Malaysian Journal of Analytical Sciences, Vol 28 No 6 (2024): 1458 - 1481

ENHANCED CO₂ CAPTURE PERFORMANCE OF TITANIUM-MODIFIED SBA-15: SYNTHESIS, CHARACTERIZATION, AND FIXED-BED COLUMN ADSORPTION STUDY

(Prestasi Penjerapan CO₂ yang Dipertingkatkan bagi SBA-15 Terubahsuai Titanium: Sintesis, Pencirian dan Kajian Penjerapan Turus Lapisan Tetap)

Shalini Mahendran¹, Noorfatimah Yahaya², Bassim H. Hameed³, Dai Viet N. Vo⁴, Abdelkader Quakouak⁵, Norikazu Nishiyama⁶, Azam Taufik Mohd Din^1*

¹School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang, Malaysia

²Integrative Medicine Cluster, Advanced Medical and Dental Institute (AMDI), Universiti Sains Malaysia, 13200 Kepala Batas, Pulau Pinang, Malaysia

³Department of Chemical Engineering, College of Engineering, Qatar University, P.O. Box: 2713, Doha, Qatar,

⁴Institue of Environmental Technology and Sustainable Development, Nguyen Tat Thanh University, 298-300A Nguyen Tat Thanh, District 4, Ho Chi Minh City, 755414, Viet Nam

⁵Hydraulic and Civil Engineering Department, University of El Qued, PO Box 789, El Qued, 39000, Algeria

⁶Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan

^*Corresponding author: chazam@usm.my

Received: 17 July 2024; Accepted: 11 September 2024; Published: 29 December 2024

Abstract

Global warming is widely recognized as one of humanity's most pressing challenges. It is primarily driven by the greenhouse effect, whereby greenhouse gases, predominantly CO₂, trap heat close to the surface of the Earth. The accumulation of CO2 in high concentrations can have various negative effects on the environment, such as global warming, ocean acidification and reduced crop yields. Therefore, it is crucial to mitigate CO₂ emissions by employing carbon capture techniques. In this study, Pluronic P123 (a non-ionic surfactant) and TEOS (a silica source) were utilized in a sol-gel process to fabricate an ordered mesoporous silica, known as SBA-15, as catalyzed by hydrochloric acid (HCl). Subsequently, the synthesized adsorbent was modified with titanium (IV) isopropoxide (TIP) to enhance its physicochemical properties and adsorption capacity, which resulted in the Ti-SBA-15. This modified adsorbent was then evaluated using a fixed-bed column adsorption system to investigate the impacts of different factors, namely CO₂ adsorption temperature, inlet gas concentration, adsorbent loading, and gas flow rate. Physicochemical analyses, such as scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction analysis (XRD), Fourier transform infrared (FTIR), transmission electron microscopy (TEM), BET surface analysis, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) were conducted on the Ti-SBA-15. Experimental results were interpreted using the pseudo-first-order and pseudo-second-order kinetics, as well as the Avrami model, with the Avrami model showing the best fit. The Thomas and Yoon-Nelson models effectively predicted the CO₂ adsorption performance in the fixed-bed column. Thermodynamic modeling confirmed the exothermic and positively spontaneous nature of the reaction. Overall, Ti-SBA-15 demonstrated a promising ability as a low-cost, high-capacity CO₂ capture adsorbent, while maintaining its adsorption efficiency, even through multiple cycles of reuse.

