Dual nanofibrillar-based bio-sorbent films composed of nanocellulose and lysozyme nanofibrils for mercury removal from spring waters

Nuno H C S Silva; Paula Figueira; Elaine Fabre; Ricardo J B Pinto; Maria Eduarda Pereira; Armando J D Silvestre; Isabel M Marrucho; Carla Vilela; Carmen S R Freire

doi:10.1016/j.carbpol.2020.116210

Dual nanofibrillar-based bio-sorbent films composed of nanocellulose and lysozyme nanofibrils for mercury removal from spring waters

Carbohydr Polym. 2020 Jun 15:238:116210. doi: 10.1016/j.carbpol.2020.116210. Epub 2020 Apr 6.

Authors

Nuno H C S Silva¹, Paula Figueira², Elaine Fabre³, Ricardo J B Pinto¹, Maria Eduarda Pereira⁴, Armando J D Silvestre¹, Isabel M Marrucho⁵, Carla Vilela¹, Carmen S R Freire⁶

Affiliations

¹ CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
² CESAM and LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal; Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, 4450-208 Matosinhos, Portugal.
³ CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; CESAM and LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
⁴ CESAM and LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
⁵ Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisboa, Portugal.
⁶ CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal. Electronic address: cfreire@ua.pt.

PMID: 32299563
DOI: 10.1016/j.carbpol.2020.116210

Abstract

The present study explores the preparation of dual nanofibrillar-based bio-sorbent films composed of cellulose nanofibrils (CNFs) and lysozyme nanofibrils (LNFs) for application in the removal of Hg(II) from aqueous solutions. The free-standing films were fabricated via simple vacuum filtration of water suspensions of CNFs and LNFs and disclose good mechanical and thermal properties. The Hg(II) removal efficiency was evaluated by atomic fluorescence spectroscopy in ultra-pure and natural spring waters contaminated with environmental realistic levels of mercury (50 μg L^-1). The removal efficiency is pH-dependent reaching a maximum of 99 % after 24 h at a pH value close to the isoelectric point of the protein. Under the experimental conditions, the sorption kinetics are well described by the pseudo-second-order and Elovich models, suggesting a chemisorption mechanism. These results demonstrate the ability of the dual nanofibrillar-based films to remove Hg(II) from water samples reaching a residual concentration lower than the guideline value for water intended for human consumption (1 μg L^-1). Therefore, the CNFs/LNFs bio-sorbents might be a solution to treat low-concentrated mercury-contaminated waters.

Keywords: Bio-sorbents; Cellulose nanofibrils; Lysozyme nanofibrils; Mercury removal; Nanostructured films; Water remediation.

MeSH terms

Cellulose / chemistry*
Drinking Water / chemistry*
Mercury / isolation & purification*
Muramidase / chemistry*
Nanofibers / chemistry*
Nanogels / chemistry*
Water Pollutants, Chemical / isolation & purification
Water Purification*

Substances

Drinking Water
Nanogels
Water Pollutants, Chemical
Cellulose
hen egg lysozyme
Muramidase
Mercury