Enhanced photocatalytic conversion of (3D/2D) BiVO4@Polypyrrole/g-C3N4 ternary composites with Z-scheme band alignment for the Antibiotic removal

Adsorptive avidity of Prussian blue polypyrrole nanocomposite for elimination of water contaminants: a case study of malachite green and isoniazid

Persistent water contaminants include a variety of substances that evade natural cleaning processes posing severe risks to ecosystems. Their adsorptive elimination is a key approach to safer attenuation. Herein we present the design and development of Prussian blue incorporated polypyrrole (PPY/PB) hybrid nanocomposite as a high-performance adsorbent for the elimination of malachite green (M.G.), isoniazid (INH) and 4-nitrophenol (4-NP) water contaminants. The nanocomposite synthesis was favored by strong dopant-polymer interactions, leading to a PPY/PB material with enhanced electro-active surface area compared to pristine PPY. The structure-activity response of the nanocomposite for the adsorption of target contaminants was unveiled by evaluating its maximum adsorption capacities under environmentally viable conditions. In-depth analysis and optimization of adsorption influencing factors (pH, temperature, and adsorbent dose) were performed. Using equilibrium studies, kinetic model fitting, aided with FTIR analysis, a multi-step mechanism for the adsorption of target contaminants on the nanocomposite was proposed. Furthermore, the PPY/PB nanocomposite also acts as a catalyst, enabling contaminant elimination following a synergistic scheme that was demonstrated using 4-NP contaminant. The synergetic adsorption and catalytic degradation of 4-NP using PPY/PB as adsorbent and catalyst was demonstrated in the presence of NaBH4 as a reducing agent in absence of light. In summary, this work highlights the targeted design of adsorbent, its optimization for adsorptive avidity, and the synergistic role of adsorption trapping in the catalytic degradation of persistent contaminants.

Polypyrrole-based nanomaterials: A novel strategy for reducing toxic chemicals and others related to environmental sustainability applications

Aqueous contaminants such as pharmaceuticals, dyes, personal care products, etc., are the common water contaminants that show adverse health effects. Photocatalysis is one of the well-known techniques to treat these water contaminants. Currently, most inorganic photocatalysts show a poor balance between adsorption and photocatalytic activity. In addition, heavy metal pollution and low biosafety are significant concerns in photocatalysis. Thus, environmentally friendly photocatalysts are required to avoid the secondary pollution caused by some inorganic semiconductor-photocatalysts. Organic polymer-based photocatalysts are low-cost, stable, non-toxic, and can utilize visible and NIR light for photocatalysis. In this review, we have discussed polypyrrole as a photocatalyst. Polypyrrole is a conducting organic polymer photocatalyst that is highly stable with high charge mobility and strong binding sites for photocatalytic reactions. Besides these advantages, polypyrrole has limitations, such as high charge recombination due to a small bandgap and poor dispersity. So we have explored the modifications to polypyrrole photocatalysts, such as doping and heterojunctions. Further, we have explained the applications of polypyrrole in photocatalysis as an adsorbent, sensitizer, degradation of pollutants, and energy production. Finally, the future aspects of polypyrrole photocatalysis are also explored to improve the path of future research.

Enhanced Photocatalytic Degradation of Tetracycline and Oxytetracycline Antibiotics by BiVO4 Photocatalyst under Visible Light and Solar Light Irradiation

The efficient degradation of a toxic antibiotic from an aqueous solution is essential for environmental protection. Our research aimed to fabricate a bismuth vanadate (BiVO4) catalyst via a facile hydrothermal method. The prepared catalyst exhibited a monoclinic phase with a band gap energy of 2.33 eV, indicating the excellent visible-light-active properties of a semiconductor. The photocatalytic performance of the synthesized BiVO4 catalyst was studied by determining the removal of tetracycline (TC) and oxytetracycline (OTC) antibiotics. After 240 min, under sunlight conditions, a high performance of 72% and 83% degradation of TC and OTC, respectively, was achieved. The photocatalytic degradation of the antibiotics correlates well with a first-order reaction, with a high rate constant of 0.0102 min−1. Photogenerated electrons and holes played an important role in the removal of the pollutant. After photocatalytic study, the structural stability of the prepared bismuth vanadate photocatalyst was confirmed. The photocatalyst provided a promising performance even after five successive runs. The result indicates the excellent cycling ability of the sample. The present work demonstrates a promising route for the preparation of a BiVO4 catalyst for the complete removal of toxic antibiotics in aqueous solutions.

