Search Results (2,768)

Emerging organic pollutants, principally antibiotics, synthetic dyes and per- and polyfluoroalkyl substances (PFAS), persist in aquatic systems because of chemical stability, incomplete metabolic transformation and limited removal in conventional biological and physical treatment. Hybrid nanocatalysts coupled with advanced oxidation processes (AOPs) and, for PFAS, advanced reduction processes (ARPs) are the principal research responses. Four architectures dominate the recent literature: hollow nanostructures that improve photon utilization and shorten carrier diffusion paths; metal-free floatable composites that ease recovery and surface oxygenation; carbon-nanostructure heterojunctions; and nanomaterial-reinforced membranes that combine rejection with catalytic degradation. These materials are most often paired with visible-light or solar photocatalysis and with peroxymonosulfate (PMS) activation. Laboratory parent-compound removals commonly exceed 80–95% in synthetic single-solute solutions, yet total organic carbon (TOC) mineralization, reusability after documented regeneration, and energy or cost metrics remain sparsely reported. Electrical energy per order (EE/O) for laboratory photocatalysis is frequently greater than 100 kWh m⁻³ order⁻¹, whereas optimized ultraviolet/hydrogen peroxide (UV/H₂O₂) systems can approach 0.06 kWh m⁻³ order⁻¹ at full scale. Reported PMS treatment costs for real chemical-industry wastewater span 0.43–4.66 € kg⁻¹ chemical oxygen demand (COD) under the tariff assumed by the source study. Reactor evidence is dominated by short-duration batch slurry vessels and laboratory membrane modules; continuous-flow and multi-month operational data are scarce. This review maps design evidence, performance data and process configurations in the peer-reviewed literature from 2010 to 2026. It integrates a bibliometric reading of publication trends and keyword evolution, distinguishes parent-compound removal from TOC mineralization and from fluoride release, and identifies the experimental and sustainability gaps that currently limit confident extrapolation to engineered treatment systems. Full article

A calix[4]arene-based fluorescent chemosensor containing two quinolinium units (C4-BisQ) was synthesized and evaluated for the selective detection of cyanide (CN⁻). C4-BisQ showed a dual-mode optical response with a green-to-blue color change under ambient light and fluorescence quenching upon CN⁻ addition in CH₃CN/H₂O (9:1, v/v). UV–Vis and fluorescence titration studies indicated a 1:1 interaction between C4-BisQ and CN⁻ with an association constant of 1.08 × 10⁵ M⁻¹. The limits of detection were 0.080 µM by ratiometric UV–Vis analysis and 0.54 µM by fluorescence spectroscopy. C4-BisQ was highly selective for CN⁻ in the presence of common competing anions and metal cations such as F⁻, Cl⁻, Br⁻, I⁻, ClO₄⁻, NO₃⁻, H₂PO₄⁻, HSO₄⁻, Ac⁻, and Li⁺, Na⁺, Mg²⁺, Ca²⁺, Mn²⁺, Fe³⁺, Co²⁺, Zn²⁺, Cd²⁺, Al³⁺. Spectroscopic data suggest that cyanide recognition mainly involves deprotonation and is accompanied by fluorescence quenching under the applied conditions. Recovery experiments in tap water and seawater, together with visual detection in apricot and peach kernel extracts, confirmed the applicability of the sensor. Overall, C4-BisQ offers a simple dual-mode approach for cyanide detection in environmental water and food-related samples. Full article

