| 1. |
- Nejström, Malin, et al.
(författare)
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On Structural and Molecular Order in Cellulose Acetate Butyrate Films
- 2023
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 15:9
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Tidskriftsartikel (refereegranskat)abstract
- Cellulose acetate butyrate (CAB) is a possible candidate, being a raw material derived from renewable resources, to replace fossil-based materials. This is due to its thermoplastic properties and the relative ease with which it could be implemented within the existing industry. With a significant amount of variation in CAB on the market today, a knowledge gap has been identified regarding the understanding of the polymer structural arrangement in films. This relates to the underlying mechanisms that regulate CAB film material properties, insights that are important in product development. In this study, commercially available CAB was investigated with XRD, SEM, AFM, and TOPEM DSC in order to obtain physicochemical information related to its micro-structural features in solvent-cast films. The film-forming ability relates mostly to the number of hydroxyl groups, and the semi-crystallinity of the films depends on the type and position of the side groups along the cellulose backbone. The appearance of signs of possible cholesteric ordering in the films could be connected to higher amounts of hydroxyl groups along the backbone that disturb the helix arrangement, while the overall order was primarily related to the butyrate substitution and secondarily related to the molecular weight of the particular CAB studied. Cold crystallization was also observed in one CAB sample.
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| 2. |
- Dahlström, Christina, 1977-, et al.
(författare)
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Triboelectric Performance Of Regenerated Cellulose
- 2023
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Ingår i: Book of Abstracts EPNOE 2023. - : Graz University of Technology. ; , s. 116-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Cellulose has shown great potential in the development of green triboelectric nanogenerators (TENG) [1]. Particularly, regenerated cellulose (R-cellulose) has shown remarkably high output power density but the structural features and key parameters that explain such superior performance remain unexplored. In this work, wood cellulose fibers were dissolved in a LiOH(aq)-based solvent to produce a series of R-cellulose films. Regeneration in different alcohols (from methanol to n-pentanol) was performed and the films’ structural features and triboelectric performance were assessed. Nonsolvents of increased hydrophobicity led to R-cellulose films with higher hydrophilic character; the films showed a (1- 10) diffraction peak of larger amplitude and higher apparent crystallinity. An open-circuit voltage (VOC) of up to ca. 260 V and a short-circuit current (ISC) of up to ca. 150 μA were measured for R-cellulose against polytetrafluoroethylene (as negative counter-layer). However, R-cellulose showed an increased VOC of 175% (from 88.1 V) against polydimethylsiloxane from methanol to n-pentanol. The corresponding ISC and output power also increased by 76% (from 89.9 μA) and by 382% (from 8.8 W m–2), respectively. The higher R-cellulose hydrophilicity, combined with soft counter-layer that follow the surface structures increasing the effective contact area, are the leading reasons for a superior triboelectric performance.[1] Zhang, R., Dahlström, C., Zou, H., Jonzon, J., Hummelgård, M., Örtegren, J., Blomquist, N., Yang, Y., Andersson, H., Olsen, M., Norgren, M., Olin, H. & Wang, Z.L. Adv. Mater. 32, 2002824, 2020; https://doi.org/10.1002/adma.202002824
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| 3. |
- Dupaul, Gabriel, et al.
(författare)
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Fiberbanks as substrate and feedstock for biological remediation : A practical analytical method development for organic pollutants analysis
- 2020
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Ingår i: Book of Abstracts. - : ABA Publishing. - 9789189081031
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Konferensbidrag (refereegranskat)abstract
- Fiberbanksfrom the pulp and paper industry are typically contaminated with a wide range ofchlorinated aromatic and aliphatic toxins such as HCB and other chlorinated benzenes, PCB,HCH, DDT, PCDD, PCDF and Chlorophenols. This poses a formidable challenge for theanalyst to develop appropriate analytical methodology for the monitoring of the progress ofremediation.In preparation to this undertaking, an examination of a practical analytical method using oneextraction method, one clean-up and one analysis method for the aforementioned targetcompounds found in the fibrous sediment. This method was performed using acceleratedsolvent extraction (ASE), a modified silica gel column and GC-FID/ECD. Additionally,an assessment of the levels of organic pollutants was conducted,with the purposeofmeasuringthe potential alteration in contaminantswhenfreeze-drying, air-drying andautoclavingpretreatments are applied to the sediment samples, prior to be used as a media forbiological remediation.The results showed that the ASE is a very fast and reliable method of extraction, with yieldscomparableorhigher than the reference Soxhlet extraction method. Theactivatedsilica gelcolumn demonstrated adequate purification of the sediment extract for analysisusingthe twodetectors, FID and ECD, whichwere able to identify the target analytes fromonlyone purifiedextract. The method employed in this study has the potentialto reduceboth processing timeand materialusedfor analytical sample preparation. Lastly, some modifications inconcentrations anddistribution of target analyteswere revealedin thesediments pre-treated byautoclave and air-driedwhencompared withthefreeze-dried sediments, which can helpunderstanding the development of the biological remediation process.
