Removal of Pb(II) ions from aqueous solutions by Brevibacillus agri-loaded clay: Kinetic, isotherm, and artificial neural network modeling

Öz

Brevibacillus agri was immobilized onto an abundant natural clay through a simple synthesis route to develop a novel and efficient adsorbent for the removal of Pb(II) ions from aqueous media. The adsorption behavior of Brevibacillus agri-loaded clay (BLC) was evaluated using batch experiments by investigating the effects of initial solution pH, BLC dosage, contact time, initial Pb(II) concentration, temperature, and the presence of foreign ions. The optimum conditions were determined to be an initial solution pH of 5.0 and a contact time of 120 min. Isotherm models were applied to elucidate the interactions between Pb(II) ions and BLC, while kinetic studies were conducted to evaluate the adsorption performance and underlying mechanisms. The maximum adsorption capacity of BLC was 65.4 mg g-1. Thermodynamic parameters revealed that Pb(II) adsorption on BLC was exothermic, feasible, and spontaneous at 25ºC. Artificial neural network (ANN) studies provided highly accurate predictions by modeling and confirmed the reliability and applicability of the model for Pb(II) removal in industrial applications. This study presents an innovative and sustainable approach for heavy metal removal, offering an effective solution applicable to environmental remediation processes.

Anahtar Kelimeler

• Brevibacillus agri loaded bentonite
• Pb(II) adsorption
• ANN
• isotherms
• kinetics

Brevibacillus agri Yüklü Kil ile Sulu Çözeltilerden Pb(II) İyonlarının Giderimi: Kinetik, İzoterm ve Yapay Sinir Ağı Modellemesi

Öz

Brevibacillus agri, sulu ortamlardan Pb(II) iyonlarının uzaklaştırılması amacıyla yeni ve etkili bir adsorban geliştirmek için basit bir sentez yöntemiyle bol bulunan doğal bir kil üzerine immobilize edilmiştir. Brevibacillus agri yüklü kilin (BLC) adsorpsiyon davranışı; başlangıç çözeltisi pH’ı, BLC dozu, temas süresi, başlangıç Pb(II) konsantrasyonu, sıcaklık ve yabancı iyonların varlığı gibi parametrelerin etkisi incelenerek kesikli deneylerle değerlendirilmiştir. Optimum koşullar, başlangıç çözeltisi pH’ının 5.0 ve temas süresinin 120 dakika olması şeklinde belirlenmiştir. Pb(II) iyonları ile BLC arasındaki etkileşimleri açıklamak için izoterm modelleri uygulanmış, adsorpsiyon performansını ve temel mekanizmaları değerlendirmek amacıyla kinetik çalışmalar gerçekleştirilmiştir. BLC’nin maksimum adsorpsiyon kapasitesi 65.4 mg g-1 olarak bulunmuştur. Termodinamik parametreler, Pb(II)’nin BLC üzerine adsorpsiyonunun ekzotermik, uygulanabilir ve 25°C’de kendiliğinden gerçekleşen bir süreç olduğunu göstermiştir. Yapay sinir ağı (ANN) çalışmaları, modelleme yoluyla oldukça yüksek doğrulukta tahminler sağlamış ve modelin endüstriyel uygulamalarda Pb(II) giderimi için güvenilirliğini ve uygulanabilirliğini doğrulamıştır. Bu çalışma, ağır metal giderimi için yenilikçi ve sürdürülebilir bir yaklaşım sunmakta olup, çevresel iyileştirme süreçlerinde uygulanabilir etkili bir çözüm önermektedir.

