Nacre-Templated Synthesis of Highly Dispersible Carbon Nanomeshes for Layered Membranes with High-Flux Filtration and Sensing Properties

Seafood waste derived carbon nanomaterials for removal and detection of food safety hazards

Nanobiotechnology and the engineering of nanomaterials are currently the main focus of many researches. Seafood waste carbon nanomaterials (SWCNs) are a renewable resource with large surface area, porous structure, high reactivity, and abundant active sites. They efficiently adsorb food contaminants through π-π conjugated, ion exchange, and electrostatic interaction. Furthermore, SWCNs prepared from seafood waste are rich in N and O functional groups. They have high quantum yield (QY) and excellent fluorescence properties, making them promising materials for the removal and detection of pollutants. It provides an opportunity by which solutions to the long-term challenges of the food industry in assessing food safety, maintaining food quality, detecting contaminants and pretreating samples can be found. In addition, carbon nanomaterials can be used as adsorbents to reduce environmental pollutants and prevent food safety problems from the source. In this paper, the types of SWCNs are reviewed; the synthesis, properties and applications of SWCNs are reviewed and the raw material selection, preparation methods, reaction conditions and formation mechanisms of biomass-based carbon materials are studied in depth. Finally, the advantages of seafood waste carbon and its composite materials in pollutant removal and detection were discussed, and existing problems were pointed out, which provided ideas for the future development and research directions of this interesting and versatile material. Based on the concept of waste pricing and a recycling economy, the aim of this paper is to outline current trends and the future potential to transform residues from the seafood waste sector into valuable biological (nano) materials, and to apply them to food safety.

Hard-Carbon Negative Electrodes from Biomasses for Sodium-Ion Batteries

With the development of high-performance electrode materials, sodium-ion batteries have been extensively studied and could potentially be applied in various fields to replace the lithium-ion cells, owing to the low cost and natural abundance. As the key anode materials of sodium-ion batteries, hard carbons still face problems, such as poor cycling performance and low initial Coulombic efficiency. Owning to the low synthesis cost and the natural presence of heteroatoms of biomasses, biomasses have positive implications for synthesizing the hard carbons for sodium-ion batteries. This minireview mainly explains the research progress of biomasses used as the precursors to prepare the hard-carbon materials. The storage mechanism of hard carbons, comparisons of the structural properties of hard carbons prepared from different biomasses, and the influence of the preparation conditions on the electrochemical properties of hard carbons are introduced. In addition, the effect of doping atoms is also summarized to provide an in-depth understanding and guidance for the design of high-performance hard carbons for sodium-ion batteries.

From the teapot effect to tap-triggered self-wetting: a 3D self-driving sieve for whole blood filtration

Achieving passive microparticle filtration with micropore membranes is challenging due to the capillary pinning effect of the membranes. Inspired by the teapot effect that occurs when liquid (tea) is poured from a teapot spout, we proposed a tap-triggered self-wetting strategy and utilized the method with a 3D sieve to filter rare cells. First, a 3D-printed polymer tap-trigger microstructure was implemented. As a result, the 3 µm micropore membrane gating threshold (the pressure needed to open the micropores) was lowered from above 3000 to 80 Pa by the tap-trigger microstructure that facilated the liquid leakage and spreading to self-wet more membrane area in a positive feedback loop. Then, we implemented a 3D cone-shaped cell sieve with tap-trigger microstructures. Driven by gravity, the sieve performed at a high throughput above 20 mL/min (DPBS), while the micropore size and porosity were 3 µm and 14.1%, respectively. We further filtered leukocytes from whole blood samples with the proposed new 3D sieve, and the method was compared with the traditional method of leukocyte isolation by chemically removing red blood cells. The device exhibited comparable leukocyte purity but a higher platelet removal rate and lower leukocyte simulation level, facilitating downstream single-cell analysis. The key results indicated that the tap-triggered self-wetting strategy could significantly improve the performance of passive microparticle filtration.

Preparation and application performance study of biomass-based carbon materials with various morphologies by a hydrothermal/soft template method

Nitrogen-doped carbon materials with controllable morphologies were prepared via a soft template method using chitosan as the carbon and nitrogen source and F127 or ionic liquid as the template. The performance of the materials as electrodes and adsorbents for carbon dioxide removal were evaluated. Carbon spheres (CSs) with developed micropore structures were obtained without a template, whereas a tubular structure (CSF) containing mesopores with long-range order was obtained using F127. Layered carbon (CSI) containing micro-/mesopores with short- and long-range order was obtained using an ionic liquid. The samples exhibited graphite-like structure and the soft template increased the graphitization degree. Nitrogen existed mainly in the form of pyridine and pyridone groups in CSs and CSF and as pyridine, pyridone, and quaternary groups in CSI. The specific capacitances of CSs, CSF, and CSI were 144, 161, and 178 F g^-1, respectively, at a current density of 1.0 A g^-1 in 1 M sulfuric acid. The carbon dioxide adsorption capacities of CSs, CSF, and CSI were 142, 73, and 115 mg g^-1, respectively; CSs displayed the highest value because of its developed micro- and ultramicroporous structure. Our results indicated that these carbon materials with various morphologies can be used as both electrodes and adsorbents.