English

• Endocrine disrupting chemicals (EDCs) are synthetic compounds that can interfere with the function of endocrine glands and organs in both humans and animals by mimicking hormones and competing with natural hormones for receptor binding in target cells [1]. Bisphenol A (BPA), as one of the most detected EDCs has been heavily found in water and other environmental matrixes, consumer products and even humans since its extensive applications [2]. Nevertheless, BPA has been confirmed to act like estrogen, potentially causing changes in reproductive development and increasing the risk of breast cancer in humans [3]. BPA has been banned in multiple domains (Canada and EU member states have banned BPA from children's food contact materials and childcare products). Nevertheless, it remains exposed to the environment and potentially enters human body through the food chain due to its stable chemical structure and anti-biodegradation properties [4]. Therefore, it is urgent to implement an efficient wastewater remediation technology containing BPA pollutants.

  Advanced oxidation processes (AOPs) are extensively utilized as an effective method for wastewater treatment due to their high efficiency and potent oxidation capabilities [5]. However, the conventional AOPs such as the Fenton reaction and ozone oxidation have some deficiencies, including a limited pH range, the hardness of H₂O₂ transportation [6,7]. Persulfate-based advanced oxidation processes are among the most extensively employed methods for breaking down contaminants in wastewater, thanks to the prolonged half-life and broad pH range compatibility of reactive oxygen species [8]. To enhance the efficiency of PMS based AOPs for breaking down pollutants, PMS activation could be attained by plenty of techniques, such as photolysis, thermolysis, piezocatalysis, and the use of transition metal ions [9-16]. However, the above methods may lead to high energy consumption, secondary pollution and other deficiencies. Consequently, creating an effective catalyst with strong PMS activation capabilities is crucial for water pollutant treatment [17].

  Bismuth oxohalides (BiOX, X = Br, Cl) is a layered oxide semiconductor catalyst containing a [Bi₂O₂]²⁺ plate sandwiched in a dihalogenide anionic layer [18], which is a type of cost effective catalyst and showed high performance in photocatalysis. Therein, the BiOBr (BOB) were always used as photocatalysts involved in pollutant degradation. However, the oxidation ability of BOB alone was usually limited, in which only 65.7% of SMX was removed in BOB/PMS system within 60 min [19]. It is important to highlight that O_v frequently occur as defects in transition-metal oxide catalysts. The presence of O_v on material surfaces has shown potential for enhancing PMS activation and increasing catalyst conductivity [20,21]. Earlier studies have shown that O_v enhances electron movement and refines the active site by generating electrophilic atomic centers on catalyst surface, thus aiding PMS activation and boosting the production of reactive oxygen species (ROS) [22]. For instance, the NF/MXene-Co₃O₄ enriched with O_v, employed as a potent and durable PMS catalyst, successfully eliminated 99.6% of 1, 4-dioxane in just 20 min [23]. Therefore, the presence of O_v is a key for electron transfer between catalysts and PMS, thereby enhancing the PMS activation and removing pollutants. Due to the high concentration of oxygen atoms generated by the Bi-O bonds in BiOX, it serves as an appropriate model matrix for creating oxygen vacancies through the removal of oxygen atoms [16].

  Herein, the O_v rich BOB was chosen as the activator for PMS to remove BPA, in which BOB can act as a bridge to transfer electrons to effectively activate PMS and realize the BPA removal in water without any external input of energy. Firstly, the degradation performance of BOB was explored through a series of comparative experiments. Then the main reactive species was demonstrated by the quenching tests, the electron paramagnetic resonance (EPR) procedures and the XPS. Additionally, experimental tests uncovered the breakdown processes of BPA and the toxicity of its byproducts, demonstrating the appropriateness of the system for practical use.

