| 1. |
- Castro, Daniele Oliveira, et al.
(författare)
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The use of a pilot-scale continuous paper process for fire retardant cellulose-kaolinite nanocomposites
- 2018
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Ingår i: Composites Science And Technology. - : Elsevier Ltd. - 0266-3538 .- 1879-1050. ; 162, s. 215-224
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Tidskriftsartikel (refereegranskat)abstract
- Nanostructured materials are difficult to prepare rapidly and at large scale. Melt-processed polymer-clay nanocomposites are an exception, but the clay content is typically below 5 wt%. An approach for manufacturing of microfibrillated cellulose (MFC)/kaolinite nanocomposites is here demonstrated in pilot-scale by continuous production of hybrid nanopaper structures with thickness of around 100 μm. The colloidal nature of MFC suspensions disintegrated from chemical wood fiber pulp offers the possibility to add kaolinite clay platelet particles of nanoscale thickness. For initial lab scale optimization purposes, nanocomposite processing (dewatering, small particle retention etc) and characterization (mechanical properties, density etc) were investigated using a sheet former (Rapid Köthen). This was followed by a continuous fabrication of composite paper structures using a pilot-scale web former. Nanocomposite morphology was assessed by scanning electron microscopy (SEM). Mechanical properties were measured in uniaxial tension. The fire retardancy was evaluated by cone calorimetry. Inorganic hybrid composites with high content of in-plane oriented nanocellulose, nanoclay and wood fibers were successfully produced at pilot scale. Potential applications include fire retardant paperboard for semi structural applications and as reinforcement mats in molded thermoset biocomposites.
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| 2. |
- Goetz, Lee, et al.
(författare)
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All cellulose electrospun water purification membranes nanotextured using cellulose nanocrystals
- 2018
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Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 25:5, s. 3011-3023
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Tidskriftsartikel (refereegranskat)abstract
- 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 degrees-0 degrees thereby creating an anti-fouling membrane surface structure. The membranes showed rejection of 20-56% for particles of 0.5-2.0 mu m, 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.
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| 3. |
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| 4. |
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| 5. |
- Karim, Zoheb, et al.
(författare)
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Chapter 14: Bacterial cellulose : Preparation and characterization
- 2017
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Ingår i: Cellulose-Reinforced Nanofibre Composites: Production, Properties and Applications. - : Elsevier Inc.. - 9780081009659 - 9780081009574 ; , s. 327-340
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter reports the most relevant aspects related to the isolation, production, and characterization of bacterial nanocellulose (BC). Furthermore, various used strains for high-yield production of BC were summarized. Some vital parameters (e.g., mode of culture, type of bioreactor, media, etc.) for high-yield production of BC were further exemplified. Moreover, various characterization techniques were reported to understand the physiochemical properties of BC. Specific focus has been given to morphological, structural, and mechanical characterization, to utilize these properties for further application. © 2017 Elsevier Ltd. All rights reserved.
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| 6. |
- Karim, Zoheb, et al.
(författare)
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Chitosan based nanocomposite membranes with cellulose nanowhisker as nanoadditive
- 2013
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Konferensbidrag (refereegranskat)abstract
- Biobased nanocomposite membranes were prepared using chitosan as te matrix and cellulose nano whisker as the reinforcing phase. Cellulosee production. Atomic force microscopy of the nanowhiskers showed diameters of 10 -20nm and lengths of 250 - 350nm. Nanocomposites were prepared in 1:1, 1:2 and 1:3 ratios to investigate the effect of nanoadditive concentration on the membrane properties. The nanocomposites were prepared by solution mixing followed by freeze-drying, to obtain porous structures with high degree of internal surface area. These nanocomposites were further treated with ammonia vapours to prepare the crosslinked nanocomposites and thereby stabilize it towards moisture and pH variations. The morphology, surface area, crystallinity, porosity, and mechanical properties of prepared membranes were studied. The effect of the nanocomposite composition, crosslinking and the pore size distribution on the water transport through the membranes was also evaluated.
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| 7. |
- Karim, Zoheb, et al.
(författare)
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Enhanced sieving of cellulosic microfiber membranes : Via tuning of interlayer spacing
- 2020
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Ingår i: Environmental Science: Nano. - : Royal Society of Chemistry. - 2051-8153 .- 2051-8161. ; 7:10, s. 2941-2952
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Tidskriftsartikel (refereegranskat)abstract
- Functionally active membranes made of cellulosic microfibers (CMFs) have emerged as promising sorbents for the removal of nano-sized pollutants from water. The adsorption efficiency of these membranes has been increased through surface functionalization of pristine-CMFs using various chemistries. Still, until now, the produced materials consist of highly dense 2D networks that make the membranes inadequate as filters because of the very short interlayer spacing. Here, we report on novel tuned CMF functionalization procedures, namely carboxylation, phosphorylation, and methylation, that can overcome this problem by modulating the interlayer separation in the 2D membranes. To test our approach, fabricated nanolaminate membranes with grafted functional groups were subjected for the separation of metal ions, a dye and two drugs, and their separation efficiencies are being correlated with the degree of functionalization and tuned intercapillary spacing.
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| 8. |
- Karim, Zoheb, et al.
(författare)
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Forming a cellulose based nanopaper using XPM
- 2017
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Ingår i: International Conference on Nanotechnology for Renewable Materials 2017. - : TAPPI Press. - 9781510850897 ; , s. 399-407
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Konferensbidrag (refereegranskat)
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| 9. |
- Karim, Zoheb, et al.
(författare)
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Fully biobased nanocomposite membranes: removal of heavy metals from polluted water
- 2014
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Konferensbidrag (refereegranskat)abstract
- Biobased nanoparticles viz cellulose nanocrystals (CNCs) and cellulose nanofiber (CNFs) isolated by mechanical process (grinding) were used to fabricate of fully biobased nanocomposite membranes. Biobased nanofibers were used as support layer via a very simple process of vacuum filtration was used for the fabrication of CNF support layer. In order to coat CNCs or CNCbio on the two sides to CNF layer, the membrane was dipped in a solution of cellulose nanocrystals. Scanning electron microscopy (SEM) confirmed the infusion of functional layer within supportive layer. Tensile strength was measured in dry as well as in wet conditions, illustrated mechanical performances compareble to commercially available membranes. To increase the flux, membranes were treated with acetone for 24 and 72 h. The drastic increase in the flux for acetone treated membranes confirmed the discontinuities of hydrogen . The membranes succefully removed two metal ions Ag+ and As3- from real wastewater, from mirror making and mining industries respectively, within Europe. Complete removal of Ag+ was reported after 24 h of incubation. The study concludes that, the developed membranes having good mechanical stability in wet conditions, high water flux and adsorption efficiency are potential candidates for heavy metal ion remediation of industrial effluents.
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| 10. |
- Karim, Zoheb, et al.
(författare)
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High-flux affinity membranes based on cellulose nanocomposites for removal of heavy metal ions from industrial effluents
- 2016
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Ingår i: RSC Advances. - 2046-2069. ; 6:25, s. 20644-20653
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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