| 1. |
- Changqing, Ruan, et al.
(author)
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A green and simple method for preparation of an efficient palladium adsorbent based on 2,3-dialdehyde cellulose
- 2015
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Conference paper (peer-reviewed)abstract
- An efficient and green palladium adsorbent was prepared from 2,3-dialdehyde cellulose by reductive amination with a palladium chelating ligand in a facile one-pot procedure, and adsorption properties for palladium including adsorption isotherm, kinetics, desorption and recycling of the adsorbent obtained were studied. The successful reductive amination with the ligand and 2,3-dialdehyde cellulose was verified by FT-IR and XPS, and the adsorbent was characterized by SEM, XRD, gas adsorption and TGA. The adsorbent has a high adsorption capacity and enables fast adsorption of palladium from solution. Adsorbent materials suitable for both filters and column matrixes could be obtained.
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| 2. |
- Changqing, Ruan, et al.
(author)
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A green and simple method for preparation of an efficient palladium adsorbent based on cysteine functionalized2,3-dialdehyde cellulose
- 2016
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In: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 23:4, s. 2627-2638
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Journal article (peer-reviewed)abstract
- A green and efficient adsorbent for adsorption of palladium ions was prepared from 2,3-dialdehyde cellulose (DAC) originating from nanocellulose from the green algae Cladophora. The DAC was functionalized with cysteine via reductive amination in a convenient one-pot procedure to provide the adsorbent. The adsorption properties for adsorbing palladium(II) ions, including capacity, adsorption isotherm and kinetics, were studied. The successful reductive amination of cysteine with 2,3-dialdehyde cellulose was confirmed by FT-IR, elemental analysis and XPS. The adsorbent was characterized by SEM, XRD, gas adsorption and TGA. The adsorbent had a high adsorption capacity (130 mg palladium per gram adsorbent) and enabled fast adsorption of palladium(II) ions from solution (80 % of maximum capacity reached in 2 h). Adsorbent materials suitable for both filters (fibrous) and column matrixes (spherical particles) could be obtained in an efficient manner by controlling the degree of oxidation while producing the DAC material.
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| 3. |
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| 4. |
- Lindh, Jonas, et al.
(author)
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Preparation of Porous Cellulose Beads via Introduction of Diamine Spacers
- 2016
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 32:22, s. 5600-5607
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Journal article (peer-reviewed)abstract
- The current work presents a synthesis route based on the reductive amination of 2,3-dialdehyde cellulose beads with diamines to render micrometer-sized beads with increased specific surface area (SSA) and porosity in the mesoporous range. Specifically, the influence of the reductive amination of 2,3-dialdehyde cellulose (DAC) using aliphatic and aromatic tethered mono- and diamines on bead microstructure was investigated. Aliphatic and aromatic tethered monoamines were found to have limited utility for producing porous beads whereas the introduction of diamines provided beads with a porous texture and an SSA increasing from <1 to >30 m(2)/g. Both aliphatic and aromatic diamines were found to be useful in producing porous beads having a pore size distribution range of 10 to 100 nm, as verified by N-2 gas adsorption and mercury intrusion porosimetry analyses. The true density of the functionalized DAC beads decreased to an average of about 1.36 g/cm(3) as compared to 1.48 g/cm(3) for the unfunctionalized, fully oxidized DAC beads. The total porosity of the beads was, according to mercury porosimetry, in the range of 54-64%. Reductive amination with 1,7-diaminoheptane provided beads that were stable under alkaline conditions (I M NaOH). It was concluded that the introduction of tethered diamines into DAC beads is a facile method for producing mesoporous beads.
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| 5. |
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| 6. |
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| 7. |
- Ruan, Changqing, et al.
(author)
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Carbonized cellulose beads for efficient capacitive energy storage
- 2018
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In: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 25:6, s. 3545-3556
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Journal article (peer-reviewed)abstract
- Natural biomaterials, including polysaccharides and amino acids, provide a sustainable source of functional carbon materials for electric energy storage applications. We present a one-pot reductive amination process to functionalize 2,3-dialdehyde cellulose (DAC) beads with chitosan and l-cysteine to provide single (N)- and dual (N/S)-doped materials. The functionalization enables the physicochemical properties of the materials to be tailored and can provide carbon precursors with heteroatom doping suitable for energy storage applications. Scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis were used to characterize the changes to the beads after functionalization and carbonization. The results of X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy verified that the doping was effective, while the nitrogen sorption isotherms and pore-size distributions of the carbonized beads showed the effects of doping with different hierarchical porosities. In the electrochemical experiments, three kinds of carbon beads [pyrolyzed from DAC, chitosan-crosslinked DAC (CS-DAC) and l-cysteine-functionalized DAC] were used as electrode materials. Electrodes of carbonized CS-DAC beads had a specific capacitance of up to 242 F g(-1) at a current density of 1 A g(-1). These electrodes maintained a capacitance retention of 91.5% after 1000 charge/discharge cycles, suggesting excellent cycling stability. The results indicate that reductive amination of DAC is an effective route for heteroatom doping of carbon materials to be used as electrode active materials for energy storage.
