Abstract: Cellulose nanofibrils (CNFs) produced from waste lignocellulosic biomass have emerged as a sustainable source material for high value-added applications. In the current study, previously unreported entangled cellulose nanofibril and nanosheet (CNF/CNS) were obtained using Agave Tequilana Weber var. Azul leaves by means of a microfluidization process. These nanomaterials were investigated as potential biosorbents of Pb 2+, for which three adsorption mechanisms were identified by XPS. At low initial concentrations of Pb 2+ (C 0 ' 100 ppm), the adsorption-mechanism is governed by electrostatic interactions between carboxylate groups and Pb 2+; meanwhile, at (C 0 = 1000 ppm) mono and bi-dentate complexes dominate the adsorption-mechanism. Finally, when 110 ' C 0 ' 1000 ppm, both mechanisms co-exist. The maximum adsorption capacity was 43.55 mg/g, according to the Langmuir model, while CNF/CNS showed the characteristic diffraction peaks of cellulose type II. Our results highlight the high potential of these novel CNF/CNS biosorbents in the treatment of wastewater contaminated with toxic metals and afford new insights on adsorption mechanisms. Graphic abstract: [Figure not available: see fulltext.].
Bibliographical noteFunding Information:
E. Hernández would like to acknowledge CONACYT (Consejo Nacional de Ciencia y Tecnología) for providing a Ph.D. scholarship. T. Lara and C.Y. Yin would like to acknowledge CONACYT and the British Council for providing bilateral grants through the Institutional Links-FONCICYT Program (Grant No. 276243) and the British Council Institutional Links programme (Newton Fund) (Grant No. 264232317). Also, the authors would like to thank Nayely Pineda and Alejandro Arizpe for assistance in SEM characterization, Gerardo Silva for help on XPS acquisitions and Isabel Mendivil for providing sputtered-coating samples.
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