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The adsorption is widely used to remove dyes from wastewater because of its low cost, simple preparation, and environmental friendliness. However, the existing adsorbents suffer from difficult recycling, inconvenient use, and a low regeneration rate. In this study, polyacrylonitrile (PAN) and graphene oxide (GO) was mixed for electrospinning GO/PAN...
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The extraction of quinolone antibiotics (QAs) is crucial for the environment and human health. In this work, polyacrylonitrile (PAN)/covalent organic framework TpPa–1 nanofiber was prepared by an electrospinning technique and used as an adsorbent for dispersive solid-phase extraction (dSPE) of five QAs in the honey and pork. The morphology and stru...
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... One effective strategy to enhance the stability of GO layers is to introduce cross-linking agents. Chitosan (CS), with its high stability and ultra-high dye adsorption capacity, is a good choice for a crosslinking agent [34,35] . For example, Lu et al. constructed CS-GO/polyacrylonitrile (PAN) nanofiber membranes by grafting CS onto GO. ...
Graphene oxide (GO) membranes hold significant promise for the water purification. However, they also face the problem of structural swelling, which limits their use in water treatment applications. In this work, a novel dual-modulated core-shell metal-organic framework@Chitosan (MOF@CS) was successfully synthesized and used as an intercalation cross-linker to optimize the interlayer spacing and stability of GO membranes. Molecular dynamics simulation confirms that MOF@CS, acting as an intercalator, accelerates the water diffusion rate within the channels of the GO layer compared to a pure GO layer. At the same time, Fourier Transform Infrared Spectroscopy analysis reveals that MOF@CS serves as a cross-linker for covalently cross-linking the GO layer. The nanofiltration performance and stability of the improved MOF@CS-GO composite membranes were significantly enhanced. Compared to the pure GO membranes, the MOF@CS-GO composite membranes exhibited enhanced Congo red rejection rates (from 76.5% to 95.6%) while maintaining a high pure water flux (34.5 L·m-2·h-1·bar-1) and good structural stability (stable dye removal performance over 120 h). This dual regulation strategy is expected to effectively solve the swelling problem of GO membranes in aqueous media and open up avenues for advancing their performance.
... Both membranes showed the characteristic peaks for PAN: C≡ stretching vibration and C-H stretching vibration were observed at 2244 cm −1 and 344 cm −1 , respectively [48]. Additionally, the C=O stretching vibration at 1667 cm −1 may b derived from the hydrophilic polymer during the PAN synthesis [49]. FTIR spectroscopy was used to analyze the functional groups in the PAN and H-PAN membranes [46,47]. ...
... Both membranes showed the characteristic peaks for PAN: C≡N stretching vibration and C-H stretching vibration were observed at 2244 cm −1 and 3448 cm −1 , respectively [48]. Additionally, the C=O stretching vibration at 1667 cm −1 may be derived from the hydrophilic polymer during the PAN synthesis [49]. Figure 5b shows the XPS spectra of the PAN and H−PAN membranes, while Tabl shows the changes occurring in the elemental contents. ...
This study used polyacrylonitrile (PAN) and heat-treated polyacrylonitrile (H-PAN) membranes to enrich nutmeg essential oils, which have more complex compositions compared with common oils. The oil rejection rate of the H-PAN membrane was higher than that of the PAN membrane for different oil concentrations of nutmeg essential oil-in-water emulsions. After heat treatment, the H-PAN membrane showed a smaller pore size, narrower pore size distribution, a rougher surface, higher hydrophilicity, and higher oleophobicity. According to the GC-MS results, the similarities of the essential oils enriched by the PAN and H-PAN membranes to those obtained by steam distillation (SD) were 0.988 and 0.990, respectively. In addition, these two membranes also exhibited higher essential oil rejection for Bupleuri Radix, Magnolia Officinalis Cortex, Caryophylli Flos, and Cinnamomi Cortex essential oil-in-water emulsions. This work could provide a reference for membrane technology for the non-destructive separation of oil with complex components from oil-in-water emulsions.