The objective of this study was to evaluate the solar photocatalytic degradation of the disperse textile dye 2-(4-amino-2-nitrophenyl)-1,3-benzothiazole using titanium dioxide nanoparticles (TiO₂ P25) under a mean solar irradiance of 492 ± 58 W/m², evaluating the effects of pH, photocatalyst concentration, and continuous aeration on process efficiency. The degradation of the dye was determined by monitoring its concentration by UV–Visible spectrophotometry, while the mineralization was evaluated by chemical oxygen demand (COD). Likewise, kinetic behavior was analyzed using pseudo-first-order and pseudo-second-order models. The results showed that the degradation efficiency increased with the concentration of TiO₂, reaching the highest yield with 400 ppm of TiO₂ and continuous aeration, which confirms that both variables are determining operating factors for maximizing photocatalytic efficiency. pH exerted a significant influence on the activity of the system, obtaining the highest degradation efficiencies and the greatest reductions in COD under slightly alkaline conditions (pH 8–9), a behavior attributed to the greater colloidal stability of TiO₂ and the modification of its surface properties with respect to its point of zero charge (pHpzc ≈ 6.2). The pseudo-second-order model generally provided an adequate empirical description of the experimental data; however, the best-fitting model varied depending on the experimental condition. The simultaneous decrease in the concentration of the dye and the COD confirmed that the treatment produced not only the decolorization of the solution, but also the progressive oxidation of the organic matter. Integrating kinetic analysis with the simultaneous assessment of decolorization and COD enabled clear experimental differentiation between adsorption and photocatalysis, strengthening the interpretation of TiO₂-based solar photocatalytic systems. In conclusion, solar photocatalysis using TiO₂ and the optimization of operational variables constitute an effective treatment strategy that takes advantage of solar irradiation as the primary energy source, thereby reducing dependence on conventional artificial UV irradiation. Within the scope of this study, the combination of solar radiation, continuous aeration and appropriate operating conditions demonstrated promising potential for the treatment of textile wastewater containing persistent dyes. Full article

UV/NaOCl and UV/H₂O₂/NaOCl treatments of sulfamethoxazole (SMX) were compared across several reagent ratios using pseudo-first-order kinetics, LC-DAD/LC-MS screening of transformation products (TPs), multi-trophic bioassays, and quantitative structure–activity relationship (QSAR)-based toxicity and fate screening. Increasing the NaOCl proportion from an SMX:NaOCl molar ratio of 1:1 to 1:10 increased the pseudo-first-order rate constant from 0.215 to 0.818 min⁻¹, but faster SMX removal did not correspond to a more favorable post-treatment bioassay profile. The 1:1 and 1:2 UV/NaOCl systems achieved substantial SMX removal within 10 min and gave the lowest responses among the treated systems in the Microtox^®, Daphtox F^®, and Lemna sp. assays. Higher NaOCl loadings and the mixed-oxidant systems produced stronger post-treatment bioassay responses and larger signals for ECOSAR-prioritized chlorinated aromatics and coupling products. Fate screening further distinguished more persistent, strongly sorbing products from TPs with lower sorption or greater predicted transport potential. The tested reagent ratios therefore revealed a trade-off between removal kinetics and the biological and environmental profile of the resulting mixtures. Full article

New deep-blue-emitting materials are crucial for Organic Light-Emitting Diode (OLED) technology, as iridium-based blue emitters often suffer from degradation and inadequate colour purity. Indium(III) complexes offer an alternative, since the d¹⁰ configuration of In³⁺ precludes metal-centred transitions, and emission arises from ligand-centred states via the chelation-enhanced fluorescence (CHEF) effect. We previously reported complexes 1 ([In(L^H)(H₂O)Cl₃]) and 2 ([In(L^Me)₂Cl₂][InCl₄]), which exhibited excitation-dependent emission, and the electronic transitions were assigned as ILCT for 1 and mixed ILCT/LL’CT for 2. Herein, we present a new complex, complex 3, i.e., [In(L^Morph)₂Cl₂][InCl₄], where L^Morph contains electron-donating morpholine substituents, in contrast to the acceptor chloride group in L^H and L^Me. Complex 3 was characterised by elemental CHN analysis, infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), ultraviolet–visible spectroscopy (UV-Vis), single-crystal X-ray diffraction analysis (SC-XRD), and photoluminescence. The ionic structure of 3 is analogous to 2, with a cis-octahedral [In(L^Morph)₂Cl₂]⁺ cation and tetrahedral [InCl₄]⁻ anion. The UV-Vis spectrum of 3 shows a significant bathochromic shift relative to 1 and 2 which is attributable to the morpholine group. TD-DFT calculations were employed to assign the electronic transitions. The introduction of a morpholino group into the pyridazine ring resulted in significant changes to the solid-state photoluminescence properties of the indium complex: (i) the emission maximum shifted to the red region (CIE 1931 coordinates: 0.1725, 0.2487), (ii) the lifetime increased by an order of magnitude, and (iii) the quantum yield rose to 15%. This work highlights that substituent variation on the pyrazolyl–pyridazine scaffold provides a versatile route to tune the structural and photophysical properties of indium(III) complexes. Full article

