Development of hydrogels based on xylan and poly (acrylic acid) for melamine adsorption in batch and continuous mode: experimental design, kinetics, isotherms, recyclability, and fixed-bed column

Two hydrogels were synthesized, characterized, and applied as alternative materials to remove melamine (MEL) from aqueous media by adsorption. For the first time, a complete study of MEL adsorption is presented, including optimization, kinetics, isotherm, reuse, and column studies with these new mat...
Ausführliche Beschreibung

Two hydrogels were synthesized, characterized, and applied as alternative materials to remove melamine (MEL) from aqueous media by adsorption. For the first time, a complete study of MEL adsorption is presented, including optimization, kinetics, isotherm, reuse, and column studies with these new materials. One hydrogel is based on xylan and poly (acrylic acid) and was named HXy, and the other is based on the same components functionalized with activated carbon and was named HXy-AC. The materials were synthesized by free radical polymerization and characterized by FTIR, XRD, TGA, DSC, SEM, zeta potential, point of zero charge, $ N_{2} $ adsorption isotherms (BET), helium gas pycnometry, Archimedes method, swelling analysis, and stability tests. The characterization results confirmed the intended synthesis and showed the thermal, morphological, textural, structural, and compositional profile, as well as the adsorption characteristics of the materials. The adsorption studies in batch process included experimental design, kinetics, isotherms, and recyclability, and in continuous mode, the studies included fixed-bed column experiments. The full factorial design showed that adsorbent dosage, pH, and ionic strength are significant for adsorption capacity and removal percentage responses. Doehlert design enabled the definition of the values of adsorbent dosage and pH that were most suitable for MEL adsorption into the materials, indicating the optimal adsorption conditions. The kinetics were well described by the pseudo-first-order model, with R2 above 0.9920 for both materials at all concentrations tested. The isotherm obeyed the Langmuir model, with R2 above 0.9939 for both materials at all temperatures tested. Equilibrium was attained at 180 min, and the maximum experimental adsorption capacity was up to 132.46 and 118.96 mg $ g^{−1} $ at pH 7, with adsorbent dosage of 0.5 g $ L^{−1} $, and 298 K for HXy and HXy-AC, respectively. Furthermore, HXy and HXy-AC materials maintained about 58 and 70% of their initial adsorption capacity at the end of five adsorption/desorption cycles, respectively. Breakthrough curves were described by the Yan model and presented a maximum adsorption capacity of 30.2 and 30.4 mg $ g^{−1} $, treating 3.4 and 6.1 L of influent until the breakthrough point of 0.5 mg $ L^{−1} $ with HXy-AC using 2.0 and 4.0 g of material, respectively. These findings show that the hydrogels produced present the potential to be applied in the adsorption of basic molecules, such as MEL. Graphical abstract Ausführliche Beschreibung

Autor*in:	Fröhlich, Andressa Cristiana [verfasserIn] Mazur, Luciana Prazeres da Silva, Adriano de Andrade Maranhão, Tatiane Parize, Alexandre Luis

Format:	E-Artikel
Sprache:	Englisch

Erschienen:	2023

Schlagwörter:	Adsorption Adsorbent material Melamine Basic molecule removal Response surface methodology Breakthrough curve

Anmerkung:

© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Übergeordnetes Werk:	Enthalten in: Environmental science and pollution research - Berlin : Springer, 1994, 30(2023), 49 vom: 25. Sept., Seite 107970-107992
Übergeordnetes Werk:	volume:30 ; year:2023 ; number:49 ; day:25 ; month:09 ; pages:107970-107992

Links:	Volltext

DOI / URN:	10.1007/s11356-023-29891-x

Katalog-ID:	SPR053548078