- Email: [email protected]
incipient wetness impregnation approach
Materials Letters 262 (2020) 127190
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Facile synthesis of magnetic mesoporous silica spheres by a solgel/surface-protected etching/incipient wetness impregnation approach Sun Liang ⇑, Hu Dehao, Zhang Ziyu, Deng Xiaoyan College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, Shandong, China
a r t i c l e
i n f o
Article history: Received 9 November 2019 Received in revised form 14 December 2019 Accepted 16 December 2019 Available online 17 December 2019 Keywords: Magnetic mesoporous silica spheres Surface-protected etching Magnetic materials Oxidation
a b s t r a c t We recently synthesized the magnetic mesoporous silica spheres (MMSS) by a sol-gel/surface-protected etching/incipient wetness impregnation approach. Silica spheres (SS) were firstly synthesized by the Stöber method, and surface-protected etching allowed convenient conversion of sol-gel derived silica into mesoporous structures (mesoporous silica spheres, MSS). The immobilization of magnetic nanoparticles over MSS supports was addressed by incipient wetness impregnation. XRD, TEM, and nitrogen sorption technique showed successful synthesis as desired. The iron loadings could reach to 32.67 wt% and narrow pore size distribution centered at ca. 4 nm was found. MMSS exhibits superior persulfate (PDS) activation as well as stability for removing the organic compounds. In addition, magnetic separation of the materials offers great prospects for fast and economical reuse. Ó 2019 Elsevier B.V. All rights reserved.
1. Introduction Magnetic nanoparticles, which consist of small particle size and large specific surface area resulting in a high activity and fast reaction rate, are widely used in many technological applications, such as catalysis [1–3], adsorption [4,5], and so on [6–8]. However, the direct use of magnetic nanoparticles meets some problems such as their serious agglomeration in the solution and easily flowing away with water in the practical application [9]. To overcome these drawbacks, previous researchers found that the immobilization of magnetic nanoparticles on the inert support materials to form composite materials could help to prevent their aggregation and improve their chemical reactivity and stability [10,11]. For example, magnetic particles have been loaded onto various supporters such as zeolite [12], carbon [13] and graphene [14]. Silica, a widely used oxide support, has been reported as an ideal host for loading metal oxide particles [15]. However, the silica spheres prepared by the Stöber method might not allow for the efficient immobilization of metal oxide nanoparticles. [16–18]. Boats et al. have prepared Fe2O3/SiO2 by two step sol-gel/ incipient wetness impregnation process: the percentage of iron incorporated over the powder ranged from 15 to 18 wt%, and the prepared materials depicted broad pore size distributions. This might influence the composite’s catalytic activity [19]. As a result, mesoporous silica spheres (MSS), which show a narrow size distri⇑ Corresponding author. E-mail address: [email protected] (S. Liang). https://doi.org/10.1016/j.matlet.2019.127190 0167-577X/Ó 2019 Elsevier B.V. All rights reserved.
bution and an obvious quantum confinement effect for the loaded nanocrystals, have been intensively pursued in the past decade [20,21]. In recent years, a ‘‘surface-protected etching” approach has been successfully developed to fabricate MSS, using polymers and extremely corrosive etching agents [22]. As compared with other methods, the ‘‘surface-protected etching” approach shows facile and economical [20,22]. In this paper, we developed a sol-gel/surface-protected etching/incipient wetness impregnation route to magnetic mesoporous silica spheres (MMSS), which show an excellent catalysis property, stability and practical reusability for methylene blue (MB) removal with PDS-based advanced oxidation process. 2. Experimental Fig. 1 shows the synthesis route of the MMSS and the detailed procedure can be found in the Supporting Information. 3. Results and discussion The XRD analysis of the samples is shown in Fig. 2(a). According to the magnetite standard card (PDF#88–0315), the prepared materials (MMSS and magnetic SS) showed that six lattice planes of magnetite matched with pure magnetite phases at 2h
30:2 ð220Þ, 35:4 ð311Þ, 43:1 ð400Þ, 54:5 ð422Þ, 57:1 ð511Þ, and
62:6 ð440Þ. No diffraction peak corresponding to SiO2 was
2
S. Liang et al. / Materials Letters 262 (2020) 127190
Fig. 1. The synthesis route of the MMSS.