Ultrasensitive electrochemical detection of furazolidone in biological samples using 1D-2D BiVO4@MoS2 hierarchical nano-heterojunction composites armed electrodes

In this work, the hydrothermally synthesized of BiVO₄@MoS₂ hierarchical nano-heterojunction composite is employed as a novel electrocatalyst for electrochemical sensing of Furazolidone (FZE) drug by modifying the glassy carbon electrodes (GCE). The Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy are used to thoroughly investigate the functional groups, vibrational modes, crystal structure, elemental composition and surface topography of the heterojunction composite. The physical characterization results revealed the successful construction of 1D-2D BiVO₄@MoS₂ hierarchical nano-heterojunction composite. When these unique architectures are reinforced on GCE surface, we achieved an enhanced electroactive surface area of 0.154 cm². The electrochemical performance of 1D-2D BiVO₄@MoS₂ is examined though cyclic voltammetry and differential pulse voltammetry (DPV) analysis. The BiVO₄@MoS₂ composites exhibited an excellent electrocatalytic activity in sensing of FZE with superior linear detection ranges of 0.01-14 and 14-614 μM. The limit of detection (LOD) of the BiVO₄@MoS₂ based sensor is determined to be 2.9 nM which is far superior than other reported FZE sensors. Consequently, it is evident from the investigation that the BiVO₄@MoS₂ based FZE sensor can be recommended for analyzing real time samples like human urine and blood serum with appreciable recovery.

Self-assembled supramolecule for synthesizing highly thermally conductive Cellulose/Carbon nitride nanocomposites with improved flame retardancy

The fabrication of polymer composites with excellent thermal conductivity typically involves complex matrix or fillers modifications. This study proposed a simple technique based on precursor selection for obtaining highly thermally conductive cellulose nanofiber (CNF)/supramolecule-synthesized carbon nitride (SCN) composites. Fourier-transform infrared tests demonstrated the construction of hydrogen bonds between CNF and SCN; a highly ordered structure and relatively compact in-plane stacking were confirmed via scanning electron microscopy and X-ray diffraction characterizations. Consequently, the resultant CNF/SCN composites exhibited remarkable in-plane thermal conductivity of 11.83 ± 0.41 W m^-1 K^-1 at 30 wt% SCN content, which was attributed to the significantly reduced interfacial phonon scattering. It also showed evident improvements in electrical insulation and flame retardancy compared with the pure CNF film, where the volume resistivity, peak heat release rate, and total heat release were remarkably enhanced by 1242% and reduced by 59.9% and 15.8%, respectively. Further analysis of char residuals revealed a relatively dense surface, high concentration of carbon materials, and a high degree of graphitization, indicating that the char residual functioned as a robust physical barrier to effectively inhibit combustion. This study provides a facile approach to achieving high-efficiency improvements in thermal conductivity and flame retardancy, and simultaneously facilitating broader applications of carbon nitride in thermal management.

Construction of a Z-scheme g-C3N4/NBGO/BiVO4 heterostructure with visible-light driven photocatalytic degradation of tetracycline: efficiency, reaction pathway and mechanism

In this study, an aminated graphene-like biochar (NGBO) was used as a solid-state electron mediator at a g-C3N4/BiVO4 interface to construct a hybrid Z-scheme system (g-C3N4/NBGO/BiVO4) for the photocatalytic degradation of tetracycline (TC) from aqueous solutions.