  The BOB and BOC were synthesized by hydrothermal method (Text in Supporting information) [24], and the microstructure and morphology of the BOB were investigated by field emission scanning electron microscopy (SEM) and field emission transmission microscopy (TEM) in Fig. S1 (Supporting information). Fig. 1a exhibited lattice fringes of 2.78 Å, corresponding to the BOB (110) crystal plane [40]. Moreover, O_v was observed in the surface lattice of BOB as shown in Fig. 1b. The X-ray diffraction (XRD) patterns and the corresponding Fourier transform infrared spectrum (FT-IR) for the BOB and BOC samples were exhibited in Figs. S2a and b (Supporting information) [25-29]. The surface chemical composition and electronic structure of the samples were analyzed by X-ray photo-electron spectroscopy (XPS) [18,30,31]. The high-resolution of Bi 4f, O 1s, Br 3d and C 1s was shown in Fig. 1c and Fig. S2 (Supporting information) separately. Specifically, the detailed Bi 4f spectrum of BOB revealed two peaks at 163.7 and 158.4 eV, attributed to Bi 4f_7/2 and Bi 4f_5/2, respectively, confirming the presence of Bi³⁺ in BOB. Similarly, the other two peaks at 164.9 and 159.5 eV were attributed to Bi⁴⁺ [27,32]. Furthermore, the O 1s spectra of BOB and BOC displayed two distinct peaks. More precisely, the peak at 529.5 eV was attributed to the Bi-O bond, while the peak at 531.3 eV might be caused by O_v [18,33]. Surprisingly, compared with BOC, BOB showed a higher peak at 531.3 eV which meant that BOB may obtain more O_v attributed to PMS activation and BPA degradation than BOC. The EPR was performed to further determine the existence of O_v and more O_v compared to BOC in BOB catalyst. As the result shown in Fig. 1d, BOB and BOC exhibited an obvious EPR signal at g = 2.003, which can be attributed to paramagnetic O_v [34]. At the same time, the signal strength at g = 2.003 for BOB was 4.34 times higher than for BOC, indicating a greater presence of O_v in BOB, aligning with the earlier XPS analysis findings.

  Figure 1

  

  Figure 1.  SEM images of BOB (a), HRTEM pattern of BOB (b), XPS spectra of O 1s for BOB and BOC before use (c), and EPR spectra of O_v in BOB and BOC (d).

  DownLoad: Full-Size Img PowerPoint

  Multiple experiments were conducted to evaluate how effectively O_v-rich BOB activated PMS and broke down BPA. Fig. 2a demonstrated the consequences of BPA degradation by BOB and BOC in the existence of PMS. After 60 min of reaction, the catalytic breakdown of BPA showed BOB outperforming BOC, achieving removal efficiencies of 95.6% and 13.5%, respectively. Furthermore, the pseudo-first-order kinetic formula -ln(C_t/C₀) = kt (with k denoting the reaction rate constant) was applied to determine the degradation rates of BOB/PMS and BOC/PMS. Fig. 2b showed that the k values were 0.049 min^-1 and 0.00038 min^-1, respectively, which meant that BOB/PMS system was 129 times to the compared BOC/PMS system. Additionally, the open-circuit potential curves test (OCPT) showed that in contrast to BOB, BOC exhibited a less significant change, particularly following the introduction of PMS as shown in Fig. 2d. The differences in electrochemical oxidation activity between BOB and BOC also indicated the result by linear sweep voltammogram (LSV) in Fig. 2e [37]. It showed the current increase in the BOB/PMS system relative to that of BOC/PMS [35]. Moreover, findings from electrochemical impedance spectroscopy (EIS) showed that BOB with a higher concentration of O_v exhibited a reduced arc radius relative to BOC, indicating lower charge transfer resistance on the BOB surface and improved electron transfer (Fig. 2c). The results above manifested that O_v-rich BOB was the better catalyst to activate PMS. In addition, as shown in Fig. 2a, just 14.2% of BPA was eliminated when only BOB was used, indicating that BOB had a restricted ability to adsorb BPA. When PMS was used by itself, around 4.2% of BPA was broken down, suggesting that PMS had limited self-decomposition capabilities. Notably, the degradation rate reached 95.6% within 60 min in the BOB/PMS system, demonstrating BOB effectively activated PMS and realized the degradation of BPA. Additionally, the k value for the BOB/PMS system was 60 times and 148 times greater than those of the BOB and PMS systems, respectively (Fig. 2b). It suggested that BOB enhanced PMS activation and boosted BPA breakdown, with EIS data corroborating this conclusion (Fig. 2c) [36]. The swift electron transfer in the BOB/PMS system suggested that BOB could serve as a bridge to efficiently activate PMS, enhancing ROS generation and speeding up BPA elimination. In addition, the OCPT of BOB from Fig. 2d observed a notable rise in potential following the introduction of PMS into the solutions. It indicated that PMS interacted with BOB and electrons were transferred from BOB to PMS after adding PMS. Simultaneously, after adding BPA, the potential also increased obviously due to the electrons transfer from BPA to the PMS [37]. These findings additionally indicated that O_v-rich BOB substances could expedite electron transfer, there by facilitating PMS activation.