Fig. 2. XRD patterns (a), TEM images (b) of the prepared materials.
observed except the broad peaks around 2h23 which indicated the amorphous SiO2 support formation [19]. TEM images of the prepared materials are shown in Fig. 2. The diameter of the magnetic SS was determined about 300 nm, and the diameter of MMSS seemed as same as SS. The etching process
usually decreases the diameter of materials [22], but the protection by PVP allows the SS to retain their original size, while selective etching at the interior produces mesoporous structures. As shown in Fig. 2(b), the surface of MMSS showed mesoporous as desired, in agreement with the surface-protected etching strategy. The
S. Liang et al. / Materials Letters 262 (2020) 127190 Table 1 Characterization data of catalysts supported over silica materials. Material
Sbet (m2/g)
Vp (cm3/g)
Fe (wt. %)
SS MS Magnetic SS MMSS
18.7954 34.0255 31.2924 161.1357
0.0576 0.0862 0.1074 0.5591
– – 15.42 32.67
loading monodispersed magnetic particles, which the diameter of these particles was about 2–3 nm, can be easily seen on the surface of the two spheres. Obviously, there are many more particles loaded on the surface of MSS than SS. The isotherm shape of MMSS sample is type IV with H3-type hysteresis loop (Fig. S1), characteristic of mesoporous materials. The surface area and pore volume of MMSS was about 161.1357 m2/g and 0.5571 cm3/g, which was 8 and 10 times more than those of SS (Table 1). Fig. S2 shows pore size distribution profiles of different materials. No obvious pore size distribution peak could be observed for SS, MSS, and magnetic SS. The narrow pore size distribution centered at ca. 4 nm (between 2 and 60 nm) was found in MMSS, which is similar to the previous research [23]. In addition, the percentage of iron incorporated over the SS reached to 15.42 wt%, whereas it could be increased to 32.67 wt % for MMSS. Removal of MB via PDS-based oxidation used the prepared materials is investigated as shown in Fig. 3(a). PDS without any catalyst showed no activity for the degradation of MB. Bare Fe3O4 (synthesized according to the previous paper [24]) showed relatively low catalytic activity with only 5%. There is 10% of MB that can be adsorbed by SS, while it increased to 36.5% for MSS. About 60%, 72%, and 90% of the MB removed using the catalysts as Fe3O4, magnetic SS, and MMSS after 60 min, respectively. Mandal et al. synthesized the porous SiO2 spheres loaded with Fe2O3 nanoparticles by the sol-gel process and evaluated the photocatalytic oxidation ability of the materials. For MB removal, the highest removal efficiency was 88% after 240 min [25]. It can be found that the MMSS shows excellent catalytic activity which can be used in PDS-based oxidation for removal of organic waste from the solution.
3
To evaluate the stability and practical reusability of prepared catalysts, a five-run catalyst recycling test is performed (Fig. 3 (b)). In the experiments, the catalysts were magnetically fixed (using an external magnet) at the bottom of the flask (Fig. S3) and the liquid decanted. Then the catalysts were washed by deionized water three times. Fresh MB and PDS was added into the flask to proceed for the next run. For comparison, when the Fe3O4 nanoparticles were firstly used as a catalyst, the removal efficiency was 60%, but it decreased to 10% sharply after 5 cycles, indicating the occurrence of severe aggregation. The removal efficiency of magnetic SS was decreased from 72% to 60% and the removal efficiency of MMSS was not changed significantly (from 90% to 84%). It is obvious that the presence of MSS support is sufficient for stabilizing the catalytic magnetic nanoparticles by preventing their aggregation; at the same time, the prepared materials exhibited effective magnetic properties and were easily separated within a few minutes of the completion by using an external magnetic field, improving practical reusability.
