Visible-light-driven heterostructured g-C₃N₄/Bi-TiO₂ floating photocatalyst with enhanced charge carrier separation for photocatalytic inactivation of Microcystis aeruginosa

Highlights

• Bi doping in TiO₂ enhanced the separation of photo-generated electron-hole.

• The performance of photocatalytic degradation of MC-LR was improved.

• Coexisting substances have no influence on algal removal performance.

• The key reactive oxygen species were h⁺ and ^•OH in the photocatalytic process.

Abstract

The increase in occurrence and severity of cyanobacteria blooms is causing increasing concern; moreover, human and animal health is affected by the toxic effects of Microcystin-LR released into the water. In this paper, a floating photocatalyst for the photocatalytic inactivation of the harmful algae Microcystis aeruginosa (M. aeruginosa) was prepared using a simple sol-gel method, i.e., coating g-C₃N₄ coupled with Bi-doped TiO₂ on Al₂O₃-modified expanded perlite (CBTA for short). The impact of different molar ratios of Bi/Ti on CBTA was considered. The results indicated that Bi doping in TiO₂ inhibited photogenerated electron-hole pair recombination. With 6 h of visible light illumination, 75.9% of M. aeruginosa (initial concentration= 2.7 × 10⁶ cells/L) and 83.7% of Microcystin-LR (initial concentration= 100 μg/L) could be removed with the addition of 2 g/L CBTA-1% (i.e., Bi/Ti molar ratio= 1%). The key reactive oxygen species (ROSs) in the photocatalytic inactivation process are h⁺ and ^•OH. The induction of the Bi⁴⁺/Bi³⁺ species by the incorporation of Bi could narrow the bandgap of TiO₂, trap electrons, and enhance the stability of CBTA-1% in the solutions with coexisting environmental substances.

Graphical abstract

Keywords

Bi doping / Visible light / Algal removal / Charge carrier separation

References

[1] Alam U, Fleisch M, Kretschmer I, Bahnemann D, Muneer M (2017). One-step hydrothermal synthesis of Bi-TiO₂ nanotube/graphene composites: An efficient photocatalyst for spectacular degradation of organic pollutants under visible light irradiation. Applied Catalysis B: Environmental, 218: 758–769

[2] Andersen J, Han C, O’shea K, Dionysiou D D (2014). Revealing the degradation intermediates and pathways of visible light-induced NF-TiO₂ photocatalysis of microcystin-LR. Applied Catalysis B: Environmental, 154– 155: 259–266

[3] Chandraboss V L, Kamalakkannan J, Senthilvelan S (2016). Synthesis of activated charcoal supported Bi-doped TiO₂ nanocomposite under solar light irradiation for enhanced photocatalytic activity. Applied Surface Science, 387: 944–956

[4] Chang F, Zhang J, Xie Y C, Chen J, Li C L, Wang J, Luo J R, Deng B Q, Hu X F (2014). Fabrication, characterization, and photocatalytic performance of exfoliated g-C₃N₄-TiO₂ hybrids. Applied Surface Science, 311: 574–581

[5] Chen J S, Qin S Y, Liu Y D, Xin F, Yin X H (2014). Preparation of a visible light-driven Bi₂O₃-TiO₂ composite photocatalyst by an ethylene glycol-assisted sol-gel method, and its photocatalytic properties. Research on Chemical Intermediates, 40(2): 637–648

[6] Chen W, Westerhoff P, Leenheer J A, Booksh K (2003). Fluorescence excitation-emission matrix regional integration to quantify spectra for dissolved organic matter. Environmental Science & Technology, 37(24): 5701–5710

[7] Chen Y Q, Xie P C, Wang Z P, Shang R, Wang S L (2017). UV/persulfate preoxidation to improve coagulation efficiency of Microcystis aeruginosa. Journal of Hazardous Materials, 322: 508–515

[8] Coral L A, Zamyadi A, Barbeau B, Bassetti F J, Lapolli F R, Prevost M (2013). Oxidation of Microcystis aeruginosa and Anabaena flos-aquae by ozone: Impacts on cell integrity and chlorination by-product formation. Water Research, 47(9): 2983–2994

[9] Dai K, Lu L H, Liang C H, Liu Q, Zhu G P (2014). Heterojunction of facet coupled g-C₃N₄/surface-fluorinated TiO₂ nanosheets for organic pollutants degradation under visible LED light irradiation. Applied Catalysis B: Environmental, 156– 157: 331–340

[10] Ding J, Xu W, Wan H, Yuan D, Chen C, Wang L, Guan G, Dai W L (2018). Nitrogen vacancy engineered graphitic C₃N₄-based polymers for photocatalytic oxidation of aromatic alcohols to aldehydes. Applied Catalysis B: Environmental, 221: 626–634