  Figure 2

  

  Figure 2.  BPA elimination rates across various systems (a), the associated first-order kinetic graphs for each system (b), EIS Nyquist plots for BOB, BOC and BOB/PMS system (c), open-circuit potential curves for two different systems (d), and LSV curves of BOB/PMS and BOC/PMS system (e) and comparison of the performance of BOB/PMS system for degradation of pollutant with previously reported BiOX-based catalyst systems (f). Experimental conditions: [PMS] = 0.10 g/L, [BOB] = 0.50 g/L, [BPA] =10 mg/L, initial pH 5.0.

  DownLoad: Full-Size Img PowerPoint

  These phenomena indicated the rich O_v-BOB possessed a better catalytic activity than BOC, further demonstrating that BOB was more suitable to be a bridge for electrons transfer. The differences in catalytic activity between BOB and BOC may be related to O_v. O_v on the surface of BOB can optimize the active sites and speed up electron transfer, thereby boosting PMS activation. Additionally, the O_v-rich BOB/PMS system outperformed a lot of BiOX-based systems not only BOC in this paper for pollutant degradation (Fig. 2f and Table S1 in Supporting information), manifesting that O_v-rich BOB had great potential in acting as a PMS activator for wastewater treatment.

  To elucidate the ROS in the BOB/PMS system, quenching experiments and EPR analyses were conducted. As shown in Figs. 3a and b, SO₄^•−, ^•OH, O₂^•− and ¹O₂ were scavenged with MeOH, TBA, p-BQ and L-histidine (L-His) respectively [24,38]. With the addition of 200 mmol/L MeOH, no apparent inhibition of BPA degradation was observed and the k_obs decreased only 0.012 min^-1, which manifested the insignificant contribution of SO₄^•− and ^•OH in the BOB/PMS system. While TBA only quenched the ^•OH in the BOB/PMS system. Therefore, loss of ^•OH had similarly a little effect on the BPA removal. The ATZ with electron-deficient groups can be effectively attacked by the free radical (^•OH and SO₄^•−) [39]. The removal of ATZ as a target contaminant in the BOB/PMS system was < 7.0% within 60 min (Fig. 3e), which may further suggest that the contribution of ^•OH and SO₄^•− were almost negligible in the BOB/PMS system. What is more, p-BQ was employed to quench O₂^•−, the removal efficiency of BPA decreased to 34.6% in the presence of 5.0 mmol/L p-BQ in 60 min (the k_obs decreased from 0.049 min^-1 to 0.0068 min^-1), indicating that O₂^•− played a key role in PMS activation in the BOB/PMS system. However, the inhibition of SO₄^•−, ^•OH and O₂^•− was incomplete, manifesting that the non-radical pathway presented in the BOB/PMS system [40]. Therefore, L-His was used as a scavenger for ¹O₂ and inhibited BPA degradation to 44.4% within 60 min (k_obs = 0.0058 min^-1), indicating that ¹O₂ probably acted as another main active species for the BPA removal. EPR spectral to further identify the ROS generated in the BOB/PMS system (Figs. 3c and d), the characteristic signals for DMPO—O₂^•− and TEMP-¹O₂ adduct with 1:1:1 triple peak were clearly observed in the BOB/PMS system which were corresponding to the result of quenching tests. Nevertheless, the EPR results revealed no obvious signal of DMPO—O₂^•− and TEMP-¹O₂ appeared in the BOB alone system compared with the BOB/PMS system, which inferred the BOB/PMS system possessed a superior removal performance. Moreover, the DMPO—HOO^• signal could be found in the system in Fig. S4 (Supporting information). Previous reports have found that O₂^•− could be hydrolyzed to HOO^• which further confirmed the existence of O₂^•− [48]. In conclusion, O₂^•− and ¹O₂ played major roles in BOB/PMS system. The distinct mechanisms governing the formation of O₂^•− and ¹O₂ remain ambiguous, necessitating further exploration.

