The development of sustainable and efficient adsorbents for dye removal is essential in addressing industrial water pollution. This study focuses on the performance and mechanistic behavior of oxidized-nitrogen rich carbon sheets (NeO-) derived from azo-dyes under continuous-flow conditions, demonstrating their practical viability beyond laboratory-scale batch systems. The synthesized material, CR-C-700, was prepared by pyrolyzing Congo red at 700 °C under nitrogen atmosphere, resulting in a porous carbon structure enriched with NeO- functional groups.
Continuous-flow experiments were conducted using a filtration system comprising a peristaltic pump, a CR-C-700-coated filter paper, and a collection vessel. The results showed that the coated filter effectively removed approximately 85% of methyl blue (MB) from aqueous solutions, significantly outperforming plain filter paper, which achieved only about 23% removal. This high efficiency confirms the suitability of CR-C-700 for real-time, scalable wastewater treatment applications. The process operates without external pressure or complex equipment, highlighting its simplicity and potential for integration into decentralized or point-of-use water purification systems.
The adsorption mechanism remains consistent with batch studies: the primary interaction is chemisorption driven by electron-donor-acceptor (EDA) reactions between the electron-deficient MB molecule and the electron-rich NeO- sites on the carbon surface. At pH 5.5, MB exists as a zwitterion, enhancing hydrophobic interactions with the carbon matrix, thereby facilitating close proximity between the dye and active sites. This synergistic effect enables rapid and high-capacity uptake even under dynamic flow conditions.
XPS analysis post-adsorption revealed a significant decrease in the intensity and positive shift (~0.5 eV) of the NeO- peak, confirming the consumption of these sites during MB binding.105650-23-5 Synonym Additionally, the disappearance of the C=N stretching peak at 1482 cm⁻¹ further supports covalent interaction via EDA mechanisms.70-25-7 References These findings validate that the adsorption is not merely physical but involves irreversible chemical bonding, contributing to the material’s high retention capacity.
Notably, despite the low BET surface area (7.PMID:28613756 62 m²/g), the adsorption capacity under continuous flow remained remarkably high—exceeding many commercial materials. This underscores the dominance of chemical functionality over surface area in determining performance. Furthermore, the material’s recyclability was confirmed through thermal regeneration: after drying and calcination at 700 °C under N₂, the regenerated r-CR-C-700 retained full activity across three cycles, proving long-term stability and economic feasibility.
This work demonstrates that azo-dye-derived NeO- carbon sheets are not only effective in batch systems but also highly suitable for continuous operation, making them ideal candidates for industrial-scale wastewater treatment. Their ability to combine high adsorption capacity, fast kinetics, excellent reusability, and simple fabrication processes positions them as a next-generation solution for sustainable dye removal. By transforming hazardous azo-dyes into valuable adsorbents, this approach offers a dual benefit: environmental remediation and resource recovery.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com
