Authors : Ndukwu D. E.; Ogukwe C. E.; Enenebeaku C. K.; Akalezi C. O.; Didacus D. E.; Chukwueke K. A.; Igbomezie M. C.

Volume/Issue : Volume 11 - 2026, Issue 7 - July

Google Scholar : https://tinyurl.com/mrt2any7

Scribd : https://tinyurl.com/yfkphxz8

DOI : https://doi.org/10.38124/ijisrt/26jul1844

Note : A published paper may take 4-5 working days from the publication date to appear in PlumX Metrics, Semantic Scholar, and ResearchGate.

Abstract : Chromium showed peak adsorption at pH 2 (67%), consistent with electrostatic attraction of chromate anions to protonated surface sites, while the four cationic metals performed best at pH 6. Unlike many lignocellulosic biosorbents, equilibrium data for all five metals including Cr(VI) conformed to the Langmuir isotherm model (R² = 0.957–0.998), indicating predominantly monolayer adsorption on a comparatively homogeneous set of binding sites across the tubular, lignocellulosic COS matrix. The PseudoSecond-Order kinetic model provided an excellent fit for all metals (R² = 0.997–0.999), with calculated equilibrium capacities closely matching experimental values, implicating chemisorption as the dominant rate-controlling mechanism. Thermodynamic analysis yielded negative ΔG° (−0.414 to −0.731 kJ/mol), negative ΔH°, and positive ΔS° values for all five metals, confirming that adsorption is spontaneous, mildly exothermic, and entropically driven. Scanning electron micrographs showed the characteristic rough tubular pre-adsorption texture becoming densely aggregated after metal loading, while FTIR spectroscopy identified hydroxyl, carboxylic, thiol, and aliphatic C–H groups as primary binding sites, with post-adsorption shifts in the O–H stretching region confirming metal–ligand complexation. These findings establish COS as a high-performing, and readily available biosorbent for metal water remediation.

Keywords : Biosorption; Corn Stalk; Zea Mays; Heavy Metals; Langmuir Isotherm; Pseudo-Second-Order Kinetics; Thermodynamics; Agricultural Waste; Wastewater Treatment.

References :