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| 8. |
- Ruan, Changqing, et al.
(author)
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Cellulose nanofibers prepared via pretreatment based on Oxone® oxidation
- 2017
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In: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 22:12
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Journal article (peer-reviewed)abstract
- Softwood sulfite bleached cellulose pulp was oxidized with Oxone (R) and cellulose nanofibers (CNF) were produced after mechanical treatment with a high-shear homogenizer. UV-vis transmittance of dispersions of oxidized cellulose with different degrees of mechanical treatment was recorded. Scanning electron microscopy (SEM) micrographs and atomic force microscopy (AFM) images of samples prepared from the translucent dispersions showed individualized cellulose nanofibers with a width of about 10 nm and lengths of a few hundred nm. All results demonstrated that more translucent CNF dispersions could be obtained after the pretreatment of cellulose pulp by Oxone (R) oxidation compared with the samples produced without pretreatment. The intrinsic viscosity of the cellulose decreased after oxidation and was further reduced after mechanical treatment. Almost translucent cellulose films were prepared from the dispersions of individualized cellulose nanofibers. The procedure described herein constitutes a green, novel, and efficient route to access CNF.
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| 9. |
- Ruan, Changqing, et al.
(author)
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Favored Surface-limited Oxidation of Cellulose with Oxone® in Water
- 2017
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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 7:64, s. 40600-40607
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Journal article (peer-reviewed)abstract
- A novel method for favored primary alcohol oxidation of cellulose was developed. Cellulose pulp andCladophora nanocellulose were oxidized in a one-pot procedure by Oxone® (2KHSO5$KHSO4$K2SO4)and efficient reaction conditions were identified. The effects of the reaction on the morphology,viscosity and chemical structure of the products obtained were studied. The primary alcohol groupswere oxidized to carboxyl groups and the content of carboxyl groups was determined byconductometric titration. SEM, capillary-type viscometry and XRD were applied to characterize theproducts and to investigate the influence of oxidation. For the first time, low-cost and stable Oxone®was used as a single oxidant to oxidize cellulose into carboxyl cellulose. The oxidation is an inexpensiveand convenient process to produce carboxylic groups on the surface of the cellulose fibers and to makethe cellulose fibers charged. Particularly, this method can avoid the use of halogens and potentially toxicradicals and constitute a green route to access carboxylated cellulose. Further, sodium bromide could beused as a co-oxidant to the Oxone® and increase the carboxylic acid content by 10–20%. The Oxone®oxidation is a promising method for oxidation of cellulose and might facilitate the production of CNC.
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| 10. |
- Ruan, Changqing, et al.
(author)
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Preparation of Porous 2,3-dialdehyde Cellulose Beads Crosslinked with Chitosan and their Application in Adsorption of Congo Red Dye
- 2018
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In: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 181, s. 200-207
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Journal article (peer-reviewed)abstract
- Micrometer sized 2,3-dialdehyde cellulose (DAC) beads were produced via a recently developed method relying on periodate oxidation of Cladophora nanocellulose. The produced dialdehyde groups and pristine hydroxyl groups provided the DAC beads with a vast potential for further functionalization. The sensitivity of the DAC beads to alkaline conditions, however, limits their possible functionalization and applications. Hence, alkaline-stable and porous cellulose beads were prepared via a reductive amination crosslinking reaction between 2,3-dialdehyde cellulose beads and chitosan. The produced materials were thoroughly characterized with different methods. The reaction conditions, including the amount of chitosan used, conditions for reductive amination, reaction temperature and time, were investigated and the maintained morphology of the beads after exposure to 1 M NaOH (aq.) was verified with SEM. Different washing and drying procedures were used and the results were studied by SEM and BET analysis. Furthermore, FTIR, TGA, EDX, XPS, DLS and elemental analysis were performed to characterize the properties of the prepared beads. Finally, the alkaline-stable porous chitosan cross-linked 2,3-dialdehyde cellulose beads were applied as adsorbent for the dye Congo red. The crosslinked beads displayed fast and high adsorption capacity at pH 2 and good desorption properties at pH 12, providing a promising sorption material.
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