Novel Magnetic Chitosan@Slag/Fe-MNP Nanocomposites for Methyl Orange Removal and Circular Valorization
7 affiliations
- 1Materials Science and Nanotechnology Department, Faculty of Postgraduate Studies for Advanced Sciences, Beni-Suef University, Beni-Suef 62528, Egypt
- 2Department of Biology, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11623, Saudi Arabia
- 3Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia
- 4Minerals Beneficiation and Agglomeration Department, Central Metallurgical Research and Development Institute, El Tebbin, P.O. Box 87, Cairo 11421, Egypt
- 5Environmental Science and Industrial Development Department, Faculty of Postgraduate Studies for Advanced Science, Beni-Suef University, Beni-Suef 62511, Egypt
- 6Department of Pathology, College of Veterinary Medicine, King Faisal University, Al-Ahsa 31982, Saudi Arabia
- 7Chemistry Department, Faculty of Science, Beni-Suef University, Beni-Suef 62511, Egypt
Abstract
The pervasive contamination of water by synthetic dyes such as methyl orange (MO) presents a critical global challenge, compounded by the vast, underutilized volumes of industrial solid waste such as steel slag. This study addresses this dual problem via a circular-economy strategy that transforms waste into a functional material. A novel, magnetically separable adsorbent was developed via nickel-ion crosslinking of chitosan (CS) onto a composite of slag and slag-derived magnetic iron nanoparticles (Chitosan@Slag/Fe-MNPs). The material was characterized by FTIR, XRD, BET, and FESEM, and its adsorption performance was evaluated through systematic batch studies. The composite achieved a maximum monolayer adsorption capacity of 98.52 mg g−1 for MO at 25 °C, following the Elovich model and a Langmuir isotherm. MO removal is primarily driven by electrostatic attraction and surface complexation between the anionic dye and the protonated amine/metal-oxide sites of the composite, with pseudo-second-order-consistent kinetics indicating a possible partial contribution from surface-reaction-limited (chemisorption-type) steps. The composite showed high selectivity for anionic dyes at acidic pH, excellent magnetic recovery, and moderate reusability, retaining approximately 47% of its initial removal efficiency after four regeneration cycles. Beyond adsorption, the spent MO-saturated composite was successfully repurposed as an electrocatalyst for the urea oxidation reaction (UOR), achieving a current density of 234.30 mA cm−2 at 1.0 M urea, representing a result attributable to urea oxidation rather than MO redox activity, as confirmed by the urea-concentration-dependence of the response. This waste-to-adsorbent-to-electrocatalyst strategy supports a sequential remediation-to-energy conversion pathway consistent with circular economy principles.
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BibTeX
@article{mahgoub2026novel,
title = {{Novel Magnetic Chitosan@Slag/Fe-MNP Nanocomposites for Methyl Orange Removal and Circular Valorization}},
author = {Samar M. Mahgoub and Ahmed A. Allam and Hala Mohamed and Haifa E. Alfassam and Ahmed Abdelazim Khalifa and Amal Zaher and Asmaa F. Khafaga and Rehab Mahmoud},
journal = {Catalysts},
year = {2026},
month = oct,
doi = {10.3390/catal16110968},
url = {https://www.mdpi.com/2073-4344/16/11/968},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Novel Magnetic Chitosan@Slag/Fe-MNP Nanocomposites for Methyl Orange Removal and Circular Valorization
AU - Samar M. Mahgoub
AU - Ahmed A. Allam
AU - Hala Mohamed
AU - Haifa E. Alfassam
AU - Ahmed Abdelazim Khalifa
AU - Amal Zaher
AU - Asmaa F. Khafaga
AU - Rehab Mahmoud
PY - 2026
DA - 2026/10/30
JO - Catalysts
DO - 10.3390/catal16110968
UR - https://www.mdpi.com/2073-4344/16/11/968
AB - The pervasive contamination of water by synthetic dyes such as methyl orange (MO) presents a critical global challenge, compounded by the vast, underutilized volumes of industrial solid waste such as steel slag. This study addresses this dual problem via a circular-economy strategy that transforms waste into a functional material. A novel, magnetically separable adsorbent was developed via nickel-ion crosslinking of chitosan (CS) onto a composite of slag and slag-derived magnetic iron nanoparticles (Chitosan@Slag/Fe-MNPs). The material was characterized by FTIR, XRD, BET, and FESEM, and its adsorption performance was evaluated through systematic batch studies. The composite achieved a maximum monolayer adsorption capacity of 98.52 mg g−1 for MO at 25 °C, following the Elovich model and a Langmuir isotherm. MO removal is primarily driven by electrostatic attraction and surface complexation between the anionic dye and the protonated amine/metal-oxide sites of the composite, with pseudo-second-order-consistent kinetics indicating a possible partial contribution from surface-reaction-limited (chemisorption-type) steps. The composite showed high selectivity for anionic dyes at acidic pH, excellent magnetic recovery, and moderate reusability, retaining approximately 47% of its initial removal efficiency after four regeneration cycles. Beyond adsorption, the spent MO-saturated composite was successfully repurposed as an electrocatalyst for the urea oxidation reaction (UOR), achieving a current density of 234.30 mA cm−2 at 1.0 M urea, representing a result attributable to urea oxidation rather than MO redox activity, as confirmed by the urea-concentration-dependence of the response. This waste-to-adsorbent-to-electrocatalyst strategy supports a sequential remediation-to-energy conversion pathway consistent with circular economy principles.
SN - 2073-4344
ER -