Anahtar Kelimeler

• Brevibacillus agri yüklü bentonit
• Pb(II) adsorpsiyonu
• yapay sinir ağı (ANN)
• izoterm
• kinetik

Kaynakça

1. P. Adhya, S.S. Chowdhury, S. De, T. Mondal, M. Kaushal, Polymer-grafted silica based hybrid macrobeads for Pb(II) and Cr(VI) removal from water, Sep Purif Technol, 358, 2025, 130279.
2. S. Kocaoba, M.D. Parlak, M. Arisoy, The use of Phanerochaete chrysosporium for modification of bentonite for preconcentration and determination of heavy metals, J Anal Sci Technol, 12, 2021, 24.
3. M.L. Sall, B. Fall, I. Diédhiou, E.H. Dièye, M. Lo, A.K.D. Diaw, D. Gningue-Sall, N. Raouafi, M. Fall, Toxicity and Electrochemical Detection of Lead, Cadmium and Nitrite Ions by Organic Conducting Polymers: A Review, Chem Afr, 3, 2020, 499-512.
4. J. Liu, X. Wang, S. Guo, A. Lu, H. Jiang, Preparation of nitrogen doped magnetic carbon aerogel by sol-gel method combined with in-situ carbonization for simultaneous removal of p-nitrophenol and Pb(II), Sep Purif Technol, 358, 2025, 130307.
5. Z. Zang, Z. Hu, Z. Li, Q. He, X. Chang, Synthesis, characterization and application of ethylenediamine-modified multiwalled carbon nanotubes for selective solid-phase extraction and preconcentration of metal ions, J Hazard Mater, 172, 2009, 958-963.
6. C. Wang, G. Lin, Y. Xi, X. Li, Z. Huang, S. Wang, J. Zhao, L. Zhang, Development of mercaptosuccinic anchored MOF through one-step preparation to enhance adsorption capacity and selectivity for Hg(II) and Pb(II), J Mol Liq, 317, 2020, 113896.
7. M.M. Rao, D.K. Ramana, K. Seshaiah, M.C. Wang, S.W.C. Chien, Removal of some metal ions by activated carbon prepared from Phaseolus aureus hulls, J Hazard Mater, 166, 2009, 1006-1013.
8. H. Saravaia, H. Gupta, P. Popat, P. Sodha, V. Kulshrestha, Single-step synthesis of magnesium-doped lithium manganese oxide nanosorbent and their polymer composite beads for selective heavy metal removal, ACS Appl Mater Interfaces, 10, 2018, 44059-44070.