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| 4. |
- Eivazihollagh, Alireza, et al.
(författare)
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Controlled Synthesis of Cu and Cu2O NPs and Incorporation of Octahedral Cu2O NPs in Cellulose II Films
- 2018
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Ingår i: Nanomaterials. - : MDPI AG. - 2079-4991. ; 8:4
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Tidskriftsartikel (refereegranskat)abstract
- In this study, Cu and Cu2O nanoparticles (NPs) were synthesized through chemical reduction of soluble copper-chelating ligand complexes using formaldehyde as a reducing agent. The influence of various chelating ligands, such as ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), and a surface-active derivative of DTPA (C12-DTPA), as well as surfactants (i.e., hexadecyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium chloride (DoTAC), sodium dodecyl sulfate (SDS), and dimethyldodecylamine-N-oxide (DDAO)), on morphology and the composition of produced NPs was investigated. In the absence of surfactants, spherical copper particles with polycrystalline structure could be obtained. X-ray diffraction (XRD) analysis revealed that, in the presence of EDTA, the synthesized NPs are mainly composed of Cu with a crystallite size on the order of 35 nm, while with DTPA and C12-DTPA, Cu2O is also present in the NPs as a minority phase. The addition of ionic surfactants to the copper–EDTA complex solution before reduction resulted in smaller spherical particles, mainly composed of Cu. However, when DDAO was added, pure Cu2O nano-octahedrons were formed, as verified by high-resolution scanning electron microscopy (HR-SEM) and XRD. Furthermore, a hybrid material could be successfully prepared by mixing the octahedral Cu2O NPs with cellulose dissolved in a LiOH/urea solvent system, followed by spin-coating on silica wafers. It is expected that this simple and scalable route to prepare hybrid materials could be applied to a variety of possible applications.
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| 5. |
- Eivazihollagh, Alireza, et al.
(författare)
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Electrochemical recovery of copper complexed by DTPA and C12-DTPA from aqueous solution using a membrane cell
- 2018
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Ingår i: Journal of chemical technology and biotechnology (1986). - : Wiley. - 0268-2575 .- 1097-4660. ; 93:5, s. 1421-1431
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUNDThe electrochemical recovery of copper from DTPA and C12-DTPA (a surface-active derivative of DTPA) complex solutions was investigated in a membrane flow cell. Electrolysis time, solution flow rate, applied current density, and solution pH were evaluated.RESULTSThe chelating surfactant C12-DTPA can promote the kinetics of copper electrodeposition more than DTPA depending on the experimental conditions. At a current density of 30 A m–2, a solution flow rate of 0.6 L min–1, and pH 10 after 180 min treatment, the copper recovery and current efficiency were 50% and 43.3%, respectively, in the Cu(II)-DTPA system and about 65% and 53.6%, respectively, in the Cu(II)-C12-DTPA system. The differences in the amount of recovery could be explained in terms of differences in the diffusion of copper complexes with DTPA and C12-DTPA to the cathode, as well as their solution behavior and pH-dependent conditional stability constants (log10 K’CuDTPA3-).CONCLUSIONElectrochemical methods could be effectively combined with foam flotation for the chelating surfactant C12-DTPA, to recover copper and C12-DTPA. This makes the overall treatment more sustainable, and can be helpful in complying with the increasingly stringent environmental regulations
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| 6. |
- Eivazihollagh, Alireza, et al.
(författare)
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Influences of the operational variables on electrochemical treatment of chelated Cu(II) in alkaline solutions using a membrane cell
- 2017
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Ingår i: Journal of chemical technology and biotechnology (1986). - : Wiley. - 0268-2575 .- 1097-4660. ; 92:6, s. 1436-1445
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUNDThe electrochemical recovery of copper and chelating agent from their complex solution using a membrane flow cell was investigated. The parameters electrolysis time, solution pH, current density, and temperature were investigated.RESULTSElectrochemical investigation indicated that chelating ligands can be recovered by the electrodeposition of copper ions on the cathode. For copper and EDTA recovery, the results indicated that recovery efficiency was affected by time, current density, and temperature. The recovery process was not influenced by pH in the range studied (pH 8–12), which can be explained by the low variation in the conditional stability constant, i.e. Δlog10 K' ≤ 0.7, over the pH range. However, when NTA, EDTA, and DTPA were compared, the results indicated that the recovery efficiency decreased as the conditional stability constant of the chelating agent–Cu(II) complex increased. The maximum current efficiency of copper and EDTA recovery after 5 h of treatment was approximately 85%, whereas the recovery was 80% of the initial concentration (0.05 mol L−1) at a current density of 1 A dm−2, temperature of 333 K, and pH of 10.CONCLUSIONRelatively high recovery efficiency makes the process fairly sustainable and hinders the discharge of copper ions and chelating ligands as pollutants into the environment.