[11] Długosz M, Waś J, Szczubiałka K, Nowakowska M (2014). TiO₂-coated EP as a floating photocatalyst for water purification. Journal of Materials Chemistry. A, Materials for Energy and Sustainability, 2(19): 6931–6938

[12] Dong C L, Chen W, Liu C (2014). Flocculation of algal cells by amphoteric chitosan-based flocculant. Bioresource Technology, 170: 239–247

[13] Fang Y, Huang Y K, Ni Z J, Wang Z L, Kang S F, Wang Y G, Li X (2017). Co-modified commercial P25 TiO₂ by Fe doping and g-C₃N₄ coating as high performance photocatalyst under visible light irradiation. International Journal of Electrochemical Science, 12(7): 5951–5963

[14] Fang Y, Huang Y, Yang J, Wang P, Cheng G (2011). Unique ability of BiOBr to decarboxylate D-Glu and D-MeAsp in the photocatalytic degradation of microcystin-LR in water. Environmental Science & Technology, 45(4): 1593–1600

[15] Gao M Y, Jiang D, Sun D K, Hou B, Li D B (2014). Synthesis of Ag/N-TiO₂/SBA-15 photocatalysts and photocatalytic reduction of CO₂ under visible light irradiation. Acta Chimica Sinica, 72(10): 1092–1098

[16] Hosseini S, Borghei S, Vossoughi M, Taghavinia N (2007). Immobilization of TiO₂ on perlite granules for photocatalytic degradation of phenol. Applied Catalysis B: Environmental, 74(1–2): 53–62

[17] Hoyos L J, Rivera D F, Gualdrón-Reyes A F, Ospina R, Rodríguez-Pereira J, Ropero-Vega J L, Niño-Gómez M E (2017). Influence of immersion cycles during n-b-Bi₂O₃ sensitization on the photoelectrochemical behaviour of N-F-codoped TiO₂ nanotubes. Applied Surface Science, 423: 917–926

[18] Hu Y, Cao Y T, Wang P X, Li D Z, Chen W, He Y H, Fu X Z, Shao Y, Zheng Y (2012). A new perspective for effect of Bi on the photocatalytic activity of Bi-doped TiO₂. Applied Catalysis B: Environmental, 125: 294–303

[19] Huang J, Cheuk W, Wu Y, Lee F S, Ho W (2012). Fabrication of Bi-doped TiO2 spheres with ultrasonic spray pyrolysis and investigation of their visible-light photocatalytic properties. Journal of Nanotechnology, 2012: 214783

[20] Jiao Z B, Shang M D, Liu J M, Lu G X, Wang X S, Bi Y P (2017). The charge transfer mechanism of Bi modified TiO₂ nanotube arrays: TiO₂ serving as a “charge-transfer-bridge”. Nano Energy, 31: 96–104

[21] Kai G, Greil P, Zollfrank C (2011). Carbon auto-doping improves photocatalytic properties of biotemplated ceramics. Applied Catalysis B: Environmental, 103(1): 240–245

[22] Kim S C, Lee D K (2005). Preparation of TiO₂-coated hollow glass beads and their application to the control of algal growth in eutrophic water. Microchemical Journal, 80(2): 227–232

[23] Kong X, Ma J, Le-Clech P, Wang Z, Tang C Y, Waite T D (2020). Management of concentrate and waste streams for membrane-based algal separation in water treatment: A review. Water Research, 183: 115969

[24] Lee S W, Obregon S, Rodriguez-Gonzalez V (2015). The role of silver nanoparticles functionalized on TiO₂ for photocatalytic disinfection of harmful algae. RSC Advances, 5(55): 44470–44475

[25] Li C, Sun Z, Zhang W, Yu C, Zheng S (2018). Highly efficient g-C₃N₄/TiO₂/kaolinite composite with novel three-dimensional structure and enhanced visible light responding ability towards ciprofloxacin and S. aureus. Applied Catalysis B: Environmental, 220(Supplement C): 272–282

[26] Li G Y, Nie X, Chen J Y, Jiang Q, An T C, Wong P K, Zhang H M, Zhao H J, Yamashita H (2015a). Enhanced visible-light-driven photocatalytic inactivation of Escherichia coli using g-C₃N₄/TiO₂ hybrid photocatalyst synthesized using a hydrothermal-calcination approach. Water Research, 86: 17–24

[27] Li H Y, Wang D J, Wang P, Fan H M, Xie T F (2009). Synthesis and studies of the visible-light photocatalytic properties of near-monodisperse Bi-doped TiO₂ nanospheres. Chemistry-a European Journal, 15(45): 12521–12527

[28] Li J J, Li B, Li J J, Liu J L, Wang L, Zhang H W, Zhang Z H, Zhao B (2015b). Visible-light-driven photocatalyst of La-N-codoped TiO₂ nano-photocatalyst: Fabrication and its enhanced photocatalytic performance and mechanism. Journal of Industrial and Engineering Chemistry, 25: 16–21

