Search Results (65)

The persistent discharge of cationic dyes into aquatic systems necessitates advanced adsorbents with precisely tunable interfacial properties and high removal efficiency. Herein, we report for the first time the synthesis of composition-controlled sulfonated polymeric nanoparticles (NPs) based on polystyrene (PSt) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) via a surfactant-free precipitation polymerization approach. Our findings showed that the NPs exhibited well-defined composition-dependent evolution in physicochemical properties, with hydrodynamic size decreasing from 1224 to 327 nm and surface charge rising from −36.1 to −51.0 mV with increasing PAMPS content. Furthermore, adsorption performance toward methylene blue (MB) and crystal violet (CV) demonstrated strong dependence on surface charge density, with removal efficiencies of 97–98% at low initial dye concentrations (10–20 mg L⁻¹) and still above 82–87% at a higher initial concentration (100 mg L⁻¹). At low initial dye concentrations (10–20 mg L⁻¹), the most highly sulfonated nanoparticles (NP-PSt/AMPS-50) reach equilibrium capacities of approximately 9.25–971 mg g⁻¹, while at 100 mg L⁻¹, the capacities increase to about 82–86 mg g⁻¹ for both MB and CV. Notably, the adsorption capacity (q_e) increases systematically with the sulfonation degree, reflecting enhanced ion-exchange capacity and accessibility of surface-exposed –SO₃⁻ functionalities. Rapid uptake behavior is observed, with >60–70% removal achieved within 15 min and equilibrium established within 100–120 min. Importantly, the enhanced adsorption performance of NPs can be attributed to their self-organized core–shell-like architecture. Considering this structure, hydrophobic PSt-rich domains form the particle interior, while PAMPS segments are localized at particle–water interface, creating a sulfonate-enriched surface layer. This enhances active-site accessibility and electrostatic interactions with cationic dyes. The composition-dependent evolution of sulfonate functional groups, as evidenced by FTIR spectroscopy, along with the systematic decrease in hydrodynamic size and increase in zeta potential magnitude with increasing AMPS content, collectively indicate the surface localization of charged PAMPS segments. Overall, our findings provide a mechanistic framework for the rational design of charge-regulated polymeric nano adsorbents and highlight the potential of PSt/PAMPS NPs as scalable and sustainable materials for cationic dye removal in wastewater treatment systems. Full article

Processed meat products represent a major challenge for proteomic species identification due to extensive thermal treatment and protein structural changes. In this study, species-specific peptides in pork, chicken, and bovine meat products were identified using a directed fragmentation-assisted de novo sequencing workflow that combines 4-formylbenzene-1,3-disulfonic acid (FBDA) peptide derivatization, dual-polarity data-independent mass spectrometry (DIA-MS), and Protein Acrobat de novo sequencing software. Comparative analysis of non-fractionated and strong cation exchange (SCX)-fractionated pork luncheon samples improved peptide and protein identification after fractionation, with 312 peptides and 115 protein groups detected exclusively in fractionated samples. Species-specific peptides were predominantly assigned to conserved muscle-related proteins, including myosin, troponin, and tropomyosin, while sequence variability enabled reliable species discrimination despite protein conservation across species. To evaluate applicability for food fraud detection, mixed meat samples containing 10% chicken in pork or bovine matrices were analyzed, reflecting potential economically motivated adulteration through substitution with lower-cost meat components. Several chicken-specific peptides remained detectable in both mixtures, demonstrating robustness of the FBDA-assisted peptide sequencing combined with SCX fractionation and DIA-MS for detection of adulteration in complex processed food matrices. These findings establish a mass spectrometry-driven orthogonal method to ELISA testing for fast, reliable and accurate metaproteome analysis of highly processed food. Full article

