Laboratory microcosm evidence for denitrification-driven iodine mobilization in coastal groundwater systems: Implications for salinity and redox control

Pollution of water systems by dyes such as acridine orange (AO), turquoise blue X-GB (TB), and atrazon pink FG (AP) is a public health concern. To address the concern, boron carbon nitride (BCN) was incorporated into erbium ferrite (ErFe2O4) immobilized on graphene oxide (GO) to produce ErFe2O4–BCN@GO- a photocatalyst to degrade AO, TB and AP in a water system. Characterization results of ErFe2O4–BCN@GO revealed a Brunauer-Emmett-Teller (BET) surface area as 15.85 m2 g−1, and an energy bandgap (Eg) being 1.81 eV. The X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray spectroscopy (EDS) confirmed the elemental composition as Er, Fe, O, B, C and N. Scanning electron microscopy (SEM) micrograph confirmed the surface as being heterogeneous with irregularly shaped particles, while the transmission electron microscopy (TEM) micrograph showed hexagonal-like particles. ErFe2O4–BCN@GO exhibited a 100% degradation of AO, TB and AP in aqueous solution with a pseudo-first-order kinetic in the order AO (0.0125 min−1) > TB (0.0105 min−1) > AP (0.0080 min−1). The hydroxyl (•OH) and superoxide ion (•O2−) radicals were the main contributors to AO, TB and AP degradation. Furthermore, in a multi-dye solution system of AO, TB, and AP, the degradation performance was reduced from 100% in a single dye solution to values of≥ 70%. The regeneration capacity of ErFe2O4–BCN@GO was not <70% at its 7th regeneration cycle. Interestingly, ErFe2O4–BCN@GO compared favorably with photocatalysts and adsorbents in literature, which suggests its suitability as a photocatalyst for removing AO, TB and AP from water.

A Comparative Study of Caerin 1.1/1.9 and Calcium Hydroxide in the Treatment of Apical Periodontitis in Rats.

The strategic selection of alkali metal nitrates in molten salt synthesis critically governs the structural evolution and electrocatalytic performance of iridium oxide hydrate (IrOx·nH2O) catalysts for oxygen evolution reaction (OER). While NaNO3-mediated synthesis has shown superior catalytic activity, we systematically investigated LiNO3 and KNO3 as alternative molten salt media to elucidate structure-property relationships. X-ray pair distribution function (PDF) analysis revealed that the LiNO3-derived catalysts retained a significant amount of unreacted amorphous IrCl3 precursor, yielding the poorest electrocatalytic efficiency. This incomplete conversion is attributed to the exceptionally high viscosity of molten LiNO3, which severely restricts precursor diffusion and crystal growth. In contrast, KNO3-mediated synthesis produced a local structure that can be described as a mixture of hollandite- and rutile-type motifs, delivering intermediate performance. The emergence of rutile-type IrO6 octahedral connectivity due to localized thermal hotspots arising from the lower thermal conductivity of molten KNO3 relative to NaNO3 promotes temperature-induced phase transformations. These findings establish a fundamental correlation between the physicochemical properties of molten salts and catalyst architecture, demonstrating that NaNO3-facilitated hollandite-type local structures optimize ion transport pathways and electrocatalytic activity. This work highlights the critical importance of rational molten salt selection in the design of high-performance OER catalysts.

Context While human activities are the primary source of elevated soil metal concentration, natural geological processes can also contribute significantly. Aims This study investigated the influence of parent rock lithology on the concentration of arsenic, chromium, copper, nickel, lead, and zinc in soils of the O’Higgins Region, central Chile. Methods The soils developed on five distinct lithologies: andesites (intermediate volcanic rocks), felsic volcaniclastics, mixed (intermediate and felsic) volcanics, plutonic rocks, and metamorphic rocks. A total of 38 topsoil samples (0–10 cm) and their corresponding 22 parent rock samples were collected from watersheds selected to represent background conditions. Selective dissolution using citrate–bicarbonate–dithionite and hydroxylamine hydrochloride was employed to quantify trace element association with iron oxides (FeOx) and manganese oxides (MnOx). Key results Adsorption onto FeOx was the primary control on trace element retention across all soils. Notably, FeOx retained over 50% of total soil arsenic, reflecting the strong affinity between arsenate and FeOx surfaces, likely driven by binuclear inner-sphere complexation, whereby an arsenate ion replaces two hydroxyl ions on the FeOx surface. Conclusions This study demonstrates that the influence of parent rock lithology on soil trace element content is not a direct relationship, but is instead mediated by the complex interplay between FeOx and MnOx. Implications The novelty of this work lies in highlighting the differential influence of these oxide phases on the retention of As relative to divalent metals.

