Vol. 29 No. 3 (2026) Cover Image
Vol. 29 No. 3 (2026)

Published: September 20, 2026

Pages: 482-489

Articles

Experimental and Simulation Study on Removing Congo Red Dye from Neutral Wastewater Using Green Activated Carbon

Hind Thwaini 1 Ammar S. Abbas 1 Rasha Salman 1 Sarmad Al-Anssari 2
1 Department of Chemical Engineering, College of Engineering, University of Baghdad, Baghdad, Iraq.
2 Department of Petroleum Engineering, College of Engineering, Al-Naji University
History
  • Received: December 13, 2025
  • Revised: January 3, 2026
  • Accepted: January 30, 2026
  • Available Online: September 20, 2026
DOI

https://doi.org/10.29194/NJES.29030482

Abstract

The removal of Congo red dye from industrial wastewater before its discharge to the environment is a critical problem, as it is non-biodegradable, toxic, and carcinogenic. Activated carbon was synthesized from a suggested sustainable source (sugarcane waste) and used as an adsorbent for the dye. Isotherm adsorption models and adsorption kinetics were investigated, and a simulated adsorption column model was proposed and developed based on the modified general rate model. The batch results showed that the highest removal rate achieved was 87.1% of the initial dye concentration (30 mg/L). The Freundlich isotherm model best described the equilibrium data, as evidenced by the high correlation coefficient (0.9535). Meanwhile, the maximum adsorption capacity was found to be 149.25 mg/g using the Langmuir isotherm. Furthermore, the kinetic results indicate that the pseudo-second-order model accurately describes the concentration-time relationship.  A simulated maximum dynamic adsorption capacity of 0.096 mg/g was achieved at an optimal volumetric flow rate of 0.1 mL/min, with a dye concentration of 30 mg/L and a bed length of 39.69 cm. The continuous column efficiency increased with column length, reaching a maximum of 75% at 66.15 cm. Also, as the dye concentration increased, the column efficiency and dynamic adsorption capacity decreased. The study demonstrated an innovative approach to removing Congo red dye from its aqueous solution in a neutral medium using sustainably produced activated carbon derived from a sustainable source. A continuous removal process was simulated by developing a mathematical model based on adsorption curves and adsorption kinetics, which successfully described the adsorption process. This type of modeling, rather than relying on pre-existing equations, enables more efficient, scalable design.

Keywords

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