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.

Autor: Fröhlich AC; POLIMAT, Grupo de Estudos em Materiais Poliméricos, Chemistry Department-Federal University of Santa Catarina-UFSC, Campus Reitor João David Ferreira Lima, s/n-Trindade, Florianópolis, SC, 88040-900, Brazil., Mazur LP; BIOMAT, Laboratório de Biomateriais, Faculty of Chemical Engineering, Department of Materials Engineering and Bioprocess, University of Campinas, Cidade Universitária Zeferino Vaz, 13083-852, Campinas, SP, Brazil., da Silva A; LABMASSA, Laboratório de Transferência de Massa, Chemical Engineering Department-Federal University of Santa Catarina-UFSC, Campus Reitor João David Ferreira Lima, s/n-Trindade, 88040-900, Florianópolis, SC, Brazil., de Andrade Maranhão T; LEMA/LARES, Laboratório de Espectrometria de Massas e Atômica/Laboratório de Análises de Resíduos, Chemistry Department-Federal University of Santa Catarina-UFSC, Campus Reitor João David Ferreira Lima, s/n-Trindade, Florianópolis, SC, 88040-900, Brazil., Parize AL; POLIMAT, Grupo de Estudos em Materiais Poliméricos, Chemistry Department-Federal University of Santa Catarina-UFSC, Campus Reitor João David Ferreira Lima, s/n-Trindade, Florianópolis, SC, 88040-900, Brazil. alexandre.parize@ufsc.br.
Jazyk: angličtina
Zdroj: Environmental science and pollution research international [Environ Sci Pollut Res Int] 2023 Oct; Vol. 30 (49), pp. 107970-107992. Date of Electronic Publication: 2023 Sep 25.
DOI: 10.1007/s11356-023-29891-x
Abstrakt: 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 R 2 above 0.9920 for both materials at all concentrations tested. The isotherm obeyed the Langmuir model, with R 2 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.
(© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
Databáze: MEDLINE
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