In this study, the hydrogel materials of reduced graphene oxide (RGO)/chitosan/silver nanoparticle composites were designed and prepared via a self-assembly process and simultaneous reduction of chitosan molecules with GO. These as-prepared hydrogels were characterized by different techniques. The morphology of the internal network structure of the nanocomposite hydrogels was investigated. The catalytic capacity results demonstrate that the prepared GO-based composite hydrogels can efficiently remove two tested dye molecules from wastewater in good accordance with the pseudo-second-order model. The dye photocatalytic capacity of the obtained hydrogels is mainly attributed to the silver nanoparticle on RGO sheets, whereas the chitosan molecule was incorporated to facilitate the gelation process of the GO sheets. Interestingly, the as-prepared catalytic composite material serves as a good photocatalyst for two presently used dyes even for dye mixtures, suggesting the potentially real applications of the GO composite materials for wastewater treatment as well as the removal of harmful dyes.
New
hierarchical bioinspired nanocomposite materials of poly(vinyl
alcohol)/poly(acrylic acid)/carboxylate graphene oxide nanosheet@polydopamine
(PVA/PAA/GO-COOH@PDA) were successfully prepared by electrospinning
technique, thermal treatment, and polydopamine modification. The obtained
composite membranes are composed of polymeric nanofibers with carboxylate
graphene oxide nanosheets, which are anchored on the fibers by heat-induced
cross-linking reaction. The preparation process demonstrate eco-friendly
and controllable manner. These as-formed nanocomposites were characterized
by various morphological methods and spectral techniques. Due to the
unique polydopamine and graphene oxide containing structures in composites,
the as-obtained composite demonstrate well efficient adsorption capacity
toward dye removal, which is primarily due to the specific surface
area of electrospun membranes and the active polydopamine/graphene
oxide components. In addition, the composite membranes reported here
are easy to regenerate. In comparison with other composite adsorbents,
the preparation process of present new composite materials is highly
eco-friendly and facile to operate and regulate, which demonstrates
potential large-scale applications in wastewater treatment and dye
removal.
MXene
as a kind of two-dimensional nanomaterial has aroused people’s
strong research interest because of its excellent properties. In the
present study, we introduced a new poly(vinyl alcohol)/poly(acrylic
acid)/Fe
3
O
4
/MXene@Ag nanoparticle composite
film fabricated by electrospinning and heat treatment as well as self-reduction
reaction process. The obtained composite films showed high self-reduction
ability because of the incorporation of MXene flakes. The intercalated
MXene flakes in the composite nanofibers were evenly distributed,
which not only solved the aggregation problem from MXene dispersion
but also could self-reduce Ag nanoparticles in situ in composite materials.
In addition, the composite nanofiber films exhibited good fiber structure,
thermal stability, and magnetic properties. Moreover, the composite
nanofiber films demonstrated excellent catalytic ability and cycle
stability to 4-nitrophenol and 2-nitroaniline.
Two-dimensional
(2D) carbon nanomaterials generally display some
limitations in adsorption applications due to easy agglomeration.
To solve this problem, as-synthesized sandwiched nanocomposites made
of Fe3O4 nanoparticles, poly(allylamine) hydrochloride
molecules, and carboxylate graphene oxide sheets were prepared using
a layer-by-layer (LbL) self-assembly method. The successfully synthesized
sandwiched structures in the present nanocomposites have outstanding
organic dye adsorption performance, stability, and recycling. The
agglomeration of carboxylate graphene oxide was reduced with increased
specific surface area because the Fe3O4 nanoparticles
play important roles in interpenetrating and supporting graphene oxide
sheets layers. In comparison with other kinds of composite adsorbents,
the preparation process of the present new sandwiched composite materials
is facile to operate and regulate, which demonstrates potential large-scale
applications in wastewater treatment and dye removal.
Recently, air pollution has become more serious and started to have a dramatic effect on the health of humans in many large cities. Generally, outdoor personal protection, such as commercial masks, cannot effectively prevent the inhalation of many pollutants. Particulate matter (PM) pollutants are a particularly serious threat to human health. Here we introduce a new efficient air filtration mat that can be used for outdoor protection. The new efficient air filter's nanocomposite materials were successfully fabricated from poly(εcaprolactone)/polyethylene oxide (PCL/PEO) using an electrospinning technique and solvent vapor annealing (SVA). SVA treatment endows the wrinkled fiber surface and enhances the PM2.5 capture capacity of protective masks. This nanowrinkled air filtration mat can effectively filter PM2.5 with a removal efficiency of 80.01% under seriously polluted conditions (PM2.5 particle concentration above 225 mg m −3). Our field test in Qinhuangdao indicated that the air filtration mat had a high PM2.5 removal efficiency under thick haze. Compared to commercial masks, the fabricated SVA-treated PCL/PEO air filter mat demonstrated a simpler and ecofriendly preparation process with excellent degradation characteristics, showing wide potential applications with a high filtration efficiency.
The application of polyelectrolyte multilayer films is a new, versatile approach to surface modification of decellularized tissue, which has the potential to greatly enhance the functionality of engineered tissue constructs derived from decellularized organs. In the present study, we test the hypothesis that Heparin- vascular endothelial growth factor (VEGF) multilayer film can not only act as an antithrombotic coating reagent, but also induce proliferation of endothelial progenitor cells (EPCs) on the decellularized aortic heart valve. SEM demonstrated the adhesion and geometric deformation of platelets. The quantitative assay of platelet activation was determined by measuring the production of soluble P-selectin. Binding and subsequent release of heparin and VEGF from valve leaflets were assessed qualitatively by laser confocal scanning microscopy and quantitatively by ELISA methods. Human blood derived EPCs were cultured and the adhesion and growth of EPCs on the surface modified valvular scaffolds were assessed. The results showed that Heparin-VEGF multilayer film improved decellularized valve haemocompatibility with respect to a substantial reduction of platelet adhesion. Release of VEGF from the decellularized heart valve leaflets at physiological conditions was sustained over 5 days. In vitro biological tests demonstrated that EPCs achieved better adhesion, proliferation and migration on the coatings with Heparin-VEGF multilayer film. Combined, these results indicate that Heparin-VEGF multilayer film could be used to cover the decellularized porcine aortic valve to decrease platelet adhesion while exhibiting excellent EPCs biocompatibility.
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