ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Application of greenness assessment tools for sustainable methyl orange dye removal using MWCNT/MnFe₂O₄ nanocomposite: a comprehensive study

Ruba Fahmi Abbas, Rasha Wali Mohi Alsaedi, Shurooq Abdulfattah Hasan, and Mohammed Jasim M. Hassan

Chemistry Department, College of Science, Mustansiriyah University, Baghdad, Iraq

E-mail: rubaf1983@uomustansiriyah.edu.iq

Received: 13 September 2024  Accepted: 12 June 2025

Abstract:

Methyl orange azo dye (M.O) is classified as water pollutant detrimental to humans, organism’s entities, aquatic plants, and aquatic fauna. M.O dye was effectively removed from water by MWCNT/MnFe₂O₄. Synthesis of MWCNT/MnFe₂O₄ nanocomposite was achieved via a simple co-precipitation method and characterized by XRD, EDX, and FESEM techniques. The effects of the variables such as initial M.O dye concentration (4–12 mg/L), pH of solution (2.5–10), temperature (298 K–313 K), and contact time (5–25 min) were examined with fixed dosage of (30 mg/10 mL) MWCNT/MnFe₂O₄. The experimental data were compared linear and nonlinear adsorption kinetics and isotherms to estimate the best fit of the equilibrium data. Error functions were applied to assess deviations between experimental and predicted values. The values of error functions were lower for both nonlinear PFO and PSO than linear form. Similarly, the error function values were lower for the nonlinear isotherm forms of Langmuir and Temkin compared to their linear forms, while the linear form of the Freundlich isotherm provided a better fit. A UV–Visible spectrophotometry assay method was developed and validated. MWCNT/MnFe₂O₄ is an eco-friendly and economical nanocomposite that can be recovered and reused using an external magnetic field. In this work, four new greenness assessment tools, GAPI, ComplexGAPI, ComplexMoGAPI, and BAGI were employed to effectively evaluate the suitability of the proposed analytical UV–Visible spectrophotometer method. These tools showed good green scores. GAPI tool exhibited eight green colors, while both ComplexGAPI and ComplexMoGAPI tools displayed 16 green colors, showing a high yield of 93.75% and low E-factor parameter value of 0.067, signifying minimal waste generation from reagents and side products. BAGI tool displayed a blue scale color, and score of 75.0 indicates excellent applicability of this adsorption procedure.

Graphical Abstract

Keywords: MWCNT/MnFe2O4; Methyl orange; ComplexMoGAPI; Greenness assessment; PSO

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04207-0

Chemical Papers 79 (10) 6607–6625 (2025)