4. Conclusion In summary, we developed a sol-gel/surface-protected etching/ incipient wetness impregnation route to synthesize the magnetic mesoporous silica spheres. The iron loadings of the prepared materials could reach to 32.67 wt% (2 times more than those of previous researches), and narrow pore size distribution centered at ca. 4 nm was found. 90% of MB can be degraded by the PDS-based advanced oxidation process catalyzed by MMSS, and the removal efficiency remained to more than 80% after 5 times cycle use. We thus believe that the strategy reported herein will stimulate chemists to explore its further promising applications, such as confined catalysis.
CRediT authorship contribution statement Sun Liang: Conceptualization, Project administration, Writing original draft. Hu Dehao: Data curation, Investigation. Zhang Ziyu: Investigation. Deng Xiaoyan: Writing - review & editing.
Fig. 3. (a) PDS-based oxidation of MB via different materials; (b) The cycles of MB degradation with different materials.
4
S. Liang et al. / Materials Letters 262 (2020) 127190
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. Acknowledgements We gratefully acknowledge the generous support provided by the National Natural Science Foundation of China (NO. 51408295), Key Research and Development Project of Shandong Province (NO. 2017GSF217013, NO. 2018GSF117007). Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi.org/10.1016/j.matlet.2019.127190. References [1] L.W. Zhao, K. Zheng, J.Y. Tong, J.Z. Jin, C. Shen, Catal. Lett. 149 (2019) 2606– 2613. [2] H. Hibst, E. Schwab, Mater. Sci. Tech-Lond. 190 (1994) 110–122. [3] M.A. Uddin, H. Tsuda, S.J. Wu, E. Sasaoka, Fuel 87 (2008) 451–459. [4] C.L. Wu, G.F. Zhu, J. Fan, J.J. Wang, RSC Adv. 6 (2016) 86428–86435. [5] L.J. Han, F.Y. Ge, G.H. Sun, X.J. Gao, H.G. Zheng, Dalton T. 48 (2019) 4650–4656. [6] F. Gazeau, C. Baravian, J.C. Bacri, R. Perzynski, Phys. Rev. E. 56 (1997) 614–618. [7] J.M. Perez, T.O. Loughin, F.J. Simeone, R. Weissleder, L. Josephson, J. Am. Chem. Soc. 124 (2002) 2856–2857.
[8] A.A. Kuznetsovac, I.F. Victor, N.A. Renat, N.L. Torshinab, O.A. Kuznetsov, J. Magn. Magn. Mater. 225 (2001) 95–100. [9] J.H. Lu, Q. Liu, Z.D. Xiong, Z.J. Xu, Y.J. Cai, Q. Wang, J. Chem. Technol. Biot. 92 (2017) 1601–1612. [10] G. Calleja, J.A. Melero, F. Martı0 nez, R. Molina, Water Res. 39 (2005) 1741. [11] Y.J. Ma, X.X. Jiang, Y.K. Lv, Chem-Asian J. 14 (2019) 3515–3530. [12] E. Nyankson, J. Adjasoo, J.K. Efavi, R. Amedalor, A. Yaya, G.P. Manu, K. Asare, N. A. Amartey, J. Chem-NY. 2019 (2019), https://doi.org/10.1155/2019/8090756. [13] H. Liu, S.H. Luo, D.B. Hu, X. Liu, Q. Wang, Z.Y. Wang, Y.L. Wang, L.J. Chang, Y.G. Liu, T.F. Yi, Y.H. Zhang, A.M. Hao, Appl. Surf. Sci. 495 (2019), https://doi.org/ 10.1016/j.apsusc.2019.143590. [14] F. Ebrahimi-Tazangi, S.H. Hekmatara, J. Seyed-Yazdi, J. Alloy. Compd. 