Search Results (1,953)

High-fluoride hot springs serve as a natural laboratory for investigating microbial adaptation and variations in community structure under extreme environments. This study utilized water chemistry analysis and 16S rRNA gene sequencing to investigate the correlation between high-fluoride hot springs and microbial community structure and diversity. The results show that the five hot springs exhibited an average F^- content of 15.04 mg/L, with weakly alkaline pH, high total dissolved solids, and Na⁺ as the dominant cation. The hydrochemical type was classified as HCO₃⋅SO₄-Na, consistent with the chemical characteristics of high-fluorine water. Microbial abundance and diversity were significantly reduced in the hot springs as compared to the surface water and groundwater samples. The dominant phyla in the study area included Pseudomonadota, Cyanobacteriota, Bacteroidota, and Actinomycetota. The genus-level composition varied significantly across samples, with no dominant genus observed universally. The specific genera present in different samples exhibit unique functional attributes, such as Tepidimonas, Rhodobacter, Hyphomonas, Parvibaculum, Polynucleobacter and Limnohabitans. Cluster analysis confirmed that dissimilarity coefficients highlight the significant influence of microbial abundance on inter-sample differences among hot springs. Redundancy analysis of the top 11 phyla by abundance in water samples revealed that the presence of F^- exerts inhibitory effects on microbial growth. Full article

The extraction of lithium and potassium from salt lakes has led to the generation of substantial amounts of magnesium-rich waste streams. These by-products, with their high magnesium content, have contributed to severe environmental degradation in salt lake regions. Therefore, recovering and utilizing magnesium from salt lake resources is a crucial challenge for achieving sustainable development. In this study, magnesium and lithium were separated from evaporated brine—obtained via solar pond technology—using membrane electrolysis. Magnesium was converted into Mg(OH)₂ as a flame retardant, while lithium was refined into battery-grade Li₂CO₃. The final products exhibited high purity, exceeding 99.5% for Mg(OH)₂ and 99.99% for Li₂CO₃. This work systematically investigated the influence of electrolysis temperature on the physicochemical properties of Mg(OH)₂ extracted via membrane electrolysis. The variation in electrolyte temperature was also analyzed in relation to other process parameters, such as electrolyte concentration, current density, and processing time. Results demonstrated that the electrolysis process could maintain a favorable operating temperature through self-heating, even under ambient conditions. Using this electrolysis approach for magnesium–lithium separation from brine, extraction rates of 95.86% for magnesium and 67.46% for lithium were achieved. Full article

In this study, two γ-carbon-substituted dialkylphosphinic acids—symmetrical di-(3,5,5-trimethylhexyl)phosphinic acid (P355) and unsymmetrical (2-ethylhexyl)(3,5,5-trimethylhexyl)phosphinic acid (P227-355)—were synthesized via a precise free radical addition method. Their chemical structures were fully characterized using ESI-HRMS, ¹H NMR, ³¹P NMR, and FT-IR. Their middle REE extraction/separation performance, anti-emulsification behavior, and underlying mechanisms were investigated. Key results showed that P355 had better Dy saturation capacity (357.51 mg/L) and good selectivity for middle REEs (their average value of β_{N + 1/N} = 3.18), while P227-355 showed higher back-extraction efficiency (≈90% Dy stripping at ≥0.02 mol/L H₂SO₄). Methyl n-pentyl ketone (MNPK) eliminated emulsification and boosted saturation capacity (324.18 mg/L Sm and 357.51 mg/L Dy for P355). Mechanistically, the extraction followed cation exchange (Sm³⁺ + 2(HL)₂ ↔ Sm·L₃·(HL) + 3H⁺); MNPK formed hydrogen-bonded associates (HL·MNPK) with free extractants, slightly reducing the effective concentration of (HL)₂ but not altering the core cation exchange mechanism. Full article

