Covalent organic frameworks: Pioneering remediation solutions for organic pollutants

Covalent Organic Frameworks (COFs) have emerged as a promising class of crystalline porous materials with customizable structures, high surface areas, and tunable functionalities. Their unique properties make them attractive candidates for addressing environmental contamination caused by pharmaceuticals, pesticides, industrial chemicals, persistent organic pollutants (POPs), and endocrine disruptors (EDCs). This review article provides a comprehensive overview of recent advancements and applications of COFs in removing and remedying various environmental contaminants. We delve into the synthesis, properties, and performance of COFs and their potential limitations and future prospects.

A high valence binary metal-organic framework as an electrode material for aqueous asymmetric supercapacitors

This study presents the chemical transformation of nickel-based metal-organic frameworks into binary metal-organic frameworks by introducing cobalt metal ions. The resulting NiCo-BDC hierarchical nanostructure exhibited higher oxidation states, resulting in an impressive capacitance of 1431 F g-1. Additionally, the device based on this material exhibited exceptional capacity retention over 3000 cycles.

Hydrothermal integration of MoO2-MoS2@rGO nanoframe networks: A promising approach for efficient bacterial disinfection in wastewater

The efficient disinfection of bacterial contaminants in wastewater is a critical challenge in the field of environmental remediation. Herein, we present a novel approach for efficient bacterial disinfection using hydrothermally integrated MoO2-MoS2@rGO nanoframe networks. The developed nanoframe networks exhibit a unique architecture comprising of molybdenum dioxide (MoO2) and molybdenum disulfide (MoS2) impregnated on algae biomass reduced graphene oxide (rGO). The as-synthesized nanoframe networks demonstrate exceptional antibacterial activity against Escherichia coli bacteria. The disinfection efficiency was evaluated by measuring the bacterial viability and observing the morphological changes using scanning electron microscopy. The MoO2-MoS2@rGO nanoframe networks exhibited a remarkable antibacterial effect, achieving a high disinfection rate of 95.8% within a short contact time of 10 min. The efficient bacterial disinfection capability of the nanoframe networks can be attributed to the synergistic effects of MoO2, MoS2, and rGO components. The MoO2 nanoparticles generate reactive oxygen species (ROS), persuading oxidative stress and leading to bacterial inactivation. The MoS2 nanoparticles possess inherent antibacterial properties through the release of Mo and S ions. The rGO nanosheets provide a conductive and stable platform, facilitating the charge transfer during the antibacterial process. Furthermore, the hydrothermal integration method enables easy scalability and cost-effectiveness of the MoO2-MoS2@rGO nanoframe networks. The nanoframe networks can be easily recovered and reused, reducing waste generation and promoting sustainability. Overall, this study presents a promising approach for efficient bacterial disinfection in wastewater using hydrothermally integrated MoO2-MoS2@rGO nanoframe networks. The remarkable antibacterial performance, along with the advantages of scalability and reusability, makes these nanoframe networks a potential candidate for practical applications in environmental remediation and water treatment processes.

Scalable approach to fabricate paper-based biomass reduced graphene sensor for the detection of exhaled diabetic breath

Herein, we demonstrate a microwave-assisted chemical reduction technique to exfoliate a few layers of graphene from the natural waste material, 'coconut shell'. The microwave irradiation coconut shell is subjected to structural, morphological and functional groups characterization methods including SEM, Raman, FTIR and XPS spectroscopic analyses. The formation of biomass reduced graphene (BRG) has been confirmed through Raman and FTIR spectroscopic analyzes with the presence of D, G and 2D and other functional spectral bands, respectively. The surface topography of the BRG exhibits two-dimensional mat structures with wrinkle topography, imaged by electron microscopic techniques. The metallic behaviour of the BRG is evaluated by band structure calculation using density functional theory. The synthesized nanostructure has been evaluated for exhaled diabetic breath sensing application by fabricating sensor device on the paper-based substrate by roll-to-roll coating technique. The BRG sensor exhibited enhanced sensing response at a very lower concentration of diabetic biomarker with long term stability and rapid response/recovery time of 1.11 s/41.25 s, respectively. Based on our findings, the microwave-assisted BRG is a potential candidate for fabricating highly scalable, inherently safe, economically viable and excellent sensing performance to detect exhaled diabetic breath at room temperature.

Bioactivity and hemocompatibility of sol–gel bioactive glass synthesized under different catalytic conditions

In bioactive glass synthesis by sol–gel method, HCl catalyst induces biocompatible wollastonite crystallization and supports higher apatite formation.