... It also provides new functional groups that act as active sites for contaminants [23]. Several research studies have documented the use of grafted CHS for the removal of contaminants such as Cr (VI) [24], anionic methyl orange dye [25], sunset yellow dye [26], Co 2+ and Sr 2+ metal ions [27], Cu 2+ ions [28], and anti-inflammatory pharmaceuticals [29]. Aromatic rings are one type of functional groups that can be grafted on the CHS's backbone to offer an aromatic system capable of interacting with the aromatic system of RO16 dye via π-π interaction, thus enhancing the adsorption of organic dyes containing aromatic rings [30]. ...
The present study employed the hydrothermal technique to graft biopolymer chitosan (CHS) with an aromatic aldehyde (salicylaldehyde, SA) for the adsorption of an acidic azo dye (reactive orange 16, RO 16) from an aqueous environment. The obtained hydrothermally achieved Schiff’s base (chitosan-salicylaldehyde, CHS-SA) material was analyzed using BET, CHN-O, FTIR, SEM, XRD, and pHpzc. The impacts of A: CHS-SA dosage (0.02–0.08 g/100 mL), B: pH (4–10), and C: time (5–25 min) factors on the adsorption performance of CHS-SA towards RO16 dye were fully examined using Box-Behnken design (BBD). The pseudo-second-order model exhibited the greatest match for the adsorption of RO16 dye by CHS-SA, whilst the equilibrium isotherm observations matched the Freundlich model. The maximal adsorption capacity of CHS-SA as established by the Langmuir model was 143.4 mg/g. Several pathways, including electrostatic attraction, π-π stacking, n-π interaction, and H-bonding drive the RO16 adsorption by CHS-SA. This work supports the idea of a hydrothermal way to produce grafted CHS-SA capable of removing harmful contaminants from an aquatic environment.
... During heat treatment, the carboxyl group on GO sheets nucleophilically attacks the carbon of the cyano group to initiate the anionic cyclization of the PAN molecular chain, which in turn connects GO and PAN to form a more stable membrane structure [26]. Graphene oxide-polyacrylonitrile composites have applications in the fields of electrochemistry, dye removal, and VOC adsorption [27][28][29][30] but have been rarely used in direct immersion SPME. ...
Pufferfish is nutritious and delicious, but the tetrodotoxin (TTX) that may exist in its body poses a serious safety hazard. It is important to use scientific and effective methods to detect the TTX in pufferfish, but most of the existing methods require complex pre-treatment steps and have sample lethality. The solid-phase microextraction (SPME) technology can be used for in vivo detection due to its advantages such as no solvent demand, simple operation, and fast detection speed. In this study, the GO-PAN@PNE SPME fibers were made via a dipping method, and their extraction effect was verified in the TTX aqueous and spiked fish. The established method has good reproducibility, and the limit of detection of TTX in pufferfish was 32 ng·g−1, and the limit of quantitation was 150 ng·g−1, which can meet the detection needs of pufferfish for safe consumption. This method was used to in vivo detect the Takifugu obscurus exposed to the TTX, to determine the content of TTX in the pufferfish muscle. The detection method established in this study can relatively quickly and easily realize the in vivo detection of TTX in the pufferfish, which can provide theoretical support for improvement in the food safety level of the pufferfish.
