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Karim, Zoheb
Publications (10 of 22) Show all publications
Goetz, L., Naseri, N., Nair, S. S., Karim, Z. & Mathew, A. P. (2018). All cellulose electrospun water purification membranes nanotextured using cellulose nanocrystals. Cellulose (London), 25(5), 3011-3023
Open this publication in new window or tab >>All cellulose electrospun water purification membranes nanotextured using cellulose nanocrystals
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2018 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, no 5, p. 3011-3023Article in journal (Refereed) Published
Abstract [en]

Cellulose acetate (CA) fibers were electrospun on a mesh template to create specific surface and pore structures for membrane applications. The mesh template CA fiber mats were impregnated with cellulose nanocrystals at varying weight percentages. The membranes showed nanotextured surfaces and improved mechanical properties post impregnation. More importantly, the hydrophilicity of the original CA fibers was increased from a hydrophobic contact angle of 102°–0° thereby creating an anti-fouling membrane surface structure. The membranes showed rejection of 20–56% for particles of 0.5–2.0 μm, indicating potential of these membranes in rejecting microorganisms from water. Furthermore, high rejection of dyes (80–99%) by adsorption and potential application as highly functional affinity membranes was demonstrated. These membranes can therefore be utilized as all-cellulose, green, scalable and low cost high flux membranes (> 20,000 LMH) for water cleaning applications in food industry where microorganisms and charged contaminants are to be removed.

Place, publisher, year, edition, pages
Springer, 2018
National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-68002 (URN)10.1007/s10570-018-1751-1 (DOI)000431788000020 ()
Note

Validerad;2018;Nivå 2;2018-05-24 (andbra)

Available from: 2018-03-19 Created: 2018-03-19 Last updated: 2018-09-14Bibliographically approved
Karim, Z., Hakalahti, M., Tammelin, T. & Mathew, A. P. (2017). In situ TEMPO surface functionalization of nanocellulose membranes for enhanced adsorption of metal ions from aqueous medium. RSC Advances, 7(9), 5232-5241
Open this publication in new window or tab >>In situ TEMPO surface functionalization of nanocellulose membranes for enhanced adsorption of metal ions from aqueous medium
2017 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 7, no 9, p. 5232-5241Article in journal (Refereed) Published
Abstract [en]

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.

National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-61628 (URN)10.1039/C6RA25707K (DOI)000393753200042 ()2-s2.0-85010409286 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-02-07 (andbra)

Available from: 2017-01-25 Created: 2017-01-25 Last updated: 2018-07-10Bibliographically approved
Karim, Z., Afrin, S., Hussain, Q. & Danish, R. (2017). Necessity of enzymatic hydrolysis for production and functionalization of nanocelluloses. Critical reviews in biotechnology, 37(3), 355-370
Open this publication in new window or tab >>Necessity of enzymatic hydrolysis for production and functionalization of nanocelluloses
2017 (English)In: Critical reviews in biotechnology, ISSN 0738-8551, E-ISSN 1549-7801, Vol. 37, no 3, p. 355-370Article in journal (Refereed) Published
Abstract [en]

Nanocellulose (NC) from cellulosic biomass has recently gained attention owing to their biodegradable nature, low density, high mechanical properties, economic value and renewability. They still suffer, however, some drawbacks. The challenges are the exploration of raw materials, scaling, recovery of chemicals utilized for the production or functionalization and most important is toxic behavior that hinders them from implementing in medical/pharmaceutical field. This review emphasizes the structural behavior of cellulosic biomass and biological barriers for enzyme interactions, which are pertinent to understand the enzymatic hydrolysis of cellulose for the production of NCs. Additionally, the enzymatic catalysis for the modification of solid and NC is discussed. The utility of various classes of enzymes for introducing desired functional groups on the surface of NC has been further examined. Thereafter, a green mechanistic approach is applied for understanding at molecular level

National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-62150 (URN)10.3109/07388551.2016.1163322 (DOI)000395153900007 ()27049593 (PubMedID)2-s2.0-84962336490 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-02-24 (andbra)