The effectiveness of periodate-assisted photocatalysis in removing the cationic dye Safranin O (SO) was evaluated using a UV/TiO₂/IO₄⁻ process operated at room temperature under near-neutral pH conditions. Under base conditions ([IO₄⁻] = 0.15 mM, [TiO₂] = 0.4 g/L, [SO] = 10 mg/L), the ternary system achieved a pseudo-first-order rate constant of 0.6212 min⁻¹, outperforming the UV/TiO₂ and UV/IO₄⁻ processes by approximately 21- and 29-fold, respectively. This yielded a synergy ratio of about 12 compared to the sum of the binary processes. Targeted quenching experiments revealed the operative pathways. Strong inhibition by ascorbic acid and phenol indicates that interfacial holes and ^•OH are key oxidants. Methanol caused a moderate slowdown, consistent with ^•OH and hole scavenging. Benzoquinone and oxalate suppressed removal by intercepting the electron and O₂^•− pathways, respectively. Dichromate markedly inhibited the process via optical screening and competition for electrons. Azide had little effect, suggesting a minor role for singlet oxygen. Matrix studies showed progressively slower kinetics from deionized water to mineral water to seawater. This was due to halides, sulfate, alkalinity, and TiO₂ aggregation driven by ionic strength. Additional tests confirmed that the dominant modulators of performance were humic acid (site fouling and light screening), chloride and sulfate (radical speciation and surface effects), nitrite (near-diffusion radical quenching), and bicarbonate at pH 8.3 (conversion of ^•OH to CO₃^•−). Nonionic surfactants (Tween 80, Triton X-100) also depressed SO removal through micellar sequestration and competitive adsorption on TiO₂. The study confirms the potential of UV/TiO₂/IO₄⁻ as a tunable AOP capable of delivering rapid and reliable dye degradation under a wide range of water quality conditions. The mechanistic mapping unifies two roles for IO₄⁻, an electron acceptor that inhibits recombination and a photochemical precursor of iodine centered and ^•OH radicals and connect these roles to the observed synergy and to the trend across deionized water, mineral water, and seawater. The scavenger outcomes assign the main oxidant flux to holes and ^•OH radicals with a contributory electron or O₂^•− branch from IO₄⁻ reduction. Full article

There is a knowledge gap about the effect of pharmaceutical agents on the biodegradation of Mg-based resorbable implants. The present work investigates how three common antibiotics and three anti-inflammatory drugs affect the corrosion of high-purity Mg, with and without ceramic and hybrid ceramic/polymeric coatings, using electrochemical impedance spectroscopy and hydrogen evolution tests. A Ca-P-Si-based ceramic coating is developed using plasma electrolytic oxidation (PEO), after the AC voltage and frequency parameters are optimized. A hybrid coating included a PEO and a poly(ε-caprolactone) (PCL) top layer formed by dip coating. High-purity Mg exhibited an instantaneous onset of corrosion with a corrosion rate of 90 μm/year after 24 h of immersion in a modified α-MEM. A hybrid PEO/PCL coating prevents the onset of corrosion for at least 5 h and reduces the H₂ evolution during the following 90 h by two times by the precipitation of 5–40 μm thick Ca-P surface deposits. Gentamicin, naproxen, streptomycin, ciprofloxacin and paracetamol were found to be corrosion accelerators with respect to bare h.p. Mg, whereas aspirin was found to be an inhibitor. Streptomycin-functionalized PEO/PCL system exhibited an active protection mechanism, triggered upon the release of the coating and substrate cations, associated with the coating defect-blocking action of the insoluble Me(II)-streptomycin chelates. Full article

The study evaluated the influence of dietary supplementation with nano-encapsulated cumin oil, B. subtilis, or a combination of both to mitigate the impacts of heat stress on the performance and health of growing rabbits. In the feeding trial, a total of eighty-four growing New Zealand White (35 days, 781.3 ± 1.8 g average body weight) were randomly distributed in a completely randomized design into four groups; each had 21 rabbits arranged in 7 replicates (3 rabbits each). The experiment lasted 42 days (35 days to 77 days). Growing rabbits received a basal diet (first group, CON) without additives, while the other groups were supplemented with nano-encapsulated cumin oil (NECO, 200 mg/kg), B. subtilis (BS, 500 mg/kg), or both (BSNO, 500 mg BS plus 200 mg/kg NECO). Adding BSNO significantly enhanced body weight gain, carcass weight, and feed conversion ratio and reduced mortality rate (p < 0.05). Additionally, the BSNO enhanced digestive system performance by increasing the secretion of trypsin enzymes, as well as nutrient digestibility, especially for protein and fiber (p < 0.05). Supplementing BSNO enhanced oxidative stability and immunity via higher levels of superoxide dismutase (SOD), IgA, IgG, triiodothyronine (T3), thyroxine (T4) and lower malondialdehyde (MDA) levels (p < 0.05), indicating a better ability to adapt to stress. During the examination of gut health, pathogenic bacteria counts decreased, as well as down-regulation of interleukin-6 (IL-6) gene expression and up-regulation of cationic amino acid transporter-1 (CAT-1), interleukin-10 (IL-10), and mucin-2 (MUC-2) gene expression (p < 0.05), supporting gut integrity. This study highlights the potential of mixing nano-encapsulated cumin oil and B. subtilis in growing rabbits’ diets as an effective strategy to counteract the negative effects of heat stress caused by high ambient temperatures. Full article

