The increasing contamination of aquatic environments by persistent organic and inorganic pollutants has intensified the need for sustainable and environmentally responsible water‐treatment technologies. Green nanotechnology offers a promising route for producing functional nanomaterials from biological resources while reducing reliance on hazardous chemicals and energy‐intensive synthesis. This review critically examines recent advances in the biological synthesis of metallic, metal‐oxide, and composite nanomaterials using plants, bacteria, fungi, algae, and agro‐industrial residues, with emphasis on the roles of biomolecules in nanoparticle nucleation, growth, stabilization, and surface functionalization. The relationships between biological precursors, synthesis conditions, physicochemical properties, and remediation performance are discussed, followed by a critical assessment of applications in the removal and transformation of dyes, phenolic compounds, pesticides, pharmaceutical pollutants, and heavy metals from aqueous environments. Particular attention is given to adsorption, photocatalytic, catalytic, and advanced oxidation mechanisms, together with catalyst recyclability and transformation products. Key challenges affecting practical implementation, including synthesis reproducibility, nanoparticle recovery, metal leaching, catalyst regeneration, scale‐up, and limited validation in real wastewater, are critically evaluated. Environmental safety and life‐cycle considerations are also addressed, emphasizing nanomaterial toxicity, secondary pollution, environmental fate, and the need for integrated risk assessment. Finally, future research priorities are proposed, including standardized synthesis and reporting protocols, mechanism‐guided material design, real‐wastewater and pilot‐scale validation, and life‐cycle, techno‐economic, and environmental risk assessment. Biologically derived nanomaterials offer substantial potential for sustainable water purification and environmental remediation; however, their practical implementation requires an integrated assessment of treatment performance, scalability, economic viability, and environmental safety.
The scientific community has witnessed a surge in research on boron nanomaterials over the past decade, covering elemental boron nanoparticles, boron quantum dots, borophene, boron nitride, boron carbide, and various modified boron nanostructures. On the basis of extensive theoretical investigations, researchers have successfully prepared and optimized a wide range of boron nanomaterials with diverse compositions through experimental approaches. These materials exhibit diverse size‐, composition‐, and surface‐dependent properties, including quantum‐confined optical behavior, photothermal conversion, fluorescence, and tunable interactions with biological interfaces, which have driven their broad application potential in the biomedical field. Despite the rapid progress in boron nanomaterial research, comprehensive reviews specifically addressing their biomedical application value remain relatively scarce. This review systematically summarizes the synthesis strategies, functional properties, and recent advances of boron nanomaterials in boron neutron capture therapy, phototherapy, drug delivery, biomedical imaging, and biosensing. It also discusses the biodistribution and safety profiles of these materials, providing a reference and outlook for the translation of boron nanomaterials from versatile laboratory systems into reproducible and clinically applicable biomedical platforms.
Agricultural waste‐derived porous biochar has attracted incremental attention in microwave absorption because of its low price, lightweight, good porosity, and conductivity. Herein, corncob is adopted as the carbon source to prepare magnetic Fe 3 O 4 /biochar composites via a FeCl 3 ‐assisted one‐step pyrolysis route. Annealing temperature and FeCl 3 dosage significantly affect the electromagnetic parameters and the microwave absorption performances of the Fe 3 O 4 /biochar composites. Minimal reflection loss (RL min ) of −49.4 dB and maximal effective absorption bandwidth (EAB) of 6.96 GHz are achieved at annealing temperature of 600 °C and mass ratio of Fe precursor to corncob of 2:1, which are likely due to the optimal impedance and the strong attenuation capability. Good synergy of conductive biochars and magnetic Fe species significantly optimize the impedance matching and distinctly enhance the wave dissipating capacity of the Fe 3 O 4 /biochar composite, thereby resulting in broadband and efficient microwave absorption over CC600Fe2.
Amine‐based synthesis of mixed‐halide perovskite nanocrystals often suffers from dynamic surface‐ligand desorption, leading to defect formation, reduced photophysical properties, and poor environmental stability. Herein, we report an amine‐free strategy for synthesizing CsPb(Cl, Br) 3 mixed‐halide perovskite nanocrystals using 1‐bromo‐3‐chloropropane (CBP) as a bifunctional halide precursor that simultaneously supplies Cl and Br within a single reaction system. This approach enables the formation of phase‐pure mixed‐halide perovskite nanocrystals without separate halide precursors or amine ligands. Systematic variation of CBP concentration promotes the formation of Br‐rich CsPb(Cl, Br) 3 nanocrystals, as confirmed by UV–visible absorption, photoluminescence spectroscopy, and X‐ray diffraction analyses. Increasing the CBP concentration enhances the photoluminescence quantum yield (PLQY) from 5% to 70% and improves ambient stability, attributed to reduced defect densities under optimized halide‐rich conditions. However, excessive CBP concentration decreases the PLQY, indicating an optimal composition. The enhanced PLQY of Br‐rich nanocrystals promotes stronger visible‐light absorption and more efficient photogenerated exciton generation, resulting in improved photocurrent response. Defect‐rich samples exhibit slower photocurrent rise and decay due to increased charge trapping and recombination, whereas optimized compositions demonstrate faster and more stable photoresponse. Overall, this work provides a facile and versatile amine‐free route for compositionally tunable mixed‐halide perovskite nanocrystals for photodetector and optoelectronic applications.
Sustainable conversion of agricultural residues into functional nanomaterials offers new opportunities for biomass valorization and advanced biomedical applications. Herein, we report a single‐feedstock strategy for converting rice husk into cellulose nanocrystals (CNCs) and lysine‐doped carbon dots (L‐CDs), followed by their integration into a hybrid nanocarrier system. CNCs were obtained through alkali bleaching and sulfuric acid hydrolysis, while L‐CDs were synthesized via hydrothermal carbonization with in situ lysine doping. The resulting CNC/L‐CD hybrid exhibited excitation‐dependent photoluminescence, enhanced thermal stability, altered surface charge, and an increased optical bandgap (4.91 eV). Spectroscopic and surface analyses confirmed successful hybrid formation through electrostatic and hydrogen bonding interactions. To evaluate drug delivery performance, the CNC/L‐CD hybrid was incorporated into sodium alginate (SA) beads for tetracycline loading and release studies. SA‐CNC beads showed the highest tetracycline loading capacity (7.56 mg g −1 ), whereas SA‐CNC/L‐CD beads exhibited enhanced pH‐responsive release behavior under physiologically relevant conditions. The released tetracycline retained antibacterial activity against Escherichia coli , Staphylococcus aureus , and Salmonella typhimurium . Control experiments confirmed that unloaded carrier materials exhibited no intrinsic antibacterial activity. These findings demonstrate the potential of rice husk‐derived CNC/L‐CD hybrids as sustainable nanocarriers for pH‐responsive tetracycline delivery and highlight a practical route for transforming agricultural waste into value‐added biomedical materials.