809 (2019), https://doi.org/10.1016/j.jallcom.2019.151779. [15] K. Ueno, H. Negishi, T. Okuno, H. Tawarayama, S. Ishikawa, M. Miyamoto, S. Uemiya, Y. Oumi, Micropor. Mesopor. Mat. 289 (2019), https://doi.org/ 10.1016/j.micromeso.2019.109645. [16] J.S. Gao, S.C. Wu, F. Tan, H. Tian, J. Liu, G.Q.M. Lu, Prog. Nat. Sci-Mater. 28 (2018) 242–245. [17] S.A. Sorokina, N.V. Kuchkina, B.P. Lawson, I.Y. Krasnova, N.A. Nemygina, L.Z. Nikoshvili, V.N. Talanova, B.D. Stein, M. Pink, D.G. Morgan, E.M. Sulman, L.M. Bronstein, Z.B. Shifrina, Appl. Surf. Sci. 488 (2019) 865–873. [18] N. Crowther, F. Larachi, Appl. Catal. B: Environ. 46 (2003) 293–305. [19] J.A. Botas, J.A. Melero, F. Martinez, M.I. Pariente, Catal. Today 149 (2010) 334– 340. [20] J. Zong, Y.H. Zhu, X.L. Yang, C.Z. Li, J. Alloy. Compd. 509 (2011) 2970–2975. [21] N. Yuan, H. Cai, T. Liu, Q. Huang, X.L. Zhang, Adsorpt. Sci. Technol. 37 (2019) 333–348. [22] Q. Zhang, T.R. Zhang, J.P. Ge, Y.D. Yin, Nano Lett. 8 (2008) 2867–2871. [23] N. Yuan, Y.N. Sun, Z.W. Liu, B.H. Han, J. Porous. Mat. 25 (2018) 1715–1721. [24] T. Chen, Q.F. Wang, J.F. Lu, P. Bai, X.H. Guo, Sep. Purif. Technol. 231 (2020), https://doi.org/10.1016/j.seppur.2019.115930. [25] S. Mandal, S. Adhikari, S.Y. Pu, X.K. Wang, D.H. Kim, R.K. Patel, Chemosphere 234 (2019) 596–607.
Contents lists available at ScienceDirect
Materials Letters journal homepage: www.elsevier.com/locate/mlblue
Facile synthesis of magnetic mesoporous silica spheres by a solgel/surface-protected etching/incipient wetness impregnation approach Sun Liang ⇑, Hu Dehao, Zhang Ziyu, Deng Xiaoyan College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, Shandong, China
a r t i c l e
i n f o
Article history: Received 9 November 2019 Received in revised form 14 December 2019 Accepted 16 December 2019 Available online 17 December 2019 Keywords: Magnetic mesoporous silica spheres Surface-protected etching Magnetic materials Oxidation
a b s t r a c t We recently synthesized the magnetic mesoporous silica spheres (MMSS) by a sol-gel/surface-protected etching/incipient wetness impregnation approach. Silica spheres (SS) were firstly synthesized by the Stöber method, and surface-protected etching allowed convenient conversion of sol-gel derived silica into mesoporous structures (mesoporous silica spheres, MSS). The immobilization of magnetic nanoparticles over MSS supports was addressed by incipient wetness impregnation. XRD, TEM, and nitrogen sorption technique showed successful synthesis as desired. The iron loadings could reach to 32.67 wt% and narrow pore size distribution centered at ca. 4 nm was found. MMSS exhibits superior persulfate (PDS) activation as well as stability for removing the organic compounds. In addition, magnetic separation of the materials offers great prospects for fast and economical reuse. Ó 2019 Elsevier B.V. All rights reserved.