The present study reports a hierarchical supercapacitor electrode that integrates poly(2-aminothiophenol) (P2-ATH) with a cobalt-nickel heterostructure comprising cobalt carbonate hydroxide hydrate (CCHH) and cobalt-nickel oxide (CNO). The hybrid is synthesized by hydrothermal growth of CCHH/CNO nanoneedles, followed by in situ oxidative polymerization of P2-ATH to yield conformal nanoflakes. This interpenetrating architecture furnishes a porous, electrically percolated network that shortens ion-diffusion paths and accelerates electron transport, thereby coupling the redox activity of P2-ATH with the multiple Faradaic sites of the Co-Ni phase. Electrochemical tests in different electrolytes (NaOH, NaCl, and HCl) demonstrate a strong electrolyte dependence, with 0.5 M HCl yielding the best performance. At 0.4 A g-1, the specific capacitance reaches 113.87 F g-1 in HCl, compared with 27.89 F g-1 in NaOH and 7.73 F g-1 in NaCl. In 0.5 M HCl, the electrode delivers an energy density of 5.69 Wh kg-1 at a specific power of 479.7 W kg-1. The results highlight the synergistic interplay between the conductive P2-ATH and the Co-Ni nanoneedle, establishing P2-ATH/CNO-CCHH as a promising platform for high-rate, durable supercapacitors and broader electrochemical energy-storage applications.

Enhanced adsorption removal of fluoride by multifunctional polymer-based hydrated neodymium oxide: Capacity evaluation and mechanism.

Interface engineering of nickel molybdenum nitride@nickel cobalt molybdenum layered double hydroxide heterostructure with enhanced hydroxyl ion adsorption ability for supercapacitors.

Interlaminar shear strength (ILSS) is a critical parameter for assessing the durability of fiber-reinforced polymer (FRP) bars. However, the effects of fiber types on ILSS degradation of epoxy-based glass and carbon FRP (GFRP and CFRP) bars in marine concrete environments remain insufficiently explored. This study investigates the degradation behavior and failure modes of epoxy-based G/CFRP bars through accelerated marine concrete exposure at 25°C, 40°C, and 55°C for up to 84 days. ILSS testing and microscopic observations, including super-depth-of-field and scanning electron microscopy, are conducted to examine the damage progression and degradation mechanisms. Experimental results reveal that, although carbon fibers remain chemically stable under marine exposure, epoxy-based CFRP bars exhibit more severe ILSS degradation than GFRP bars, primarily due to their larger fiber–matrix interfacial areas and weaker interfacial bonding. Moreover, the ILSS failure modes of G/CFRP bars are found to depend on the damage levels. In addition, the hydroxyl ion diffusion model (HIDM) and 2D finite element analysis are developed to predict ILSS degradation, with experimental validation of the predicted ILSS retentions. The findings systematically identify the ILSS durability of epoxy-based GFRP and CFRP bars under marine exposure and provide an efficient modeling framework for the durability assessment of FRP-marine concrete structures.

Understanding catalyst reconstruction is crucial for the rational design of oxygen evolution reaction (OER) electrocatalysts, yet spontaneous chemical reconstruction in alkaline environments remains insufficiently understood. Herein, we demonstrate that alkali-triggered chemical reconstruction, rather than electrochemical activation, can effectively generate highly active surface species. Using the Ruddlesden-Popper perovskite La0.5Sr1.5Ni0.75Fe0.25O4±δ (LSNF) as a model catalyst, an approximately 17-fold enhancement in OER current density at 1.55 V versus RHE is achieved after KOH immersion, accompanied by a reduced overpotential of 287 mV at 10 mA cm-2 (86 mV lower than pristine LSNF). Spectroscopic and microscopic analyses reveal that KOH immersion triggers elemental leaching and Ni reconfiguration, forming an amorphous Ni hydr(oxy)oxide surface layer enriched with Fe. This strategy is also applied to other perovskites (La1-xSrxNi0.75Fe0.25O3-δ, x = 0.2, 0.5), demonstrating its general applicability. This work highlights the role of concentrated alkali in driving chemical reconstruction and linking dynamic structural evolution with catalytic performance.

