Microstructure plays important role in developing thermoelectric materials. In recent times, half-Heusler alloys have attracted attention as an important class of thermoelectric material. In this work, we investigate the Ni-rich quaternary ZrFe0.4Ni0.6Sb (termed Ni-60) which is known to form double half-Heusler structure. Through controlled isothermal heat treatments at 1173 K for various times, we map the structural evolution from a matrix phase with an orthorhombic crystal structure with Fe-rich segregates at the dendritic boundaries, to a diffusioncontrolled growth of half-Heusler phase (hH phase) with two distinct morphologies. An initial diffusioncontrolled growth from the dendritic boundaries (BhH) is followed by a unique plate-like growth of the hH phase (PLM) in the residual orthorhombic matrix. Detailed microscopy and crystallographic analysis show that these hH plates grow with a distinct orientation relation. Contrary to this, the hH islands that nucleate and grow from the iron rich segregates at the dendritic boundaries do not exhibit orientation relation with the orthorhombic matrix. The interface between the hH plate and orthorhombic matrix for plates is semi-coherent. These discrete transformation pathways compete yielding a complex microstructure that is expected to have an influence on the reported thermoelectric properties.

Nanoplastics pose a significant environmental concern as they enter aquatic systems through various anthropogenic pathways. Consequently, the removal of nanoplastics from water, particularly polystyrene, is of paramount importance. This work focuses on the separation of polystyrene nanoplastics from aqueous systems, utilising polydopamine (PDA), a conjugated biopolymer, to induce flocculation. The synthesised conjugated biopolymer demonstrated a significant removal efficiency of approximately 75% for polystyrene nanoplastics within 24 hours. This was achieved by adding PDA to simulated water containing polystyrene nanoparticles (20 mg L-1) and adjusting the pH value to 2, with a PDA dosage of approximately 1 mg per 8 mL of water. The successful flocculation of polystyrene nanoplastics was confirmed through SEM and FTIR analysis. Quantification of polystyrene removal was accomplished using UV-vis spectroscopy. Additionally, regeneration studies of PDA from the formed flocs were conducted to maintain the sustainability of the removal process. Overall, this study highlights the efficacy of using the conjugated biopolymer PDA in the flocculation-based removal of polystyrene nanoplastics. The findings underscore the importance of exploring more sustainable biopolymers for the efficient removal of nanoplastics from aqueous environments.

Increasing levels of water pollution involving heavy metals have demanded the exploration and development of efficient, sustainable approaches for the decontamination of these pollutants. In this study, copper oxide nanoparticles (CuO NPs) were synthesized using Haldina cordifolia for the removal of a persistent heavy metal from water. Advanced characterization analyses confirm both their successful synthesis and their distinctive adsorption characteristics toward Pb(ii) from water. The highest-ranked docked conformation attained in molecular docking simulations showed a binding energy of -0.36 kcal mol-1. The negative binding energy attained indicates a favourable affinity of the CuO NPs towards Pb(NO3)2. The maximum adsorption capacity of Pb(ii) onto CuO NPs is 1032.57 mg g-1 under the optimum conditions (pH 6, dose 50 g L-1, and contact time 2 h). The adsorption mechanism is driven by both chemical (complexation, precipitation, and ion exchange) and physical electrostatic attractions. The kinetic study reveals that five kinetic models, namely, pseudo-first-order, pseudo-second-order, mixed first- and second-order, Avrami, and intraparticle diffusion, can describe the adsorption of Pb(ii) onto CuO NPs, depending on the initial Pb(ii) concentration. Adsorption isotherm modelling shows that among the eleven models studied, Freundlich isotherm best describes the adsorption system, with strong agreement between experimental and calculated data. Future research can thus focus on enhancing the synthesis process while examining the selectivity and reusability of CuO NPs for decontaminating the diverse metals present in intricate wastewater systems.

The rational design of molecular sensors with well-defined recognition mechanisms is essential for improving selectivity toward metal ions. In this study, a benzothiadiazole–pyridine-based organic molecule (BTDP) was designed as a fluorescent sensor by strategically integrating nitrogen- and sulfur-containing donor sites to enable selective interaction with ferric ions. The sensing behaviour was systematically investigated using a combination of photophysical measurements and density functional theory calculations. The interaction mechanism between BTDP and Fe ^3+ was elucidated through X-ray photoelectron spectroscopy, non-covalent interaction analysis, and electrostatic potential mapping, providing complementary experimental and theoretical insight into charge redistribution and coordination behaviour at the molecular level. Fluorescence quenching studies further supported the proposed interaction pathway. The Limit of detection (LOD) and Limit of quantification (LOQ) in this study was found to be 2.3 μM and 6.99 μM respectively. This work emphasizes a structure-interaction-response approach, offering a mechanistic framework for the rational development of fluorescent metal-ion sensors.