Keywords: Ordered mesoporous silica, Ti-SBA-15, CO₂ adsorption, fixed-bed column adsorption, kinetics modeling

Abstrak

Pemanasan global diiktiraf secara meluas sebagai salah satu cabaran paling mendesak umat manusia. Ia terutamanya didorong oleh kesan rumah hijau, di mana gas rumah hijau, kebanyakannya CO₂, memerangkap haba dekat dengan permukaan Bumi. Pengumpulan CO₂ dalam kepekatan tinggi boleh menyebabkan kesan-kesan negatif ke atas persekitaran seperti pemanasan global, asidifikasi lautan dan mengurangkan hasil tanaman. Oleh itu, adalah penting untuk mengurangkan pelepasan CO₂ dengan menggunakan teknik penangkapan karbon. Dalam kajian ini, Pluronic P123 (surfaktan bukan ionik) dan TEOS (sumber silika) telah digunakan dalam proses sol-gel untuk menghasilkan silika mesoliang tersusun, dikenali sebagai SBA-15, seperti yang dimangkinkan oleh asid hidroklorik (HCl). Selepas itu, penjerap tersintesis telah diubah suai dengan titanium (IV) isopropoksida (TIP) untuk meningkatkan sifat fizikokimia dan kapasiti penjerapannya, yang menghasilkan Ti-SBA-15. Bahan penjerap yang diubah suai ini kemudiannya dinilai menggunakan sistem penjerapan turus lapisan tetap untuk menyiasat kesan faktor yang berbeza, iaitu suhu penjerapan CO₂, kepekatan gas masuk, pemuatan penjerap, dan kadar aliran gas. Analisis fizikokimia, seperti pengimbasan mikroskop elektron (SEM), spektroskopi sinar-X penyebaran tenaga (EDX), analisis pembelauan sinar-X (XRD), inframerah transformasi Fourier (FTIR), mikroskop elektron penghantaran (TEM), analisis permukaan BET, X -spektroskopi fotoelektron sinar (XPS), dan mikroskopi daya atom (AFM) telah dijalankan pada Ti-SBA-15. Keputusan eksperimen telah ditafsirkan menggunakan kinetik pseudo-tertib pertama dan pseudo-kedua, serta model Avrami, dengan model Avrami menunjukkan kesesuaian terbaik. Model Thomas dan Yoon-Nelson secara berkesan meramalkan prestasi penjerapan CO₂ dalam turus lapisan tetap. Pemodelan termodinamik mengesahkan sifat eksotermik dan spontan positif tindak balas. Secara keseluruhan, Ti-SBA-15 menunjukkan keupayaan yang menjanjikan sebagai penjerap tangkapan CO₂ berkos rendah dan berkapasiti tinggi, sambil mengekalkan kecekapan penjerapannya, walaupun melalui pelbagai kitaran penggunaan semula.

Kata kunci: Silika mesoliang tersusun, Ti-SBA-15, penjerapan CO₂, penjerapan turus lapisan tetap, pemodelan kinetik

References

1. IEA. (2019). CO₂ emisions from fuel combustion. IEA Publications, pp. 1-165.

2. Kabir, M., Habiba, U. E., Khan, W., Shah, A., Rahim, S., Rios-Escalante, P. R. D. los, Farooqi, Z. U. R., and Ali, L. (2023). Climate change due to increasing concentration of carbon dioxide and its impacts on environment in 21st century; a mini review. Journal of King Saud University - Science, 35(5): 102693.

3. Shivanna, K. R. (2022). Climate change and its impact on biodiversity and human welfare. Proceedings of the Indian National Science Academy, 88(2): 160-171.

4. Delbeke, J., Runge-Metzger, A., Slingenberg, Y., and Werksman, J. (2019). The Paris Agreement. Towards a Climate-Neutral Europe: Curbing the Trend, 24-45.

5. Nasiritousi, N., and Bäckstrand, K. (2019). International climate politics in the post-Paris Era. Nordic Economic Policy Review, 2018: 21-50.

6. Gür, T. M. (2022). Carbon dioxide emissions, capture, storage and utilization: Review of materials, processes and technologies. Progress in Energy and Combustion Science, 89: 100965.

7. Lobus, N. V., Knyazeva, M. A., Popova, A. F., and Kulikovskiy, M. S. (2023). Carbon footprint reduction and climate change mitigation: A review of the approaches, technologies, and implementation challenges. C-Journal of Carbon Research, 9(4): 120.

