The role of soot oxidation on the optimization of chitosan/soot aerogel beads for heavy metals and dyes adsorption
- 1Department of Chemical, Materials, and Production Engineering (INSTM Consortium-UdR Naples), University of Naples Federico II P.le Tecchio 80 80125 Naples Italy [email protected].
- 2Hephaestus Laboratory, School of Chemistry, Faculty of Sciences, Democritus University of Thrace GR-65404 Kavala Greece [email protected].
Abstract
The development of sustainable, shape-stable, and tunable adsorbents is a key challenge for water remediation, especially when pollutants differ in charge, structure, and adsorption mechanism. In this work, flame-generated soot particles were upcycled as carbonaceous fillers in crosslinked chitosan-based aerogel beads for the removal of two chemically distinct model contaminants: hexavalent chromium, Cr(vi), and Rhodamine 6G (R6G). Pristine and nitric-acid-oxidized soot were incorporated into the chitosan matrix at different ratios to investigate how the filler surface chemistry and the aerogel composition affect the adsorption performance. The resulting nanocomposite aerogels retained a porous bead morphology and displayed pH-dependent adsorption behavior. Cr(vi) removal was favored by chitosan-rich formulations under acidic conditions (highest experimental adsorption capacity around 75 mg g⁻¹ obtained with the CS : soot-ox 2 : 1 sample at 40 °C), consistently with the role of protonated chitosan sites in attracting anionic chromate species. In contrast, R6G uptake increased with the content of oxidized soot (highest experimental adsorption capacity around 100 mg g⁻¹ obtained with the CS : soot-ox 1 : 2 sample at 50 °C), highlighting the contribution of carbonaceous aromatic domains and oxygen-containing surface functionalities to dye adsorption. Kinetic and equilibrium adsorption measurements indicated heterogeneous adsorption behavior, well described by the Elovich and Toth models, respectively. Regeneration tests further indicated that beads containing oxidized soot preserved their removal ability over repeated cycles more effectively than neat chitosan, particularly for R6G. Overall, this study shows that soot oxidation and CS : soot ratio can be used as simple design parameters to tailor chitosan-based aerogel beads toward different classes of water pollutants, combining waste-carbon valorization with reusable biopolymer adsorbents.
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BibTeX
@article{ahmad2026role,
title = {{The role of soot oxidation on the optimization of chitosan/soot aerogel beads for heavy metals and dyes adsorption}},
author = {Shehryar Ahmad and Konstantinos N Maroulas and Mariano Sirignano and Martina Salzano de Luna and George Z Kyzas},
journal = {RSC advances},
year = {2026},
month = nov,
doi = {10.1039/d6ra09330b},
url = {https://europepmc.org/article/PMC/PMC13726629},
note = {CC BY},
}
RIS
TY - JOUR
TI - The role of soot oxidation on the optimization of chitosan/soot aerogel beads for heavy metals and dyes adsorption
AU - Shehryar Ahmad
AU - Konstantinos N Maroulas
AU - Mariano Sirignano
AU - Martina Salzano de Luna
AU - George Z Kyzas
PY - 2026
DA - 2026/11/02
JO - RSC advances
DO - 10.1039/d6ra09330b
UR - https://europepmc.org/article/PMC/PMC13726629
AB - The development of sustainable, shape-stable, and tunable adsorbents is a key challenge for water remediation, especially when pollutants differ in charge, structure, and adsorption mechanism. In this work, flame-generated soot particles were upcycled as carbonaceous fillers in crosslinked chitosan-based aerogel beads for the removal of two chemically distinct model contaminants: hexavalent chromium, Cr(vi), and Rhodamine 6G (R6G). Pristine and nitric-acid-oxidized soot were incorporated into the chitosan matrix at different ratios to investigate how the filler surface chemistry and the aerogel composition affect the adsorption performance. The resulting nanocomposite aerogels retained a porous bead morphology and displayed pH-dependent adsorption behavior. Cr(vi) removal was favored by chitosan-rich formulations under acidic conditions (highest experimental adsorption capacity around 75 mg g⁻¹ obtained with the CS : soot-ox 2 : 1 sample at 40 °C), consistently with the role of protonated chitosan sites in attracting anionic chromate species. In contrast, R6G uptake increased with the content of oxidized soot (highest experimental adsorption capacity around 100 mg g⁻¹ obtained with the CS : soot-ox 1 : 2 sample at 50 °C), highlighting the contribution of carbonaceous aromatic domains and oxygen-containing surface functionalities to dye adsorption. Kinetic and equilibrium adsorption measurements indicated heterogeneous adsorption behavior, well described by the Elovich and Toth models, respectively. Regeneration tests further indicated that beads containing oxidized soot preserved their removal ability over repeated cycles more effectively than neat chitosan, particularly for R6G. Overall, this study shows that soot oxidation and CS : soot ratio can be used as simple design parameters to tailor chitosan-based aerogel beads toward different classes of water pollutants, combining waste-carbon valorization with reusable biopolymer adsorbents.
SN - 2046-2069
ER -