Facile Synthesis of Mesoporous Reduced Graphene Oxide Microspheres with Well-Distributed Fe2O3 Nanoparticles for Photochemical Catalysis

Low-cost and sensitive chemiluminescence detection of phthalates in environment by signal sensing of carbon-based materials from PVC/coal gangue dechlorination

BACKGROUND

The detection of plasticizers in the environment is important to prevent environmental risks and people's health hazards. Improving recycling efficiency of waste PVC still faced challenges.

RESULTS

In this work, it was found that solid products from waste PVC/coal gangue dechlorination in subcritical water (dPVC) had strong catalysis activity for luminol-H2O2 chemiluminescence (CL) reaction. Phthalates, common plasticizers, could bond and adsorb on dPVC, which greatly inhibited the luminol-H2O2-dPVC CL reaction. Based on this, a low-cost CL analysis was constructed for the detection of phthalates combinations (PACs) and di-(2-ethylhexyl) phthalate (DEHP) in the environment. The detection limit for PACs and DEHP was 0.048 ng/L and 0.13 ng/L, respectively. Compared with HPLC standard method, the dPVC CL analysis had accuracy and reliability for the detection of phthalates in actual environmental samples. Besides, the results of life cycle assessment (LCA) revealed that dPVC for CL sensing materials had significantly small global warming potential (GWP).

SIGNIFICANCE

The use of dPVC for CL sensing not only improved the recycling efficiency of PVC, but also reduced carbon emissions of obtaining CL sensing materials.

N/P co-doped MXene hollow microcapsules by surfactants assisted hydrothermal-freeze drying for adjustable permeability

The assembly of MXene materials into microcapsules has drawn great attentions due to their unique properties. However, rational design and synthesis of MXene-based microcapsules with specific nanostructures at the molecular scale remains challenging. Herein, we report a strategy to synthesize N/P co-doped MXene hollow flower-like microcapsules with adjustable permeability via dual surfactants assisted hydrothermal-freeze drying method. In contrast to anionic surfactants, cationic surfactants exhibited effective electrostatic interactions with MXene nanosheets during the hydrothermal process. Manipulation of dual surfactants in hydrothermal process realized N and P co-doping of MXene to improve flexibility and promoted the generation of abundant internal cavities in flower-like microcapsules. Based on the unique microstructure, the prepared hollow flower-like microcapsules showed excellent performance, stability and reusability in size-selective release of small organic molecules. Moreover, the release rate can be controlled by turning the oxidation state and type of MXene. The strategy delineates promising prospects for the design of MXene-based microcapsules with specific structures.

Tailored engineering of Fe3O4 and reduced graphene oxide coupled architecture to realize the full potential as electrode materials for lithium-ion batteries

Developing advanced electrode materials with appropriate compositions and exquisite configurations is crucial in fabricating lithium-ion batteries (LIBs) with high energy density and fast charging capability plateau. Herein, a Fe₃O₄@reduced graphene oxide (Fe₃O₄@rGO) coupled architecture was rationally designed and in-situ synthesized. Monodispersed mesoporous Fe₃O₄ nanospheres were homogeneously formed and strongly bound on interconnected macroporous rGO frameworks to form well-defined three-dimensional (3D) hierarchical porous morphologies. This tailored Fe₃O₄@rGO coupled architecture fully exploited the advantages of Fe₃O₄ and rGO to overcome their inherent challenges, including spontaneous aggregating/excessive restacking tendency, sluggish ions diffusion/electrons transportation, and severe volume expansion/structural collapse. Benefitting from their synergistic effects, the optimized Fe₃O₄@rGO composite electrode exhibited an improved electrochemical reactivity, electrical conductivity, electrolyte accessibility, and structural stability. The optimized composite electrode displayed a high specific capacity of 1296.8 mA h g^-1 at 0.1 A g^-1 after 100 cycles, even retaining 555.1 mA h g^-1 at 2 A g^-1 after 2000 cycles. The electrochemical kinetics analysis revealed the predominantly pseudocapacitive behaviors of the Fe₃O₄@rGO heterogeneous interfaces, accounting for the excellent electrode performance. This study proposes a viable strategy for use in engineering hybrid composites with coupled architectures to optimize their potential as high-performance electrode materials for use in LIBs.

