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

    32 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

    Fingerprint

    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.",
    author = "Zoheb Karim and Minna Hakalahti and Tekla Tammelin and Mathew, {Aji P.}",
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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

    Y1 - 2017/1/1

    N2 - 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.

    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

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    EP - 5241

    JO - RSC Advances

    JF - RSC Advances

    SN - 2046-2069

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