1. Introduction Magnetic nanoparticles, which consist of small particle size and large specific surface area resulting in a high activity and fast reaction rate, are widely used in many technological applications, such as catalysis [1–3], adsorption [4,5], and so on [6–8]. However, the direct use of magnetic nanoparticles meets some problems such as their serious agglomeration in the solution and easily flowing away with water in the practical application [9]. To overcome these drawbacks, previous researchers found that the immobilization of magnetic nanoparticles on the inert support materials to form composite materials could help to prevent their aggregation and improve their chemical reactivity and stability [10,11]. For example, magnetic particles have been loaded onto various supporters such as zeolite [12], carbon [13] and graphene [14]. Silica, a widely used oxide support, has been reported as an ideal host for loading metal oxide particles [15]. However, the silica spheres prepared by the Stöber method might not allow for the efficient immobilization of metal oxide nanoparticles. [16–18]. Boats et al. have prepared Fe2O3/SiO2 by two step sol-gel/ incipient wetness impregnation process: the percentage of iron incorporated over the powder ranged from 15 to 18 wt%, and the prepared materials depicted broad pore size distributions. This might influence the composite’s catalytic activity [19]. As a result, mesoporous silica spheres (MSS), which show a narrow size distri⇑ Corresponding author. E-mail address: [email protected] (S. Liang). https://doi.org/10.1016/j.matlet.2019.127190 0167-577X/Ó 2019 Elsevier B.V. All rights reserved.
bution and an obvious quantum confinement effect for the loaded nanocrystals, have been intensively pursued in the past decade [20,21]. In recent years, a ‘‘surface-protected etching” approach has been successfully developed to fabricate MSS, using polymers and extremely corrosive etching agents [22]. As compared with other methods, the ‘‘surface-protected etching” approach shows facile and economical [20,22]. In this paper, we developed a sol-gel/surface-protected etching/incipient wetness impregnation route to magnetic mesoporous silica spheres (MMSS), which show an excellent catalysis property, stability and practical reusability for methylene blue (MB) removal with PDS-based advanced oxidation process. 2. Experimental Fig. 1 shows the synthesis route of the MMSS and the detailed procedure can be found in the Supporting Information. 3. Results and discussion The XRD analysis of the samples is shown in Fig. 2(a). According to the magnetite standard card (PDF#88–0315), the prepared materials (MMSS and magnetic SS) showed that six lattice planes of magnetite matched with pure magnetite phases at 2h
30:2 ð220Þ, 35:4 ð311Þ, 43:1 ð400Þ, 54:5 ð422Þ, 57:1 ð511Þ, and
62:6 ð440Þ. No diffraction peak corresponding to SiO2 was
2
S. Liang et al. / Materials Letters 262 (2020) 127190
Fig. 1. The synthesis route of the MMSS.
Fig. 2. XRD patterns (a), TEM images (b) of the prepared materials.
observed except the broad peaks around 2h23 which indicated the amorphous SiO2 support formation [19]. TEM images of the prepared materials are shown in Fig. 2. The diameter of the magnetic SS was determined about 300 nm, and the diameter of MMSS seemed as same as SS. The etching process
usually decreases the diameter of materials [22], but the protection by PVP allows the SS to retain their original size, while selective etching at the interior produces mesoporous structures. As shown in Fig. 2(b), the surface of MMSS showed mesoporous as desired, in agreement with the surface-protected etching strategy. The
S. Liang et al. / Materials Letters 262 (2020) 127190 Table 1 Characterization data of catalysts supported over silica materials. Material
Sbet (m2/g)
Vp (cm3/g)
Fe (wt. %)
SS MS Magnetic SS MMSS
18.7954 34.0255 31.2924 161.1357
0.0576 0.0862 0.1074 0.5591
– – 15.42 32.67
loading monodispersed magnetic particles, which the diameter of these particles was about 2–3 nm, can be easily seen on the surface of the two spheres. Obviously, there are many more particles loaded on the surface of MSS than SS. The isotherm shape of MMSS sample is type IV with H3-type hysteresis loop (Fig. S1), characteristic of mesoporous materials. The surface area and pore volume of MMSS was about 161.1357 m2/g and 0.5571 cm3/g, which was 8 and 10 times more than those of SS (Table 1). Fig. S2 shows pore size distribution profiles of different materials. No obvious pore size distribution peak could be observed for SS, MSS, and magnetic SS. The narrow pore size distribution centered at ca. 4 nm (between 2 and 60 nm) was found in MMSS, which is similar to the previous research [23]. In addition, the percentage of iron incorporated over the SS reached to 15.42 wt%, whereas it could be increased to 32.67 wt % for MMSS. Removal of MB via PDS-based oxidation used the prepared materials is investigated as shown in Fig. 3(a). PDS without any catalyst showed no activity for the degradation of MB. Bare Fe3O4 (synthesized according to the previous paper [24]) showed relatively low catalytic activity with only 5%. There is 10% of MB that can be adsorbed by SS, while it increased to 36.5% for MSS. About 60%, 72%, and 90% of the MB removed using the catalysts as Fe3O4, magnetic SS, and MMSS after 60 min, respectively. Mandal et al. synthesized the porous SiO2 spheres loaded with Fe2O3 nanoparticles by the sol-gel process and evaluated the photocatalytic oxidation ability of the materials. For MB removal, the highest removal efficiency was 88% after 240 min [25]. It can be found that the MMSS shows excellent catalytic activity which can be used in PDS-based oxidation for removal of organic waste from the solution.