A novel alkali activated magnesium silicate as an effective and mechanically strong adsorbent for methylene blue removal

A novel, cheap, and easy-to-synthesize sepiolite-based alkali-activated material (Sep-AAM), synthesized by the reaction of a magnesium silicate source, sepiolite, with sodium silicate solution, demonstrating high mechanical strength and methylene blue (MB) removal performance is introduced. Kinetics data indicated that MB adsorption occurs through pseudo-second-order adsorption kinetics model, while the Langmuir isotherm model provided a better fit to adsorption isotherms. The Sep-AAM provided a removal capacity of 99.92 mg g^-1 at 50 °C, setting a new benchmark value among the materials used for this purpose. Thermodynamical parameters indicated that the adsorption of MB onto Sep-AAM was endothermic and the interaction between Sep-AAM and MB included weak chemical bonding. Regenerability of the Sep-AAM in powder and monolith forms was confirmed up to four-cycles. Structural parameters determined by several characterization tools demonstrated that the surface hydroxyl groups are responsible for the superior MB adsorption performance. The mechanical strength measurements showed that Sep-AAM in monolith form displayed a remarkable compressive strength value of 40 MPa. To establish a new approach forward on the development of AAMs for wastewater treatment, this study shows that sepiolite can effectively be utilized and Sep-AAM provides a sustainable solution for dye removal with advanced mechanical properties.

Guanidyl-functionalized graphene/polysulfone mixed matrix ultrafiltration membrane with superior permselective, antifouling and antibacterial properties for water treatment

Mixed matrix membranes blended with graphene-based nanomaterials have great potential in water and wastewater treatment on account of their multiple functionalities. To solve the complicated biofouling problem and diversify the applications of membranes, novel synergistic antibacterial guanidyl-functionalized graphene/polysulfone (GFG/PSF) mixed matrix ultrafiltration membranes were prepared by a non-solvent induced phase separation method. The guanidyl-functionalized graphene nanosheets were achieved by a two-step grafting process consisting of amination and guanidination and exhibited high dispersibility in the casting solution, which showed good compatibility with the polymer matrix. Besides the advantages of partially reduced graphene oxide (GO) nanosheets in creating a stronger interaction with the bacterial cell membrane to destroy the bacteria, the induced bidendate binding between guanidyl groups and phosphate groups on the cell wall can make high sterilization rate even at low concentrations. Different techniques including XRD, FTIR, XPS, SEM, TEM, EDX, contact angle meter, filtration and antibacterial experiments were employed to characterize and investigate the performance of nanosheets and membranes. Compared with pure PSF membrane, the GFG/PSF mixed matrix membranes not only exhibited superior permeability and prominent antifouling property performance toward bovine serum albumin (BSA), but also displayed excellent antimicrobial activity and long-term duration toward Escherichia coli and Staphylococcus aureus.

Effect of reduced graphene oxide on the structural, optical, adsorption and photocatalytic properties of iron oxide nanoparticles

Effect of reduced graphene oxide on the structural and photocatalytic properties of Fe₂O₃ nanoparticles.

MOF the beaten track: unusual structures and uncommon applications of metal-organic frameworks

Over the past few decades, metal-organic frameworks (MOFs) have proved themselves as strong contenders in the world of porous materials, standing alongside established classes of compounds such as zeolites and activated carbons. Following extensive investigation into the porosity of these materials and their gas uptake properties, the MOF community are now branching away from these heavily researched areas, and venturing into unexplored avenues. Ranging from novel synthetic routes to post-synthetic functionalisation of frameworks, host-guest properties to sensing abilities, this review takes a sidestep away from increasingly 'traditional' approaches in the field, and details some of the more curious qualities of this relatively young family of materials.