Available from: 2017-02-24 Created: 2017-02-24 Last updated: 2018-07-10Bibliographically approved
Goetz, L., Karim, Z. & Mathew, A. P. (2016). Effect of micropatterned cellulose acetate membranes impregnated with cellulose and chitin nanocrystals on water filtration membrane behavior (ed.).
Open this publication in new window or tab >>Effect of micropatterned cellulose acetate membranes impregnated with cellulose and chitin nanocrystals on water filtration membrane behavior
2016 (English)Manuscript (preprint) (Other academic)
National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-12827 (URN)bfa1e171-295f-4a4a-8edf-ca98d501f082 (Local ID)bfa1e171-295f-4a4a-8edf-ca98d501f082 (Archive number)bfa1e171-295f-4a4a-8edf-ca98d501f082 (OAI)
Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24
Karim, Z., Mathew, A. P., Kokol, V., Wei, J. & Grahn, M. (2016). High-flux affinity membranes based on cellulose nanocomposites for removal of heavy metal ions from industrial effluents (ed.). RSC Advances, 6(25), 20644-20653
Open this publication in new window or tab >>High-flux affinity membranes based on cellulose nanocomposites for removal of heavy metal ions from industrial effluents
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2016 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 25, p. 20644-20653Article in journal (Refereed) Published
Abstract [en]

Fully biobased affinity membrane processing and its application in the removal of heavy metal ions from mirror industry effluents were successfully demonstrated; indicating the potential use of these membranes in point-of-use or point-of-entry water cleaning products that are cheap, environmentally friendly and efficient. Layered cellulose nanocomposite membranes were fabricated using cellulose microfiber sludge as a support layer and cellulose nanocrystals (CNCSL, CNCBE or PCNCSL) in a gelatin matrix as the functional layer. Scanning electron microscopy (SEM) studies revealed the bi-layered morphology of the membrane and well-individualized nanocelluloses in the functional layer. Bubble point measurements confirmed the membrane pore structure in the microfiltration range (5.0-6.1 μm), which provided very high water permeability (900-4000 L h-1 m-2) at <1.5 bars. A tensile strength of 16 MPa in dry conditions and a wet strength of 0.2 MPa, was considered sufficient for use of these membranes in spiral wound modules. Mirror industry effluent laden with metal ions (Ag+ and Cu2+/Fe3+/Fe2+) when treated with cellulose nanocomposite membranes, showed high ion removal capacity, being 100% for PCNCSL followed by CNCBE than CNCSL. The removal of metal ions was expected to be driven by interactions between negatively charged nanocellulose and the positively charged metal ions.

National Category
Bio Materials Chemical Process Engineering
Research subject
Wood and Bionanocomposites; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-2929 (URN)10.1039/C5RA27059F (DOI)000371019000026 ()2-s2.0-84959122673 (Scopus ID)0aa68333-5b84-4a15-b691-1e9f63edee4b (Local ID)0aa68333-5b84-4a15-b691-1e9f63edee4b (Archive number)0aa68333-5b84-4a15-b691-1e9f63edee4b (OAI)
Note

Validerad; 2016; Nivå 2; 20160217 (magr)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Karim, Z., Khan, M. J., Maskat, M. Y. & Adnan, R. (2016). Immobilization of horseradish peroxidase on β-cyclodextrin-capped silver nanoparticles: Its future aspects in biosensor application (ed.). Preparative Biochemistry & Biotechnology, 46(4), 321-327
Open this publication in new window or tab >>Immobilization of horseradish peroxidase on β-cyclodextrin-capped silver nanoparticles: Its future aspects in biosensor application
2016 (English)In: Preparative Biochemistry & Biotechnology, ISSN 1082-6068, E-ISSN 1532-2297, Vol. 46, no 4, p. 321-327Article in journal (Refereed) Published
Abstract [en]

This study aimed to work out a simple and high-yield procedure for the immobilization of horseradish peroxidase on silver nanoparticle. Ultraviolet–visible (UV-vis) and Fourier-transform infrared spectroscopy and transmission electron microscopy were used to characterize silver nanoparticles. Horseradish peroxidase was immobilized on β-cyclodextrin-capped silver nanoparticles via glutaraldehyde cross-linking. Single-cell gel electrophoresis (Comet assay) was also performed to confirm the genotoxicity of silver nanoparticles. To decrease toxicity, silver nanoparticles were capped with β-cyclodextrin. A comparative stability study of soluble and immobilized enzyme preparations was investigated against pH, temperature, and chaotropic agent, urea. The results showed that the cross-linked peroxidase was significantly more stable as compared to the soluble counterpart. The immobilized enzyme exhibited stable enzyme activities after repeated uses.