The agricultural and environmental application of Miscanthus × giganteus biomass ash (MBA) as a soil amendment requires a thorough assessment of its properties, nutrient potential, and associated risks. This study characterizes the elemental composition, pH, cation exchange capacity (CEC), and polycyclic aromatic hydrocarbons (PAHs) content of MBA in comparison with other common biomass ashes (crops, wood, and sewage sludge) referred to the international regulatory standards. The ash exhibits a strong alkaline pH (11.03), suggesting potential to improve soil pH in acid soils, but requires careful controlled application to prevent excessive alkalization. The main nutrients detected include K (5.54%), Ca (2.07%), Mg (0.37%), and P (0.86%), indicating its potential as a soil amendment, though long-term use may cause nutrient imbalances. Micronutrients such as Zn (240.67 mg·kg⁻¹), Mn (297 mg·kg⁻¹), and Cu (33.5 mg·kg⁻¹) are found in concentrations suitable for agricultural use, while potentially toxic elements (PTEs), including Cd, Cr, Ni, and Pb, are below detection limits, thereby reducing the risk of pollution. As (8.3 mg·kg⁻¹) and ΣPAHs (1.63 mg·kg⁻¹) remain within safety thresholds, suggesting a low environmental toxicity of MBA. The low Na content (0.12%) indicates a minimal risk of salinity accumulation, distinguishing MBA from high-sodium biomass ashes. Soil alkalization, disruptions in nutrient balance, and element leaching are risks to be considered. Despite these concerns, its composition is in agreement with established safety guidelines, supporting its feasibility for valorization as a sustainable soil amendment and remediation material. To maximize agronomic benefits and mitigate environmental risks, it is important to utilize the ash, considering site conditions and carry out regular monitoring of the soil. Full article

First-principles calculations are employed to systematically investigate the dynamic evolution from Al(O_h) to Al(T_d) in zeolites induced by proton–cation exchange (Cu⁺, Li⁺, Na⁺, NH₄⁺). The protons directly bonded to Al(O_h) are found to be essential for structural stability. Single cation exchange preserves the six-coordinated Al(O_h), while double exchange triggers spontaneous conversion to four-coordinated Al(T_d), accompanied by stepwise detachment of two water molecules. Different cations exhibit variations in spatial occupation patterns and water-binding strength. The coordination effect of metal cations and the hydrogen bonding effect of NH₄⁺ dominate the transformation of the aluminum coordination configurations. Protons directly bonded to Al(O_h) serve as strong Brønsted acid sites. Single exchange indirectly reduces the activity of adjacent protons, whereas double exchange eliminates Al–O–H bonds to stabilize Al(T_d). This work reveals a cooperative mechanism among cation species, exchange number, water binding, and electronic coupling that controls the Al(O_h) to Al(T_d) transformation, providing a theoretical basis for activating Al species and for designing high-performance catalysts with controlled acid site distributions via ion exchange. Full article

Soil health is critical for the sustainability of tropical plantation ecosystems, However, the ecological factors driving productivity gradients remain inadequately understood. This study investigated rubber plantations on Hainan Island with varying yield levels to assess soil health and its underlying ecological mechanisms using a minimum data set (MDS) approach. Twenty-seven soil physical, chemical, and biological indicators were analyzed at two depths (0–20 cm and 20–40 cm). Principal component analysis identified seven key indicators for the MDS: soil organic matter (OM), alkaline-hydrolyzable nitrogen (AN), cation exchange capacity (CEC), dissolved organic carbon (DOC), microbial biomass phosphorus (MBP), acid phosphatase activity (ACP), and microbial diversity (Shannon-Wiener index, SHDI). The soil health indices derived from the MDS showed strong correlations with those generated from the total data set (TDS) (p < 0.001), confirming the reliability of the MDS framework. Overall, soil health levels were rated low to moderate with no significant differences across low-yield plantations (≤900 kg·ha⁻¹), medium-yield plantations (900–1200 kg·ha⁻¹), and high-yield plantations (≥1200 kg·ha⁻¹)., suggesting a decoupling of soil health and rubber productivity under uniform management practices. Random forest analysis identified microbial-driven phosphorus cycling, particularly MBP and ACP, as the primary determinant of soil health across soil layers, with DOC and SHDI also contributing significantly. These findings highlight the critical role of microbial-mediated nutrient cycling in maintaining soil health in rubber plantations and suggest that current management practices prioritize short-term yields over long-term soil ecological stability. Enhancing microbial activity and increasing organic matter inputs may be essential for improving soil health and ensuring the sustainability of rubber production in tropical agroecosystems. Full article