Developing sustainable strategies for monitoring pesticide contamination is vital to protect water quality and human health. In the present work, cobalt oxide nanoparticles were synthesized via a green route using the aqueous leaf extract of Bauhinia purpurea L. as a bio-reducing agent. A series of analytical techniques, including XRD, TGA, SEM, UV-Vis, XPS, and FTIR, was employed to verify the structural, morphological, optical, and surface chemical characteristics of the nanoparticles. The resulting Cobalt oxide nanoparticles exhibited strong electrocatalytic behavior and were utilized for the electrochemical determination of atrazine. Computational docking studies supported experimental observations by indicating stable interactions between atrazine molecules and the cobalt oxide surface, predominantly through hydrogen bonding. The fabricated sensor demonstrated a linear response from 20-200 & micro;M with a detection limit of 11.8 & micro;M and good selectivity toward atrazine. Application to distilled and wastewater samples demonstrated satisfactory recovery, confirming its practical utility. The study highlights an environmentally benign approach for nanoparticle fabrication and presents an effective platform for rapid atrazine monitoring in aqueous environments.

Abstract The elimination of toxic lead from emerging photovoltaics is a critical imperative for sustainable chemical engineering. While tin halide perovskites (THPs) offer an environmentally benign alternative, their industrial viability is currently stifled by rapid oxidation kinetics and structural instabilities. Guanidinium (GA+) has been widely documented in lead-based perovskites as a primary structural anchor for high-efficiency alternating cation interlayer (ACI) phases and as a versatile functional additive. Building upon preliminary baseline studies of tin-based ACI-derived frameworks, this work investigates the systematic optimization of the ACI-derived quasi-two-dimensional tin halide perovskite platform using a high-n (n = 10) stoichiometric approach. We demonstrate that the inherent electronic defects and energetic misalignment of this ACI-derived motif can be systematically unlocked through synergistic compositional engineering with methylammonium bromide (MABr). Multimodal characterization confirms that MA+ and Br– participate in the bulk compositional modification of the perovskite framework, leading to measurable changes in lattice parameters, energetic disorder, and charge-transport characteristics. This bulk modification triggers a cascade of physical and electronic improvements: a drastic collapse in energetic disorder, near-zero Stokes shifts, and a nearly two-order-of-magnitude increase in ambipolar carrier mobility. These refinements enable enhanced photovoltaic performance within the investigated ACI-derived tin framework. Beyond device efficiency, we establish the functional reliability of this platform through a statistically rigorous evaluation encompassing ∼two-year (710-day) dark shelf-life tracking and continuous fixed-bias operational stability measurements on unencapsulated devices. The optimized ACI-derived framework exhibits enhanced environmental resilience and suppressed interfacial hysteresis, providing valuable design principles for the development of stable lead-free perovskite photovoltaic technologies.

An aluminium-based metal-organic framework (Al-MOF), constructed using 2,6-naphthalenedicarboxylic acid (2,6-NDC) as a linker, was synthesized for the selective electrochemical detection of atrazine (ATZ) in water. This study explores the molecular interactions between the Al-MOF and ATZ, supported by docking simulations and quantum chemical calculations, which reveal a strong binding affinity and electronic interaction. The sensor electrode modified with Al-MOF exhibited prominent enhancement in the peak current responses for ATZ compared to the bare carbon paste electrode, attributed to improved sensitivity and selectivity. Its performance was consistent across diverse water samples, with reproducibility demonstrated over multiple fabricated electrodes. Optimal detection was achieved using 0.1 M HCl as the supporting electrolyte, while interference studies confirmed a selective response for ATZ over other pesticides. The analysis revealed that the detection process is predominantly adsorption-controlled, and the method proved viable for real-world monitoring in drinking water and wastewater. Structural, compositional, and morphological characterization validated the integrity and stability of the synthesized Al-MOF. The overall findings highlight the practical utility of the Al-MOF-based sensing platform as an affordable and reliable approach for the environmental monitoring of persistent herbicides such as ATZ.