8. Bhavsar, A., Hingar, D., Ostwal, S., Thakkar, I., Jadeja, S., and Shah, M. (2023). The current scope and stand of carbon capture storage and utilization ∼ A comprehensive review. Case Studies in Chemical and Environmental Engineering, 8(7): 100368.

9. Khandaker, T., Hossain, M. S., Dhar, P. K., Rahman, S., Hossain, A., and Ahmed, M. B. (2020). Efficacies of Carbon-Based Adsorbents for Carbon Dioxide Capture. pp. 1-17.

10. Ghanbari, T., Abnisa, F., and Wan Daud, W. M. A. (2020). A review on production of metal organic frameworks (MOF) for CO₂ adsorption. Science of the Total Environment, 707: 135090.

11. Boer, D. G., Langerak, J., and Pescarmona, P. P. (2023). Zeolites as selective adsorbents for CO₂ separation. ACS Applied Energy Materials, 6(5): 2634-2656.

12. Amaraweera, S. M., Gunathilake, C. A., Gunawardene, O. H. P., Dassanayake, R. S., Cho, E. B., and Du, Y. (2023). Carbon capture using porous silica materials. Nanomaterials, 13(14): 2050.

13. Gkiliopoulos, D., Tsamesidis, I., Theocharidou, A., Pouroutzidou, G. K., Christodoulou, E., Stalika, E., Xanthopoulos, K., Bikiaris, D., Triantafyllidis, K., and Kontonasaki, E. (2022). SBA-15 mesoporous silica as delivery vehicle for rhbmp-2 bone morphogenic protein for dental applications. Nanomaterials, 12(5): 822.

14. Dziejarski, B., Serafin, J., Andersson, K., and Krzyżyńska, R. (2023). CO₂ capture materials: a review of current trends and future challenges. Materials Today Sustainability, 24: 100483.

15. Paulista, L. O., Ferreira, A. F. P., Castanheira, B., Ðolić, M. B., Martins, R. J. E., Boaventura, R. A. R., Vilar, V. J. P., and Silva, T. F. C. V. (2024). Solar-driven thermo-photocatalytic CO₂ methanation over a structured RuO2:TiO₂/SBA-15 nanocomposite at low temperature. Applied Catalysis B: Environmental, 340(5): 123232.

16. Ruchomski, L., Ozimek, J., Siedliska, K., Raftopoulos, K. N., and Pielichowski, K. (2023). Characterization of Ti/SBA-15 composites synthesized by chemical vapour deposition of organic titanium compounds. Crystals, 13(2): 1-15.

17. Guo, W., Hensen, E. J. M., Qi, W., Heeres, H. J., and Yue, J. (2022). Titanium phosphate grafted on mesoporous SBA-15 silica as a solid acid catalyst for the synthesis of 5-hydroxymethylfurfural from glucose. ACS Sustainable Chemistry and Engineering, 10(31): 10157-10168.

18. Wu, W., Bhattacharyya, K., Gray, K., and Weitz, E. (2013). Photoinduced reactions of surface-bound species on titania nanotubes and platinized titania nanotubes: An in situ FTIR study. Journal of Physical Chemistry C, 117(40): 20643-20655.

19. Almohammadi, G., O’Modhrain, C., Kelly, S., and Sullivan, J. A. (2020). Ti-doped SBA-15 catalysts used in phenol oxidation reactions. ACS Omega, 5(1): 791-798.

20. Koh, M. H., Haji Azaman, S. A., Hameed, B. H., and Mohd Din, A. T. (2017). Surface morphology and physicochemical properties of ordered mesoporous silica SBA-15 synthesized at low temperature. IOP Conference Series: Materials Science and Engineering, 206(1): 012056.

21. Li, L., Liu, D., Guo, Z., Liu, Y., and Chu, W. (2020). Improved facile synthesis of mesoporous SBA-15-CTA using citric acid under mild conditions. Journal of Solid State Chemistry, 282(10): 121079.