9. Y.S. Ok, J.E. Yang, Y.S. Zhang, S.J. Kim, D.Y. Chung, Heavy metal adsorption by a formulated zeolite-Portland cement mixture, J Hazard Mater, 147, 2007, 91-96.
10. S. Cheng, Y. Liu, B. Xing, X. Qin, C. Zhang, H. Xia, Lead and cadmium clean removal from wastewater by sustainable biochar derived from poplar saw dust, J Clean Prod, 314, 2021, 128074.
11. J. Yin, C. Deng, Z. Yu, X. Wang, G. Xu, Effective Removal of Lead Ions from Aqueous Solution Using Nano Illite/Smectite Clay: Isotherm, Kinetic, and Thermodynamic Modeling of Adsorption, Water, 10, 2018, 210.
12. A. Maleki, Z. Hajizadeh, V. Sharifi, Z. Emdadi, A green, porous and eco-friendly magnetic geopolymer adsorbent for heavy metals removal from aqueous solutions, J Clean Prod, 215, 2019, 1233-1245.
13. K. Liang, X.Q. Wang, C.L. Chow, D. Lau, A review of geopolymer and its adsorption capacity with molecular insights: A promising adsorbent of heavy metal ions, J Environ Manage, 322, 2022, 116066.
14. L. Qin, L. Yan, J. Chen, T. Liu, H. Yu, B. Du, Enhanced removal of Pb2+, Cu2+, and Cd2+ by amino-functionalized magnetite/kaolin clay, Ind Eng Chem Res, 55, 2016, 7344-7354.
15. A. Ghahremani, M. Manteghian, H. Kazemzadeh, Removing lead from aqueous solution by activated carbon nanoparticle impregnated on lightweight expanded clay aggregate, J Environ Chem Eng, 9, 2021, 104478.
16. M. Zbair, Z. Anfar, H.A. Ahsaine, Reusable bentonite clay: modelling and optimization of hazardous lead and p-nitrophenol adsorption using a response surface methodology approach, RSC Adv, 9, 2019, 5756-5769.
17. U. Kadak, Multivariate fuzzy neural network interpolation operators and applications to image processing, Expert Syst Appl, 206, 2022, 117771.
18. G. Zhang, B.E. Patuwo, M.Y. Hu, Forecasting with artificial neural networks: The state of art, Int J Forecast, 14, 1998, 35-62.
19. E. Allahkarami, A. Igder, A. Fazlavi, B. Rezai, Prediction of Co(II) and Ni(II) ions removal from wastewater using artificial neural network and multiple regression models, Physicochem Probl Miner Process, 53, 2017, 1105-1118.
20. S.S. Fiyadh, S.M. Alardhi, M.A. Omar, M.M. Aljumaily, M.A.A. Saadi, S.S. Fayaed, S.N. Ahmed, A.D. Salman, A.H. Abdalsalm, N.M. Jabbar, A. El-Shafi, A comprehensive review on modelling the adsorption process for heavy metal removal from waste water using artificial neural network technique, Heliyon, 9, 2023, e15455.
21. A.Y. Camoglu, C. Duran, D. Ozdes, A. Nalcaoglu, K.I. Bektas, A.O. Belduz, Efficient extraction and determination of Au(III) ions from acid mine drainage and water samples using silica gel immobilized with Brevibacillus borstelensis, Anal Methods, 17, 2025, 539-551.
22. C.A. Mahan, J.A. Holcombe, Immobilization of algae cells on silica gel and their characterization for trace metal preconcentration, Anal Chem, 64, 1992, 1933-1939.
23. R.T. Kapoor, M. Rafatullah, A. Vashisht, M. Alam, M.R. Siddiqui, Removal of Microplastics by CTAB-Modified Magnetic Palm Kernel Shell Biochar: Insights into Reusability and Phytotoxicity Studies, ChemistrySelect, 10, 2025, e02030.
24. R.S. Hebbar, A.M. Isloor, B. Prabhu, Inamuddin, A.M. Asiri, A.F. Ismail, Removal of metal ions and humic acids through polyetherimide membrane with grafted bentonite clay, Sci Rep, 8, 2018, 4665.
25. A.S. Purnomo, S.R. Putra, H.S. Putro, A. Hamzah, N.A. Rohma, A.A. Rohmah, H.D. Rizqi, Asranudin, B.V. Tangahu, I.D.A.A. Warmadewanthi, K. Shimizu, The application of biosurfactant-producing bacteria immobilized in PVA/SA/bentonite bio-composite for hydrocarbon-contaminated soil bioremediation, RSC Adv, 13, 2023, 21163-21170.
26. I. Erkan, I. Alp, M.S. Çelik, Characterization of Organo-Bentonites Obtained from Different Linear-Chain Quaternary Alkylammmonium Salts, Clays Clay Miner, 58, 2010, 792-802.