  Figure 3

  

  Figure 3.  The scavenging tests (a), the corresponding first-order kinetic curves for BOB/PMS system (b), EPR spectra of DMPO (c) and TEMP (d) and the removal of different pollutants by BOB (e). Experimental conditions: [BOB] = 0.50 g/L, [PMS] = 0.10 g/L, initial pH 5.0, [p-BQ] = 5.0 mmol/L, [MeOH] = 0.20 mol/L, [TBA] = 0.20 mol/L, [L-His] = 2.0 mmol/L, [BPA] = [ATZ] = [CBZ] = [IMI] = [BPE] =10 mg/L.

  DownLoad: Full-Size Img PowerPoint

  The presence of O_v has been previously demonstrated in XPS and EPR assays (Figs. 1c and d). Previous studies found that O_v can enhance the activation efficiency of PMS and facilitate more ROS production by depressing the reaction barrier of PMS decomposition [20,41]. This may be attributed to the fact that a number of O_v was beneficial to PMS adsorption and dissociation, and accommodated the O atoms in the peroxygen bond, leading to the breaking of the O—O bond. The effects of N₂ in the BOB/PMS system suggested that dissolved oxygen had a weak effect on the degradation of BPA (Fig. S5 in Supporting information). Thus, the main source of reactive oxygen species was the activation of PMS. Herein, a series of XPS spectra analyses were conducted to clarify the activation mechanism of PMS. In Fig. 4a, the XPS spectra of O 1s showed that approximately 15.6% of O_v transformed into Bi-O after the reaction indicating that the generation of O_v promoted the redox cycle of Bi³⁺/Bi⁴⁺ in the lattice and favored interfacial electron transfer [42,49]. Therefore, O_v at the interface of the catalyst played an important role in the formation of ROS. Furthermore, in order to clarify the relationship between O_v and the valence variation of Bi element. The surface oxidation states of BOB before and after degradation experiments were analyzed by XPS analyses. It could be found that in Fig. 4b, the relative contents of Bi³⁺ and Bi⁴⁺ changed from 86.1% to 35.4% and 13.9% to 64.6%, respectively. The formation of Bi⁴⁺ species could be attributed to the oxidation of Bi³⁺ by PMS, suggesting that the Bi³⁺/Bi⁴⁺ cycle participated in the activation of PMS.

  Figure 4

  

  Figure 4.  XPS spectra of O 1s (a) and Bi 4f (b) for BOB before and after use, removal efficiency of BPA in different actual water systems (c) and recycling investigation of BPA in BOB/PMS system (d). [PMS] = 0.10 g/L, [BOB] = 0.50 g/L, [BPA] = 10 mg/L, initial pH 5.0.

  DownLoad: Full-Size Img PowerPoint

  Based on the above discussion, the O_v in BOB can activate PMS to form ¹O₂ and HSO₄^- (Eq. 1) [43,44]. The SO₅^2- formed by the decomposition of PMS reacted with H₂O to emerge O₂^•− (Eqs. 2 and 3) [20]. Bi³⁺ as an active site accelerated O₂^•− production (Eq. 4) [40]. In addition, HSO₅^- produced by PMS hydrolysis can bring Bi⁴⁺ back to Bi³⁺, which provided good support for the next catalytic cycle (Eq. 5) [45]. Whatever, ¹O₂ not only originated from the self-decomposition of PMS but also came from the conversion of O₂^•−, while HOO^• was also generated during this process (Eqs. 6 and 7) [37,46]. Then the generated ¹O₂ and O₂^•− co-contributed to BPA degradation (Eq. 8).

