Adsorptive Sequestration of Zinc(II) Ions from Industrial Effluents Using Phosphorylated Cocoa Pod Husk Biomass

International Journal of Chemistry | Vol. 9, No. 12, December 2018 | pp. 81–88

DOI: 10.46882/2018/IJC/000122

Article Type: Original Research Paper

Title: Adsorptive Sequestration of Zinc(II) Ions from Industrial Effluents Using Phosphorylated Cocoa Pod Husk Biomass

Names of Authors: E. N. Chidi¹, J. A. M. Ahmed²*

Authors’ Affiliations:
¹Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria.
²Department of Chemical Engineering, Cairo University, Giza, Egypt.

Abstract: Heavy metal contamination of surface waters from metallurgical and electroplating industries requires the development of low-cost, chemically stable, and efficient agricultural waste remediation matrices. This study explores the adsorptive performance of a modified cocoa pod husk prepared via chemical functionalization with phosphoric acid (phosphorylated biomass). The surface chemistry and porosity of the adsorbent were studied using scanning electron microscopy (SEM) and FT-IR spectroscopy. The analytical data confirmed that phosphorylation successfully integrated phosphorus-rich phosphate functional groups onto the lignocellulosic biomass network. Batch extraction experiments evaluated parameters of solution pH, contact time, adsorbent dosage, and initial Zn(II) concentrations. Maximum Zn(II) removal occurred at an optimum pH of 6.0, using an equilibrium contact period of 90 minutes. Equilibrium data matched the Langmuir model closely, showing a maximum monolayer adsorption capacity of 48.55 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 constants showed that the adsorption process was spontaneous (delta G° = -4.18 kJ/mol) and endothermic, establishing phosphorylated biomass as an affordable choice for wastewater treatment plant designs.

Keywords: Cocoa pod husk; Chemical modification; Phosphorylation; Zinc removal; Adsorption kinetics; Chemisorption

Manuscript Timeline: Received: March 20, 2018; Revised: May 02, 2018; Accepted: June 15, 2018; Published: December 05, 2018.

Citation: Chidi, E. N., & Ahmed, J. A. M. (2018). Adsorptive Sequestration of Zinc(II) Ions from Industrial Effluents Using Phosphorylated Cocoa Pod Husk Biomass. International Journal of Chemistry, 9(12), 81–88.

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