[29] Li P, Song Y, Yu S (2014). Removal of Microcystis aeruginosa using hydrodynamic cavitation: Performance and mechanisms. Water Research, 62: 241–248

[30] Li X, Yu J, Jaroniec M (2016). Hierarchical photocatalysts. Chemical Society Reviews, 45(9): 2603–2636

[31] Li X, Yu J, Jaroniec M, Chen X (2019). Cocatalysts for selective photoreduction of CO₂ into solar fuels. Chemical Reviews, 119(6): 3965–3968

[32] Linkous C A, Carter G J, Locuson D B, Ouellette A J, Slattery D K, Smitha L A (2000). Photocatalytic inhibition of algae growth using TiO₂, WO₃, and cocatalyst modifications. Environmental Science & Technology, 34(22): 4754–4758

[33] Ma J Z, Wang C X, He H (2016). Enhanced photocatalytic oxidation of NO over g-C₃N₄-TiO₂ under UV and visible light. Applied Catalysis B: Environmental, 184: 28–34

[34] Ma M, Liu R P, Liu H J, Qu J H (2012). Chlorination of Microcystis aeruginosa suspension: Cell lysis, toxin release and degradation. Journal of Hazardous Materials, 217– 218: 279–285

[35] Matsunaga T, Tomoda R, Nakajima T, Wake H (1985). Photoelectrochemical sterilization of microbial cells by semiconductor powders. FEMS Microbiology Letters, 29(1–2): 211–214

[36] Muñoz-Batista M J, Nasalevich M A, Savenije T J, Kapteijn F, Gascon J, Kubacka A, Fernandez-Garcia M (2015). Enhancing promoting effects in g-C₃N₄-Mⁿ⁺/CeO₂-TiO₂ ternary composites: Photo-handling of charge carriers. Applied Catalysis B: Environmental, 176– 177: 687–698

[37] Pinho L X, Azevedo J, Brito Â, Santos A, Tamagnini P, Vilar V J P, Vasconcelos V M, Boaventura R A R (2015a). Effect of TiO₂ photocatalysis on the destruction of Microcystis aeruginosa cells and degradation of cyanotoxins microcystin-LR and cylindrospermopsin. Chemical Engineering Journal, 268: 144–152

[38] Pinho L X, Azevedo J, Miranda S M, Ângelo J, Mendes A, Vilar V J P, Vasconcelos V, Boaventura R A R (2015b). Oxidation of microcystin-LR and cylindrospermopsin by heterogeneous photocatalysis using a tubular photoreactor packed with different TiO₂ coated supports. Chemical Engineering Journal, 266: 100–111

[39] Shao P H, Tian J Y, Zhao Z W, Shi W X, Gao S S, Cui F Y (2015). Amorphous TiO₂ doped with carbon for visible light photodegradation of rhodamine B and 4-chlorophenol. Applied Surface Science, 324: 35–43

[40] Shen R, Jiang C, Xiang Q, Xie J, Li X (2019). Surface and interface engineering of hierarchical photocatalysts. Applied Surface Science, 471: 43–87

[41] Song J, Wang X, Ma J, Wang X, Wang J, Xia S, Zhao J (2018a). Removal of Microcystis aeruginosa and Microcystin-LR using a graphitic-C₃N₄/TiO₂ floating photocatalyst under visible light irradiation. Chemical Engineering Journal, 348: 380–388

[42] Song J, Wang X, Ma J, Wang X, Wang J, Zhao J (2018b). Visible-light-driven in situ inactivation of Microcystis aeruginosa with the use of floating g-C₃N₄ heterojunction photocatalyst: Performance, mechanisms and implications. Applied Catalysis B: Environmental, 226: 83–92

[43] Su J F, Shao S C, Ma F, Lu J S, Zhang K (2016). Bacteriological control by Raoultella sp R11 on growth and toxins production of Microcystis aeruginosa. Chemical Engineering Journal, 293: 139–150

[44] Sun L, Wan S, Yu Z, Wang L (2014). Optimization and modeling of preparation conditions of TiO₂ nanoparticles coated on hollow glass microspheres using response surface methodology. Separation and Purification Technology, 125: 156–162

[45] Tang Y, Chen J, Wang X, Wang X, Zhao Y, Mao Z, Wang D (2019). Fabrication of highly N-Doped graphene-like carbon templated from g-C₃N₄ nanosheets as promising Li-ions battery anode. Electrochimica Acta, 324: 134880

[46] Wang X, Wang X, Zhao J, Song J, Su C, Wang Z (2018). Adsorption-photocatalysis functional expanded graphite C/C composite for in-situ photocatalytic inactivation of Microcystis aeruginosa. Chemical Engineering Journal, 341: 516–525

