2022, 7(11): 2200255

[37] ShenY-b, ZhouP-f, ZhaoS-k, et al. . Synthesis of high-efficient TiO₂/clinoptilolite photocatalyst for complete degradation of xanthate [J]. Minerals Engineering, 2020, 159106640

[38] ShuK-q, ChuaichamC, NoguchiY, et al. . In-situ hydrothermal synthesis of Fe-doped hydroxyapatite photocatalyst derived from converter slag toward xanthate photodegradation and Cr(VI) reduction under visible-light irradiation [J]. Chemical Engineering Journal, 2023, 459141474

[39] ZhengY-f, YuanF, GaoD-z, et al. . Improved visible-light-driven activity of micro graphite/BiOI nanocomposite for effective removal of xanthate from wastewater [J]. Materials Research Bulletin, 2023, 158112080

[40] ZhouP-f, ShenY-b, ZhaoS-k, et al. . Facile synthesis of clinoptilolite-supported Ag/TiO₂ nanocomposites for visible-light degradation of xanthates [J]. Journal of the Taiwan Institute of Chemical Engineers, 2021, 122231-240

[41] RasouliK, AlamdariA, SabbaghiS. Ultrasonic-assisted synthesis of α-Fe₂O₃@TiO₂ photocatalyst: Optimization of effective factors in the fabrication of photocatalyst and removal of non-biodegradable cefixime via response surface methodology-central composite design [J]. Separation and Purification Technology, 2023, 307122799

[42] van TranC, LaD D, Thi HoaiP N, et al. . New TiO₂-doped Cu-Mg spinel-ferrite-based photocatalyst for degrading highly toxic Rhodamine B dye in wastewater [J]. Journal of Hazardous Materials, 2021, 420126636

[43] ClarkS J, SegallM D, PickardC J, et al. . First principles methods using CASTEP [J]. Zeitschrift Für Kristallographie - Crystalline Materials, 2005, 220(5–6): 567-570