| 1. |
- Kebria, Mohammad Reza Shirzad, et al.
(författare)
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Hyper-branched dendritic structure modified PVDF electrospun membranes for air gap membrane distillation
- 2020
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Ingår i: Desalination. - : ELSEVIER. - 0011-9164 .- 1873-4464. ; 479, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Dendrimers are a new class of polymeric materials owning unique properties such as hydrophobicity. In this study, hydrophobic hyper-branched dendritic (HB-Den) structures were synthesized via a polycondensation reaction between hydroxyl groups of boehmite and carboxylic groups of nitrilotriacetic acid (NTA) and was used to improve the hydrophobicity of electrospun nanofibrous membranes (ENMs). Effects of the different contents of HB-Den structures on membrane morphology, elemental properties, surface hydrophobicity, desalination performance and antifouling properties were assessed by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), water contact angle measurements and air gap membrane distillation (AGMD) experiments. Digital microscopy images showed monodisperse dendrimers with a tree-like structure. The water contact angle and liquid entry pressure (LEP) increased from around 129.3 degrees and 101 +/- 3.1 kPa for a neat PVDF membrane to 138.3 degrees and 121 +/- 2.2 kPa upon loading with 0.075 wt% HB-Den structures. FTIR analysis of the HB-Den containing ENMs confirmed the presence of carboxylic groups of NTA on the membrane surface. After desalination experiments, the 0.075 wt% HB-Den ENM showed a stable flux of 10.7 kg/m(2) h and 99.9% NaCl rejection over 15 h filtration of a 3.5 g/l NaCI solution. The anti-fouling properties of the ENMs were also enhanced by incorporation of the dendritic structures. The 0.075 wt% HB-Den ENM showed flux recovery of about 94% after 20 h desalination experiment using real seawater as a feed solution.
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| 2. |
- Mousavinejad, Atiyeh, et al.
(författare)
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Nickel-Based Metal–Organic Frameworks to Improve the CO2/CH4 Separation Capability of Thin-Film Pebax Membranes
- 2020
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 59:28, s. 12834-12844
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Tidskriftsartikel (refereegranskat)abstract
- Incorporating metal–organic frameworks (MOFs) into the thin layer of thin-film composite (TFC) membranes is an effective way of improving the CO2/CH4 separation performance. In this study, porous polyethersulfone (PES) membranes were surface-coated with a novel CO2-permeable layer consisting of CO2-philic Pebax and nickel-based MOF particles. The MOF particles were synthesized using nickel(II) acetate tetrahydrate as a metal source and 2-amino-1,4-dicarboxybenzene (NH2-BDC) as an organic linker. The properties and performance of the MOFs and synthesized membranes were assessed using analytical techniques including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM), and dynamic light scattering (DLS). DLS analysis showed that the MOF particle size range was in a range of 350–650 nm. Moreover, cross-sectional FE-SEM images depicted that a uniform and dense Pebax layer was shaped on top of the PES substrate. Well dispersion of the particles was demonstrated by surface FE-SEM imaging. DSC analysis showed that embedding Ni-NH2-BDC MOF particles into the Pebax-1657 film increased the crystallinity degree and the glass-transition temperature (Tg) of resulted membranes. To evaluate the membrane’s separation performance, permeation experiments were performed with CO2, CH4, and CO2/CH4 mixtures at ambient temperature. Embedding 5 wt % Ni-based MOF particles improved the CO2 permeability and CO2/CH4 selectivity from 19.05 Barrer and 32.2 to 31.55 Barrer and 94, respectively, compared to MOF-free membranes. Loading MOF particles into the Pebax matrix also improved the real gas separation factor. The obtained results demonstrate the great potential of the fabricated TFC membranes for gas separation.
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| 3. |
- Shirzad Kebria, Mohammad Reza, et al.
(författare)
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Efficient removal of perfluorobutanesulfonic acid from water through a chitosan/polyethyleneimine xerogel
- 2023
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Ingår i: Chemical Engineering Journal. - 1385-8947. ; 466
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Tidskriftsartikel (refereegranskat)abstract
- Due to the recently ratified legislations, the use of long-chain poly- and perfluoroalkyl substances (PFASs) must be reduced and in the absence of a safe alternative, short-chain PFASs are currently used in their place. The continuously growing utilization of the short-chain PFASs, results in their abrupt introduction in the environment, and highlights the importance of adopting efficient remediation strategies. This study addresses an appropriate solution to remove perfluorobutanesulfonic acid (PFBS) from aqueous media through a static adsorption process. Specifically, a chitosan/polyethyleneimine based composite xerogel was prepared and its ability to remove PFBS from water was studied in detail. Behavioral patterns of the PFBS adsorption process were perused over a broad range of concentrations from ppb to ppm, and the adsorption studies reveal that the maximum PFBS adsorption capacity reaches up to 305 mg/g within 24 h from the beginning of the process. In addition to the electrostatic interaction between the amine groups of the xerogels and the negatively charged PFBS molecules, the formation of hydrogen bonds were also revealed by the chemical characterization and confirmed by molecular dynamics simulation studies.
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