22. Mu, Y., Huang, X., Tang, Z., and Wang, Q. (2022). Ordered mesoporous TiO2/SBA-15 confined CexWy catalysts for selective catalytic reduction of NO using NH₃. New Journal of Chemistry, 203(10): 1-10.

23. Ibrahim, M., Hameed, B. H., Ouakouak, A., and Mohd Din, A. T. (2022). Effect of hydrothermal carbonization parameters and performance of carbon dioxide adsorption on pineapple peel waste biochar. Chemical Engineering and Technology, 2022: 1-9.

24. Azimov, F., Markova, I., Stefanova, V., and Sharipov, K. (2012). Synthesis and characterization of SBA-15 AND Ti-SBA-15 nanoporous materials for DME catalysts. Journal of the University of Chemical Technology and Metallurgy, 47(3): 333-340.

25. Makuch, E., and Wroblewska, A. (2013). Preparation of titanium silicate Ti-SBA-15 catalyst. Chemik, 67(9): 811-816.

26. Ganiyu, S. A., Ali, S. A., and Alhooshani, K. (2017). Simultaneous HDS of DBT and 4,6-DMDBT over single-pot Ti-SBA-15-NiMo catalysts: Influence of Si/Ti ratio on the structural properties, dispersion and catalytic activity. RSC Advances, 7(35): 21943–21952.

27. Gao, X., Yang, S., Hu, L., Cai, S., Wu, L., and Kawi, S. (2022). Carbonaceous materials as adsorbents for CO₂ capture: synthesis and modification. Carbon Capture Science and Technology, 3(2): 100039.

28. Esperanza Adrover, M., Pedernera, M., Bonne, M., Lebeau, B., Bucalá, V., and Gallo, L. (2020). Synthesis and characterization of mesoporous SBA-15 and SBA-16 as carriers to improve albendazole dissolution rate. Saudi Pharmaceutical Journal, 28(1): 15-24.

29. Iro, E. O. (2017). Synthesis, characterization and testing of Au / SBA-15 catalysts for elimination of volatile organic compounds by complete oxidation at low temperatures. Doctoral Thesis, Teesside University.

30. Zhai, Q. Z. (2019). Use of SBA-15 ordered nano mesoporous silica for removal of copper(II) from aqueous media: Studies on equilibrium, isotherm, kinetics and thermodynamics. Journal of Environmental Chemical Engineering, 7(3): 103069.

31. Almohammadi, G., O’Modhrain, C., Kelly, S., and Sullivan, J. A. (2020). Ti-Doped SBA-15 catalysts used in phenol oxidation reactions. ACS Omega, 5(1): 791-798.

32. Zhao, A., Samanta, A., Sarkar, P., and Gupta, R. (2013). Carbon dioxide adsorption on amine-impregnated mesoporous SBA-15 sorbents: Experimental and kinetics study. Industrial and Engineering Chemistry Research, 52(19): 6480-6491.

33. Ullah, R., Atilhan, M., Aparicio, S., Canlier, A., and Yavuz, C. T. (2015). Insights of CO₂ adsorption performance of amine impregnated mesoporous silica (SBA-15) at wide range pressure and temperature conditions. International Journal of Greenhouse Gas Control, 43: 22-32.

34. Shen, J., and Hess, C. (2020). High surface area VOX/TiO₂/SBA-15 model catalysts for ammonia SCR prepared by atomic layer deposition. Catalysts, 10(12): 1-25.

35. Popescu, T., Oktaviani Matei, C., Culita, D. C., Maraloiu, V. A., Rostas, A. M., Diamandescu, L., Iacob, N., Savopol, T., Ilas, M. C., Feder, M., Lupu, A. R., Iacoban, A. C., Vlaicu, I. D., and Moisescu, M. G. (2022). Facile synthesis of low toxicity iron oxide/TiO2 nanocomposites with hyperthermic and photo-oxidation properties. Scientific Reports, 12(1) : 1-23.

