Metal sulfides (MSs) exemplify a pivotal category of materials for solar light driven photocatalysis owing to their broad range of light absorption capacity, supreme negative conduction band potential and tunable electronic properties across binary, ternary, and quaternary systems. In addition, surface plasmonic resonance and photothermal properties of few selected MSs stimulate their catalytic properties spanning the NIR region. As the single phase semiconductors exhibit poor efficiency, heterojunction with MSs has acquired enormous interests due to the synergism in the charge carrier separation proficiency and enhanced optical properties. In this regard, S-scheme heterojunction (SSH) have recently transpired as an advanced charge transfer strategy that is capable of resolving the persistent conflict between the efficient charge separation and strong redox capability. This review bestows a systematic and holistic outline of MS-SSH, beginning with tentative classification of MSs as OP and RP based on their band edge positions. It further examines the fabrication strategies of MS-SSH such as selfassembly, solvent evaporation, in-situ growth and interfacial sulfidation, and co-precipitation, with emphasis on MOF/COF-derived architectures and common-cationic heterojunctions. The key design principles consisting of band-gap responses, interfacial engineering, defect engineering, hierarchical architectures (0D-3D), and dual SSH are critically discussed. The photocatalytic performance of MS-SSH towards H2 evolution, CO2 reduction, pollutant degradation and heavy metal reduction, nitrogen fixation and H2O2 synthesis are underscored. Finally, the unresolved challenges including photocorrosion, uncertainties in validating the S-scheme charge-transfer mechanisms, and future direction of the research are proposed.
Flowable concrete (FC) is characterised by its high self-compaction ability and improved form-filling, which are important for producing high-quality concrete. Recycled concrete aggregates (RCA) are expected to grow as a sustainable alternative to natural aggregates (NA) in concrete mixes, offering environmental benefits, economic advantages, and waste reduction. RCA are representing a key path towards sustainable concrete construction. Present studies show a number of complex issues when considering their use in prestressed structural elements. characteristics of FC incorporating RCA. This review highlights the fresh, mechanical, durability, and structural performance and sustainability properties of FC. It discusses the essential aspects of using RCA in FC, including benefits, challenges, and material properties, with a specific focus on Prestressed Concrete (PSC) applications. This paper concludes that including RCA typically results in lower workability, stiffness, and durability due to the presence of adhered mortar and increased porosity. These effects can be effectively mitigated through proper design of the optimised concrete mix, treatment of the aggregates, and use of supplementary cementitious materials (SCMs). Overall, structural evaluations show that PSC structures made with moderate levels of RCA can achieve nearly the same ultimate strength and failure modes as those made with conventional concrete (CC) but typically offer lower serviceability than CC. Existing evidence for the PSC applications remains limited in scope and is largely experimental, based on laboratory experiments.
This study reports the synthesis and multifunctional performance of hierarchical PANI/g-C3N4/ZnO ternary composites prepared via in situ chemical oxidative polymerization technique. The synergistic integration of polyaniline (PANI), graphitic carbon nitride (g-C3N4), and zinc oxide (ZnO) has been studied for structural, optical, and electrical characteristics, as confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), photoluminescence (PL) spectra, field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDAX) analyses, Brunauer–Emmett–Teller (BET) and X-ray photoelectron Spectroscopy (XPS). The photocatalytic efficiency of the composites was evaluated by measuring the degradation of malachite green (MG) under UV irradiation. The ternary composite achieved 96.5
The concentration of 222Rn in groundwater samples was analysed in the Gogi region of Yadgiri district, Karnataka, South India, an area known for its uranium mineralisation and for future mining activities. A total of 210 samples were analysed from various zones, with Gogi as the common centre for all study zones. The 222Rn bubbling method was employed to determine the activity concentration of 222Rn, which varied from 0.6 to 275.0 Bq/L. The concentration of 222Rn in most groundwater samples was comparable to levels observed in other parts of India and worldwide. The observed 222Rn activity concentration for the core zone was found to be higher than that in the other two zones. Only 10
The growing discharge of toxic dyes into water sources necessitates efficient and reusable photocatalysts fabrication. In this study, a novel BiOBr/Ce-doped CoFe2O4 (BB/CFCe) heterostructured nanocomposite was synthesized via a co-precipitation approach. Structural and spectroscopic analyses confirmed the coexistence of BiOBr (BB), CoFe2O4 (CF), and CeO2 phases, with the formation of a strong interfacial heterojunction facilitating charge transfer. Ce doping induced mixed Ce3+/Ce4+ states and oxygen vacancies, enhancing visible light absorption and carrier mobility. The crystallite size estimated from the TEM matches well with the Bragg reflections. The optical energy band gap calculated using Tauc's relation was found to be 2.92, 0.69, 1.78, 2.27, 2.79, 2.85 eV for BB, CF, CFCe, BB/CFCe1, BB/CFCe2 and BB/CFCe3 NCs respectively. Among all samples, BB/CFCe1 exhibited superior photocatalytic activity, achieving 97.8% Rhodamine B degradation within 120 min and a rate constant (k) of 0.0385 min-1, nearly 48 times higher than pristine BB. The material also demonstrated excellent stability and recyclability over multiple cycles. The synergistic interaction between BB and CFCe establishes an efficient Z-scheme mechanism, offering a cost-effective and magnetically recoverable photocatalyst for sustainable wastewater remediation.