The integration of metal-organic framework (MOF) thin films into functional devices is currently hindered by high temperatures, prolonged processing times, and complex additives required by conventional fabrication methods. We demonstrated a plasma-assisted strategy to directly synthesize crystalline MOF films on metal substrates under ambient conditions and overcome these kinetic and processing limitations. We used a HKUST-1 on a copper substrate as a model system and demonstrated that continuous crystalline films are formed within minutes in an ethylene glycol solution without the need for thermal annealing or external metal precursors. The mechanistic investigation revealed that the plasma-liquid-solid interface functions as a unique reaction field providing a dual driving force. The plasma treatment induced a reaction by functioning as an electrochemical driver for anodic metal dissolution while simultaneously assisting in ligand deprotonation through the generation of reactive species such as hydroxyl and superoxide ions. This process is governed by a kinetic balance, where a specific processing window defined by the metal electrode potential and the ligand acidity distinguishes copper from other metals. These results indicate that atmospheric pressure plasma serves as a potent tool for interfacial coordination chemistry, provided that the electrochemical ion supply and acid-base kinetics are synchronized. This work establishes a design principle for the rapid and additive-free fabrication of MOF films, thus offering a foundation for the streamlined integration of functional porous layers into next-generation devices.

Arsenate adsorption onto hydrous ferric oxide: Insights from triple layer surface complexation modeling

Nanoconfinement engineering enhances HFO stability: Dual proton-sponge and size-exclusion strategy for robust heavy-metal sequestration in real electroplating effluents.

To evaluate the physicochemical properties of a novel strontium silicate-based root canal sealer (C-Root SP) in comparison with a calcium silicate-based sealer (TotalFill BC) and an epoxy resin-based sealer (AH Plus). Setting time, net mass change (apparent solubility behavior), pH changes, and surface characteristics were assessed based on ISO 6876 and ANSI/ADA Specification No. 57, with minor methodological modifications. Net mass change and pH were evaluated over 28 days. Surface morphology and elemental composition were analyzed after dry and aqueous aging in deionized water using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Data were analyzed using one-way and repeated-measures ANOVA with Tukey's post hoc test (α = 0.05). AH Plus exhibited the longest initial and final setting times (10.93 ± 0.65 h and 37.33 ± 0.13 h), whereas TotalFill BC showed the shortest (7.98 ± 0.32 h and 30.18 ± 0.20 h); C-Root SP demonstrated intermediate values (9.35 ± 0.38 h and 32.75 ± 0.57 h) (p < 0.001). C-Root SP exhibited positive net mass change values (indicative of net mass loss), ranging from 5.32 ± 4.72% at 24 h to 6.83 ± 5.55% at 28 days, significantly higher than AH Plus and TotalFill BC (p < 0.001), which showed negative values indicative of apparent mass gain. All sealers demonstrated alkaline conditions, with C-Root SP maintaining the highest apparent pH values throughout the evaluation period (p < 0.001). Surface and compositional changes were observed in the bioceramic sealers following aqueous aging, with increased detectable strontium content in C-Root SP. C-Root SP exhibited physicochemical behavior consistent with a strontium-modified calcium silicate-based sealer, characterized by hydration-driven hydroxyl ion release resulting in apparent alkalinity and ion exchange-associated behavior, and dynamic surface changes consistent with those reported for bioceramic materials. Strontium incorporation may influence hydration-mediated physicochemical behavior; however, further in vitro and in vivo studies are required to determine its clinical relevance.

1D hydrogen titanium oxide hydrate with large interlayer spacing as an intercalation-type anode material for low-temperature sodium-ion batteries.