Highly reactive crystalline-phase-embedded strontium-bioactive nanorods for multimodal bioactive applications

In the present work, a crystallization-induced strontium-bioactive material, with a composition similar to Bioglass 45S5 system, was obtained using a sol-gel-assisted microwave method with nanorod morphologies of 30-80 nm in size. The effect of crystallization induced in the glass network, and its influence on the bioactivity and mechanical properties of bone and dentin regeneration, were the main novel findings of this work. Rietveld analysis of X-ray diffraction spectra showed the best fit with sodium (combeite, Na2Ca2Si3O9) and calcium (clinophosinaite, Ca2Na6O14P2Si2; calcium strontium silicate, Ca1.5O4SiSr0.5; and calcium carbonate, CaCO3) enriched crystal systems. Multinuclear solid-state NMR studies provided detailed atomistic insight into the presence of crystalline mineral phases in the bioactive material. The dentin matrix and antibacterial studies showed good results for 5% strontium-substituted calcium compared with basic 45S5 composition due to its smaller particle size (30 nm), which suggested applications to dentin regeneration. Simulation studies have been demonstrated with clinophosinaite crystal data from the XRD spectra, with the glycoprotein salivary metabolites also showing that 5% strontium-substituted calcium has a higher binding affinity for the salivary compound, which is suitable for dentin regeneration applications. In vitro apatite formation studies showed that this material is suitable for bone regeneration applications.

Graphene based nanoassembly for simultaneous detection and degradation of harmful organic contaminants from aqueous solution

Graphene based nanoassemblies that can simultaneously detect and degrade harmful organic contaminants from water are important for conquering the risk of hazardous chemicals.

Morphology Dependent Photocatalytic Activity of α-MoO3 Nanostructures Towards Mutagenic Acridine Orange Dye

The morphological evolutions of orthorhombic molybdenum oxide nanostructures with high crystalline nature have been successfully synthesized by combining low-temperature sol-gel and annealing processes. Strong influence of gelation temperature is a factor facilitated to control the material morphology. Morphological transformations like nanospheres, nanoplatelets, mixtures of hexagonal platelets, and one-dimensional nanobars were obtained. The possible morphological formation mechanism has been proposed as a self-assemble process of nucleation and a mechanism for particle growth by Ostwald ripening. The as-prepared nanostructures were recognized as photocatalysts for the degradation of Acridine Orange under Ultra Violet light. The obtained mixed morphology (hexagonal nanoplatelets and nanobars) showed a high photocatalytic property to degrade mutagenic Acridine Orange dye. Moreover, they could be easily recycled without changing the photocatalytic activity due to their 1-Dimensional and 2-Dimensional nanostructure property.

Nanostructuring of a GNS-V2O5–TiO2 core–shell photocatalyst for water remediation applications under sun-light irradiation

The GNS-V₂O₅–TiO₂ composite, as a new class of nanoarchitecture, has been successfully fabricated by a facile hydrothermal process followed by a sol–gel technique.

Facile synthesis of ZnO/TiO2 core-shell nanostructures and their photocatalytic activities

We reveal a new strategy for synthesizing ZnO/TiO2 core-shell nanostructures with different TiO2 shell thickness by wet chemical method. This is a facile and rapid process, requires inexpensive precursors with excellent fidelity. The thickness of a typical core-shell nanostructure ranges from 20-50 nm in size with TiO2 shell thickness of 3-6 nm which were confirmed by Transmission electron microscopy (TEM). X-ray diffraction peaks intensity of TiO2 gradually increased while we increase precursor ratio which confirmed the increase of shell thickness. X-ray photoelectron spectroscopy (XPS) results indicated that zinc ions did not enter TiO, lattice and more likely to bonded with oxygen atoms to form TiO2 coupled on the surface of ZnO. However, the PL intensity gradually increased with the increase of the TiO2 shell thickness, indicating charge transfer between the two materials of the ZnO/TiO2 core-shell nanostructures. Further investigation, revealed that the core-shell nanostructures possessed significantly higher solar light photocatalytic activity which was twice than that of original 1-D ZnO nanostructures. The mechanism of the optimal TiO2 shell thickness to reach the maximum photocatalytic activity in the ZnO/TiO2 core-shell nanostructures are proposed and discussed. It is believed that this facile, rapid wet chemical process is scalable and can be applied to synthesize other (oxide/oxide) core-shell nanostructures for various applications.