National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-7633 (URN)10.1080/10826068.2015.1031389 (DOI)000377930000001 ()25830286 (PubMedID)2-s2.0-84975842559 (Scopus ID)60853416-75c7-4478-9d51-56e0f91d9b82 (Local ID)60853416-75c7-4478-9d51-56e0f91d9b82 (Archive number)60853416-75c7-4478-9d51-56e0f91d9b82 (OAI)
Note

Validerad; 2016; Nivå 2; 20160613 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Karim, Z. (2016). Nanocellulose based affinity membranes for water purification: Processing technologies for optimal adsorption of dyes and metal ions (ed.). (Doctoral dissertation). Paper presented at . : Luleå tekniska universitet
Open this publication in new window or tab >>Nanocellulose based affinity membranes for water purification: Processing technologies for optimal adsorption of dyes and metal ions
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The aim of current study was to fabricate high flux affinity membrane with mechanical stability, porosity and high functionality for capturing of contaminants (dyes and metal ions) from water. Cellulose nanocrystals (CNCSL) and cellulose nanofibers (CNFSL) as well as a special grade of cellulose nanocrystals (CNCBE) isolated following bioethanol pilot scale process were used for the membrane fabrication. To improve the functionality and adsorption capacity of the membranes, enzymatic phosphorylated CNCSL (PCNCSL) and in situ TEMPO functionalized CNCBE (TEMPO-CNCBE) membranes were adopted. The removal of water contaminants via adsorption on carboxyl, sulphonic and phosphoryl functional groups on nanocellulose based membranes was evaluated. Freeze-drying was used as one approach to fabricate CNCSL based hybrid membranes. In spite of high percentage removal of positively charges dyes, low water flux and mechanical stability was recorded. Very fast and effective process, viz. vacuum-filtration was further used to fabricate layered membranes with improved mechanical properties. CNFSL based support layer was coated with more functional nanomaterials (CNCSL and CNCBE) via dipping. The study showed that it was possible to tailor the specific surface area, pore sizes, water flux and wet strength of the membranes based on drying conditions (105 °C at a load of 100kN and 28 oC at ≈20N) and acetone treatment. This study was further extended to fabricate high flux bi-layered membrane having support layer of micro-sized cellulose sludge and top layer of CNCSL, CNCBE and PCNCSL within gelatin matrix for adsorption. The aim of this approach was to provide mechanical stability without decreasing the water flux significantly. In the final study, to increase the adsorption capacity of CNCBE layered membranes; in situ functionalization (TEMPO oxidation) of top layer was performed. Furthermore, CNFSL was introduced in support layer to understand the structural and functional behavior of CNFSL. All membranes were subjected to pollutants removal [dyes and Ag(I), Cu(II), Fe(II)/Fe(III) metal ions]. Remarkable increase in adsorption capacity towards metal ions was recorded after modification of nanocellulose (phosphorylation and in situ functionalization). The outstanding performance of nanocellulose reveals the possibility of next generation affinity membranes for water purification.

Place, publisher, year, edition, pages
Luleå tekniska universitet, 2016. p. 50
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-26165 (URN)cf195591-1217-4ced-bf7e-4a42f333cfc0 (Local ID)978-91-7583-624-9 (ISBN)978-91-7583-625-6 (ISBN)cf195591-1217-4ced-bf7e-4a42f333cfc0 (Archive number)cf195591-1217-4ced-bf7e-4a42f333cfc0 (OAI)
Note
Godkänd; 2016; 20160509 (zohkar); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Zoheb Karim Ämne: Trä och bionanokompositer /Wood and Bionanocomposites Avhandling: Nanocellulose Based Affinity Membranes for Water Purification: Processing Technologies for Optimal Adsorption of Dyes and Metal Ions Opponent: Professor Monica Ek, Avd för träkemi och massateknologi, Skolan för kemivetenskap, Kungliga tekniska högskolan, Stockholm. Ordförande: Biträdande professor Aji Mathew, Avd för materialvetenskap, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet, Luleå. Tid: Torsdag 16 juni, 2016 kl 10.00 Plats: E632, Luleå tekniska universitetAvailable from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-24Bibliographically approved
Karim, Z., Claudpierre, S., Grahn, M., Oksman, K. & Mathew, A. P. (2016). Nanocellulose based functional membranes for water cleaning: Tailoring of mechanical properties, porosity and metal ion capture (ed.). Journal of Membrane Science, 514, 418-428
Open this publication in new window or tab >>Nanocellulose based functional membranes for water cleaning: Tailoring of mechanical properties, porosity and metal ion capture
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2016 (English)In: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 514, p. 418-428Article in journal (Refereed) Published
Abstract [en]

Multi-layered nanocellulose membranes were prepared using vacuum-filtration of cellulose nanofibers (CNF) suspensions followed by dip coating with cellulose nanocrystals having sulphate (CNCSL) or carboxyl surface groups (CNCBE). It was possible to tailor the specific surface area, pore structure, water flux and wet strength of the membranes based on drying conditions and acetone treatment. CNF coated with CNCBE showed the highest a tensile strength (95 MPa), which decreased in wet conditions (≈3.7 MPa) and with acetone (2.7 MPa) treatment. The water dried membranes showed pore sizes in nanofiltration range (74 Å) from liquid nitrogen adsorption/desorption data and the acetone treatment increased the average pore sizes to tight ultrafiltration range (194Å) with a concomitant increase (7000%) of the BET surface area. The water flux, also increased from zero to 25 Lm-2h-1 at a pressure differential of 0.45 MPa, for acetone treated ones. The membranes irrespective of the surface functionality showed exceptional capability (≈100%) to remove Ag+, Cu2+ and Fe3+ ions from mirror industry effluents. Surface adsorption followed by microprecipitation was considered as the possible mechanism of ion removal, which opens up a new generation of ultrafiltration membranes with high selectivity towards ions and low-pressure demands.