This study synthesized a low-molecular-weight donkey-hide gelatin peptide–zinc chelate (LMW DHGP–Zn) using peptides derived from donkey-hide gelatin. Under optimized conditions (zinc concentration of 32 mg/mL, peptide-to-zinc mass ratio of 8:1, pH 6.5, 60 °C, 70 min), a maximum chelation rate of 41.34% ± 0.23% was achieved. Comprehensive characterization via scanning electron microscopy, ultraviolet–visible spectroscopy, fluorescence spectroscopy, zeta potential, particle size, Fourier transform infrared spectroscopy, and circular dichroism confirmed substantial structural and physicochemical alterations post-chelation. After chelation, the surface charge is neutralized, and the distribution of particles is more even. Furthermore, analysis indicated an elevated content of acidic amino acids (glutamic acid and aspartic acid), and spectroscopic data confirmed the coordination of zinc ions with amino and carboxyl groups on the peptide. Consequently, the LMW DHGP–Zn chelate demonstrated significantly enhanced ABTS radical cation scavenging activity. These results provide a scientific foundation for its potential application as a natural antioxidant in the food, cosmetic, and pharmaceutical industries. Full article

Textile industries release dyes into wastewater, and when present above certain levels, these dyes pose serious risks because of their high toxicity. This study investigates the removal of Sunset Yellow (SY) and Methylene Violet (MV) dyes from wastewater using chitosan (CS) and polysilicate acid (pSi) in the structure of aluminum-based coagulants, resulting in hybrid formulations (CS@Al, Al/pSi, and CS@Al/pSi). Among the various treatment methods that have been applied for the removal of dyes, the coagulation/flocculation process was chosen in the present study, as it is a cheap and effective method. Coagulation performance was optimized for pH, coagulant dosage, temperature and mixing time. The Al/pSi coagulant achieved nearly complete SY removal (98.8%) at 25 mg/L dosage and pH 3.0. MV removal in single-dye solutions was limited, with Al/pSi achieving only 26.6% removal at pH 3.0. However, in mixed-dye systems (SY/MV), synergistic interactions increased MV removal up to 94.4% and SY removal to 100%. Hybrid CS@Al/pSi showed lower SY removal (36.4%) for SY at 50 mg/L but provided stable floc formation, particularly in mixtures of anionic and cationic dyes. Application to real textile wastewater confirmed the high efficiency of the optimized coagulants, particularly with Al/pSi_20,A and AlCl₃, indicating their potential for industrial wastewater treatment. SEM, EDS, XRD, and FTIR analyses revealed structural consolidation, increased surface area, and successful dye adsorption, explaining the high removal efficiency. Full article

The excessive use of chemical fertilizers results in environmental issues, including loss of soil fertility, eutrophication, increased soil acidity, alterations in soil characteristics, and disrupted plant–microbe symbiosis. Here, we synthesize recent studies available from up to 2025, focusing on engineered biochar and its application in addressing issues of soil nutrient imbalance, soil pollution from inorganic and organic pollutants, soil acidification, salinity, and greenhouse gas emissions from fields. Application of engineered biochar enhanced the removal of Cr (VI), Cd²⁺, Ni²⁺, Zn²⁺, Hg²⁺, and Eu³⁺ by 85%, 73%, 57.2%, 12.7%, 99.3%, and 99.2%, respectively, while Cu²⁺ and V⁵⁺ removal increased by 4 and 39.9 times. Adsorption capacities for Sb⁵⁺, Tl⁺, and F⁻ were 237.53, 1123, and 83.05 mg g⁻¹, respectively, and the optimal proportion of polycyclic aromatic hydrocarbon (PAH) removal was 57%. Herbicides such as imazapyr were reduced by 23% and 78%. Low-temperature pyrolyzed biochar showed high cation exchange capacity (CEC) resulting from improved surface functional groups. Although biochar application led to a yield increase of 43.3%, the biochar–compost mix enhanced it by 155%. The analysis demonstrates the need for future studies on the cost-effectiveness of biochar post-processing, large-scale biochar aging studies, re-application impact, and studies on biochar–compost or biochar–fertilizer mix productivity. Full article