  $ \mathrm{O}_{\mathrm{v}}+\mathrm{HSO}_5{ }^{-} \rightarrow{ }^1 \mathrm{O}_2+\mathrm{HSO}_4{ }^{-} $

  (1)

  $ \mathrm{HSO}_5{ }^{-} \rightarrow \mathrm{SO}_5{ }^{2-}+\mathrm{H}^{+} $

  (2)

  $ \mathrm{SO}_5{ }^{2-}+\mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{O}_2{ }^{\cdot-}+\mathrm{SO}_4{ }^{2-}+\mathrm{H}^{+} $

  (3)

  $ \mathrm{Bi}^{3+}+2 \mathrm{HSO}_5{ }^{-} \rightarrow \mathrm{Bi}^{4+}+2 \mathrm{O}_2 { }^{\cdot-}+\mathrm{SO}_5{ }^{\cdot-}+\mathrm{H}_2 \mathrm{O} $

  (4)

  $ \mathrm{Bi}^{4+}+\mathrm{HSO}_5{ }^{-} \rightarrow \mathrm{Bi}^{3+}+\mathrm{SO}_5{ }^{-}+\mathrm{H}^{+} $

  (5)

  $ \mathrm{O}_2{ }^{\cdot-}+\mathrm{H}_2 \mathrm{O} \rightarrow \mathrm{HOO}^{\cdot}+\mathrm{OH}^{-} $

  (6)

  $ \mathrm{O}_2{ }^{\cdot-}+\mathrm{HOO}^{\cdot} \rightarrow{ }^1 \mathrm{O}_2+\mathrm{HOO}^{-} $

  (7)

  $ { }^1 \mathrm{O}_2 / \mathrm{O}_2{ }^{\cdot-}+\mathrm{BPA} \rightarrow \text { degradation products } $

  (8)

  In order to explore the potential for practical application in the system, the reservoir water, the living water, the lake water and the rainwater were selected to perform the degradation experiments. The results in Fig. 4c showed that the removal efficiency of BPA was 92.9%, 80.0%, 83.6% and 87.7% in the reservoir water, the living water, the lake water and the rainwater respectively, indicating that the influence of the four actual wastewater in BOB/PMS system on degradation of BPA was negligible. Besides, the degradation performances of the BOB/PMS to different contaminants were also investigated (Fig. 3e). It was worth noting that, 81.1% of BPE was removed within 60 min, which meant that the BOB might have an obvious degradation effect on a series of bisphenol pollutants. There was 82.6% of CBZ removed, which was consistent with other research (67.3% of CBZ was removed in BOB/PMS system) [27]. However, no ATZ and IMI were oxidized under the same reaction conditions. Therefore, the differences in eliminating different kinds of pollutants indicated the selectivity of BOB/PMS system, which can avoid the competition between some coexisting components and the target pollutants in a complex water environment [47]. Moreover, the reusability of the BOB in BOB/PMS system was assessed by the recyclability experiment. As shown in Fig. 4d, the removal efficiency declined to 66.8% after five cycling tests. The slight decline may be related to the decreased O_v in BOB by the oxidation effect of oxygen during test. To further elucidate the reusability of BOB, the used BOB was collected and tested for XPS (Fig. S8 in Supporting information). It showed that the XPS spectra of BOB after reaction was essentially unchanged compared to the one before reaction and no other impurity peaks were generated. Therefore, BOB still had some of its original catalytic capacity [12]. To sum up, the BOB had desirable stability and reusability in the real environment. These also provided potential technical supports for the removal of BPA in the actual environment.

  In this study, BiOX were successfully synthesized which activated PMS in the degradation of BPA. O_v-rich BOB showed outstanding performance in the activation of PMS and the degradation of BPA (95.6% of BPA was removed within 60 min) compared with BOC. It indicated that O_v in BOB acted as the bridge of electrons transfer between Bi³⁺/Bi⁴⁺ pairs and PMS. Quenching experiments, EPR tests and electrochemical experiments confirmed that the O₂^•− and ¹O₂ were the dominant ROS during the degradation of BPA. Moreover, the degradation pathways of BPA were proposed, which reduced the toxicity of intermediates in BOB/PMS system. Besides, the influence of other elements on the system further confirmed the practical application potential of this process. In summary, the study efficiently utilized O_v without any external energy to activate PMS and remove BPA, which provided an energy-efficient avenue for handling BPA contaminated wastewater.

