Organic Amine-Mediated Synthesis of Polymer and Carbon Microspheres: Mechanism Insight and Energy-Related Applications

New strategy for reinforcing polylactic acid composites: Towards the insight into the effect of biochar microspheres

Having even particle size and regular morphology of biochar microspheres (BM) provides the possibility for preparing polylactic acid (PLA) films. Hence, the novelty is proposing a strategy for reinforcing PLA by BM. It was found that BM exhibited regular morphology, higher thermal stability, even particle size, and better pore characteristics. Although adding BM decreased the toughness of PLA due to the poor compatibility between BM and PLA, the nucleation effect of BM facilitated the crystallization in the PLA system. The tensile strength and modulus of BM/PLA composite films increased first and then decreased with increasing BM content. The stress concentration formed by BM particle agglomeration was responsible for the tensile strength and modulus decreases of BM/PLA composite films under higher BM addition. 2% BM added and 3% added composite films exhibited the best tensile strength and modulus with 64.99 MPa and 1.59 GPa, which was mainly attributed to the proper proportion of BM to PLA and the uniform distribution of BM in PLA. The results of this study confirmed the positive reinforcing effect of BM in PLA and are expected to be available in the composite film field.

Developing Eco-Friendly and Cost-Effective Porous Adsorbent for Carbon Dioxide Capture

To address the issue of global warming and climate change issues, recent research efforts have highlighted opportunities for capturing and electrochemically converting carbon dioxide (CO₂). Despite metal doped polymers receiving widespread attention in this respect, the structures hitherto reported lack in ease of synthesis with scale up feasibility. In this study, a series of mesoporous metal-doped polymers (MRFs) with tunable metal functionality and hierarchical porosity were successfully synthesized using a one-step copolymerization of resorcinol and formaldehyde with Polyethyleneimine (PEI) under solvothermal conditions. The effect of PEI and metal doping concentrations were observed on physical properties and adsorption results. The results confirmed the role of PEI on the mesoporosity of the polymer networks and high surface area in addition to enhanced CO₂ capture capacity. The resulting Cobalt doped material shows excellent thermal stability and promising CO₂ capture performance, with equilibrium adsorption of 2.3 mmol CO₂/g at 0 °C and 1 bar for at a surface area 675.62 m²/g. This mesoporous polymer, with its ease of synthesis is a promising candidate for promising for CO₂ capture and possible subsequent electrochemical conversion.

Preparation of Strong Antioxidative, Therapeutic Nanoparticles Based on Amino Acid-Induced Ultrafast Assembly of Tea Polyphenols

Nanoformulations offer the opportunity to overcome the shortcomings of drug molecules, such as low solubility, side effects, insufficient stability, etc., but in most of the current nanomedicines, nanocarriers as excipients do not directly participate in the therapy procedure. Accordingly, it is promising to develop the nanotherapeutics composed entirely of pharmaceutically active molecules. Tea polyphenols, especially epigallocatechin gallate (EGCG), are a kind of natural antioxidants with various biological and health beneficial effects and are extensively investigated as nutrients and anticancer drugs. Here, the size-tunable and highly active polyphenol nanoparticles were conveniently synthesized in water and could be massively produced with a simple facility. Compared to the previous strategies, either molecular assembly via oxidative coupling or combination with other biomacromolecules, the present preparation was conducted by the amino acid-triggered Mannish condensation reactions, thus permitting the flexible molecular design of various polyphenol nanoparticles by selecting different amino acids. This straightforward and ultrafast method actually opens up a novel means to make use of naturally reproducible polyphenols. Moreover, inheriting the salient properties of EGCG, these nanoparticles show strong antioxidation capacity, 10-fold higher than the extensively investigated polydopamine nanoparticles, and they are biosafe but have therapeutic effects, according to the in vitro and in vivo assessments of anticancer activity, which is promising for various biomedical purposes.

