A novel and cost-effective double-capsule nanocomposite coating based on carbon hollow spheres with self-healing performance for corrosion protection

The ability of a cost-effective self-healing nanocomposite system to restore its protection functionality in case of a coating defect is of pivotal importance to ensure durable performance under demanding corrosive conditions. In this research, a self-healing epoxy coating was fabricated by incorporation of carbon hollow spheres (CHSs) doped separately with epoxy and polyamine as film forming agents. Graphene-based CHSs were synthesized via silica templating method in presence of sucrose as a carbon precursor. After encapsulation of epoxy and polyamine agents in CHSs denoted as Ep-DCSs and Am-DCSs, respectively, 10 wt. % and 5 wt. % of Ep-DCSs and Am-DCSs were introduced in an epoxy matrix. The final nanocomposite coating was applied on the surface of mild steel substrates. A blank epoxy coating was also used as a control sample. The synthesized CHSs were characterized before and after the silica core removal using field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The CHSs loaded with the film forming agents were evaluated using thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. Furthermore, the protective and self-healing properties of the coatings were studied using electrochemical impedance spectroscopy (EIS), scanning vibrating electrode technique (SVET) and salt spray testing. The obtained results showed that the fabricated nanocomposite epoxy coating can heal appropriately the scratches applied on the surface of the coating barricading the accessibility of corrosive species to the metal substrate (Figure 1). Please click Additional Files below to see the full abstract

UiO-66 metal-organic frameworks for water treatment

Metal-organic frameworks (MOFs), specifically Zr-based UiO-66, have gained attention for removing toxic pollutants due to their unique attributes. These include a large surface area, high porosity, active adsorption sites, tunable chemistry, pore control, and robust host-guest interactions. However, the practical use of pure MOF powders in water treatment faces limitations such as insolubility, processability, brittleness, safety concerns, and separation challenges. One of the significant concerns when using MOFs for water treatment is how well they maintain stability when exposed to aqueous environments. Therefore, this thesis demonstrates the stability of UiO-66 MOF over one year in water and chloroform, with minor changes observed in structure when exposed to dimethylformamide (DMF). The results from the stability studies contribute to a better understanding of UiO-66's stability in aqueous media. UiO-66 exhibits effective removal of organic pollutants, including methyl red (MR), methyl orange (MO), malachite green (MG), and methylene blue (MB), which possess different charges. The stable UiO-66 polycrystalline MOFs still grapple with the challenge of effective separation from the treated water. This thesis pursued a magnetic approach for the magnetization of UiO-66, coupled with subsequent post-modification. This strategy aimed to facilitate the efficient separation of UiO-66 from treated water using an external magnet. A two-step post-modification procedure, utilizing 2,4,6-trichloro-1,3,5-triazine (TCT) and 5-phenyl-1H-tetrazole (PTZ) agents, was introduced to enhance the adsorption performance of the magnetic nanocomposite. Despite a reduction in porosity and specific surface area compared to the pristine UiO-66-NH2, the resulting magnetic post-modified UiO-66 exhibited significantly improved adsorption capacity. Notably, magnetic UiO-66-TCT demonstrated a high adsorption capacity of approximately 298 mg/g for methyl orange (MO), offering facile MOF separation via an external magnet. The research further underscores the significance of post-modifying UiO-66 with novel functional groups to create effective adsorbents for the removal of organic contaminants. Combining MOFs with electrospun nanofibers offers efficient water treatment, addressing challenges linked to polycrystalline MOFs and their separation from treated water. This thesis employed a hybrid approach by integrating UiO-66 with thermally oxidized nanodiamond (TOND) to enhance its affinity for removing targeted organic contaminants. These hybrid UiO-66 particles were then incorporated into chitosan/ polyvinyl alcohol (PVA) nanofibers. The resulting nanofiber composite, containing 1.5 wt% hybrid UiO-66, exhibited a twofold increase in the maximum adsorption capacity for anionic Congo red dye (1429 mg/g) compared to the unfilled nanofiber (769 mg/g). Further advancements in UiO-66 nanofiber composite development were achieved by functionalizing UiO-66-NH2 with TCT and PTZ, followed by their incorporation into chitosan/PVA nanofibers. The optimal composite, consisting of 7 wt% functionalized MOF, exhibited a remarkable maximum adsorption capacity for MO (619 mg/g), surpassing most previously reported adsorbents such as activated carbon.Applied Science, Faculty ofEngineering, School of (Okanagan)Graduat