  Declaration of competing interest

  The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

  CRediT authorship contribution statement

  Siyang Xue: Writing – review & editing, Writing – original draft, Methodology, Investigation, Formal analysis, Data curation, Conceptualization. Chen Cheng: Writing – review & editing, Writing – original draft, Methodology, Investigation, Formal analysis, Data curation, Conceptualization. Jieqiong Kang: Methodology, Investigation, Data curation. Kaixuan Zheng: Investigation. Adela Jing Li: Resources, Project administration, Funding acquisition. Renli Yin: Writing – review & editing, Resources, Project administration, Funding acquisition, Conceptualization.

  Acknowledgments

  The present study was financially supported by the National Key Research and Development Program of China (No. 2022YFC3703103), National Natural Science Foundation of China (Nos. 22206053, 42277427), the Guangzhou Science and Technology Plan Project (No. 2024A04J4058).

  Supplementary materials

  Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.cclet.2024.110776.

  
  
• 1. [1]

     M.G. Antoniou, A.A. de la Cruz, D.D. Dionysiou, Appl. Catal. B: Environ. 96 (2010) 290–298. doi: 10.1016/j.apcatb.2010.02.013

  2. [2]

     Y. Bao, W. Lee, C. Guan, et al., Sep. Purif. Technol. 276 (2021) 119203. doi: 10.1016/j.seppur.2021.119203

  3. [3]

     Y. Bu, H. Li, W. Yu, et al., Environ. Sci. Technol. 55 (2021) 2110–2120. doi: 10.1021/acs.est.0c07274

  4. [4]

     H. Cai, J. Zou, J. Lin, et al., Chem. Eng. J. 429 (2022) 132438. doi: 10.1016/j.cej.2021.132438

  5. [5]

     Y. Cai, Y. Xu, J. Xiang, et al., J. Environ. Sci. 137 (2024) 321–332. doi: 10.1016/j.jes.2023.01.005

  6. [6]

     Y. Yang, Z. Song, W. Ren, et al., Appl. Catal. B: Environ. 359 (2024) 124470. doi: 10.1016/j.apcatb.2024.124470

  7. [7]

     Z. Song, Y. Zhang, Y. Yang, et al., Environ. Sci. Ecotechnol. 22 (2024) 100452. doi: 10.1016/j.ese.2024.100452

  8. [8]

     Y. Cao, J. Yao, T. Š. Knudsen, et al., Chemosphere 312 (2023) 137169. doi: 10.1016/j.chemosphere.2022.137169

  9. [9]

     H. Chen, Z. Han, S. Cao, et al., Chem. Eng. J. 453 (2023) 139660. doi: 10.1016/j.cej.2022.139660

  10. [10]

      L. Chen, X. Zuo, L. Zhou, et al., Chem. Eng. J. 345 (2018) 364–374. doi: 10.1016/j.cej.2018.03.169

  11. [11]

      N. Chen, D. Lee, H. Kang, et al., J. Environ. Chem. Eng. 10 (2022) 107654. doi: 10.1016/j.jece.2022.107654

  12. [12]

      Y. Chen, X. Bai, Y. Ji, D. Chen, J. Hazard. Mater. 441 (2023) 129912. doi: 10.1016/j.jhazmat.2022.129912

  13. [13]

      Y. Chen, S. Lan, M. Zhu, Chin. Chem. Lett. 32 (2021) 2052–2056. doi: 10.1016/j.cclet.2020.11.016

  14. [14]

      X. Cheng, H. Guo, Y. Zhang, X. Wu, Y. Liu, Water Res. 113 (2017) 80–88. doi: 10.1016/j.watres.2017.02.016

  15. [15]

      D. Colón, E.J. Weber, J.L. Anderson, Environ. Sci. Technol. 42 (2008) 6538–6543. doi: 10.1021/es8004249

  16. [16]

      D. Cui, H. He, W. Xie, et al., J. Hazard. Mater. 465 (2024) 133155. doi: 10.1016/j.jhazmat.2023.133155

  17. [17]