National Category
Bio Materials Chemical Process Engineering
Research subject
Wood and Bionanocomposites; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-16251 (URN)10.1016/j.memsci.2016.05.018 (DOI)000378060100042 ()2-s2.0-84968820846 (Scopus ID)fdda6f07-9ddd-484b-8c82-cc39d8a49eb3 (Local ID)fdda6f07-9ddd-484b-8c82-cc39d8a49eb3 (Archive number)fdda6f07-9ddd-484b-8c82-cc39d8a49eb3 (OAI)
Note

Validerad; 2016; Nivå 2; 20160318 (zohkar)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Mautner, A., Maples, H. A., Kobkeatthawin, T., Kokol, V., Karim, Z., Li, K. & Bismarck, A. (2016). Phosphorylated nanocellulose papers for copper adsorption from aqueous solutions (ed.). Paper presented at . Journal of Environmental Science and Engineering A, 13(8), 1861-1872
Open this publication in new window or tab >>Phosphorylated nanocellulose papers for copper adsorption from aqueous solutions
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2016 (English)In: Journal of Environmental Science and Engineering A, ISSN 2162-5298, E-ISSN 2162-5301, Vol. 13, no 8, p. 1861-1872Article in journal (Refereed) Published
Abstract [en]

Copper is a major problem in industrial wastewater streams, seriously affecting the quality of potential drinking water. Several approaches, including continuous membrane processes or batch-wise application of adsorbents, are in use to tackle this problem. Unfortunately, these processes suffer from their particular drawbacks, such as low permeance or disposal of saturated adsorbents. However, a combination of these processes could constitute a step towards a more efficient copper removal solution. Here, we present a nanopaper ion-exchanger prepared from cellulose nanofibrils produced from fibre sludge, a paper industry waste stream, for the efficient, continuous removal of copper from aqueous solutions. This nanopaper ion-exchanger comprises phosphorylated cellulose nanofibrils that were processed into nanopapers by papermaking. The performance of these phosphorylated nanopaper membranes was determined with respect to their rejection of copper and permeance. It was shown that this new type of nanopaper is capable of rejecting copper ions during a filtration process by adsorption. Results suggest that functional groups on the surface of the nanopapers contribute to the adsorption of copper ions to a greater extent than phosphate groups within the bulk of the nanopaper. Moreover, we demonstrated that those nanopaper ion-exchangers could be regenerated and reused and that in the presence of calcium ions, the adsorption capacity for copper was only slightly reduced

National Category
Bio Materials
Research subject
Wood and Bionanocomposites
Identifiers
urn:nbn:se:ltu:diva-13926 (URN)10.1007/s13762-016-1026-z (DOI)000379709700001 ()2-s2.0-84978741621 (Scopus ID)d3e5b2ab-0f1e-4d0f-b01d-0d6f45e98846 (Local ID)d3e5b2ab-0f1e-4d0f-b01d-0d6f45e98846 (Archive number)d3e5b2ab-0f1e-4d0f-b01d-0d6f45e98846 (OAI)
Note
Validerad; 2016; Nivå 2; 20160318 (zohkar)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Karim, Z., Mathew, A. P., Oksman, K. & Grahn, M. (2015). Cellulose nanocrystals based nanocompositemembranes for water purification: Process-Property correlation (ed.). In: (Ed.), : . Paper presented at International Polysaccharide Conference : 18/10/2015 - 22/10/2015.
Open this publication in new window or tab >>Cellulose nanocrystals based nanocompositemembranes for water purification: Process-Property correlation
2015 (English)Conference paper, Oral presentation only (Other academic)
National Category
Bio Materials Chemical Process Engineering
Research subject
Wood and Bionanocomposites; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-38178 (URN)c7d79525-063a-4edb-9007-a73cc47947f1 (Local ID)c7d79525-063a-4edb-9007-a73cc47947f1 (Archive number)c7d79525-063a-4edb-9007-a73cc47947f1 (OAI)
Conference
International Polysaccharide Conference : 18/10/2015 - 22/10/2015
Note

Godkänd; 2015; 20160323 (zohkar)

Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
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