A zirconium-based metal-organic framework, UiO66-NDC, constructed using 2,6-naphthalenedicarboxylic acid as an organic linker, was synthesized for the selective electrochemical detection of fluoride in water. The UiO66-NDC modified carbon paste electrode exhibited a significant enhancement in current response toward fluoride relative to the unmodified electrode, reflecting improved sensitivity and selectivity. Molecular docking analysis revealed a spontaneous and thermodynamically favorable interaction between fluoride and the UiO66-NDC surface, with the most stable binding conformation exhibiting a binding energy of -3.0 kcal mol-1 and an estimated inhibition constant (Ki) of 6.23 mM, supporting the affinity between UiO66-NDC and fluoride ions observed experimentally. The sensor demonstrated consistent performance across different aqueous matrices, including tap water and milk samples, and showed good repeatability and operational stability over multiple measurements. Optimal sensing conditions were achieved in both acidic and alkaline medium environments, and interference studies confirmed selective detection of fluoride over common competing anions. The limit of detection was found to be 0.33 and 0.11 & micro;M in NaOH and Acidic medium respectively. Comprehensive structural, morphological, and compositional characterization confirmed the stability and integrity of the synthesized UiO66-NDC. Overall, the findings establish UiO66-NDC as an efficient, cost-effective sensing platform suitable for environmental monitoring of fluoride contamination.

ABSTRACT In this study, we present an approach to the selective detection of mercury (Hg 2+ ) using organic fluorophores, guided by biomimetic design principles. Conventional approaches predominantly employ sulfur‐containing functionalities, which, although effective, often suffer from cross‐reactivity with competing metal ions such as As 3+ , Pb 2+ , and Cu 2+ . Here, oxygen‐ and nitrogen‐based functional groups are incorporated with naphthalene diimide (NDI) derivatives, inspired by biological coordination environments, to enhance selectivity. NDI derivatives, including NDI‐A, NDI‐A*, and NDI‐Cys*, are synthesized with strategically positioned hydroxyl and carboxylate moieties to modulate metal‐ligand interactions. Among the prepared compounds, the NDI‐A* derivative exhibits improved selectivity toward Hg 2+ over fifteen potential interfering ions and demonstrates suitability for real‐sample analysis. The sensing performance is further evaluated by fluorescence spectroscopy and density functional theory (DFT) calculations. DFT studies provide mechanistic insights, which reveal favourable binding energies and a ligand‐to‐metal charge‐transfer (LMCT) pathway governing fluorescence quenching. The NDI‐A* derivative‐based sensor achieves a limit of detection of ∼ 42 ppb and a limit of quantification of ∼141 ppb, with a linear detection range spanning 42–1330 ppb for selective Hg 2+ detection.

The proliferation of portable and wearable electronics necessitates flexible, high-performance energy storage devices. Flexible supercapacitors are poised to meet these demands due to their high power density, flexibility, and durability but scalable fabrication remains challenging due to costly and complex manufacturing methods. This study addresses this issue by implementing scalable, cost-effective spray coating and screen printing techniques to fabricate flexible micro-interdigitated supercapacitors (FMIS) based on Polyaniline (PANI) composites with carbon nanomaterials, using organic acids as crosslinking agents synthesized via hydrogel strategy. The formation of PANI emeraldine salt was verified through X-ray photoelectron spectroscopy, indicating key amine and imine functionalities, while scanning electron microscopy revealed surface morphologies with enhanced active surface areas beneficial for charge storage. Advanced 3D tomography maps porosity distribution and surface area per unit volume, correlating with electroactive areas calculated from the Randles-Sevcik equation. Electrochemical testing via cyclic voltammetry demonstrates an impressive areal capacitance of 173.2 +/- 9.6 mF cm-2 at 10 mV s-1 with Dunn's method distinguishing capacitive from diffusive contributions. Furthermore, EIS measurements highlight lower solution resistance in screen-printed devices, emphasizing the advantages of optimized electrode morphology for efficient charge transport. This study establishes a scalable approach for high-performance flexible supercapacitors, paving the way for next-generation energy storage solutions.