[47] Wang X, Wang X, Zhao J, Song J, Wang J, Ma R, Ma J (2017). Solar light-driven photocatalytic destruction of cyanobacteria by F-Ce-TiO₂/expanded perlite floating composites. Chemical Engineering Journal, 320: 253–263

[48] Wang X, Zhou C, Shi R, Liu Q, Waterhouse G I N, Wu L, Tung C H, Zhang T (2019). Supramolecular precursor strategy for the synthesis of holey graphitic carbon nitride nanotubes with enhanced photocatalytic hydrogen evolution performance. Nano Research, 12(9): 2385–2389

[49] Wang Y, Rao L, Wang P, Guo Y, Shi Z, Guo X, Zhang L (2020). Synthesis of nitrogen vacancies g-C₃N₄ with increased crystallinity under the controlling of oxalyl dihydrazide: Visible-light-driven photocatalytic activity. Applied Surface Science, 505: 144576

[50] Wu G S, Wen J L, Wang J P, Thomas D F, Chen A C (2010). A facile approach to synthesize N and B co-doped TiO₂ nanomaterials with superior visible-light response. Materials Letters, 64(15): 1728–1731

[51] Xiong X, Wang Z, Zhang Y, Li Z, Shi R, Zhang T (2020). Wettability controlled photocatalytic reactive oxygen generation and Klebsiella pneumoniae inactivation over triphase systems. Applied Catalysis B: Environmental, 264: 118518

[52] Xu J, Wang W Z, Shang M, Gao E P, Zhang Z J, Ren J (2011). Electrospun nanofibers of Bi-doped TiO₂ with high photocatalytic activity under visible light irradiation. Journal of Hazardous Materials, 196: 426–430

[53] Yang N, Li G Q, Wang W L, Yang X L, Zhang W F (2011). Photophysical and enhanced daylight photocatalytic properties of N-doped TiO₂/g-C₃N₄ composites. Journal of Physics and Chemistry of Solids, 72(11): 1319–1324

[54] Yu Y M, Geng J F, Li H, Bao R Y, Chen H Y, Wang W Z, Xia J X, Wong W Y (2017). Exceedingly high photocatalytic activity of g-C₃N₄/Gd-N-TiO₂ composite with nanoscale heterojunctions. Solar Energy Materials and Solar Cells, 168: 91–99

[55] Zhang J, Wang X, Wang X, Song J, Huang J, Louangsouphom B, Zhao J (2015a). Floating photocatalysts based on loading Bi/N-doped TiO₂ on expanded graphite C/C (EGC) composites for the visible light degradation of diesel. RSC Advances, 5(88): 71922–71931

[56] Zhang W J, Xin H L, Chen J L, He H B (2014). Photocatalytic degradation of methyl orange on La-In co-doped TiO₂. Current Nanoscience, 10(4): 582–587

[57] Zhang Y, Lu J N, Hoffmann M R, Wang Q, Cong Y Q, Wang Q, Jin H (2015b). Synthesis of g-C₃N₄/Bi₂O₃/TiO₂ composite nanotubes: enhanced activity under visible light irradiation and improved photoelectrochemical activity. RSC Advances, 5(60): 48983–48991

[58] Zhou J, Zhang M, Zhu Y (2015). Photocatalytic enhancement of hybrid C₃N₄/TiO₂ prepared via ball milling method. Physical Chemistry Chemical Physics, 17(5): 3647–3652

[59] Zhou L, Wang L Z, Lei J Y, Liu Y D, Zhang J L (2017). Fabrication of TiO₂/Co-g-C₃N₄ heterojunction catalyst and its photocatalytic performance. Catalysis Communications, 89: 125–128

[60] Zhu M, Zhai C, Sun M, Hu Y, Yan B, Du Y (2017). Ultrathin graphitic C₃N₄ nanosheet as a promising visible-light-activated support for boosting photoelectrocatalytic methanol oxidation. Applied Catalysis B: Environmental, 203: 108–115

[61] Zhu Z D, Murugananthan M, Gu J, Zhang Y R (2018). Fabrication of a Z-scheme g-C₃N₄/Fe-TiO₂ photocatalytic composite with enhanced photocatalytic activity under visible light irradiation. Catalysts, 8(3): 112

Acknowledgements

We gratefully acknowledge the support of this research by the National Natural Science Foundation of China (Grant Nos. 22008057 and 51909165). This work was financially supported by the PhD. Scientific Research Starting Foundation of Henan Normal University (No. 5101219170135) and Postdoctoral Research Foundation of Henan Normal University (No. 5101219470222).

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s11783-021-1417-3 and is accessible for authorized users.

RIGHTS & PERMISSIONS

2021 Higher Education Press