| 1. |
- Feng, Zhaoxuan, et al.
(författare)
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Nano graphene oxide creates a fully biobased 3D-printed membrane with high-flux and anti-fouling oil/water separation performance
- 2024
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Ingår i: Chemical Engineering Journal. - : Elsevier B.V.. - 1385-8947 .- 1873-3212. ; 485
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Tidskriftsartikel (refereegranskat)abstract
- Facile fabrication of green and renewable bio-based membranes with good anti-fouling and oil/water separation performance is of great importance to solve the oil spills and industrial oily wastewater threatening the ecological environment. Here, a fully biobased oil/water separation membrane with an ordered porous structure was 3D printed ultraviolet-assisted direct ink writing. The components of the bio-ink were obtained by methacrylation of chitosan (CS) and gelatin (GEL) to synthesize methacrylated chitosan (CSMA) and methacrylated gelatin (GELMA), while the nanographene oxide (nGO) was derived from CS through a simple microwave-assisted hydrothermal carbonization followed by oxidation step. The addition of nGO boosted the printability of the bio-ink, and the anti-fouling property and water permeation flux of the printed membranes. As a result, the membrane M−CSMA/GELMA/nGO-0.7 with the optimal performance possessed a low water contact angle in air of 0°, and high underwater oil contact angle of 161.5°, demonstrating a combination of superhydrophilic and underwater superoleophobic properties. M−CSMA/GELMA/nGO-0.7 has good corrosion resistance and long service life as evidenced from the separation efficiency of n-heptane/water, which kept above 99.5 % and a high water permeation flux above 38,300 L m−2h−1 after 20 cyclic tests in the harsh aquatic conditions containing 1 M NaCl, 1 M HCl, or 1 M NaOH, respectively. This shows promising potential for real-life applications.
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| 2. |
- Rusli, Andri, et al.
(författare)
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Eco-Friendly fabrication of nanoplastic particles and fibrils using polymer blends as templates
- 2024
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 495
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Tidskriftsartikel (refereegranskat)abstract
- Plastic pollution poses a critical global environmental challenge, and within this context, nanoplastics (NPs), the smallest plastic fragments, remain poorly understood. The progress in studying NP toxicity and developing analytical methods highly depends on access to well-defined NP materials. Herein, a straightforward and ecofriendly method for fabricating NP particles and fibrils using polymer blends as templates is presented. The process began with blending plastics with a water-soluble polymer (polyvinyl alcohol (PVA)), followed by the dissolution of the PVA matrix in water and the isolation of the NPs through a two-stage filtration process. NP materials from three widely used plastics, polyethylene, polypropylene, and polystyrene, were prepared, underscoring the versatility of this method. The resulting NPs were primarily submicron in size, and their size distribution was tuned by varying the blend ratio. Furthermore, by incorporating a stretch operation during the extrusion, the NP shape could be varied, enabling the fabrication of NP fibril materials. This method, which does not rely heavily on specialized equipment and avoids the use of harsh solvents, offers a viable and eco-friendly approach to fabricating NP samples suitable for a broad range of research applications.
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| 3. |
- Alongi, Jenny, et al.
(författare)
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Superior flame retardancy of cotton by synergetic effect of cellulose-derived nano-graphene oxide carbon dots and disulphide-containing polyamidoamines
- 2019
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Ingår i: Polymer degradation and stability. - : Elsevier. - 0141-3910 .- 1873-2321. ; 169
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Tidskriftsartikel (refereegranskat)abstract
- Linear polyamidoamines containing disulphide groups (SS-PAAs) were prepared by polyaddition of L-cystine with 2,2-bisacrylamidoacetic acid (B-CYSS), N,N'-methylenebisacrylamide (M-CYSS) and 1,4-bisacryloylpiperazine (BP-CYSS). They were evaluated as flame retardants for cotton, alone or with cellulose-derived nano-graphene oxide (nGO) carbon dots, to assess whether, due to their potential as radical scavengers, the latter would improve the already good performance of SS-PAAs. In vertical flame spread tests (VEST), cotton treated with 1% nGO burned as quickly as cotton, whereas B-CYSS, M-CYSS and BP-CYSS extinguished the flame at add-ons >= 12, 16 and 20%, respectively. Probably, the gaseous products of SS-PAA thermal degradation quenched the radicals involved in oxidation. Cotton treated with 8,12 and 15%, respectively, of B-CYSS, M-CYSS and BP-CYSS burned completely, but further addition of 1% nGO either inhibited ignition or shortly extinguished the flame, demonstrating synergism between the two components. Synergism was confirmed by assessing the synergism effectiveness parameter for the residual mass fraction (RMF) and by comparing the calculated and experimental TG curves in air for the cotton/SS-PAA-nGO systems. In cone calorimetry tests, the presence of nGO did not improve the already good performances of SS-PAAs, supporting the hypothesis that the action of both takes place in the gas phase.