Two-dimensional (2D) titanium carbide (Ti 3 C 2 T x ) MXenes are promising candidates for lightweight microwave absorbers; however, the influence of flake dimensionality, composition, and exfoliation degree on electromagnetic loss mechanisms remains unclear. Here, we investigate microwave absorption in crosslinked polyvinyl butyral (XPVB)-based polymer composites incorporating Ti 3 AlC 2 MAX phase, multilayered Ti 3 C 2 T x and Ti 3 (C 2− y O y )T x (where y = 0.3) MXene, single-flake Ti 3 C 2 T x and Ti 3 (C 2− y O y )T x (where y = 0.3) MXene across the X-Ku band (8–18 GHz) frequency range. Etching Ti 3 AlC 2 MAX to Ti 3 C 2 T x MXene markedly enhances permittivity and induces finite permeability through interfacial polarization, conductive network formation, defect-assisted relaxation, and eddy-current losses. The results show that exfoliation predominantly governs dielectric loss, while multilayered MXene flakes and stacking enhance magnetic loss, enabling tunable impedance matching. An electromagnetic data-driven optimization identifies an optimal filler loading of 2.5 wt% multilayered Ti 3 C 2 T x MXene, achieving a minimum reflection loss of -59.3 dB at 12.6 GHz with an effective absorption bandwidth of 5.5 GHz at a reduced thickness of 2.2 mm. Multilayered Ti 3 C 2 T x MXene composites outperform single-flake and MAX counterparts due to synergistic dielectric-magnetic attenuation and enhanced multiple internal reflections. These findings establish dimensionality- and composition-dependent MXene architectures (with no oxygen in the X sublattice) as an effective platform for thin and broadband microwave absorbers.

Over the years, the inadequate performance of standalone wastewater treatment units under variable hydraulic and organic loading has necessitated the hybridization of technologies. Amongst, augmenting sequencing batch reactor (SBR) and membrane bioreactors has gained significant attention, but issues such as membrane fouling, biomass loss, and poor effluent quality persist. In this context, the current study uses Chlorella vulgaris coated on ZIF-67/PVA nanofibers cellulose membrane for a microalgae-based membrane bioreactor (MMBR) following an SBR to treat real wastewater treatment. The system performance was monitored at varying operating conditions, involving varying influent concentrations and operating parameters. The study was carried out over 68 days in 6 different modes of operation. The SBR-MBR system could provide more than 97%, 99%, and 98% removal for ammonia, phosphate, and COD, respectively, at an SBR cycle time of 6h and an aeration rate of 0.75L/h. The experimental results were modeled using an artificial neural network (ANN) to understand the interactive effects of different operating parameters and wastewater characteristics on overall contaminant removal efficiency and membrane fouling. The ANN model achieved an overall R value of 0.94, and sensitivity analysis indicated that wastewater parameters played a crucial role in the system performance. The findings of the study demonstrate the feasibility of integrating biological pretreatment with membrane-assisted algal polishing for enhanced wastewater reclamation.

This study reports the development of a novel and efficient electrochemical sensor for the sensitive and selective detection of mesalamine (MES), a widely used anti-inflammatory drug, using a cobalt ferrite nanoparticlemodified carbon paste electrode (CoFe2O4/CPE). The electrochemical performance of the sensor was investigated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). Under optimized conditions, the sensor exhibited a linear response to mesalamine over the 10-90 & micro;M range, with a limit of detection of 0.08 & micro;M, and a limit of quantification of 0.27 & micro;M, indicating high sensitivity. The sensor also demonstrated good selectivity toward MES in the presence of potential interfering species. Furthermore, the fabricated electrode showed satisfactory stability, reproducibility, and repeatability. The practical applicability of the developed sensor was validated through the analysis of spiked tap water samples, yielding recovery values between 98.4% and 99.9%. These results suggest that the CoFe2O4/CPE sensor provides a sensitive, reliable, and selective platform for mesalamine detection with potential applications in environmental monitoring and pharmaceutical analysis.