Honeycomb-like structure-tunable chitosan-based porous carbon microspheres for methylene blue efficient removal

Chitosan (CS) can be used for the preparation of carbon materials with different morphologies due to its excellent properties, but there are no reports on its spherical morphology. In this study, a feasible step-by-step strategy was proposed to fabricate nitrogen-containing chitosan-based porous carbon microspheres (CPCM) in HCl and KOH. The unique spherical morphology and honeycomb-like porous structure of CPCM were accurately regulated. A great quantity of micro/mesopores endowed CPCM an ultra-high specific surface area up to 2463.9 m² g^-1. Moreover, CPCM exhibited an ultra-high maximum adsorption capacity up to 1599.03 mg g^-1 for methylene blue (MB), meanwhile the adsorption process was in well agreement with the Langmuir isotherm and pseudo-second-order kinetic models. It was simultaneously a favorable reusable adsorbent with high regenerative capacity. The high dye adsorption properties suggest that chitosan can be a promising candidate for sewage treatment in the form of carbon microspheres.

Co-etching effect to convert waste polyethylene terephthalate into hierarchical porous carbon toward excellent capacitive energy storage

With the ever-increasing consumption of polyethylene terephthalate (PET) related products, how to recycle the waste PET still remains as a great challenge for the sustainable development. Converting waste PET into porous carbon material has been emerged as a promising way to address this issue. Recently, the microporous carbon derived from waste PET has drawn considerable attention in adsorption field, but its electrochemical application is still impeded by low specific surface area (SSA <1500 m² g^-1) and small meso-/macropores volume (<0.2 cm³ g^-1). Herein, hierarchical porous carbon (HPC) is successfully prepared from waste PET. The obtained HPC possesses a high SSA (2238 m² g^-1) and a large meso-/macropores volume (0.51 cm³ g^-1). The formation mechanism of hierarchical porous structure is proposed: co-etching effect of sp²/sp³ hybridized carbon produces micropores and meso-/macropores, respectively. In a three-electrode configuration, HPC based electrode achieves an outstanding capacitance of 413 F g^-1, while the traditional microporous carbon exhibits a low capacitance of 142 F g^-1. The fabricated symmetric supercapacitor shows a high energy density of 25 Wh kg^-1. This work provides a good reference to convert waste plastics into hierarchical porous carbon.

Controllable synthesis of mussel-inspired catechol-formaldehyde resin microspheres and their silver-based nanohybrids for catalytic and antibacterial applications

Size-controlled CFR microspheres and their silver-based nanohybrids were constructed and the nanohybrids display high catalytic reduction activity and antibacterial properties.

Mussel-Inspired Catechol-Formaldehyde Resin-Coated Fe3O4 Core-Shell Magnetic Nanospheres: An Effective Catalyst Support for Highly Active Palladium Nanoparticles

Magnetic Fe₃O₄@catechol-formaldehyde resin (CFR) core-shell nanospheres were fabricated via a controllable hydrothermal method. The shell thickness of Fe₃O₄@CFR nanospheres can be effectively regulated in the range of 10-170 nm via adjusting reaction parameters. In particular, catechol groups on the surface of nanospheres also play a significant role in mussel-inspired chemistry to further combine with graphene oxide (GO) to wrap the Fe₃O₄@CFR spheres. The obtained Fe₃O₄@CFR and Fe₃O₄@CFR@GO nanospheres can be used as the effective catalyst supports of small Pd nanoparticles (PdNPs, <10 nm) formed via an in situ synthesis route. The as-fabricated nanohybrid catalysts of Fe₃O₄@CFR@PdNPs and Fe₃O₄@CFR@GO@PdNPs with excellent dispersibility and stability are reusable after magnetic separation from catalytic systems. In particular, a super active performance was demonstrated for the catalytic reduction of methylene blue dye with highest turnover frequency (5260 min^-1) yet reported in the literature using a very low dosage of the Fe₃O₄@CFR@GO@PdNP catalyst. In addition, the Fe₃O₄@CFR@GO@PdNP catalyst also exhibits a highly catalytic efficiency for the Suzuki coupling reaction using pure water as a green solvent at room temperature.

Phosphonate-functionalized polystyrene microspheres with controlled zeta potential for efficient uranium sorption

A new method has been developed for effective uranium(vi) sorption from aqueous solution through phosphonate-functionalized polystyrene microspheres with controlled zeta potentials.