36. Ma, J., Li, L., Wang, H., Du, Y., Ma, J., Zhang, X., and Wang, Z. (2022). Carbon capture and storage: History and the road ahead. Engineering, 14: 33-43.

37. Koh, M. H., Haji Azaman, S. A., Hameed, B. H., and Mohd Din, A. T. (2017). Surface morphology and physicochemical properties of ordered mesoporous silica SBA-15 synthesized at low temperature. IOP Conference Series: Materials Science and Engineering, 206(1): 012056.

38. Ye, W., Lin, Z., Dong, B., Kang, J., Zheng, X., and Wang, X. (2011). Preparation and catalytic properties of Ti-SBA-15 mesoporous materials. Materials Sciences and Applications, 02(06): 661-668.

39. Zhang, G., Zhao, P., Hao, L., and Xu, Y. (2018). Amine-modified SBA-15(P): A promising adsorbent for CO₂ capture. Journal of CO₂ Utilization, 24(10): 22-33.

40. Ullah, R., Atilhan, M., Aparicio, S., Canlier, A., and Yavuz, C. T. (2015). Insights of CO₂ adsorption performance of amine impregnated mesoporous silica (SBA-15) at wide range pressure and temperature conditions. International Journal of Greenhouse Gas Control, 43: 22-32.

41. Zeitler, V. A., and Brown, C. A. (1957). The infrared spectra of some Ti-O-Si, Ti-O-Ti and Si-O-Si compounds. Journal of Physical Chemistry, 61(9): 1174-1177.

42. Yang, L., Jiang, Z., Lai, S., Jiang, C., and Zhong, H. (2014). Synthesis of titanium containing SBA-15 and its application for photocatalytic degradation of phenol. International Journal of Chemical Engineering, 2014: 691562.

43. Ren, J., Li, Z., Liu, S., Xing, Y., and Xie, K. (2008). Silica-titania mixed oxides: Si-O-Ti connectivity, coordination of titanium, and surface acidic properties. Catalysis Letters, 124(3–4): 185-194.

44. Krischok, S., Hofft, O., and Kempter, V. (2002). The chemisorption of H₂O and CO₂ on TiO₂ surfaces: studies with MIES and UPS (HeI/II). Surface Science, 510: 69-73.

45. Petrovic, B., Gorbounov, M., and Masoudi Soltani, S. (2021). Influence of surface modification on selective CO₂ adsorption: A technical review on mechanisms and methods. Microporous and Mesoporous Materials, 312(11): 110751.

46. Larina, L. L., Omelianovych, O., Dao, V. D., Pyo, K., Lee, D., and Choi, H. S. (2021). Energy band alignment at the heterointerface between a nanostructured TiO₂ layer and Au22(SG)18clusters: Relevance to metal-cluster-sensitized solar cells. Nanoscale, 13(1): 175-184.

47. Rajesh Kumar, B., and Subba Rao, T. (2012). AFM studies on surface morphology, topography and texture of nanostructured zinc aluminum oxide thin films. Digest Journal of Nanomaterials and Biostructures, 7(4): 1881-1889.

48. Noroozi Pesyan, N., Rezanejade Bardajee, G., Kashani, E., Mohammadi, M., and Batmani, H. (2020). Ni(II)-Schiff base/SBA-15: a nanostructure and reusable catalyst for one-pot three-component green synthesis of 3,4-dihydropyrano[3,2-c]chromene derivatives. Research on Chemical Intermediates, 46(1): 347-367.

49. Zauska, L., Bova, S., Benova, E., Bednarcik, J., Balaz, M., Zelenak, V., Hornebecq, V., and Almasi, M. (2021). Thermosensitive drug delivery system SBA-15-PEI for controlled release of nonsteroidal anti-inflammatory drug diclofenac sodium salt: A comparative study. Materials, 14(8): 1-25.

50. Bonenfant, D., Kharoune, M., Niquette, P., Mimeault, M., and Hausler, R. (2008). Advances in principal factors influencing carbon dioxide adsorption on zeolites. Science and Technology of Advanced Materials, 9(1): 013007.