Accurate prediction of compost maturity is vital for ensuring quality, safety, minimum substrate weight loss and agronomic performance of compost products. In this study, eight supervised machine learning (ML) classification models including Random Forest, Logistic Regression, Decision Tree, Gaussian and Multinomial Naive Bayes, K-Nearest Neighbors, Support Vector Machine, and AdaBoost were systematically evaluated for their ability to predict compost maturity using three key indicators: cation exchange capacity (CEC), carbon to nitrogen ratio (C/N), and humic acid (HA) content. A dataset comprising 756 samples (4 composting/vermicomposting systems × 7 treatments × 9 time points × 3 replicates) was generated. To reduce replicate-induced variability and ensure robust machine learning analysis, triplicates were averaged at each time point, resulting in 252 effective observations used for model development. Pearson correlation and heatmap analysis indicated strong interdependencies among CEC, HA, total nitrogen (TN) and organic matter (OM) content, confirming their collective utility in compost maturity classification. Model performance was assessed based on classification metrics (accuracy, precision, recall, F₁-score) and regression-based error indicators, including mean absolute error (MAE), mean squared error (MSE), root mean squared error (RMSE), and coefficient of determination (R²). Ensemble models, particularly RF and AdaBoost, showed the highest predictive accuracy (up to 0.98) and lowest error rates (e.g., MAE < 0.05, RMSE < 0.1, R² > 0.95) when predicting CEC and C/N-based maturity classes. HA-based predictions showed slightly lower precision and higher variance across models. Full article

Soil organic carbon (SOC) stocks in cacao agroecosystems are characterized by accumulating large amounts. They depend on the balance between organic matter inputs (plant residues, roots) and losses (decomposition, erosion), being closely related to climatic conditions, soil nature, vegetation type, topography, and land management practices. The objective of this study was to quantify SOC stocks (0–30 cm) and assess key soil fertility indicators across 107 georeferenced sampling locations in cacao production systems of Guamal (Meta, Colombian Llanos Piedmont). Soil pH varies between extremely acidic and moderately acidic (3.8–6.0; mean 4.57), while available P (Bray II) and exchangeable bases showed low concentrations. Organic carbon concentration averaged 1.18% and bulk density averaged 1.17 g cm⁻³. SOC stocks averaged 41.10 Mg C ha⁻¹, ranging from 7.49 to 81.55 Mg C ha⁻¹, evidencing marked spatial contrasts in carbon storage. Spearman correlations highlighted coupled soil chemical controls, including positive associations of pH with Ca²⁺ and P availability and strong negative associations of pH and P with exchangeable Al³⁺, consistent with acidity-driven fertility constraints. Principal component analysis (PCA) further identified a dominant fertility gradient structured by pH, P availability, and Ca²⁺, and a second axis related to organic carbon and cation retention. Spatial modeling using inverse distance weighting (IDW) in ArcGIS supported the visualization of SOC stock variability across the study area. Overall, the results indicate that SOC stocks in these predominantly sandy soils are strongly influenced by acidity-related constraints and heterogeneous nutrient status, underscoring the need for site-specific management to jointly enhance soil fertility and climate-mitigation potential in cacao systems. Therefore, it would be advisable in the future to address the study of differential variations in soil C storage related to chemical fertilizer application rates, especially in the long term. Full article

This study investigated highbush blueberry (Vaccinium corymbosum L.) plants cultivated in distinct cultivation systems (greenhouse vs. open field) to determine if they exhibited significant differences in rhizosphere microbiota, soil nutrient profiles, and fruit metabolites. A clear metabolic trade-off was observed: open-field cultivation significantly enhanced fruit secondary metabolites, including anthocyanins (9.5% higher), flavonoids (56.0% higher), and ascorbic acid (15.6% higher). In contrast, greenhouse fruits were enriched in primary metabolites such as water-soluble sugars (28.3% higher) and total organic acids (30.2% higher) (p < 0.01 for all comparisons). These divergent metabolite profiles were correlated with distinct rhizosphere microenvironments. The open field soil exhibited higher organic carbon and microbial α-diversity, while the greenhouse soil was characterized by a niche with high availability of cations, lower pH, higher electrical conductivity, and elevated levels of exchangeable Ca²⁺, Mg²⁺, and available potassium. These contrasting niches were correlated with shifts in the rhizosphere microbiota assembly. Notably, the greenhouse soil was associated with a higher relative abundance of copiotrophic bacterial taxa such as Streptomyces and Bacillus, whose abundances showed strong positive correlations with cation availability (e.g., Streptomyces vs. Ca²⁺, correlation coefficient r = 0.827, p < 0.01). Multivariate analysis integrated these patterns, revealing that soil cations were negatively correlated with fruit antioxidants but positively linked to sugars and acids. This correlative study suggests that cultivation systems are strongly associated with fruit quality, potentially through their association with functionally specific rhizosphere microbiota that covaries with a shift in the plant’s resource allocation between growth (primary metabolism) and defense (secondary metabolism). Our findings provide an integrative framework for understanding how agricultural practices are associated with the soil–plant–microbe continuum to correlate with crop quality in perennial systems and generate testable hypotheses for future mechanistic research. Full article