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| 4. |
- Feng, Zhaoxuan, et al.
(författare)
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Biobased Nanographene Oxide Creates Stronger Chitosan Hydrogels with Improved Adsorption Capacity for Trace Pharmaceuticals
- 2017
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 5:12, s. 11525-11535
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Tidskriftsartikel (refereegranskat)abstract
- A promising green strategy for the fabrication of fully biobased chitosan adsorbents for wastewater purification is presented. Nanographene oxide (nGO)-type carbon dots were derived from chitosan (nGOCS) or from cellulose (nGOCL) through a two-step process including microwave-assisted hydrothermal carbonization and oxidation. Finally, nGO were evaluated as biobased property enhancers in chitosan hydrogel adsorbents. Macroporous chitosan hydrogels were synthesized by cross-linking with genipin, and the incorporation of nGO into these hydrogels was shown to facilitate the cross-linking reaction leading to more robust 3D cross-linked networks. This was evidenced by the increased storage modulus and by the swelling ratio that decreased from 5.7 for pristine chitosan hydrogel to 2.6 for hydrogel with 5 mg/mL nGOCS and 3.3 for hydrogel with 5 mg/mL nGOCL. As a further proof of the concept the hydrogels were shown to be effective adsorbent for the common anti-inflammatory drug diclofenac sodium (DCF). Here, the addition of nGO promoted the DCF adsorption process leading to 100% removal of DCF after only 5 h. The synergistic effect of electrostatic interactions, hydrogen bonding, and pi-pi stacking could explain the high adsorption of DCF on the hydrogels. The developed biobased CS/nGO hydrogels are thus promising adsorbents with great potential for purification of trace pharmaceuticals from wastewater.
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| 5. |
- Feng, Zhaoxuan, et al.
(författare)
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Carbon dot/polymer nanocomposites : From green synthesis to energy, environmental and biomedical applications
- 2021
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Ingår i: Sustainable Materials and Technologies. - : Elsevier BV. - 2214-9937. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- Carbon dots (CDs), a novel family of multifunctional carbon-nanomaterials, has the potential to revolutionize several important fields supporting the transformation to sustainable bioeconomy. CDs are characterized by attractive properties such as tunable optoelectronic and fluorescence properties, low toxicity, good biocompatibility, bioactivity and superior water solubility. Diverse methods and precursors have been applied for the synthesis of CDs. The possibility to scale-up the synthesis of CDs by employing Green Chemistry principles is a current research hotspot and a prerequisite for large-scale production and applications. Incorporation of CDs into polymer matrices, is another emerging research area with wide potential application range. This approach endows additional desirable functions and enables easy handling and reuse. This review summarizes recent progress regarding the green synthesis of CDs, the fundamental strategies for the construction of CD/polymer nanocomposites and the state-of-art applications of the CD/polymer nanocomposites in the realm of energy storage, environment and biomedicine. Finally, the outlook including challenges and future potential of CDs and CD/polymer composites are discussed.
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| 6. |
- Feng, Zhaoxuan
(författare)
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From Polysaccharides to Functional Materials for Trace Pharmaceutical Adsorption
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The transition to bioeconomy will reduce our dependency on fossil fuels as well as contribute to a more sustainable society. Within this framework, exploitation and development of renewable substitutes to petroleum-based products provides feasible roadmap for the material design. Here a perspective is provided to how the natural polysaccharides chitosan (CS) and/or cellulose (CL) could be elaborated and transformed to high-performance materials with the explicit aim of removing trace pharmaceutical contaminants from the wastewater, thus facilitating the sustainable development. In the first part of the thesis, chitosan and cellulose were converted to the carbon spheres (C-sphere) through a microwave-assisted hydrothermal carbonization process, and C-sphere was further broken down to the nanographene oxide (nGO) via a simple oxidation route. On this foundation, a green pathway was developed for fabrication of biobased materials for wastewater purification. First, macroporous chitosan-based composite hydrogels with controllable properties were developed, where chitosan-derived nGO worked as a functional property enhancer. Second, a further development changing from the bulky hydrogels to microgels consisting of CS composite particles in the microscopic size was achieved by a fast one-pot spraying-drying process. The crosslinking reaction occurred in situ during the spray-drying. Last, the C-sphere by-itself was also believed to be a potential adsorbent for wastewater contaminants. In the next step the prepared systems were evaluated for their capacity to adsorb pharmaceutical contaminants. Diclofenac sodium (DCF) was utilized as the model drug, and the three fabricated bio-adsorbents all demonstrated effective DCF adsorption performance, with the adsorption efficiency varying from 65.6 to 100%. Moreover, the DCF adsorption kinetics, isotherms and thermodynamic study were also investigated to reveal the nature of the adsorption process with the different materials. Finally, chitosan-based microspheres were selected for the reusability study, with the adsorption efficiency above 70% retained after six adsorption-desorption cycles, thus further endowing the promising potential of the fabricated bio-adsorbents for commercial applications.