Photoaging alters polymer surface chemistry and can thereby regulate the interfacial binding of metal ions by microplastics. In this study, polyethylene (PE) and polyvinyl chloride (PVC) microplastics were exposed for three weeks to five regimes comprising UV-air, UV-ultrapure water, UV-simulated seawater, UV/H₂O₂, and UV/Cl. Changes in surface morphology, functional groups, crystallinity, hydrophobicity, and specific surface area were characterized before Cd²⁺ and Pb²⁺ adsorption. UV/Cl and UV/H₂O₂ induced the strongest transformations in both polymers, although the rate of aging decreased with exposure time. Photoaging generated surface cracks and defects, increased the accessible surface area, reduced hydrophobicity, and introduced hydroxyl, carbonyl, and carboxyl groups. These changes significantly enhanced Cd²⁺ and Pb²⁺ adsorption. Adsorption involved physical and chemical contributions, with chemical interactions predominating. FTIR, elemental mapping, and surface analyses were consistent with coordination and surface complexation at oxygen-containing sites, electrostatic attraction, and nonspecific physical retention on roughened surfaces and within defects. Variations in crystallinity and surface area further modulated adsorption. The results show that aging medium and polymer structure jointly determine the extent of surface oxidation and defect formation, establishing a structure–property relationship between photoaging-induced surface evolution and the enhanced metal-binding capacity of PE and PVC microplastics. Full article

Nickel(II) offers an appealing base for metallodrug design as it is abundant, inexpensive and forms well-defined complexes with N,O-donor ligands. Therefore, five Ni(II) complexes containing two tridentate 2-imine-8-hydroxyquinoline Schiff base ligands, derived from morpholine, piperidine, imidazole or 2-methyl-1H-limidazole, were synthesized and characterized in solution and solid state via analytical and spectroscopic techniques. Single crystals were solved using X-ray diffraction for the complex derived from 4-(2-aminopropyl)morpholine (1). This Ni(II) complex exhibits a distorted octahedrally coordinated Ni(II) center bound to two monodeprotonated NNO-tridentate ligands, adopting a meridional coordination mode, with the two oxygen atoms arranged cis to each other. The stability of the complexes in aqueous media buffered at pH 7.4 was evaluated with UV–Vis spectroscopy and their binding to bovine serum albumin (BSA) was assessed with fluorescence titrations. All complexes show strong reversible binding to BSA (K_SV ~10⁵), which stabilizes the lipophilic complexes in aqueous media. The antiproliferative activity of the complexes was screened against colon cancer cell lines (Colo205 and Colo320). They exhibit moderate anticancer activity (IC₅₀ = 15.1–92.5 μM), with structure–activity relationships favoring imidazole derivatives and maintaining activity against the doxorubicin-resistant cell line (Colo320) with resistance indices (1.3–3.1) comparable to or lower than doxorubicin. Overall, the complexes represent a platform to develop new anticancer Ni-based drugs. Full article

Antimony (Sb) nanopowder was synthesized using fine Sn powder as a reducing agent. The Sn powder was first produced by the chemical reduction of SnCl₂·2H₂O using commercial Al foil in acidic medium, yielding approximately 89% of the theoretical Sn yield. The resulting Sn powder exhibited a mean particle size of approximately 93 nm and a mean crystallite size of 57 nm, which promoted rapid reduction during Sb synthesis. Prior to synthesis, the composition of the Al foil was examined using SEM/EDS, confirming an Al-rich matrix containing minor Fe and Si impurities. High-purity Sb nanopowder was synthesized by reducing SbCl₃ in acetone at 50 °C under magnetic stirring and ultrasonic agitation, using the produced fine Sn powder as a reducing agent, achieving approximately 97% of the theoretical yield. SEM analysis revealed nearly spherical particles of black Sb nanoscale powder with the most frequent size falling within the 20–40 nm range and a mean particle size of approximately 32 nm. XRD analysis confirmed a trigonal Sb structure with a mean crystallite size of around 23 nm. For comparison, pellets prepared from synthesized Sb nanopowder and commercial Sb powder were compacted and sintered under identical conditions. Vickers microhardness measurements showed that the hardness of the sintered Sb nanopowder pellet was approximately 62% higher than that of the commercial Sb pellet. In addition, UV-Vis-NIR reflectance measurements (240–840 nm) demonstrated that the reflectance of the Sb nanopowder pellet was approximately three times higher than that of the commercial Sb pellet. These results demonstrate that fine Sn powder can serve as an efficient reducing agent for the synthesis of high-purity Sb nanopowder with enhanced mechanical and optical properties. Full article