      T. Das, B. Verma, Chem. Phys. Lett. 739 (2020) 136947. doi: 10.1016/j.cplett.2019.136947

  18. [18]

      X. Dou, Y. Chen, H. Shi, Chem. Eng. J. 431 (2022) 134054. doi: 10.1016/j.cej.2021.134054

  19. [19]

      F. Ghanbari, M. Moradi, Chem. Eng. J. 310 (2017) 41–62. doi: 10.1016/j.cej.2016.10.064

  20. [20]

      S. Guo, H. Wang, W. Yang, et al., Appl. Catal. B: Environ. 262 (2020) 118250. doi: 10.1016/j.apcatb.2019.118250

  21. [21]

      P. Intaphong, A. Phuruangrat, K. Karthik, et al., J. Inorg. Organomet. Polym. Mater. 30 (2020) 714–721. doi: 10.1007/s10904-019-01259-0

  22. [22]

      N. Li, R. Li, X. Duan, et al., Environ. Sci. Technol. 55 (2021) 16163–16174. doi: 10.1021/acs.est.1c06244

  23. [23]

      W. Li, W. Li, K. He, et al., J. Hazard. Mater. 432 (2022) 128719. doi: 10.1016/j.jhazmat.2022.128719

  24. [24]

      Z. Li, W. Mao, L. Yao, et al., J. Hazard. Mater. 424 (2022) 127549. doi: 10.1016/j.jhazmat.2021.127549

  25. [25]

      K. Lin, K.Z. Zhang, Chem. Eng. J. 313 (2017) 1320–1327. doi: 10.1016/j.cej.2016.11.025

  26. [26]

      L. Long, C. Bai, X. Zhou, et al., Sep. Purif. Technol. 297 (2022) 121432. doi: 10.1016/j.seppur.2022.121432

  27. [27]

      X. Long, C. Feng, D. Ding, et al., J. Hazard. Mater. 418 (2021) 126357. doi: 10.1016/j.jhazmat.2021.126357

  28. [28]

      D. Lopez-Rodriguez, D. Franssen, J. Bakker, A. Lomniczi, A.S. Parent, Nat. Rev. Endocrinol. 17 (2021) 83–96. doi: 10.1038/s41574-020-00436-3

  29. [29]

      X. Luo, Y. Liu, C. Yang, et al., J. Eur. Ceram. Soc. 35 (2015) 2073–2081. doi: 10.1016/j.jeurceramsoc.2015.01.024

  30. [30]

      M.V. Maffini, B.S. Rubin, C. Sonnenschein, A.M. Soto, Mol. Cell. Endocrinol. 254–255 (2006) 179–186.

  31. [31]

      F. Qiu, Y. Pan, L. Wang, et al., Sep. Purif. Technol. 330 (2024) 125139. doi: 10.1016/j.seppur.2023.125139

  32. [32]

      X. Qiu, Y. Zhao, C. Li, R. Jin, E. Mutabazi, Chem. Eng. J. 475 (2023) 146234. doi: 10.1016/j.cej.2023.146234

  33. [33]

      S. Sifakis, V.P. Androutsopoulos, A.M. Tsatsakis, D.A. Spandidos, Environ. Toxicol. Phar. 51 (2017) 56–70. doi: 10.1016/j.etap.2017.02.024

  34. [34]

      A. Takdastan, B. Kakavandi, M. Azizi, M. Golshan, Chem. Eng. J. 331 (2018) 729–743. doi: 10.1016/j.cej.2017.09.021

  35. [35]

      K. Hou, G. Zhu, Y. Feng, Y. Liu, X. Quan, Chin. Chem. Lett. 35 (2024) 108704. doi: 10.1016/j.cclet.2023.108704

  36. [36]

      H. Wang, B. Liao, T. Lu, Y. Ai, G. Liu, J. Hazard. Mater. 385 (2020) 121552. doi: 10.1016/j.jhazmat.2019.121552

  37. [37]

      H. Wang, Z. Long, R. Chen, et al., Sep. Purif. Technol. 331 (2024) 125598. doi: 10.1016/j.seppur.2023.125598

  38. [38]