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| 7. |
- Feng, Zhaoxuan, et al.
(författare)
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Microwave carbonized cellulose for trace pharmaceutical adsorption
- 2018
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 346, s. 557-566
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Tidskriftsartikel (refereegranskat)abstract
- A promising sustainable strategy to valorize cellulose to high-value adsorbents for trace pharmaceuticals, like diclofenac sodium (DCF), in the water is demonstrated. Carbon nanospheres (CN) as the DCF adsorbent were derived from cellulose through a one-pot microwave-assisted hydrothermal carbonization method. CN exhibited efficient DCF removal (100% removal of 0.001 mg/mL DCF in 30 s and 59% removal of 0.01 mg/mL DCF in 1 h). The adsorption kinetics and isotherm data were well-fitted with the pseudo-second-order kinetic model and Langmuir model, respectively. The adsorption process was endothermic and spontaneous as confirmed by the thermodynamic parameters. Multiple characterization techniques including SEM/EDS, FTIR, FTIR-imaging and zeta potential were applied to qualitatively investigate the adsorption process. π-π stacking and hydrogen bonding were proposed as the dominant adsorption interactions. CN also demonstrated effective adsorption capacity towards three other commonly-detected contaminants in the wastewater including ketoprofen (KP), benzophenone (BZP), and diphenylamine (DPA), each bearing partial structural similarity with DCF. The affinity of the contaminants towards CN followed the order DPA > BZP > DCF > KP, which could be explained by the different configurations and chemical units. It was speculated that for DCF and KP, the steric hindrance and electrostatic repulsion produced by dissociated carboxyl groups can impede the adsorption process as compared to DPA and BZP. This methodology could offer further insights into the drug adsorption on the cellulose-derived carbon adsorbents and the use of bioderived carbons for treatment of wastewaters contaminated with pharmaceuticals.
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| 8. |
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| 9. |
- Feng, Zhaoxuan, et al.
(författare)
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Photocrosslinked Chitosan Hydrogels Reinforced with Chitosan-Derived no-Graphene Oxide
- 2019
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Ingår i: Macromolecular Chemistry and Physics. - : Wiley-VCH Verlagsgesellschaft. - 1022-1352 .- 1521-3935. ; 220:13
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Tidskriftsartikel (refereegranskat)abstract
- Chitosan and chitosan-derived nano-graphene oxide carbon dots are successfully methacrylated and utilized for the fabrication of photocurable hydrogels. The addition of the nano-graphene oxide (nGO) does not significantly delay the polymer network build-up, but significantly reduces the storage modulus of the crosslinked network, with important detrimental effects on the mechanical performance. By replacing nGO with methacrylated M-nGO, the mechanical performance of the crosslinked polymer network is improved with an increase of the storage modulus as a function of increasing the M-nGO content in the photocurable formulation.
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| 10. |
- Feng, Zhaoxuan, et al.
(författare)
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Recent progress in the use of graphene/polymer composites to remove oil contaminants from water
- 2021
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Ingår i: Xinxing tancailiao. - : Elsevier BV. - 1007-8827. ; 36:2, s. 235-252
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Forskningsöversikt (refereegranskat)abstract
- Frequent oil spill accidents and the massive discharge of industrial oily sewage have destroyed the ecological balance and threatened marine life. Graphene (G) and graphene oxide (GO) have emerged as important materials in the field of oil/water separation because of their remarkable physicochemical properties including high specific surface area, low density, high porosity and tailorable surface functionality. To take full advantage of G and GO, their incorporation with polymers to build functional G/polymer and GO/polymer composites has recently gained increasing popularity because of their improved oil clean-up capability, outstanding mechanical performance, relatively low cost and adjustable surface chemical composition. Tremendous efforts have contributed to the development of G/polymer and GO/polymer composite oil clean-up sorbents and filtration membranes in 3D structural forms such as aerogels, foams, sponges and membranes. In this review, a comprehensive picture from the basic theory of the surface wettability to the recent advances in G/polymer and GO/polymer composite oil clean-up sorbents and filtration membranes are highlighted. The strategies for oil recovery and regeneration of the sorbents are also summarized. Current challenges and future research directions in this topic are provided, aimed at providing new perspectives for in-depth exploration in this field.
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