In situ TEMPO surface functionalization of nanocellulose membranes for enhanced adsorption of metal ions from aqueous medium

Zoheb Karim, Minna Hakalahti, Tekla Tammelin, Aji P. Mathew

Research output: Contribution to journalArticleScientificpeer-review

29 Citations (Scopus)

Abstract

The current work demonstrates an innovative approach to develop nanocellulose based membranes with high water permeability, mechanical stability and high functionality via (1) tailoring the composition of the support layer of sludge microfibers/cellulose nanofibers (CNFSL) and (2) in situ TEMPO functionalization of the thin functional layer of cellulose nanocrystals (CNCBE) to enhance the metal ion adsorption capacity. SEM studies showed a porous network structure of the cellulose support layer and a denser functional layer with CNCBE embedded within gelatin matrix. AFM studies indicated the presence of a nanoscaled coating and increased roughness of membranes surface after TEMPO modification whereas FT-IR and conductometric titration confirmed the introduction of carboxyl groups upon TEMPO oxidation. The contact angle measurement results showed improved hydrophilic nature of membranes after in situ TEMPO functionalization. High networking potential of CNFSL made the membrane support layer tighter with a concomitant decrease in the average pore size from 6.5 to 2.0 µm. The coating with CNCBE further decreased the average pore size to 0.78 and 0.58 µm for S/CNCBE and S-CNFSL/CNCBE, respectively. In parallel, a drastic decrease in water flux (8000 to 90 L MPa-1 h-1 m-2) after coating with CNCBE was recorded but interestingly in situ functionalization of top CNCBE layer did not affect water flux significantly. The increase in adsorption capacity of ~1.3 and ~1.2 fold was achieved for Cu(II) and Fe(II)/Fe(III), respectively after in situ TEMPO functionalization of membranes. Biodegradation study confirmed the stability of layered membranes in model wastewater and a complete degradation of membranes was recorded after 15 days in soil.
Original languageEnglish
Pages (from-to)5232-5241
Number of pages10
JournalRSC Advances
Volume7
Issue number9
DOIs
Publication statusPublished - 1 Jan 2017
MoE publication typeA1 Journal article-refereed

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Metal ions
Membranes
Adsorption
Cellulose
Coatings
Pore size
Water
Fluxes
Mechanical stability
Gelatin
Angle measurement
Nanofibers
Biodegradation
TEMPO
Titration
Nanocrystals
Contact angle
Wastewater
Surface roughness
Soils

Cite this

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title = "In situ TEMPO surface functionalization of nanocellulose membranes for enhanced adsorption of metal ions from aqueous medium",
abstract = "The current work demonstrates an innovative approach to develop nanocellulose based membranes with high water permeability, mechanical stability and high functionality via (1) tailoring the composition of the support layer of sludge microfibers/cellulose nanofibers (CNFSL) and (2) in situ TEMPO functionalization of the thin functional layer of cellulose nanocrystals (CNCBE) to enhance the metal ion adsorption capacity. SEM studies showed a porous network structure of the cellulose support layer and a denser functional layer with CNCBE embedded within gelatin matrix. AFM studies indicated the presence of a nanoscaled coating and increased roughness of membranes surface after TEMPO modification whereas FT-IR and conductometric titration confirmed the introduction of carboxyl groups upon TEMPO oxidation. The contact angle measurement results showed improved hydrophilic nature of membranes after in situ TEMPO functionalization. High networking potential of CNFSL made the membrane support layer tighter with a concomitant decrease in the average pore size from 6.5 to 2.0 µm. The coating with CNCBE further decreased the average pore size to 0.78 and 0.58 µm for S/CNCBE and S-CNFSL/CNCBE, respectively. In parallel, a drastic decrease in water flux (8000 to 90 L MPa-1 h-1 m-2) after coating with CNCBE was recorded but interestingly in situ functionalization of top CNCBE layer did not affect water flux significantly. The increase in adsorption capacity of ~1.3 and ~1.2 fold was achieved for Cu(II) and Fe(II)/Fe(III), respectively after in situ TEMPO functionalization of membranes. Biodegradation study confirmed the stability of layered membranes in model wastewater and a complete degradation of membranes was recorded after 15 days in soil.",
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In situ TEMPO surface functionalization of nanocellulose membranes for enhanced adsorption of metal ions from aqueous medium. / Karim, Zoheb; Hakalahti, Minna; Tammelin, Tekla; Mathew, Aji P.

In: RSC Advances, Vol. 7, No. 9, 01.01.2017, p. 5232-5241.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - In situ TEMPO surface functionalization of nanocellulose membranes for enhanced adsorption of metal ions from aqueous medium

AU - Karim, Zoheb

AU - Hakalahti, Minna

AU - Tammelin, Tekla

AU - Mathew, Aji P.

PY - 2017/1/1

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AB - The current work demonstrates an innovative approach to develop nanocellulose based membranes with high water permeability, mechanical stability and high functionality via (1) tailoring the composition of the support layer of sludge microfibers/cellulose nanofibers (CNFSL) and (2) in situ TEMPO functionalization of the thin functional layer of cellulose nanocrystals (CNCBE) to enhance the metal ion adsorption capacity. SEM studies showed a porous network structure of the cellulose support layer and a denser functional layer with CNCBE embedded within gelatin matrix. AFM studies indicated the presence of a nanoscaled coating and increased roughness of membranes surface after TEMPO modification whereas FT-IR and conductometric titration confirmed the introduction of carboxyl groups upon TEMPO oxidation. The contact angle measurement results showed improved hydrophilic nature of membranes after in situ TEMPO functionalization. High networking potential of CNFSL made the membrane support layer tighter with a concomitant decrease in the average pore size from 6.5 to 2.0 µm. The coating with CNCBE further decreased the average pore size to 0.78 and 0.58 µm for S/CNCBE and S-CNFSL/CNCBE, respectively. In parallel, a drastic decrease in water flux (8000 to 90 L MPa-1 h-1 m-2) after coating with CNCBE was recorded but interestingly in situ functionalization of top CNCBE layer did not affect water flux significantly. The increase in adsorption capacity of ~1.3 and ~1.2 fold was achieved for Cu(II) and Fe(II)/Fe(III), respectively after in situ TEMPO functionalization of membranes. Biodegradation study confirmed the stability of layered membranes in model wastewater and a complete degradation of membranes was recorded after 15 days in soil.

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DO - 10.1039/C6RA25707K

M3 - Article

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EP - 5241

JO - RSC Advances

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SN - 2046-2069

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ER -