51. Sanz-Pérez, E. S., Olivares-Marín, M., Arencibia, A., Sanz, R., Calleja, G., and Maroto-Valer, M. M. (2013). CO₂ adsorption performance of amino-functionalized SBA-15 under post-combustion conditions. International Journal of Greenhouse Gas Control, 17: 366-375.

52. Akpasi, S. O., and Isa, Y. M. (2022). Effect of operating variables on CO₂ adsorption capacity of activated carbon, kaolinite, and activated carbon – Kaolinite composite adsorbent. Water-Energy Nexus, 5(2022): 21-28.

53. Nwaoha, C., Supap, T., Idem, R., Saiwan, C., Tontiwachwuthikul, P., AL-Marri, M. J., and Benamor, A. (2017). Advancement and new perspectives of using formulated reactive amine blends for post-combustion carbon dioxide (CO₂) capture technologies. Petroleum, 3(1): 10-36.

54. Ayawei, N., Ebelegi, A. N., and Wankasi, D. (2017). Modelling and interpretation of adsorption isotherms. Journal of Chemistry, 2017: 3039817.

55. Gunawardene, O. H. P., Gunathilake, C. A., Vikrant, K., and Amaraweera, S. M. (2022). Carbon dioxide capture through physical and chemical adsorption using porous carbon materials: A review. Atmosphere, 13(3): 397.

56. Liao, P., Zhan, Z., Dai, J., Wu, X., Zhang, W., Wang, K., and Yuan, S. (2013). Adsorption of tetracycline and chloramphenicol in aqueous solutions by bamboo charcoal: A batch and fixed-bed column study. Chemical Engineering Journal, 228: 496-505.

57. Hu, X., Yang, X., Chen, L., Mei, M., Song, Z., Fei, Z., Dyson, P. J., and Qi, Z. (2022). Elucidating the transition between CO₂ physisorption and chemisorption in 1,2,4-triazolate ionic liquids at a molecular level. Chemical Engineering Journal, 435(P2): 134956.

58. Wu, W., Bhattacharyya, K., Gray, K., and Weitz, E. (2013). Role of the surface lewis acid and base sites in the adsorption of CO₂ on titania nanotubes and platinized titania nanotubes: An in-situ FT-IR study. Journal of Physical Chemistry C, 117(40): 20643-20655.

59. Gao, X., Yang, S., Hu, L., Cai, S., Wu, L., and Kawi, S. (2022). Carbonaceous materials as adsorbents for CO₂ capture: synthesis and modification. Carbon Capture Science and Technology, 3(2): 100039.

60. Gil, A. (2023). Classical and new insights into the methodology for characterizing adsorbents and metal catalysts by chemical adsorption. Catalysis Today, 423(12): 114016.

61. González-Barriuso, M., Gómez, L., Pesquera, C., Perdigón, A., González, F., Yedra, A., and Blanco, C. (2016). CO₂ capture at low temperature by nanoporous silica modified with amine groups. Chemical Engineering Transactions, 47: 181-186.

62. Zhang, G., Zhao, P., Hao, L., and Xu, Y. (2018). Amine-modified SBA-15(P): A promising adsorbent for CO2 capture. Journal of CO₂ Utilization, 24(10): 22-33.

63. Ho, Y. S., and McKay, G. (1999). Pseudo-second order model for sorption processes. Process Biochemistry.

64. Azizian, S. (2004). Kinetic models of sorption: A theoretical analysis. Journal of Colloid and Interface Science, 276(1): 47-52.

65. Zhao, A., Samanta, A., Sarkar, P., and Gupta, R. (2013). Carbon dioxide adsorption on amine-impregnated mesoporous SBA-15 sorbents: Experimental and kinetics study. Industrial and Engineering Chemistry Research, 52(19): 6480-6491.