Cyclohexenone derivatives have more significant attention in the last current years owing to its varied range of applications in various subject, including medicinal chemistry, materials science, and organic synthesis. A derivative of cyclohexanone was prepared by condensation of chalcone derivative with acetylacetone and ethylacetoacetate to produce new ligands with titles L1 and L2, respectively, via Michael's reaction. The Newly complexes were synthesized by coordination of L1 with transition metals (CrCl3• 6H2O, CuCl2•2H2O) and L2 with (CoCl2 • 6H2O, NiCl2 • 6H2O), and characterized by ¹H NMR and LC-MS mass spectral analysis, UV and IR spectroscopy, also the magnetic susceptibility studies, molar conductivity study, C, H, N, and atomic absorption analysis. The results confirmed that both new ligands act as bidentate ligands, coordinating with metal ions through the oxygen atoms of both the ketone and hydroxide groups for L1. In contrast, L2 coordinates through two oxygen atoms of the ketone groups to form complexes with an octahedral geometry. The antibacterial capability of new compound and corresponding metal complexes was investigated against the two kinds of pathogenic bacteria microorganisms (Escherichia còli) and (Stāphylocòccus aureus) compare with the standard drug (Cephalexin), and the results showed that the ligands and their complexes activities ranged from weak to moderately to highly active against the two categories of bacteria compared with the standard drug Cephalexin. Consequently, these complexes show potential as therapeutic agents and may emerge as strong competitors to currently available pharmaceuticals. A comprehensive theoretical investigation of the ligand and its metal complexes was conducted by density functional theory (DFT) at the B3LYP level with the 3-21G basis set to provide a consistent correlation with the experimental findings, and shows that L2 and corresponding complexes are more stable compared with L1and its complexes. L2 and its complexes exhibit the highest energy gaps and chemical hardness, confirming their kinetic stability and reduced reactivity compared to other complexes.

Enamel Composition and StructureDental enamel is an acellular, mineralized tissue composed primarily of carbonated calcium hydroxyapatite.By weight, it contains approximately 37% calcium, 52% phosphate, and 3% hydroxyl ions, forming the characteristic enamel apatite Ca(PO)(OH).

Silicon-mediated alleviation of aluminum toxicity in Eucalyptus species: Distinct Al uptake, microbial and metabolic mechanisms in sensitive and tolerant species

Objectives: (i) To compare and assess, using radiography and cone-beam computed tomography (CBCT), the dentin bridge formation achieved by autologous demineralized dentin coagulum (ADDC) versus calcium hydroxide in vital pulp therapy. (ii) To compare the ability of both materials in maintaining pulpal vitality over a 12-month period. Methods: A total of 74 patients (aged 18–30 years) with two or more deep carious lesions approximating the pulp in vital molars, and without periradicular pathology, were enrolled. Following clinical and radiographic evaluation, teeth were randomly assigned to: Group A: Calcium hydroxide (control) Group B: Autologous demineralized dentin matrix (test). For Group B, autologous dentin obtained from an indicated extraction or undermined tooth was processed using a dentin grinder, demineralized, and applied over the pulp exposure site before restoration. Patients were reviewed every three months for one year, with vitality testing and radiographic evaluation of dentin bridge formation. Dentin bridge thickness was quantified radiographically and by CBCT at 12 months. Data were analyzed using the Friedman test (p &lt; 0.001 considered significant). Results: Dentin Bridge Formation: Group A: Mean dentin bridge score decreased from 4.00 (baseline) to 3.23 at 12 months (χ 2 = 81.8, p &lt; 0.001) Group B: Mean dentin bridge score decreased from 4.00 (baseline) to 1.82 at 12 months (χ 2 = 221.0, p &lt; 0.001). Dentin Thickness Group A: Mean thickness decreased from 4.00 to 3.08 at 12 months (χ 2 = 92.4, p &lt; 0.001) Group B: Mean thickness decreased from 4.00 to 1.69 at 12 months (χ 2 = 228.9, p &lt; 0.001). Pulp Vitality Group A: 8.1% non-vital teeth Group B: 4.1% non-vital teeth Conclusions: Autologous demineralized dentin coagulum demonstrated superior clinical performance compared with calcium hydroxide, resulting in thicker and more continuous dentin bridge formation and higher rates of pulp vitality preservation. Given its rich content of bioactive molecules, stem cells, and growth factors, ADDC represents a promising biomimetic approach for regenerative vital pulp therapy.

Facile functionalization of ZIF–8 via mechanochemical post-synthetic linker exchange for improved CO2 capture performance