Process Optimization and Equilibrium, Thermodynamic, and Kinetic Modeling of Toxic Congo Red Dye Adsorption from Aqueous Solutions Using a Copper Ferrite Nanocomposite Adsorbent

Vairavel Parimelazhagan; Akhil Chinta; Gaurav Ganesh Shetty; Srinivasulu Maddasani; Wei-Lung Tseng; Jayashree Ethiraj; Ganeshraja Ayyakannu Sundaram; Alagarsamy Santhana Krishna Kumar

doi:10.3390/molecules29020418

Process Optimization and Equilibrium, Thermodynamic, and Kinetic Modeling of Toxic Congo Red Dye Adsorption from Aqueous Solutions Using a Copper Ferrite Nanocomposite Adsorbent

Molecules. 2024 Jan 15;29(2):418. doi: 10.3390/molecules29020418.

Authors

Vairavel Parimelazhagan¹, Akhil Chinta¹, Gaurav Ganesh Shetty¹, Srinivasulu Maddasani², Wei-Lung Tseng^{3

4}, Jayashree Ethiraj^{5

6}, Ganeshraja Ayyakannu Sundaram⁷, Alagarsamy Santhana Krishna Kumar^{3

8}

Affiliations

¹ Department of Chemical Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education (MAHE), Manipal 576104, Karnataka State, India.
² Department of Chemistry, Manipal Institute of Technology, Manipal Academy of Higher Education (MAHE), Manipal 576104, Karnataka State, India.
³ Department of Chemistry, National Sun Yat-sen University, No. 70, Lienhai Road, Gushan District, Kaohsiung City 80424, Taiwan.
⁴ School of Pharmacy, Kaohsiung Medical University, No. 100, Shiquan 1st Road, Sanmin District, Kaohsiung City 80708, Taiwan.
⁵ Department of Physics, School of Arts and Science, AVIT Campus, Vinayaka Mission's Research Foundation, Chennai 603104, Tamil Nadu State, India.
⁶ CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600025, Tamil Nadu State, India.
⁷ Department of Research Analytics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Poonamallee High Road, Chennai 600077, Tamil Nadu State, India.
⁸ Faculty of Geology, Geophysics and Environmental Protection, Akademia Gorniczo-Hutnicza (AGH) University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow, Poland.

PMID: 38257330
DOI: 10.3390/molecules29020418

Abstract

In the present investigation of copper ferrite, a CuFe₂O₄ nanocomposite adsorbent was synthesized using the sol-gel method, and its relevance in the adsorptive elimination of the toxic Congo red (CR) aqueous phase was examined. A variety of structural methods were used to analyze the CuFe₂O₄ nanocomposite; the as-synthesized nanocomposite had agglomerated clusters with a porous, irregular, rough surface that could be seen using FE-SEM, and it also contained carbon (23.47%), oxygen (44.31%), copper (10.21%), and iron (22.01%) in its elemental composition by weight. Experiments were designed to achieve the most optimized system through the utilization of a central composite design (CCD). The highest uptake of CR dye at equilibrium occurred when the initial pH value was 5.5, the adsorbate concentration was 125 mg/L, and the adsorbent dosage was 3.5 g/L. Kinetic studies were conducted, and they showed that the adsorption process followed a pseudo-second-order (PSO) model (regression coefficient, R² = 0.9998), suggesting a chemisorption mechanism, and the overall reaction rate was governed by both the film and pore diffusion of adsorbate molecules. The process through which dye molecules were taken up onto the particle surface revealed interactions involving electrostatic forces, hydrogen bonding, and pore filling. According to isotherm studies, the equilibrium data exhibited strong agreement with the Langmuir model (R² = 0.9989), demonstrating a maximum monolayer adsorption capacity (q_max) of 64.72 mg/g at pH 6 and 302 K. Considering the obtained negative ΔG and positive ΔH_ads and ΔS_ads values across all tested temperatures in the thermodynamic investigations, it was confirmed that the adsorption process was characterized as endothermic, spontaneous, and feasible, with an increased level of randomness. The CuFe₂O₄ adsorbent developed in this study is anticipated to find extensive application in effluent treatment, owing to its excellent reusability and remarkable capability to effectively remove CR in comparison to other adsorbents.

Keywords: Congo red dye adsorption; adsorption kinetics; copper ferrite nanocomposite; equilibrium isotherms; response surface methodology; reusability; sol–gel synthesis; thermodynamics.