The passive avoidance task ameliorate the toxic effects of bisphenol A on dopamine D1 receptor density in hippocampus, amygdala, and cerebellum of male rats

Abstract Introduction Dopamine D1 receptor seems to play a role in mediating plasticity. Therefore, the present study aimed to investigate the effects of passive avoidance tasks postexposed to BPA on dopamine D1 receptor density in the hippocampus, amygdala, and cerebellum of male rats. Methods Thirty‐five male Sprague–Dawley rats weighing 220.300 g, in standard light‐dark 12 h light/12 h dark were used in the present study; water and food were ad libitum. Animals were divided into six groups. Administration of BPA 5 and 50 mg/kg/day were gavaged for 15 days. Learning and memory assessment were done by a shuttle box after 15 days of BPA administration. The density of the dopamine D1 receptor was investigated using an immunohistochemistry (IH) procedure. For determining the color difference in IH sections, Image Analyzer software was used. The data were analyzed by one‐way ANOVA followed by Tukey's as a post hoc test. Results The data showed that BPA in both doses could significantly increase the density of dopamine D1 receptors in the hippocampus, amygdala, and cerebellum of male rats; learning in rats postexposed to BPA improves dopamine D1 receptor density significantly in three brain structures. Discussion According to the results, passive avoidance learning and memory can improve the density of dopamine D1 receptors in the hippocampus, amygdala, and cerebellum of male rats

Electrospun nanofibers of chitosan/polyvinyl alcohol/UiO-66/nanodiamond: Versatile adsorbents for wastewater remediation and organic dye removal

| openaire: EC/H2020/788489/EU//BioELCell Funding Information: Dr. Arjmand would like to thank the Canada Research Chairs program for the financial support. The authors would like to acknowledge Syilx Okanagan First Nation for allowing us to conduct research in their unceded ancestorial traditional territory. Mr. Ahmadijokani, Dr. Kamkar, and Dr. Rojas are grateful for funding support from the Canada Excellence Research Chair Program (CERC-2018-00006) and the Canada Foundation for Innovation (Project number 38623). Dr. Rojas also acknowledges the European Research Council under the European Union's Horizon 2020 research and innovation program (ERC Advanced grant No. 788489, “BioElCell”). The authors also would like to thank Mr. Aydin Badrian (aydinbadrian.com) for his efforts on the graphical parts of this study.The appeal of metal–organic frameworks (MOFs) in wastewater treatment is tempered by their polycrystalline, powdery state, and challenges associated with their deployment. In the case of UiO-66, one of the most stable and widely-used MOFs, a low tendency for removing some organic contaminants has been observed on top of the mentioned issues. To address these challenges, herein, we take two complementary steps, i.e., hybridization of UiO-66 with organic nanodiamond (ND) followed by the integration of the hybrid nanoparticles in electrospun polymeric nanofibers based on chitosan/polyvinyl alcohol (PVA). We present the electrospinning of polymer/MOFs as a promising technique to fabricate highly efficient adsorbents for water remediation. We use the electrospun chitosan/PVA nanofibers (ECPN) as a versatile host for MOF nanoparticles that remove cationic methylene blue and anionic Congo red dyes. Four nanofiber composites containing thermally oxidized nanodiamond (TOND), ND, UiO-66, and TOND@UiO-66 are utilized tounravel the effect of nanoparticles type and loading on dye adsorption capacity. It is shown that incorporation of a small loading of nanoparticles in ECPN significantly enhaces the maximum dye adsorption capacity. More importantly, the rationally engineered hybrid TOND@UiO-66 nanoparticles exhibit the best performance in dye adsorption; for instance, an 80 % increase in maximum dye adsorption capacity, from 769 to 1429 mg/g, is recorded for ECPN loaded with TOND@UiO-66 compared to the unfilled ECPN. On top of that, the designed adsorbent showed appreciable regeneration ability after 6 adsorption–desorption cycles. All in all, this study offers a new generation of engineered advanced materials to remove emerging contaminants from water streams.Peer reviewe

