Highly Efficient Solar‐Catalytic Degradation of Reactive Black 5 Dye Using Mesoporous Plasmonic Ag/g‐C 3 N 4 Nanocomposites

Unlocking the potential of biogenic Ag@g-C3N4 in sustainable water purification: A Kinetic and Photocatalytic study

This research introduces a pioneering biogenic deposition-precipitation method for synthesis of Ag@g-C3N4 nanocomposites (NCs) employing fennel seed extract (FSE). This technique involves the reduction and capping of silver nanoparticles (AgNPs) onto g-C3N4, employing polyphenolic content of FSE, consequently establishing a strong Schottky junction. The, NCs were characterized through various spectroscopic and microscopic techniques, confirming successful biogenic deposition of AgNPs and purity of prepared nanomaterials. Further, the synthesized NCs were utilized for photocatalytic degradation of various hazardous pollutants viz. Rhodamine-B (Rh-B) dye, Tetracycline (TCy) antibiotic, Imidacloprid (IMD) insecticide and deactivation of E. coli microbes. Amongst the synthesized NCs, 3wt% Ag@g-C3N4 NCs exhibited superior photocatalytic mitigation of Rh-B (99.26%, k=90.4 x 10-3 min-1), TCy (96.86%, k=40.2 x 10-3 min-1), IMD (95.7%, k=34.96 x 10-3 min-1) and E. coli deactivation (99.5%, k = 49.19 x 10-3 min-1). Moreover, the rate constants revealed many-fold increase in photocatalytic degradation of pollutants, contrary to pristine g-C3N4 (k = 11.8 x 10-3 min-1). This investigation also unveils an intricate photocatalytic mitigation pathway for the aforementioned-contaminants, elucidating key role of superoxide radical anions in photocatalytic mitigation. One of the significant highlights of this research is the sustainable and cost-effective synthesis methodology involving fennel seeds, which not only ensures the wide availability of resources but also guarantees environmental safety, in alignment with green principles.

Enhanced photocatalytic performance of Bi-doped TiO2 under sunlight and UV light: mechanistic insights and comparative analysis

Bismuth-doped metal oxides exhibit favourable photocatalytic features when exposed to both sunlight and UV light. In this approach, Bi0/TiO2 and Bi+3/TiO2 photocatalysts were prepared and their structural and optical properties are analysed using various characterization techniques. These developed photocatalysts were further tested for the photocatalytic elimination of Nitrobenzene in UV light and sunlight and compared with the performance of bare TiO2. The catalyst Bi+3/TiO2 performed better in UV light with 72.31% degradation, and 4.74 × 10-6 mol.litre-1.min-1 initial rate of reaction. However, when exposed to sunlight, Bi0/TiO2 outperformed with 73.85% degradation, and 4.63 × 10-6 mol.min-1 initial rate of reaction. This significant increase in photocatalytic activity of Bi0/TiO2 under sunlight could be accredited to increased light harvesting and enhanced efficiency in charge carrier separation, both of which were made possible by bismuth-induced surface plasmon resonance.

Continuous inactivation of human adenoviruses in water by a novel g-C3N4/WO3/biochar memory photocatalyst under light-dark cycles

Viruses transmitted by water have raised considerable concerns for public health. A novel memory photocatalyst of g-C₃N₄/WO₃/biochar was successfully developed for effective inactivation of human adenoviruses (HAdVs) in water, in which WO₃ as an electron-storage reservoir and biochar as an electron shuttle is employed to synergistically improve photocatalytic activity of g-C₃N₄. The tertiary composite exhibited continuous photocatalytic performance for HAdVs inactivation without regrowth in water under light-dark cycles, i.e., ∼3.9-log inactivation under 6-h visible light irradiation and an additional ∼1.1-log inactivation under the following 6-h dark. The enhanced virucidal mechanism was attributed to the heterojunction formation and especially the electron-transfer pathway switching via biochar incorporation, contributing to electron transfer and storage in the light phase and then electron release in the dark phase, along with obviously increased generation of the virus-killing •OH radicals under light-dark cycles.

Covalent organic frameworks as promising adsorbent paradigm for environmental pollutants from aqueous matrices: Perspective and challenges

Covalent organic frameworks (COFs) are an emerging class of new porous crystalline polymers materials having robust framework, outstanding structural regularity, highly ordered aperture size, inherent porosity, and chemical stability with designer properties, making them an ideal material for adsorbing a variety of contaminants from water bodies. Presented study focusses on the current advances and progress of pristine COFs as well as COFs based composites as an emerging substitute for the adsorption and removal of a variety of pollutants including water desalination technique, heavy metals, pharmaceuticals, dyes and organic pollutants. The absorption capabilities of COFs-derived architecture are evaluated and equated with those of other commonly used adsorbents. The interaction between sorption ability and structural property as well as some regularly utilized ways to improve the adsorption performance of COFs-based materials are also reviewed. Finally, perspective and a summary about the challenges and opportunities of COFs and COFs-derived materials are discussed to deliver some exciting data for fabricating and designing of COFs and COFs-derived materials for remediation of environmental pollutants.

Orderly Porous Covalent Organic Frameworks-based Materials: Superior Adsorbents for Pollutants Removal from Aqueous Solutions

Covalent organic frameworks (COFs) are a new type of crystalline porous polymers known for chemical stability, excellent structural regularity, robust framework, and inherent porosity, making them promising materials for capturing various types of pollutants from aqueous solutions. This review thoroughly presents the recent progress and advances of COFs and COF-based materials as superior adsorbents for the efficient removal of toxic heavy metal ions, radionuclides, and organic pollutants. Information about the interaction mechanisms between various pollutants and COF-based materials are summarized from the macroscopic and microscopic standpoints, including batch experiments, theoretical calculations, and advanced spectroscopy analysis. The adsorption properties of various COF-based materials are assessed and compared with other widely used adsorbents. Several commonly used strategies to enhance COF-based materials' adsorption performance and the relationship between structural property and sorption ability are also discussed. Finally, a summary and perspective on the opportunities and challenges of COFs and COF-based materials are proposed to provide some inspiring information on designing and fabricating COFs and COF-based materials for environmental pollution management.