3
To evaluate the stability and practical reusability of prepared catalysts, a five-run catalyst recycling test is performed (Fig. 3 (b)). In the experiments, the catalysts were magnetically fixed (using an external magnet) at the bottom of the flask (Fig. S3) and the liquid decanted. Then the catalysts were washed by deionized water three times. Fresh MB and PDS was added into the flask to proceed for the next run. For comparison, when the Fe3O4 nanoparticles were firstly used as a catalyst, the removal efficiency was 60%, but it decreased to 10% sharply after 5 cycles, indicating the occurrence of severe aggregation. The removal efficiency of magnetic SS was decreased from 72% to 60% and the removal efficiency of MMSS was not changed significantly (from 90% to 84%). It is obvious that the presence of MSS support is sufficient for stabilizing the catalytic magnetic nanoparticles by preventing their aggregation; at the same time, the prepared materials exhibited effective magnetic properties and were easily separated within a few minutes of the completion by using an external magnetic field, improving practical reusability.
4. Conclusion In summary, we developed a sol-gel/surface-protected etching/ incipient wetness impregnation route to synthesize the magnetic mesoporous silica spheres. The iron loadings of the prepared materials could reach to 32.67 wt% (2 times more than those of previous researches), and narrow pore size distribution centered at ca. 4 nm was found. 90% of MB can be degraded by the PDS-based advanced oxidation process catalyzed by MMSS, and the removal efficiency remained to more than 80% after 5 times cycle use. We thus believe that the strategy reported herein will stimulate chemists to explore its further promising applications, such as confined catalysis.
CRediT authorship contribution statement Sun Liang: Conceptualization, Project administration, Writing original draft. Hu Dehao: Data curation, Investigation. Zhang Ziyu: Investigation. Deng Xiaoyan: Writing - review & editing.
Fig. 3. (a) PDS-based oxidation of MB via different materials; (b) The cycles of MB degradation with different materials.
4
S. Liang et al. / Materials Letters 262 (2020) 127190
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. Acknowledgements We gratefully acknowledge the generous support provided by the National Natural Science Foundation of China (NO. 51408295), Key Research and Development Project of Shandong Province (NO. 2017GSF217013, NO. 2018GSF117007). Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi.org/10.1016/j.matlet.2019.127190. References [1] L.W. Zhao, K. Zheng, J.Y. Tong, J.Z. Jin, C. Shen, Catal. Lett. 149 (2019) 2606– 2613. [2] H. Hibst, E. Schwab, Mater. Sci. Tech-Lond. 190 (1994) 110–122. [3] M.A. Uddin, H. Tsuda, S.J. Wu, E. Sasaoka, Fuel 87 (2008) 451–459. [4] C.L. Wu, G.F. Zhu, J. Fan, J.J. Wang, RSC Adv. 6 (2016) 86428–86435. [5] L.J. Han, F.Y. Ge, G.H. Sun, X.J. Gao, H.G. Zheng, Dalton T. 48 (2019) 4650–4656. [6] F. Gazeau, C. Baravian, J.C. Bacri, R. Perzynski, Phys. Rev. E. 56 (1997) 614–618. [7] J.M. Perez, T.O. Loughin, F.J. Simeone, R. Weissleder, L. Josephson, J. Am. Chem. Soc. 124 (2002) 2856–2857.