Airborne polycyclic aromatic hydrocarbons (PAHs) are toxic pollutants that pose significant risks to human health. In this study, a photocatalyst-based polyacrylamide/zinc oxide (PAM/ZnO) hydrogel composite mesh with an open-mesh architecture was successfully fabricated via photoinduced polymerization of acrylamide, in which ZnO served as both the photoinitiator and photocatalyst. The resulting composite exhibited a three-dimensional interconnected porous structure with ZnO particles uniformly distributed throughout the polyacrylamide hydrogel matrix. The hydrogel exhibited typical swelling–deswelling behavior, reaching an equilibrium swelling ratio of 2.71 within 360 min, along with good water-retention capability. The photocatalytic performance of the PAM/ZnO hydrogel composite mesh was evaluated through the degradation of particulate matter (PM)-bound PAHs generated from incense smoke. The concentrations of two- to five-ring PAHs progressively decreased with increasing ultraviolet irradiation time. Complete degradation of naphthalene was achieved after 4 h of UV irradiation, whereas all detected five-ring PAHs were completely removed after 8 h. Furthermore, the mesh-engineered architecture exhibited excellent air permeability with an exceptionally low pressure drop (<120 Pa), even with multiple mesh layers, enabling energy-efficient continuous air recirculation. These characteristics, together with the photocatalytic degradation of particle-bound PAHs, make the PAM/ZnO hydrogel composite mesh a promising platform for sustainable air purification. Full article

Graphene oxide (GO) offers a high-surface-area platform for the noncovalent association of hydrophobic bioactive compounds, but its biological response depends strongly on surface chemistry. Here, GO was carboxylated with sodium chloroacetate and physically associated with curcumin (CUR) to obtain a graphene oxide–curcumin nanoadduct (GO-COOH-CUR). Ultraviolet-visible spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to assess chemical and morphological changes. XPS showed a lower C/O ratio and a higher fitted O-C=O contribution after carboxylation, although residual Na and Cl were detected. UV-vis, FTIR and XPS features were consistent with the presence of curcumin in the formulation with 83.35% of encapsulation efficiency (EE). In 24 h MTT assays, CO-COOH-CUR maintained BHK-21 metabolic activity above 70% across 3.125 µg mL⁻¹ and reduced MCF-7 metabolic activity at the higher tested concentrations. Because formulation concentrations were expressed as a total mass and curcumin concentration is not reported here, direct potency or selectivity comparisons with free curcumin were not made. Qualitative histological evaluation performed 30 days after subdermal implantation in three male Wistar rats showed preserved adjacent tissue architecture, with no evident necrosis, prominent inflammatory infiltrate, organized fibrous capsule, or foreign-body giant cell response in the sections evaluated. These findings support further evaluation of GO-COOH-CUR within the limits of MTT-based and qualitative assessment. Full article