Heating at 95 °C or boiling E. coli HT115 (DE3) cells is often used to extract heterologous dsRNA or kill bacteria, although these temperatures cause dsRNA denaturation and destruction. In this study, we examined the risk of degradation of dsRNA fragments of AT-rich genes at high temperature. The expression of dsRNA fragments of AT-rich genes encoding DNA replication enzymes from the microsporidia Vairimorpha ceranae and Nosema bombycis in E. coli HT115 (DE3) was accompanied by heating the bacteria at 95 °C for 30 min. In contrast to four control fragments with normal GC content, the AT-rich dsRNAs of microsporidia were destroyed by this treatment. The in vitro synthesis and heating of the studied dsRNAs showed the degradation of both microsporidia and control fragments. The thermal degradation of in vitro-synthesized control dsRNA with a normal GC content of 47.6% was prevented by the addition of 2 × YT media, NaCl, or low concentrations of MgSO₄. This demonstrates the important role of mono- and divalent cations in stabilizing heated fragments and helps explain the preservation of their integrity and RNAi-initiating activity despite the treatment of bacteria at temperatures that denature dsRNA. Feeding Colorado potato beetle larvae with the same in vitro-synthesized dsRNA containing fragments of three Leptinotarsa decemlineata genes showed that their thermal destruction was accompanied by a decrease in pest-suppressing activity. No dsRNA degradation was observed at 80 °C or after E. coli sonication, and these treatments, as well as increasing cation content, may help to avoid the degradation of heat-sensitive dsRNA. Full article

Over more than half a century of using zirconia in technology and industry, researchers have faced several challenges related to the performance of this material. It is believed that some issues regarding the low performance of the zirconia ceramics can be solved by using a multidoping strategy. In this study, nanoparticles with the composition (1 − x)⸱ZrO₂ − x⸱MD (where MD—multi-dopant Y:Ce:Mg:Ca with cation relationship 1:1:1:1 and x = 0.05–0.25 mol. %) were synthesized using a hydrothermal method followed by annealing. XRD and Raman spectroscopy analyses demonstrated that in the concentration range of x = 0.10–0.25 mol.%, the only detectable phase in the synthesized samples was the tetragonal phase of zirconia. SEM analysis revealed that the size of the final particles ranged from 20 to 50 nm. It was demonstrated that using obtained nanoparticles as precursors for sintering leads to the formation of multiphase ceramics. The microhardness and biaxial flexural strength of the ceramic samples vary depending on the dopant concentration in the range of 600–1400 HV and 25–200 MPa respectively. Mechanical properties mostly depend on porosity and grain size in the sintered material. The study shows that the multidoping strategy has high potential to obtain new constructional ceramics and components for solid oxide fuel cells. Full article

Adsorption studies of ciprofloxacine (CPX) and lidocaine (LID) emerging contaminants were performed on two fibrous Mg clays from the Madrid basin and Senegal. The samples were characterized by X-ray diffraction, ICP major element analysis, infrared spectroscopy, thermal analysis, optical petrography, scanning and transmission electron microscopy, cation exchange capacity (CEC), and N₂-BET analysis. Two mineral assemblages were established. Assemblage 1 mainly consists of sepiolite and minor trioctahedral smectite, while assemblage 2 is mostly composed of palygorskite, which is associated with dioctahedral smectite. The sorption was fast and reached equilibrium in 2 h. Fibrous Mg clays showed a higher adsorption capacity for CPX than for LID in the conditions studied. CPX adsorption on sepiolite and palygorskite can be the result of the combination of various mechanisms: ion exchange with permanently charged sites, electrostatic attractions with external surfaces, and an inner sphere complex with broken edges. LID adsorption mainly occurs by ion exchange and electrostatic interaction with the external surfaces of the clays. Dioctahedral smectite, as an associated phase, contributed to a higher removal percentage in palygorskite samples. By contrast, the trioctahedral smectite did not play a significant role in the adsorption of the samples with sepiolite. The mesoporous structure, high surface area, and moderate cation exchange of fibrous clays play a key role in the sorption process of CPX and LID. Full article