Detecting harmful heavy metal ions in water sources, especially lead (Pb (II)), is essential to protecting the environment and human health. This work used differential pulse voltammetry (DPV) to effectively design and electrochemically evaluate a CdFe2Oa-modified carbon paste electrode (CdFe2Oa/MCPE) for the sensitive and selective detection of Pb (II). The effective production of CdFe2Oa nanoparticles with a spinel cubic structure, nanoflake shape, and high electroactive surface area was validated by structural and morphological characterization utilizing XRD, FT-IR, TEM, and XPS. CdFe2Oa/MCPE is an effective sensing platform because of its increased conductivity, reduced charge transfer resistance (Rct), and better electron transfer kinetics, as shown by electrochemical characterization using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The most effective supporting electrolyte for Pb (II) detection among the many tested was 0.1 M HCl. With a low detection limit (LLOD) of 0.078 mu M and good linear regression, the sensor demonstrated a broad linear range (1-11 mu M). While repeatability and stability evaluations verified its steady performance and longevity over several cycles, selectivity investigations demonstrated a notable response for Pb (II) with little interference from competing metal ions. By detecting Pb (II) in tap water samples using the conventional addition technique, obtaining good recovery rates (98.9-99.8 %), and proving the sensor's effectiveness for real-world monitoring, its practical application was confirmed. CdFe2Oa/MCPE demonstrated higher sensitivity, a lower detection limit, and good repeatability compared to previously reported sensors, making it an economical and dependable sensor for industrial and environmental applications. As a scalable and effective way to monitor heavy metals in water sources, this study identifies CdFe2Oa/MCPE as a viable electrochemical sensor for detecting traces of Pb (II). For more extensive industrial and environmental applications, future research can concentrate on multi-metal detection, real-time field applications, and sensor downsizing.

There is increased interest on the challenges of health, safety and ecological sustainability posed by herbicide misuse, which highlights the urgent need for the production of an effiecnt and applicable sensor for easy, quick, and user-friendly on-site detection of herbicide residues. In this study, a novel electrochemical sensor was developed using Zinc methylimidazolate synthesized via an environmentally benign method for the detection of atrazine (ATZ), a widely used herbicide and known environmental contaminant. The green-synthesized Zinc methylimidazolate material exhibited excellent electrochemical activity, enabling sensitive and selective detection of ATZ. Complementary molecular docking studies were employed to explore the interaction dynamics between ATZ and the Zinc methylimidazolate framework, revealing a favorable binding affinity that supports the experimental observations. The sensor achieved a detection limit of 1.73 μM, underscoring its potential for real-world monitoring of pesticide residues in aqueous environments. The combined use of experimental and computational approaches provides a comprehensive understanding of the sensing mechanism, while also highlighting the value of sustainable materials in analytical applications. This work positions Zinc methylimidazolate as a promising candidate for the development of next-generation green sensors for environmental surveillance.

Per- and polyfluoroalkyl substances (PFAS), a large class of anthropogenic compounds widely used in industrial and commercial products, have recently attracted significant scientific and public concern. Prominent compounds like perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are pervasive environmental contaminants linked to endocrine disruption, plastic pollution, and serious health effects, including reduced fertility, thyroid disease, liver damage, hormonal interference, and cancer. Their chemical resilience, being thermally, biologically, hydrolytically, and photochemically stable, renders PFAS extremely persistent, complicating efforts to remediate groundwater, wastewater, and drinking water. The urgent need for efficient treatment strategies has catalyzed extensive research into PFAS removal, degradation, and toxicity. However, despite the explosion of studies on PFAS fate and treatment, detection methods have not advanced at a comparable pace. Conventional analytical techniques often struggle to meet the sensitivity, selectivity, and scalability requirements for modern environmental monitoring. Therefore, this review critically examines recent developments in PFAS detection technologies, emphasizing the necessity of innovative, rapid, and intelligent sensing systems to meet future environmental and regulatory demands. By addressing existing gaps, this review aims to guide researchers toward the next generation of PFAS monitoring tools essential for protecting ecosystems and human health, particularly in the context of evolving smart city frameworks.

Recent research has made substantial progress in understanding the wavelength-dependent performance of perovskite solar cells (PSCs) with an N-I-P architecture. In this study, methylammonium lead iodide-based PSCs with a power conversion efficiency of similar to 20% were exposed to red, green, and blue light to investigate the complexities of charge transport dynamics within the device. A detailed analysis was carried out to explore the effects of wavelength-specific charge carrier generation on the device performance. Additionally, the processes of charge generation and recombination, contributing to a notable power conversion efficiency, were examined under varying conditions such as temperature, voltage, and illumination. This work provides valuable insights into charge transport dynamics, identifying trap states at around 0.26 eV. Elemental mapping of the cross-section of the degraded devices under different illumination conditions also revealed significant insights into ion migration. The systematic exploration of PSC responses to various wavelengths offers a deeper understanding of the mechanisms influencing efficiency and stability, which are essential for the targeted design and engineering of PSCs for specific applications and operational conditions.