The nephrotoxicity and ototoxicity of Gentamicin have been extensively investigated; however, whether they induce hematotoxicity remains unclear. This study aimed to explore the binding of Gentamicin to adult hemoglobin (HbA) and its toxicological implications. The effect of Gentamicin on HbA oxidation was assessed by quantifying methemoglobin (MetHb) formation via a four-wavelength spectrophotometric method, and scavenger rescue assays were employed to elucidate the oxidative mechanism. Alterations in the oxygen-carrying capacity of both HbA and RBCs were evaluated through the acquisition of oxygen equilibrium curves and oxygen dissociation assays. The binding affinity between Gentamicin and HbA was determined by surface plasmon resonance (SPR). Furthermore, the influence of Gentamicin on the secondary and tertiary structures of HbA was examined by microfluidic modulation spectroscopy (MMS) and UV–visible absorption spectroscopy, respectively. Molecular docking was employed to predict the binding sites of Gentamicin on HbA. Molecular dynamics simulations verified the stability of the binding. Gentamicin promoted HbA autoxidation, elevating MetHb levels, and reduced the oxygen affinity of HbA. Gentamicin-promoted HbA autoxidation is primarily mediated by both direct heme-pocket perturbation and H₂O₂/iron-dependent amplification. SPR confirmed concentration-dependent specific binding between Gentamicin and HbA. MMS indicated no alteration in HbA secondary structure; however, UV–visible spectroscopy revealed that Gentamicin attenuated the Soret band, converted the oxyhemoglobin double-peak to a singlet, and generated a new band at 630 nm. Molecular docking predicted that Gentamicin binds β-chain residues via hydrogen, carbon–hydrogen, and hydrophobic interactions. This study reveals that Gentamicin exerts hematological effects in vitro. By binding to specific sites on HbA, Gentamicin affects the tertiary structure of HbA, promotes heme oxidation, ultimately increases MetHb content (oxidative damage), and decreases its oxygen-carrying capacity (functional impairment). Full article

Electrochromic tungsten oxide (WO₃) films suffer from gradual performance degradation during repeated ion insertion/extraction processes, while the relationship between electrolyte-dependent ion accommodation and structural stability remains insufficiently understood. Herein, magnetron-sputtered WO₃ thin films were systematically investigated in H₂SO₄, LiClO₄, ZnSO₄, and Al₂(SO₄)₃ electrolytes to clarify the coupling relationship among ion accommodation, electronic structure evolution, microstructural retention, and electrochromic durability. Combined electrochemical measurements with UV–visible spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and reflected electron energy loss spectroscopy (REELS) reveal that electrolyte chemistry regulates the balance between electrochemical activation and structural tolerance. Highly mobile H⁺ and strongly interacting Al³⁺ ions promote rapid ion transport and enhanced W⁶⁺ reduction but may induce excessive structural perturbation, defect accumulation, and accelerated degradation during cycling. Zn²⁺ exhibits intermediate behavior, whereas Li⁺ enables balanced ion accommodation through reversible W⁶⁺/W⁵⁺ conversion while preserving the WO₃ framework. Consequently, the LiClO₄ electrolyte achieves superior electrochromic performance with an optical modulation of 80.97% and improved cycling stability. These results demonstrate that durable electrochromic behavior is governed not by maximizing ion transport or reduction degree, but by achieving a reversible ion accommodation regime compatible with the structural tolerance of the host framework. This work provides a microstructure-oriented strategy for designing stable WO₃-based electrochromic devices through electrolyte regulation. Full article

The photo-Fenton process combines both Fenton and H₂O₂/UV processes within a single reactor for dissolved organic carbon (DOC) removal. However, the dominant mechanism—iron coagulation or OH• oxidation—at the Fenton stage remains unclear. Synthetic textile wastewater containing reactive dye and polyvinyl alcohol was treated using a batch UV photoreactor. The first 10 min was designated as the Fenton stage, while DOC removal during the initial 30 min of the photo-Fenton process was evaluated through re-dissolution experiments to quantify the relative contributions of iron coagulation and OH• oxidation. The results show that at ferrous dosages of 10–40 mg/L, the Fenton stage contributed 55.6–91.9% of the overall DOC removal achieved by the photo-Fenton process. DOC re-dissolution experiments further demonstrated that DOC removal during this stage was predominantly governed by iron coagulation, which accounted for 68.6–87.2% of the overall DOC removal. In contrast, within the photo-Fenton process, when residual H₂O₂ was present, DOC removal was predominantly driven by OH• oxidation, accounting for 64.9–86.3% of total DOC removal. In addition, the specific H₂O₂ consumption per mg of DOC removed during the Fenton stage was approximately 2–6 times higher than that in the photo-Fenton process, demonstrating that the Fenton stage consumes H₂O₂ inefficiently and fails to effectively remove DOC through OH• oxidation. To reduce H₂O₂ dosage, UV irradiation demand, and overall oxidation time, separation of the Fenton and H₂O₂/UV processes into two distinct reactors is recommended. Full article