[8] A.A. Kuznetsovac, I.F. Victor, N.A. Renat, N.L. Torshinab, O.A. Kuznetsov, J. Magn. Magn. Mater. 225 (2001) 95–100. [9] J.H. Lu, Q. Liu, Z.D. Xiong, Z.J. Xu, Y.J. Cai, Q. Wang, J. Chem. Technol. Biot. 92 (2017) 1601–1612. [10] G. Calleja, J.A. Melero, F. Martı0 nez, R. Molina, Water Res. 39 (2005) 1741. [11] Y.J. Ma, X.X. Jiang, Y.K. Lv, Chem-Asian J. 14 (2019) 3515–3530. [12] E. Nyankson, J. Adjasoo, J.K. Efavi, R. Amedalor, A. Yaya, G.P. Manu, K. Asare, N. A. Amartey, J. Chem-NY. 2019 (2019), https://doi.org/10.1155/2019/8090756. [13] H. Liu, S.H. Luo, D.B. Hu, X. Liu, Q. Wang, Z.Y. Wang, Y.L. Wang, L.J. Chang, Y.G. Liu, T.F. Yi, Y.H. Zhang, A.M. Hao, Appl. Surf. Sci. 495 (2019), https://doi.org/ 10.1016/j.apsusc.2019.143590. [14] F. Ebrahimi-Tazangi, S.H. Hekmatara, J. Seyed-Yazdi, J. Alloy. Compd. 809 (2019), https://doi.org/10.1016/j.jallcom.2019.151779. [15] K. Ueno, H. Negishi, T. Okuno, H. Tawarayama, S. Ishikawa, M. Miyamoto, S. Uemiya, Y. Oumi, Micropor. Mesopor. Mat. 289 (2019), https://doi.org/ 10.1016/j.micromeso.2019.109645. [16] J.S. Gao, S.C. Wu, F. Tan, H. Tian, J. Liu, G.Q.M. Lu, Prog. Nat. Sci-Mater. 28 (2018) 242–245. [17] S.A. Sorokina, N.V. Kuchkina, B.P. Lawson, I.Y. Krasnova, N.A. Nemygina, L.Z. Nikoshvili, V.N. Talanova, B.D. Stein, M. Pink, D.G. Morgan, E.M. Sulman, L.M. Bronstein, Z.B. Shifrina, Appl. Surf. Sci. 488 (2019) 865–873. [18] N. Crowther, F. Larachi, Appl. Catal. B: Environ. 46 (2003) 293–305. [19] J.A. Botas, J.A. Melero, F. Martinez, M.I. Pariente, Catal. Today 149 (2010) 334– 340. [20] J. Zong, Y.H. Zhu, X.L. Yang, C.Z. Li, J. Alloy. Compd. 509 (2011) 2970–2975. [21] N. Yuan, H. Cai, T. Liu, Q. Huang, X.L. Zhang, Adsorpt. Sci. Technol. 37 (2019) 333–348. [22] Q. Zhang, T.R. Zhang, J.P. Ge, Y.D. Yin, Nano Lett. 8 (2008) 2867–2871. [23] N. Yuan, Y.N. Sun, Z.W. Liu, B.H. Han, J. Porous. Mat. 25 (2018) 1715–1721. [24] T. Chen, Q.F. Wang, J.F. Lu, P. Bai, X.H. Guo, Sep. Purif. Technol. 231 (2020), https://doi.org/10.1016/j.seppur.2019.115930. [25] S. Mandal, S. Adhikari, S.Y. Pu, X.K. Wang, D.H. Kim, R.K. Patel, Chemosphere 234 (2019) 596–607.