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This study was inspired by the unique multi-scale and multi-level ‘brick-and-mortar’ (B&M) structure of nacre layers. We prepared the B&M, environmentally-friendly graphene oxide-carrageenan (GO-Car) nanocomposite films using the following steps. A natural polyhydroxy polymer, carrageenan, was absorbed on the surface of monolayer GO nanosheets through hydrogen-bond interactions. Following this, a GO-Car hybridized film was produced through a natural drying process. We conducted structural characterization in addition to analyzing mechanical properties and cytotoxicity of the films. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses showed that the nanocomposite films had a similar morphology and structure to nacre. Furthermore, the results from Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Thermogravimetric (TG/DTG) were used to explain the GO-Car interaction. Analysis from static mechanical testers showed that GO-Car had enhanced Young’s modulus, maximum tensile strength and breaking elongation compared to pure GO. The GO-Car nanocomposite films, containing 5% wt. of Car, was able to reach a tensile strength of 117 MPa. The biocompatibility was demonstrated using a RAW264.7 cell test, with no significant alteration found in cellular morphology and cytotoxicity. The preparation process for GO-Car films is simple and requires little time, with GO-Car films also having favorable biocompatibility and mechanical properties. These advantages make GO-Car nanocomposite films promising materials in replacing traditional petroleum-based plastics and tissue engineering-oriented support materials. [ABSTRACT FROM AUTHOR]

Coal fly aerogel (CFAA), as a low-cost, recyclable and highly efficient U(VI) adsorbent, was successfully prepared. Notably, the removal rate for U(VI) of CFAA was up to 94.5% (Co = 10 mg L-1, m/V = 1.0 g L-1, T = 2981<, t = 24 h and pH = 3.0), which was much higher than previous studies. Meanwhile, the maximum removal capacity of U(VI) on CFAA was 110.73 mg g-1 (m/V = 1.0 g L-1, T = 298 K, t = 24 h and pH = 3.0), which was nearly twice as much as untreated coal fly ash. Notable, the removal rate of U(VI) by CFAA was more than 80% after five cycles, indicating that CFAA was a recyclable adsorbent. In addition, Pseudo-second-order and Langmuir model were more suitable to describe the adsorption behavior on the surface of CFAA, meaning that the rate limiting step might be chemical sorption or chemisorption involving valency forces through sharing or exchange of electrons between sorbent and sorbate. The conclusions of SEM, FTLow-IR, XRD as well as XPS further illustrated that adsorption behavior for U(VI) of CFAA was mainly depended on the groups on the surface of CFAA, such as OH-, SiO- and AIO-. In conclusion, CFAA could be considered as an excellent candidate for the capture of U(VI) from wastewater. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) MoS2 coated CoS2-nitrogen doped graphene (NG) (CoS2@MoS2-NG) hybrid has been synthesized by a one step hydrothermal method as supercapacitor (SC) electrode material for the first time. Such a composite consists of NG embedded with stacked CoS2@MoS2 sheets. With a 3D skeleton, it prevents the agglomeration of CoS2@MoS2 nanoparticles, resulting in sound conductivity, rich porous structures and a large surface area. The results indicate that CoS2@MoS2-NG has higher specific capacitance (198 F g−1 at 1 A g−1), better rate performance (with about 56.57% from 1 to 16 A g−1) and an improved cycle stability (with about 96.97% after 1000 cycles). It is an ideal candidate for SC electrode materials. [ABSTRACT FROM AUTHOR]

Robust, high-strength and environmentally friendly antibacterial composite films were prepared by simply blending konjac glucomannan (KGM) and silver nanowires (Ag NWs) in an aqueous system. The samples were then characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), thermal gravimetric analysis, mechanical property tests, Fourier transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS) and antimicrobial tests. The results showed that there was a high ratio of Ag NWs uniformly distributed in the composite films, which was vital for mechanical reinforcement and stable antibacterial properties. The enhanced thermal stability and mechanical intensity increased, while the elongation at break was reduced with an increase in the amount of Ag NWs found in the composite films. When the percentage of Ag NWs in the composite films reached 5%, the tensile strength was 148.21 MPa, Young’s modulus was 13.79 GPa and the ultimate strain was 25.28%. Antibacterial tests showed that the KGM films had no antibacterial effect. After the addition of Ag NWs, the composite films had an obvious inhibitory effect on bacteria, with the uniform dispersion of Ag NWs promoting the antibacterial effect to a certain degree. These results indicated that these composite films would have a potential application in the fields of environmentally friendly packaging or medicine. [ABSTRACT FROM AUTHOR]

With the development of nuclear energy, the removal/recovery of radionuclides has attracted increasing attention. Here, an ultra-light, super-elastic, konjac glucomannan/graphene oxide composite aerogel (KGCA) as a high performance adsorbent for radionuclide removal/recovery was fabricated by a three-step process of freeze-casting, freeze-drying, and carbonization. The as-prepared bionic structured KGCA showed ultralow density, high specific surface area, desirable super-elasticity, and abundant oxygen-containing functional groups. Batch adsorption results demonstrated the maximum adsorption capacity of uranium (U(VI)) on KGCA is as high as 513.4 mg g−1, far exceeding other biomass carbon aerogels. Furthermore, KGCA showed good radiation stability, selective adsorption of U(VI), and high recycling performance. The KGCA also showed good adsorption properties even under simulated seawater or high salt concentration. Thus, these ultra-light and super-elastic biomass-derived composite aerogels could have a wide range of applications for nuclear wastewater treatment in the future. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT)-based materials have attracted tremendous interest for their high performance in oil separation. However, the preparation of CNT based materials always require harmful and expensive chemicals. Here, a biological assembly route was applied to assemble CNTs onto a fungal hyphae (FH) to produce FH/CNTs composites, followed by pyrolysis to obtain a hydrophobic CNT based aerogel for oil separation, which is a more environmentally friendly process. The as-prepared FH/CNTs-800 aerogel (pyrolyzed at 800 °C) showed hydrophobicity with a water contact angle of 143° and high specific surface area (1041.2 m2 g−1). The oil absorption results showed that the as-prepared FH/CNTs aerogels could absorb a wide range of oils with high absorption capacities ranging from 48 to 138 times their own weight. Furthermore, the oil-loaded aerogel was recycled through burning with little reduction in the oil absorption capacity. In addition, FH/CNTs-800 provided a high specific capacitance of 232 F g−1 at 1 A g−1 and maintained a capacity retention of 70.62% at 20 A g−1. Therefore, this study offers a simple, low-cost and environmentally friendly bioassembly route for large-scale assembly of CNTs into macroscopic 3D hydrophobic aerogels for highly efficient water-oil separation. [ABSTRACT FROM AUTHOR]