66. Ibrahim, M., Hameed, B. H., Ouakouak, A., and Mohd Din, A. T. (2022). Effect of hydrothermal carbonization parameters and performance of carbon dioxide adsorption on pineapple peel waste biochar. Chemical Engineering and Technology, 2022: 1-9.

67. Aboelfetoh, E. F., Zain Elabedien, M. E., and Ebeid, E. Z. M. (2021). Effective treatment of industrial wastewater applying SBA-15 mesoporous silica modified with graphene oxide and hematite nanoparticles. Journal of Environmental Chemical Engineering, 9(1): 104817.

68. Hayati, B., Maleki, A., Najafi, F., Gharibi, F., McKay, G., Gupta, V. K., Harikaranahalli Puttaiah, S., and Marzban, N. (2018). Heavy metal adsorption using PAMAM/CNT nanocomposite from aqueous solution in batch and continuous fixed bed systems. Chemical Engineering Journal, 346(12): 258-270.

69. Rathour, R. K. S., Singh, H., Bhattacharya, J., and Mukherjee, A. (2022). Sand coated with graphene oxide-PVA matrix for aqueous Pb²⁺ adsorption: Insights from optimization and modeling of batch and continuous flow studies. Surfaces and Interfaces, 32(3): 102115.

70. Patel, H. (2019). Fixed-bed column adsorption study: a comprehensive review. Applied Water Science, 9(3): 1-17.

71. Gong, J. L., Zhang, Y. L., Jiang, Y., Zeng, G. M., Cui, Z. H., Liu, K., Deng, C. H., Niu, Q. Y., Deng, J. H., and Huan, S. Y. (2015). Continuous adsorption of Pb(II) and methylene blue by engineered graphite oxide coated sand in fixed-bed column. Applied Surface Science, 330(2): 148-157.

72. Luo, J., Sun, M., Ritt, C. L., Liu, X., Pei, Y., Crittenden, J. C., and Elimelech, M. (2019). Tuning Pb(II) adsorption from aqueous solutions on ultrathin iron oxychloride (FeoCl) nanosheets. Environmental Science and Technology, 2019: 7027.

73. Omri, A., and Benzina, M. (2014). Almond shell activated carbon: adsorbent and catalytic support in the phenol degradation. Environmental Monitoring and Assessment, 186: 3875-3890.

74. Aboelfetoh, E. F., Zain Elabedien, M. E., and Ebeid, E. Z. M. (2021). Effective treatment of industrial wastewater applying SBA-15 mesoporous silica modified with graphene oxide and hematite nanoparticles. Journal of Environmental Chemical Engineering, 9(1): 104817.

75. Rathour, R. K. S., Singh, H., Bhattacharya, J., and Mukherjee, A. (2022). Sand coated with graphene oxide-PVA matrix for aqueous Pb²⁺ adsorption: Insights from optimization and modeling of batch and continuous flow studies. Surfaces and Interfaces, 32(3): 102115.

76. Bin Jumah, M. N., Eid, M. H., AL-Huqail, A. A., Mohammad, M. A., Bin-Murdhi, N. S., Abu-Taweel, G. M., Altoom, N., Allam, A. A., and AbuKhadra, M. R. (2021). Enhanced remediation of As(V) and Hg(II) ions from aqueous environments using β-cyclodextrin/MCM-48 composite: Batch and column studies. Journal of Water Process Engineering, 42(5): 102118.

77. Li, X. D., and Zhai, Q. Z. (2021). Kinetics, isotherm and thermodynamic studies of S2 adsorption by (SBA-15)-Hg(II). Water Practice and Technology, 16(4):1475-1487.

78. Çakman, G., Ceylan, S., Topcu, Y., and Geyikçi, F. (2020). Investigation of ordered mesoporous carbon potential as CO₂ adsorbent. Global Nest Journal, 22(1): 102-108.

79. Liu, Y., and Yu, X. (2018). Carbon dioxide adsorption properties and adsorption/desorption kinetics of amine-functionalized KIT-6. Applied Energy, 211(12): 1080-1088.