1. Adeyemo, A. A., Adeoye, I. O., & Bello, O. S. (2022). Thermodynamics of heavy metal biosorption onto agricultural waste-derived materials: a review. Environmental Monitoring and Assessment, 194(6), 415. https://doi.org/10.1007/s10661-022-10028-3
2. Akhtar, K., Mannan, H. A., & Bhanger, M. I. (2024). Equilibrium and mechanistic insights into chromium(VI) biosorption by agricultural waste biomass. Journal of Hazardous Materials Advances, 13, 100410. https://doi.org/10.1016/j.hazadv.2024.100410
3. Anastopoulos, I., Robalds, A., Tran, H. N., Mitrogiannis, D., Giannakoudakis, D. A., Hosseini-Bandegharaei, A., & Dotto, G. L. (2022). Removal of heavy metals by agricultural waste-derived biosorbents. Environmental Chemistry Letters, 17(1), 629–650. https://doi.org/10.1007/s10311-018-0818-7
4. Balali-Mood, M., Naseri, K., Tahergorabi, Z., Khazdair, M. R., & Sadeghi, M. (2021). Toxic mechanisms of five heavy metals: mercury, lead, chromium, cadmium, and arsenic. Frontiers in Pharmacology, 12, 643972. https://doi.org/10.3389/fphar.2021.643972
5. Bashir, A., Malik, L. A., Ahad, S., Manzoor, T., Bhat, M. A., Dar, G. N., & Pandith, A. H. (2023). Removal of heavy metal ions from aqueous solution by adsorption onto agricultural by-products: a review. Environmental Chemistry Letters, 21(2), 1059–1081. https://doi.org/10.1007/s10311-022-01540-y
6. Bilal, M., Ihsanullah, I., Shah, M. U. H., Almomani, F., & Adam, M. R. (2022). A review on environmental contamination of heavy metals and their toxic effects: source, fate and remediation approaches. Journal of Cleaner Production, 379, 134836. https://doi.org/10.1016/j.jclepro.2022.134836
7. Foo, K. Y., & Hameed, B. H. (2010). Insights into the modeling of adsorption isotherm systems. Chemical Engineering Journal, 156(1), 2–10. https://doi.org/10.1016/j.cej.2009.09.013
8. Genchi, G., Lauria, G., Catalano, A., Sinicropi, M. S., & Carocci, A. (2023). Nickel: human health effects, mechanisms, and toxicology. Toxics, 11(8), 690. https://doi.org/10.3390/toxics11080690
9. Ho, Y. S., & McKay, G. (1999). Pseudo-second order model for sorption processes. Process Biochemistry, 34(5), 451–465. https://doi.org/10.1016/S0032-9592(98)00112-5
10. Kong, H., Gao, X., Cao, M., Xu, X., Zhang, Q., & Liu, J. (2014). Characterization and adsorption capacity of corn stalk after different chemical pretreatments. Bioresources, 9(2), 2925–2940. https://doi.org/10.15376/biores.9.2.2925-2940
11. Lagergren, S. (1898). About the theory of so-called adsorption of soluble substances. Kungliga Svenska Vetenskapsakademiens Handlingar, 24(4), 1–39.
12. Liang, J., Li, X., Yu, Z., Zeng, G., Luo, Y., Jiang, L., Yang, Z., Qian, Y., & Wu, H. (2023). Amorphous MnO₂ modified biochar derived from corn stalk for efficient removal of heavy metal ions. ACS Sustainable Chemistry & Engineering, 5(6), 5049–5058. https://doi.org/10.1021/acssuschemeng.7b00542
13. Macena, M., Pereira, H., Cruz-Lopes, L., Grosche, L., & Esteves, B. (2023). Competitive adsorption of metal ions by lignocellulosic materials: a review. Separations, 12(3), 70. https://doi.org/10.3390/separations12030070
14. Michael-Igolima, U., Abbey, S. J., & Eze, V. O. (2023). A systematic review of biosorption techniques for heavy metal removal: surface modification and characterization. Heliyon, 9(11), e21586. https://doi.org/10.1016/j.heliyon.2023.e21586
15. Mitra, S., Chakraborty, A. J., Tareq, A. M., Emran, T. B., Nainu, F., Khusro, A., Idris, A. M., Khandaker, M. U., Osman, H., & Alhumaydhi, F. A. (2022). Impact of heavy metals on the environment and human health: novel therapeutic insights. Journal of King Saud University – Science, 34(3), 101865. https://doi.org/10.1016/j.jksus.2022.101865
16. Mthombeni, N. H., Ochieng, A., Onyango, M. S., & Aoyi, O. (2023). Adsorption isotherm and kinetics studies for the removal of heavy metals from aqueous solutions using corn stalk biomass. Water Practice and Technology, 18(2), 470–484. https://doi.org/10.2166/wpt.2023.027
17. Murphy, O. P., Vashishtha, M., Palanisamy, P., & Kumar, K. V. (2023). A review on the adsorption isotherms and design calculations for the optimization of adsorbent systems. ACS Omega, 8(19), 17407–17430. https://doi.org/10.1021/acsomega.3c00762
18. Onyancha, R. B., Ukhurebor, K. E., Aigbe, U. O., Kusuma, H. S., & Darmokoesoemo, H. (2024). Adsorptive removal of heavy metals from contaminated wastewater using agricultural waste biomass: kinetic and equilibrium considerations. Environmental Quality Management, 33(2), 89–104. https://doi.org/10.1002/tqem.22042
19. Raji, Z., Karim, A., Karam, A., & Khalloufi, S. (2023). Adsorption of heavy metals: mechanisms, kinetics, and applications of various adsorbents in wastewater remediation. Waste, 1(3), 775–805. https://doi.org/10.3390/waste1030045
20. Sen, T. K. (2023). Agricultural solid wastes based adsorbent materials in the remediation of heavy metal ions from water and wastewater by adsorption: a review. Molecules, 28(14), 5575. https://doi.org/10.3390/molecules28145575
21. Tran, H. N., You, S. J., & Chao, H. P. (2021). Kinetic and thermodynamic analysis of heavy metal biosorption onto agricultural residue. Adsorption Science & Technology, 2021, 5594375. https://doi.org/10.1155/2021/5594375
22. Vunain, E., Mishra, A. K., & Mamba, B. B. (2023). Dendrimers, mesoporous silicas and chitosan-based biosorbents for heavy metal removal: a review. Environmental Science and Pollution Research, 30(14), 11423–11458. https://doi.org/10.1007/s11356-022-19312-y
23. Wang, J., Wang, S., Vieira, B. J. C., Manjarrez Buenrostro, K. M., & Waite, C. A. (2022). Adsorption mechanisms and models for heavy metal removal using agricultural waste adsorbents: a review. Frontiers in Environmental Science, 10, 977822. https://doi.org/10.3389/fenvs.2022.977822
24. WHO. (2022). Guidelines for drinking-water quality (4th ed., incorporating the 2017 and 2022 addenda). World Health Organization.