Adsorptive Sequestration of Divalent Cadmium Ions Using Chemically Modified Wheat Straw Biomass

International Journal of Chemistry | Vol. 16, No. 11, November 2025 | pp. 81–88

DOI: 10.46882/2025/IJC/000205

Article Type: Original Research Paper

Title: Adsorptive Sequestration of Divalent Cadmium Ions Using Chemically Modified Wheat Straw Biomass

Names of Authors: E. N. Chidi¹, L. M. van der Westhuizen²*

Authors’ Affiliations:
¹Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria.
²Department of Chemical Engineering, Stellenbosch University, Stellenbosch, South Africa.

Abstract: Heavy metal contamination of surface waters by industrial manufacturing operations requires the development of low-cost, chemically stable, and highly active biosorption matrices. This investigation reports the adsorptive efficiency of a modified agricultural adsorbent derived from wheat straw prepared via chemical modification with citric acid under alkaline conditions. The chemical transformations and surface porous architectures of the matrix were examined through scanning electron microscopy (SEM) and FT-IR spectroscopy. The analytical data confirmed that the modification process successfully integrated carboxyl-rich active ligand networks across the cellulosic biomass strands. Batch extraction experiments evaluated parameters of solution pH, equilibrium contact time, adsorbent dosage, and initial Cd(II) concentrations. Maximum cadmium adsorption occurred at an optimum solution pH of 5.5, using an equilibrium contact period of 90 minutes. Equilibrium data matched the Langmuir model closely, showing a maximum monolayer adsorption capacity of 58.45 mg/g at 298 K. Sorption kinetics followed a pseudo-second-order model with a high correlation coefficient (R² > 0.998), proving that chemical surface complexation reactions controlled the mass transfer rates. Thermodynamic parameters confirmed process spontaneity and endothermic characteristics, highlighting this modified biomass as an affordable choice for industrial water treatment.

Keywords: Wheat straw; Citric acid modification; Cadmium removal; Adsorption kinetics; Chemisorption; Wastewater treatment

Manuscript Timeline: Received: June 02, 2024; Revised: July 15, 2024; Accepted: August 10, 2024; Published: November 09, 2025.

Citation: Chidi, E. N., & van der Westhuizen, L. M. (2025). Adsorptive Sequestration of Divalent Cadmium Ions Using Chemically Modified Wheat Straw Biomass. International Journal of Chemistry, 16(11), 81–88.

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