27. H.B. Senturk, D. Ozdes, A. Gundogdu, C. Duran, M. Soylak, Removal of phenol from aqueous solutions by adsorption onto organomodified Tirebolu bentonite: Equilibrium, kinetic and thermodynamic study, J Hazard Mater, 172, 2009, 353-362.
28. D. Ramazanoğlu, P.K. Duran, İ. Şahin, S. Subaşı, M. Maraşli, Hydrothermally Synthesized Chitosan-SnO2-CuO Nanohybrids for Antimicrobial Surface Engineering of GFRC, BioNanoSci, 16, 2026, 242.
29. D. Ramazanoğlu, A. Subaşı, A.B. Musatat, A. Demir, S. Subaşı, M. Maraşlı, Dielectric property enhancement of glass fiber-reinforced concrete via TiO2 nanocomposites, Structures, 79, 2025, 109444.
30. X. Huang, H. Zhao, G. Zhang, J. Li, Y. Yang, P. Ji, Potential of removing Cd(II) and Pb(II) from contaminated water using a newly modified fly ash, Chemosphere, 242, 2020, 125148.
31. A. Saeed, M. Iqbal, M.W. Akhtar, Removal and recovery of lead(II) from single and multimetal (Cd, Cu, Ni, Zn) solutions by crop milling waste (black gram husk), J Hazard Mater, 117, 2005, 65-73.
32. M. Feng, Z. Shi, Y. Tong, K. Zhang, Facile Synthesis of Zeolite NaX from Natural Attapulgite Clay for Pb2+ Adsorption, Chemistry, 6, 2024, 1217-1229.
33. S. Lagergren, About the theory of so-called adsorption of soluble substance, Kungl Svenska Vetenskapsakad Handl, 24, 1898, 1-39.
34. Y.S. Ho, G. McKay, Kinetic models for the sorption of dye from aqueous solution by wood, Process Saf Environ Prot, 76, 1998, 183-191.
35. W.J. Weber Jr, J.C. Morriss, Kinetics of adsorption on carbon from solution, J Sanit Eng Div, 89, 1963, 31-60.
36. A. Taha, A.H.E. Moustafa, H. Abdel-Rahman, M. Abd El-Hameed, Comperative biosorption study of Hg(II) using raw and chemically activated almond shell, Adsorpt Sci Technol, 36, 2018, 521-548.
37. P.S. Kumar, Adsorption of lead(II) ions from simulated wastewater using natural waste: A kinetic, thermodynamic and equilibrium study, Environ Prog Sustain Energy, 33, 2014, 55-64.
38. M. Constantin, I. Asmarandei, V. Harabagiu, L. Ghimici, P. Ascenzi, G. Fundueanu, Removal of anionic dyes from aqueous solutions by an ion-exchanger based on pullulan microspheres, Carbohydr Polym, 91, 2013, 74-84.
39. V.K. Garg, R. Kumar, R. Gupta, Removal of malachite green dye from aqueous solution by adsorption using agro-industry waste: a case study of Prosopis cineraria, Dyes Pigments, 62, 2004, 1-10.
40. P. Sharma, R. Kaur, C. Baskar, W.J. Chung, Removal of methylene blue from aqueous waste using rice husk and rice husk ash, Desalination, 259, 2010, 249-257.
41. A.K. Gautam, Markandeya, N.B. Singh, S.P. Shukla, D. Mohan, Lead removal efficiency of various natural adsorbents (Moringa oleifera, Prosopis juliflora, peanut shell) from textile wastewater, SN Appl Sci, 2, 2020, 288.
42. I. Langmuir, The adsorption of gases on plane surfaces of glass, mica and platinum, J Am Chem Soc, 40, 1918, 1361-1403.
43. H.M.F. Freundlich, Uber die adsorption in lösungen, Z Phys Chem, 57, 1906, 385-470.
44. M.M. Dubinin, L.V. Radushkevich, Equation of the characteristic curve of activated charcoal, Proc Acad Sci USSR Phys Chem Sect, 55, 1947, 331-333.
45. K.R. Hall, L.C. Eagleton, A. Acrivos, T. Vermeulen, Pore and Solid-Diffusion Kinetics in Fixed-Bed Adsorption Under Constant-Pattern Conditions, Ind Eng Chem Fundam, 5, 1966, 212-223.
46. F. Helfferich, Ion Exchange, 1962, New York, McGraw-Hill.
47. J.M. Smith, H.C. Van Ness, Introduction to chemical engineering thermodynamics (4th Edition), 1987, Singapore, McGraw-Hill.
48. M.C. Qhubu, B. Methula, T. Xaba, M. Moyo, V.E. Pakade, Iron-Zinc Impregnated Biochar Composite as a Promising Adsorbent for Toxic Hexavalent Chromium Remediation: Kinetics, Isotherms and Thermodynamics, Chem Afr, 5, 2022, 1797-1807.
49. A.L. Obsa, N.T. Shibeshi, E. Mulugeta, G.A. Workeneh, Bentonite/amino-functionalized cellulose composite as effective adsorbent for removal of lead: Kinetic and isotherm studies, Results Eng, 21, 2024, 101756.