Equilibrium Isotherm Studies of Bromocresol Green Dye Removal from Wastewater Using Modified Coconut Shell Adsorbent

Abstract

This study examines the synthesis and application of modified coconut shell (MCNS) adsorbent for the removal of Bromocresol Green Dye (BCGD) from wastewater as an alternative to cost intensive wastewater treatment techniques. The adsorbent was characterized for physicochemical properties, and also by utilizing Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectrometer (FTIR) and Energy Dispersive X-ray spectrometer (EDX). The effects of adsorbent dosage on percentage dye recovery were assessed. Isotherm data were fitted to isotherm models such as Brouers Weron Sotolongo-Coasta (BWS), Freundlich, Jovanovich, Langmuir and Sips by employing non-linear model equations. The outcomes uncovered that the biomass has a pH (7.10 0.101), moisture content (3.50 0.110) %, volatile matter, (9.00 0.012) %, ash content (15.70 0.111) %, fixed carbon (71.80 0.001) %, bulk density (0.769 0.000) g/cm3, surface area (1120.00 0.000) m2/g and particle size (300.00 0.000) µm. The adsorbent has high carbon content and a well-developed pore structure. The adsorbent possesses high carbon content and a well-developed pore structure. The adsorbent percentage dye removal efficiency (% R) was dosage-dependent. The adsorbent has maximum percentage dye removal of 95.5 % at the optimum dosage (0.4 g). The equilibrium isotherm data that fairly described the removal of BCGD from wastewater was Freundlich isotherm model with coefficient of determination (R2 = 0.8999), which suggests that the dye removal from the wastewater was multilayer adsorption on the heterogeneous surface which is more of physiosorption rather than chemisorption. By and large, the preparedadsorbent from MCNS was proficient, eco-friendly and economical in the treatment ofdye contaminated wastewater, ensuring legislative complianceand ease water reuse.

Introduction

Textile and industrial dyes pose a significant environmental threat due to their toxicity and persistence in ecosystems. Industries such as textile, paper, plastics, and pharmaceuticals release dye-containing effluents that harm aquatic life and human health, causing issues like skin irritation and cancer. Bromocresol green dye (BCGD), a water-soluble triarylmethane dye with reactive bromine atoms, is one such pollutant.

Coconut shell (CNS), a durable and porous natural material composed mainly of lignin, cellulose, and other organic compounds, is investigated as a low-cost adsorbent for dye removal. Modified coconut shell (MCNS) is prepared by chemical treatment with phosphoric acid and thermal activation to enhance adsorption properties.

The study involves characterizing MCNS using techniques such as Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) to identify surface morphology and functional groups. Physicochemical properties like pH, moisture content, ash content, surface area, and particle size are measured and found to meet standard quality thresholds.

Batch adsorption experiments assess the removal efficiency of BCGD dye by MCNS under varying conditions. Several adsorption isotherm models (Brouers Weron Sotolongo, Freundlich, Jovanovich, Langmuir, and Sips) are applied using software tools to analyze equilibrium data and optimize adsorption parameters.

Results indicate that MCNS has significant adsorption capacity due to its functional groups and porous structure, making it a promising adsorbent for removing hazardous dyes from industrial effluents, thus contributing to environmental protection and sustainable waste management.

Conclusion

The prepared adsorbent possesses high carbon contents, low inorganic contents, high surface area, and heterogenous pore structures that make it a viable precursor for the removal of BCGD from aqueous solution. The dye removal from the wastewater was dosage-dependent with maximum removal efficiency of 95.5 % at optimum dosage (0.4). The isotherm model that fairly described the removal of BCGD from the wastewater was Freundlich isotherm model with a coefficient of determination of (R2 = 0.8999). The prepared adsorbent stands efficient in remediating the dye polluted wastewater to serviceable status.

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Copyright © 2025 Abidemi Anthony Sangoremi . This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.