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| 7. |
- Eivazihollagh, Alireza
(författare)
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Metal-Chelate Complexes in Alkaline Solution : On Recovery Techniques and Cellulose-based Hybrid Material Synthesis
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- For decades, aminopolycarboxylate chelating agents have been extensively used in various industrial applications. The ability of chelating agents to form stable metal-chelate complexes is the main reason for using them to manage metal ions within water-based industrial processes. Considerable quantities of industrial effluent containing chelating agents and heavy metals are produced and often discharged into the environment. The toxicity of heavy metals and the non-biodegradability of the chelating agents, as well as their accumulation in the environment, has become cause for concern. The main purpose of this thesis was to evaluate and develop processes for recovery of chelated metal complexes from aqueous solution. In this regard, the membrane electrolysis technique was evaluated for recovery of copper and aminopolycarboxylic chelating ligands such as ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), and a surface-active derivative of DTPA, 2-dodecyldiethylenetriaminepentaacetic acid (C12-DTPA) from aqueous solution. By using this method, it was possible to simultaneously recover the chelating ligand for further reuse and collect the metals by electrodeposition, making the process more cost-effective and hindering the discharge of copper ions and chelating ligands as pollutants into the environment. In addition, the ion flotation technique with the chelating surfactant C12-DTPA could be employed to separate metal ions, especially from their dilute solutions, and concentrate them in a foam phase. This is because C12-DTPA has a purpose-built functionality; besides forming strong coordination complexes with metal ions, it is also surface-active and will readily adsorb at air-water interfaces. In this study, C12-DTPA was effectively used in combination with foaming agents for the removal of toxic metal ions such as Cd2+, Zn2+, and Sr2+ from aqueous solution using ion flotation. From an economical perspective, this method could be combined with the membrane electrolysis technique to recover metal and regenerate chelating surfactant so that it can be reused.The present work also shows the synthesis of metal and metal oxide(s) nanoparticles (NPs) in alkaline aqueous solution containing chelated metal ions, in order to fabricate metal NPs–cellulose hybrid materials. Cellulose is the most abundant renewable material, with good mechanical performance and chemical resistivity in a wide range of solvents, which makes it a promising material to support metal NPs. In this respect, we developed a rapid and inexpensive one-pot synthesis of spherical copper NPs in a cellulose matrix. The hybrid material displayed antibacterial properties for both the gram-negative and gram-positive bacteria. The synthesis was further developed by studying the influence of various chelating ligands and surfactants on the NPs’ morphology and chemical composition. According to the results, DDAO, a zwitterionic surfactant, was found to mediate the formation of pure octahedral Cu2O NPs. In addition, a hybrid material film composed of regenerated cellulose and synthesized Cu2O nano-octahedrons was fabricated by spin-coating.
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| 8. |
- Eivazihollagh, Alireza, et al.
(författare)
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On chelating surfactants : Molecular perspectives and application prospects
- 2019
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Ingår i: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322 .- 1873-3166. ; 278, s. 688-705
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Tidskriftsartikel (refereegranskat)abstract
- Chelating agents, molecules that very strongly coordinates certain metal ions, are used industrially as well as in consumer products to minimize disturbances and increase performance of reactions and applications. The widely used sequestering agents, nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) belong to this branch of readily water-soluble compounds. When these chemical structures also have hydrophobic parts, they are prone to adsorb at air-water interfaces and to self-assemble. Such bifunctional molecules can be called chelating surfactants and will have more extended utilization prospects than common chelating agents or ordinary ionic surfactants. The present review attempts to highlight the fundamental behavior of chelating surfactants in solution and at interfaces, and their very specific interactions with metal ions. Methods to recover chelating surfactants from metal chelates are also described. Moreover, utilization of chelating surfactants in applications for metal removal in environmental engineering and mineral processing, as well as for metal control in the fields of biology, chemistry and physics, is exemplified and discussed.
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| 9. |
- Eivazihollagh, Alireza, et al.
(författare)
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One-pot synthesis of cellulose-templated copper nanoparticles with antibacterial properties
- 2017
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Ingår i: Materials letters (General ed.). - : Elsevier BV. - 0167-577X .- 1873-4979. ; 187, s. 170-172
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Tidskriftsartikel (refereegranskat)abstract
- We report a facile in situ synthesis of spherical copper nanoparticles (NPs) templated by a gelled cellulose II matrix under alkaline aqueous reaction conditions. In under 20 min, the hybrid material could be obtained in a one-pot reaction. Field-emission scanning electron microscopy (FE-SEM) revealed that the polycrystalline NPs of 200–500 nm were well distributed in the regenerated cellulose matrix. The average Cu crystallite size was of the order of 20 nm, as estimated from both X-ray diffraction (XRD) and FE-SEM. XRD data also indicated that the composite contained up to approximately 20% Cu2O. In suspensions containing the hybrid material, growth of Escerichia coli and Staphylococcus aureus strains was inhibited by 80% and 95%, respectively, after 72 h. The synthesis procedure offers a general approach to designing various low-cost hybrid materials of almost any shape, and the concept could be extended to utilization areas such as catalysis, functional textiles, and food packaging as well as to electronic applications.
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| 10. |
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