Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Department of Pharmacology and Toxicology, College of Pharmacy, University of Mosul, Mosul, Nineveh Province, Iraq

Mater H Mahnashi¹ , Samer S Abu-Alrub¹, Mohammad W Amer², Ali O Alqarni¹

¹Department of Pharmaceutical Chemistry, College of Pharmacy, Najran University, Najran 11001, Kingdom of Saudi Arabia; ²Department of Chemistry, School of Science, The University of Jordan, Amman 11942, Jordan.

For correspondence:- Mater Mahnashi Email: dr.maternahnashi@gmail.com

Accepted: 29 February 2021 Published: 31 March 2021

Citation: Mahnashi MH, Abu-Alrub SS, Amer MW, Alqarni AO. Department of Pharmacology and Toxicology, College of Pharmacy, University of Mosul, Mosul, Nineveh Province, Iraq. Trop J Pharm Res 2021; 20(3):585-592 doi: 10.4314/tjpr.v20i3.21

© 2021 The authors.
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Abstract

Purpose: To study the adsorption of dye (E120) from aqueous solution onto activated carbon.

Method: Factors influencing adsorption were examined and optimized. Three adsorption isotherm models (Langmuir, Freundlich and Temkin) were investigated. Agitation time was set at 72 hours, E120 dye concentration at 10 – 80 mg/L, pH at 7, temperature at 25 ^oC and mass at 125 mg.

Results: Adsorption of E120 dye onto activated carbon was enhanced by decreasing the mass of activated carbon, pH and ionic strength of the solution and by increasing the temperature. Under optimal conditions, the maximum adsorption capacity of activated carbon for E120 dye was 10.1 mg/g at 30 ^oC. The model parameters were 0.307 L/mg (K_L), 10.1 mg/g (q_m), 0.9491 (R²) for the Langmuir isotherm; 2.98 (n), 0.445 mg/g (K_f), and 0.6592 (R²) for Freundlich isotherm; and 4.59 mg/L (A), 2.23 J/mol (B), and 0.5914 (R²) for Temkin isotherm. Thermodynamic studies indicate that the adsorption of E120 dye onto activated carbon is an endothermic process with an adsorption enthalpy (ΔH) of 8.7 KJ/mol. The positive values for ΔG indicate that adsorption was non-spontaneous. The kinetic study of E120 dye adsorption showed that the adsorption process obeyed pseudo-second order kinetics.

Conclusion: Commercially available activated carbon, in terms of its physical and chemical characteristics, is a superior adsorbent to other adsorbents mentioned in the literature for removal of toxic dye E120 from aqueous solutions at a high removal capacity.

Keywords: Carmine dye E120, Activated carbon, Thermodynamics, Adsorption isotherm, Kinetic models