      H. Wang, X. Wang, Y. Zhou, et al., Sep. Purif. Technol. 307 (2023) 122771. doi: 10.1016/j.seppur.2022.122771

  39. [39]

      M. Wang, B. Guo, J. Zhan, et al., Chem. Phys. Lett. 807 (2022) 140093. doi: 10.1016/j.cplett.2022.140093

  40. [40]

      X. Wang, G. Xu, Y. Tu, et al., Chem. Eng. J. 411 (2021) 128456. doi: 10.1016/j.cej.2021.128456

  41. [41]

      Y. Wang, D. Cao, X. Zhao, Chem. Eng. J. 328 (2017) 1112–1121. doi: 10.1016/j.cej.2017.07.042

  42. [42]

      Y. Wei, H. Su, Y. Zhang, et al., Chem. Eng. J. 375 (2019) 121971. doi: 10.1016/j.cej.2019.121971

  43. [43]

      J. Xie, J. Zhao, J. Han, et al., J. Colloid Interf. Sci. 652 (2023) 1588–1596. doi: 10.1016/j.jcis.2023.08.194

  44. [44]

      L. Xu, X. Wu, C. Li, et al., J. Clean. Prod. 394 (2023) 136275. doi: 10.1016/j.jclepro.2023.136275

  45. [45]

      J. Yang, T. Xie, Y. Mei, et al., Appl. Catal. B: Environ. 339 (2023) 123149. doi: 10.1016/j.apcatb.2023.123149

  46. [46]

      L. Ye, X. Jin, C. Liu, et al., Appl. Catal. B: Environ. 187 (2016) 281–290. doi: 10.1016/j.apcatb.2016.01.044

  47. [47]

      S. Zhu, X. Li, J. Kang, X. Duan, S. Wang, Environ. Sci. Technol. 53 (2019) 307–315. doi: 10.1021/acs.est.8b04669

  48. [48]

      J. Yan, J. Peng, L. Lai, et al., Environ. Sci. Technol. 52 (2018) 14302–14310. doi: 10.1021/acs.est.8b03340

  49. [49]

      M. Liu, H. Qin, H. Xu, et al., Sep. Purif. Technol. 307 (2023) 122711. doi: 10.1016/j.seppur.2022.122711

• 

  Figure 1  SEM images of BOB (a), HRTEM pattern of BOB (b), XPS spectra of O 1s for BOB and BOC before use (c), and EPR spectra of O_v in BOB and BOC (d).

  下载: 全尺寸图片 幻灯片
  

  Figure 2  BPA elimination rates across various systems (a), the associated first-order kinetic graphs for each system (b), EIS Nyquist plots for BOB, BOC and BOB/PMS system (c), open-circuit potential curves for two different systems (d), and LSV curves of BOB/PMS and BOC/PMS system (e) and comparison of the performance of BOB/PMS system for degradation of pollutant with previously reported BiOX-based catalyst systems (f). Experimental conditions: [PMS] = 0.10 g/L, [BOB] = 0.50 g/L, [BPA] =10 mg/L, initial pH 5.0.

  下载: 全尺寸图片 幻灯片
  

  Figure 3  The scavenging tests (a), the corresponding first-order kinetic curves for BOB/PMS system (b), EPR spectra of DMPO (c) and TEMP (d) and the removal of different pollutants by BOB (e). Experimental conditions: [BOB] = 0.50 g/L, [PMS] = 0.10 g/L, initial pH 5.0, [p-BQ] = 5.0 mmol/L, [MeOH] = 0.20 mol/L, [TBA] = 0.20 mol/L, [L-His] = 2.0 mmol/L, [BPA] = [ATZ] = [CBZ] = [IMI] = [BPE] =10 mg/L.

  下载: 全尺寸图片 幻灯片
  

  Figure 4  XPS spectra of O 1s (a) and Bi 4f (b) for BOB before and after use, removal efficiency of BPA in different actual water systems (c) and recycling investigation of BPA in BOB/PMS system (d). [PMS] = 0.10 g/L, [BOB] = 0.50 g/L, [BPA] = 10 mg/L, initial pH 5.0.

  下载: 全尺寸图片 幻灯片
•