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Electrochemical sensor based on green-synthesized iron oxide nanomaterial modified carbon paste electrode for Congo red electroanalysis and capacitance performance

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journal contribution
posted on 22.09.2022, 11:40 authored by Mary Sieugaing Tamwa, Jacques Romain Njimou, Bruno Boniface Nguelo, Charles Péguy Nanseu-Njiki, Ephraim Vunain, Bankim Chandra Tripathy, Emmanuel Ngameni

In this study, a facile protocol was used to convert non-valuable orange peels (OP) waste into a new sensing iron oxide orange-peel nanomaterial (FeOP). The presence of iron oxide nanoparticles in the modified OP was confirmed by physicochemical characterisations including Fourier-transform infrared spectroscopy, X-ray diffractometry, thermogravimetry, and scanning electron microscopy-energy dispersive X-ray. FeOP was used to modify a carbon paste electrode (CPE/FeOP) which displayed a significant increase in specific capacitance of 2939 F.g−1, two folds higher than that obtained with CPE at 10 m.s−1 in NaCl. The electroanalysis of Congo red (CR) in aqueous solutions using CPE/FeOP displayed detection limits of 2.8 × 10−7 mol.L−1 and 8.2 × 10−7 mol.L−1 respectively in deionised and spring waters, in the linear range of 5 to 55 µM. CPE/FeOP electrochemical sensor is therefore suitable for the determination of Congo red in wastewater.


This work was supported by the ISP through the grant offered to the African Network of Electroanalytical Chemists (ANEC); and the Indian National Science Academy through the JRD-TATA Fellowship; The authors are grateful for the Fulbright grant PS0030505 and the SEM MRI award Number: 1827176.