Structured Ultra-Flyweight Aerogels by Interfacial Complexation: Self-Assembly Enabling Multiscale Designs

| openaire: EC/H2020/788489/EU//BioELCell Lisään tiedoston kun VoR julkaistaan lehden numerossa Funding Information: The authors acknowledge the funds provided by the Canada Excellence Research Chair Program (CERC‐2018‐00006) and Canada Foundation for Innovation (Project No. 38623). R.A. also acknowledges FinnCERES GoGlobal mobility fund for her exchange between Aalto University and University of British Columbia. O.J.R. is also grateful for the support received from the ERC Advanced Grant Agreement No. 788489 (“BioElCell”). M.A. acknowledges the financial support from Zentek Ltd. U.S. acknowledges the financial support from NSERC Discovery Grant 05503/2020. M.K. acknowledges Mr. Junhua Xu for his assistance with mechanical testing. We are thankful to Ms. Faezeh Bakhshi and Ms. Ayako Takagi for drawing the schematics. Publisher Copyright: © 2022 The Authors. Small published by Wiley-VCH GmbHThe rapid co-assembly of graphene oxide (GO) nanosheets and a surfactant at the oil/water (O/W) interface is harnessed to develop a new class of soft materials comprising continuous, multilayer, interpenetrated, and tubular structures. The process uses a microfluidic approach that enables interfacial complexation of two-phase systems, herein, termed as “liquid streaming” (LS). LS is demonstrated as a general method to design multifunctional soft materials of specific hierarchical order and morphology, conveniently controlled by the nature of the oil phase and extrusion's injection pressure, print-head speed, and nozzle diameter. The as-obtained LS systems can be readily converted into ultra-flyweight aerogels displaying worm-like morphologies with multiscale porosities (micro- and macro-scaled). The presence of reduced GO nanosheets in such large surface area systems renders materials with outstanding mechanical compressibility and tailorable electrical activity. This platform for engineering soft materials and solid constructs opens up new horizons toward advanced functionality and tunability, as demonstrated here for ultralight printed conductive circuits and electromagnetic interference shields.Peer reviewe

Waste organic dye removal using MOF-based electrospun nanofibers of high amine density

Funding Information: Dr. Arjmand would like to thank the Canada Research Chairs program for its financial support. The authors would like to acknowledge Syilx Okanagan First Nation for allowing to conduct research in their unceded ancestorial traditional territory. Mr. Ahmadijokani, Dr. Kamkar, and Dr. Rojas are grateful for funding support from the Canada Excellence Research Chair Program ( CERC-2018-00006 ) and the Canada Foundation for Innovation (Project number 38623). The authors also would like to thank Mr. Aydin Badrian (aydinbadrian.com) for his efforts on the graphical parts of this study. Publisher Copyright: © 2023 The AuthorsThe exceptional structural stability of UiO-66 metal–organic framework (MOF) and ligands' functional groups render UiO-66 as a versatile candidate for multiple applications, including wastewater treatment. The possibility of a broad spectrum of post-synthetic modification of UiO-66 further expands its prospective uses. However, commercial applications of UiO-66 have been hindered by the polycrystalline nature of the powder. In this research, modification to obtain UiO-66-NH2 and post-processing with nanofibers comprising chitosan and polyvinyl alcohol (PVA) were applied to faciliate deployment as a suitable option for water decontamination. MOF nanoparticles were post-synthetically modified with 2,4,6-trichloro-1,3,5-triazine (TCT) and 5-phenyl-tetrazole (PT) to produce high-amine containing UiO-66, thus introducing active nitrogen-containing functional groups that enhanced the removal efficiency of targeted molecules from aqueous media. A systematic study was undertaken to optimize the supporting nanofibers and to demonstrate that even a low MOF functionalization, of up to 7- wt%, offered a maximum methyl orange adsorption capacity of 619 mg/g, superior to most adsorbents reported so far. Furthermore, selectivity, regeneration ability, and the effect of ambient conditions were demonstrated.Peer reviewe