Phosphorus (P) is essential to life yet constrained by finite reserves, heterogeneous distribution, and strong chemical binding to soil minerals. Pedogenesis progressively alters the availability of P: in ‘young’ soils, P associated with Ca and Mg is relatively labile, while in ‘old’ soils, acidification and leaching deplete base cations, shifting P into organic matter and recalcitrant Al- and Fe-bound pools. Podzolized soils (Spodosols) provide a unique lens for studying this transition because podzolization vertically segregates these dynamics into distinct horizons. Organic cycling dominates the surface horizon, while downward translocation of Al, Fe, and humus creates a spodic horizon that immobilizes P through sorption and co-precipitation in amorphous organometal complexes. This spatial separation establishes two contrasting P pools—biologically dynamic surface P and mineral-stabilized deep P—that may be variably accessible to plants and microbes depending on depth, chemistry, and hydrology. We synthesize mechanisms of spodic P retention and liberation, including redox oscillations, ligand exchange, root exudation, and physical disturbance, and contrast these with strictly mineral-driven or biologically dominated systems. We further propose that podzols serve as natural experimental models for ecosystem aging, allowing researchers to explore how P cycling reorganizes as soils develop, how vertical stratification structures biotic strategies for nutrient acquisition, and how deep legacy P pools may be remobilized under environmental change. By framing podzols as a spatial analogue of long-term weathering, this paper identifies them as critical systems for advancing our understanding of nutrient limitation, biogeochemical cycling, and sustainable management of P in diverse ecosystems. Full article

Melanin-based biosorbents (MiCS), derived from chestnut shells, were encapsulated in sodium alginate to obtain MiCS@Alg, useful in a column adsorption study. MiCS contains various acidic surface groups able to participate in the removal of cationic pollutants from aqueous solutions. The MiCS and MiCS@Alg were characterized by Fourier-transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Dynamic Light Scattering (DLS), while zeta potential and particle size analyses were performed to gain deeper insight into surface charge behavior. Batch adsorption experiments were carried out at three different temperatures, demonstrating that the adsorption kinetics followed a pseudo-second-order (PSO) model and that the Freundlich model best described the equilibrium data. The process was found to be endothermic and spontaneous, with maximum adsorption capacities of 300.2 mg g⁻¹ (BR2), 201.5 mg g⁻¹ (BY28) and 73.08 mg g⁻¹ (NH₃) on MiCS, and 189.3 mg g⁻¹ (BR2), 117.1 mg g⁻¹ (BY28) and 50.06 mg g⁻¹ (NH₃) on MiCS@Alg at 45 °C and compared with the unmodified chestnut shell. The MiCS and MiCS@Alg exhibited good adsorption performance, improved environmental compatibility, and greater reusability. Overall, these results highlight MiCS@Alg as a cost-effective, sustainable, and highly promising novel biosorbent for the removal of cationic pollutants (BR2, BY28, and NH₃) from water. Full article

This study investigated the structure of vegetation communities in Yongneup, a representative montane peatland on Mt. Daeamsan, Korea. It also identified key microenvironmental drivers shaping their distribution. We surveyed 200 quadrats, analyzing herbaceous plant composition alongside peat depth, water level, and soil chemical properties. Multivariate analyses, including cluster analysis and classification tree analysis (CHAID), identified nine distinct vegetation communities. Each community was correlated with specific environmental gradients. Dominant species included Sanguisorba tenuifolia and Carex thunbergii var. appendiculata, with rare species such as Carex chordorrhiza and Drosera rotundifolia present in localized habitats. Peat depth emerged as the primary determinant of vegetation distribution, followed by hydrology and nutrient levels, including phosphorus and cations (Mg²⁺, Na⁺, K⁺). Our results underscored continuous ecological gradients rather than discrete zonation, aligning with ecological continuum theory. These findings provide a robust scientific framework for ecological monitoring and restoration. They also support Korea’s national wetland conservation policies and international commitments such as the Ramsar Convention. Full article