Enhanced Dye Adsorption on Cold Plasma-Oxidized Multi-Walled Carbon Nanotubes: A Comparative Study.

Autor:	Skourti A; Laboratory of Cold Plasma and Advanced Techniques for Improving Environmental Systems, Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas (FORTH/ICE-HT), 26504 Patras, Greece.; Laboratory of Advanced Materials and Electrochemical Energy Conversion Devices, Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas (FORTH/ICE-HT), 26504 Patras, Greece., Giannoulia S; Laboratory of Cold Plasma and Advanced Techniques for Improving Environmental Systems, Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas (FORTH/ICE-HT), 26504 Patras, Greece., Daletou MK; Laboratory of Advanced Materials and Electrochemical Energy Conversion Devices, Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas (FORTH/ICE-HT), 26504 Patras, Greece., Aggelopoulos CA; Laboratory of Cold Plasma and Advanced Techniques for Improving Environmental Systems, Institute of Chemical Engineering Sciences, Foundation for Research and Technology Hellas (FORTH/ICE-HT), 26504 Patras, Greece.
Jazyk:	angličtina
Zdroj:	Nanomaterials (Basel, Switzerland) [Nanomaterials (Basel)] 2024 Aug 01; Vol. 14 (15). Date of Electronic Publication: 2024 Aug 01.
DOI:	10.3390/nano14151298
Abstrakt:	The oxidation of multi-walled carbon nanotubes (MWCNTs) using cold plasma was investigated for their subsequent use as adsorbents for the removal of dyes from aqueous solutions. The properties of MWCNTs after plasma modification and their adsorption capacities were compared with pristine and chemically oxidized nanotubes. The modification process employed a reactor where plasma was generated through dielectric barrier discharges (DBD) powered by high-voltage nanosecond pulses. Various modification conditions were examined, such as processing time and pulse voltage amplitude. The degree of oxidation and the impact on the chemistry and structure of the nanotubes was investigated through various physicochemical and morphological characterization techniques (XPS, BET, TEM, etc.). Maximum oxidation (O/C = 0.09 from O/C = 0.02 for pristine MWCNTs) was achieved after 60 min of nanopulsed-DBD plasma treatment. Subsequently, the modified nanotubes were used as adsorbents for the removal of the dye methylene blue (MB) from water. The adsorption experiments examined the effects of contact time between the adsorbent and MB, as well as the initial dye concentration in water. The plasma-modified nanotubes exhibited high MB removal efficiency, with adsorption capacity proportional to the degree of oxidation. Notably, their adsorption capacity significantly increased compared to both pristine and chemically oxidized MWCNTs (~54% and ~9%, respectively). Finally, the kinetics and mechanism of the adsorption process were studied, with experimental data fitting well to the pseudo-second-order kinetic model and the Langmuir isotherm model. This study underscores the potential of plasma technology as a low-cost and environmentally friendly approach for material modification and water purification. Competing Interests: The authors declare no conflicts of interest.
Databáze:	MEDLINE
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