The present study reports the green synthesis of iron oxide nanoparticles (α-Fe₂O₃ NPs) using Azadirachta indica leaf extract as a sustainable stabilizing agent and evaluates their antimicrobial and photocatalytic potential. The synthesized nanoparticles were characterized by UV–Visible, FT-IR, XRD, FESEM-EDS and TEM techniques. UV–Visible analysis confirmed nanoparticle formation, while XRD revealed the rhombohedral crystalline phase of α-Fe₂O₃ with high crystallinity. FT-IR analysis indicated the involvement of phytochemicals from A. indica in nanoparticle synthesis and stabilization. FESEM and TEM images showed predominantly irregular agglomerated rod-shaped nanoparticles. EDS analysis confirmed the elemental composition of iron and oxygen. Photocatalytic performance was evaluated through the degradation of Rhodamine B dye under xenon arc lamp irradiation simulating sunlight. The synthesized α-Fe₂O₃ NPs achieved a maximum degradation efficiency of 95.38% at 180 min and followed pseudo-first-order kinetics. The effects of pH, catalyst reusability, and stability confirmed the excellent photocatalytic performance and durability of the nanoparticles. The antimicrobial activity of α-Fe₂O₃ NPs was assessed against selected bacterial pathogens (E. coli, P. aeruginosa, B. subtilis, and S. aureus) and fungal strains (C. albicans, A. flavus, and A. niger) using the disk diffusion method. The nanoparticles exhibited broad-spectrum antimicrobial activity, with the highest inhibition observed against E. coli. These findings demonstrate that A. indica-mediated α-Fe₂O₃ NPs are effective multifunctional nanomaterials with significant potential for wastewater treatment, environmental remediation, and antimicrobial applications. Full article

Hierarchical titanium dioxide (TiO₂) has emerged as a promising photocatalytic material owing to its excellent chemical stability, environmental benignity, low cost, and high density of surface-active sites. Nevertheless, its practical application is constrained by rapid photogenerated charge-carrier recombination and poor visible-light utilization resulting from its wide bandgap. In the present study, a hierarchical TiO₂/CdS quantum dot (QD) nanocomposite was engineered through a facile and cost-effective pseudo-successive ionic layer adsorption and reaction (p-SILAR) technique with controlled CdS QD deposition. The structural, morphological, optical, and electrochemical properties of the synthesized photocatalysts were systematically investigated using SEM, TEM, XRD, XPS, UV-Vis spectroscopy, photoluminescence (PL), and electrochemical impedance spectroscopy (EIS). The results confirmed the successful deposition of highly dispersed CdS QDs onto the hierarchical TiO₂ framework without altering its morphology or crystal structure. The formation of the heterojunction significantly enhanced visible-light absorption and reduced the optical bandgap from 3.19 eV for pristine TiO₂ to 2.37 eV for the TiO₂/CdS QD nanocomposite. Furthermore, PL and EIS analyses demonstrated suppressed electron–hole recombination and improved interfacial charge-transfer characteristics, respectively. Owing to these synergistic effects, the optimized TiO₂/CdS QD photocatalyst achieved 85.3% degradation of methylene blue under visible-light irradiation within 120 min, exhibiting substantially superior performance to pristine hierarchical TiO₂. Radical scavenging experiments revealed that superoxide radicals ^●O₂⁻ and photogenerated holes (h⁺) were the dominant reactive species governing the degradation process. The enhanced photocatalytic activity is attributed to the combined effects of efficient visible-light harvesting, accelerated charge separation, and effective interfacial charge migration across the TiO₂/CdS QD nanocomposite. These findings highlight the potential of hierarchically structured TiO₂/CdS QD nanocomposites as efficient and economically viable photocatalysts for environmental remediation and wastewater treatment applications. Full article