For reclaiming contaminated water, nanoparticle-incorporated porous polymeric membranes provide the requisite functionality for efficient and selective adsorption of toxic molecules. To this end, a simple yet innovative material selection strategy was adopted to prepare a robust and high-performance membrane system by the phase-inversion method using thermoplastic polyurethane (TPU), Laponite, graphene oxide (GO) and a hybrid derived from their aqueous “co-dispersion”, viz., Laponite/GO (LGO). The addition of 12 wt% LGO substantially improved the hydrophilicity, porosity, pure water flux (PWF), and mechanical properties of TPU membranes. Notably, the above membrane showed a striking 20-fold increase in PWF (from ∼27 to ∼652 Lm-2h−1), a 43-fold increase in elastic modulus, a 10-fold increase in tensile strength and a 3-fold increase in toughness and displayed synergistic improvement in mechanical properties. At 12 wt% LGO, the rejection efficiency of > 98%, >95%, and ∼86%, and the adsorption capacity of ∼47 mg/g, ∼49.3 mg/g and ∼16.8 mg/g for methylene blue (MB), crystal violet (CV) and rhodamine B (RhB) dyes, respectively were observed. The dye adsorption efficiency was comparable with that of poly(vinylidene fluoride) (PVDF)-LGO membranes. Owing to the anionic functional groups in LGO, the nanocomposite membranes displayed excellent selectivity of adsorption. The dye adsorption by the nanofiller-TPU membranes showed a pseudo-2nd-order kinetic behavior, indicating chemisorption; while the pristine TPU showed marginal physisorption of dyes. The LGO-filled membranes also showed efficient adsorption of Pb2+ and As5+ ions from water, with efficiency increasing with LGO content, showing > 90% efficiency with 15 wt% LGO. The nanocomposite membranes showed no cytotoxicity effect and supported the proliferation of human epidermal keratinocytes (HaCaT) cells. On these accounts, the LGO-TPU membranes promise the development of high-performance and cost-effective filtration membranes.
In the era of rapid and conspicuous progress of water treatment technologies, combined adsorption and membrane filtration systems have gained great attention as a novel and efficient method for contaminant removal from aqueous phase. Further development of these techniques for water/wastewater treatment applications will be promising for the recovery of water resources as well as reducing the water tension throughout the world. This review introduces the state-of-the-art on the capabilities of the combined adsorption-membrane filtration systems for water and wastewater treatment applications. Technical information including employed materials, superiorities, operational limitations, process sustainability and upgradeing strategies for two general configurations i.e. hybrid (pre-adsorption and post-adsorption) and integrated (film adsorbents, low pressure membrane-adsorption coupling and membrane-adsorption bioreactors) systems has been surveyed and presented. Having a systematic look at the fundamentals of hybridization/integration of the two well-established and efficient separation methods as well as spotlighting the current status and prospectives of the combination strategies, this work will be valuable to all the interested researchers working on design and development of cutting-edge wastewater/water treatment techniques. This review also draws a clear roadmap for either decision making and choosing the best alternative for a specific target in water treatment or making a plan for further enhancement and scale-up of an available strategy.
Zein as a natural protein had been widely used in various fields due to its biodegradability and biocompatibility. However, its sensitivity to humidity and poor mechanical performance limited its application in practice. In this study, zein-based composite nanofibers loaded with curcumin were prepared by electrospinning assisted with polyvinyl alcohol (PVA). The filtration efficiency of the modified nanofibers to the particles with diameters larger than 0.5 μm was all above 98%. The loaded curcumin interacted with protein molecular chains to form a network structure within tightly connected nanofibers, which exhibited excellent moisture resistance and good adhesion to cellulose paper towels used as air filter substrates. Meanwhile, its tensile strength had also been enhanced vastly to 0.72 MPa compared with the initial tensile strength of 0.21 MPa. This study provides a new electrospinning strategy for the preparation of zein-based composite nanofibers that can be widely utilized in air filtration with high moisture resistance.
Zein as a natural protein had been widely used in various fields due to its biodegradability and biocompatibility. However, its sensitivity to humidity and poor mechanical performance limited its application in practice. In this study, zein-based composite nanofibers loaded with curcumin were prepared by electrospinning assisted with polyvinyl alcohol (PVA). The filtration efficiency of the modified nanofibers to the particles with diameters larger than 0.5 µm was all above 98%. The loaded curcumin interacted with protein molecular chains to form a network structure within tightly connected nanofibers, which exhibited excellent moisture resistance and good adhesion to cellulose paper towels used as air filter substrates. Meanwhile, its tensile strength had also been enhanced vastly to 0.72 MPa compared with the initial tensile strength of 0.21 MPa. This study provides a new electrospinning strategy for the preparation of zein-based composite nanofibers that can be widely utilized in air filtration with high moisture resistance.