This study evaluated the effects of thermocomposting followed by vermicomposting on the physicochemical properties of insect frass and its suitability as a germination and growth substrate for kale, tomato, and bell pepper. Vermicomposting improved frass stability by reducing pH, electrical conductivity, carbon content, and the C/N ratio, while increasing total nitrogen, cation exchange capacity, and calcium and magnesium availability, indicating enhanced maturity and nutrient retention. Peat–frass mixtures (20–100%), increased pH from acidic conditions in the control to near neutral in 100% frass and raised electrical conductivity from 0.67 dS m⁻¹ to the highest values in the pure frass treatment. Tomato seedlings exhibited strong tolerance and enhanced growth at all frass proportions, with seedling heights exceeding 33 cm compared with the control. Kale showed optimal growth at 20–60% frass, while 80–100% reduced early development. In bell pepper, emergence declined at high frass proportions, although seedlings grown with ≥40% frass reached heights of approximately 8.3–8.6 cm. Vermicomposted frass also influenced plant metabolism, increasing flavonoid accumulation and modifying antioxidant activity. These findings demonstrate that stabilized frass can serve as a sustainable substrate component, contributing to organic waste valorization and improved seedling production when applied at crop-specific proportions. Full article

Gel polymer electrolytes are key components in next-generation energy storage systems, particularly supercapacitors, due to their high ionic conductivity, mechanical robustness, and operational safety. Ionomer-based gels derived from perfluorosulfonic acid (PFSA) are particularly promising, as their nanophase-segregated morphology enables the formation of three-dimensional ionic clusters capable of absorbing and retaining aqueous electrolytes. In this study, the commercial PFSA D50-U (Thasar S.r.l.) membrane was investigated for the first time as a gel-state ionomer electrolyte and separator in symmetric supercapacitors using coconut shell-derived activated carbon (YP-80F Kuraray Co., Ltd.). The effects of cation type on gel swelling, ionic conductivity, and electrochemical performance were investigated using Na₂SO₄ and Li₂SO₄ aqueous electrolytes. The results showed that PFSA D50-U formed stable gel structures, resulting in low internal resistance, high specific capacitance, and excellent long-term cycling stability. These findings demonstrate that PFSA D50-U is a novel proton-exchange gel membrane with strong potential for high-performance symmetric supercapacitors and other gel-based energy storage devices. Full article

Recovery of scandium from chloride-bearing process liquors formed during titanium–magnesium production remains constrained by trace-level metal content and chemically aggressive solution matrices. Within the present study, the retention behaviour of Sc³⁺ species in strongly acidic chloride media was examined through batch-mode interaction with gel-type sulfonated cation exchangers, namely KU-2-8, Lewatit SP112H, Purosorb SAC140H, and Purolite C-150H. Quantitative evaluation of sorption efficiency was performed by calculating equilibrium uptake (q_e), phase distribution factor (K_d), and percentage recovery (R). Under identical liquid–solid ratios, the Lewatit SP112H matrix exhibited superior affinity toward dissolved scandium, achieving q_e = 179.82 mg/g and K_d = 172.41 mL/g. Equilibrium fitting procedures revealed that scandium uptake by Purosorb SAC140H conforms to monolayer-type retention described by the Langmuir formalism (R² = 0.9786), whereas sorption on Lewatit SP112H proceeds over energetically non-uniform sites and is more adequately represented by Freundlich and Dubinin–Radushkevich approximations. The observed retention characteristics establish a selection framework for ion-exchange media applicable to scandium concentration from acidic chloride hydrometallurgical streams. Full article

This study presents a sustainable valorization strategy for wastewater treatment plant (WWTP) residual sands through their hydrothermal conversion into a dual-phase FAU/LTA zeolite and evaluates its adsorption performance toward methylene blue (MB) as a model cationic contaminant. The synthesized material (ZEO-RS) exhibited a low Si/Al ratio (~1.7), well-developed FAU supercages with minor LTA domains, and high structural integrity, as confirmed by XRD, FTIR, XRF, SEM and PZC analyses. ZEO-RS demonstrated rapid adsorption kinetics, reaching approximately 92% of equilibrium uptake within 30 min and following a pseudo-second-order kinetic model (k₂= 2.73 g·mg⁻¹·h⁻¹). Equilibrium data were best described by the Langmuir isotherm, yielding a maximum adsorption capacity of 34.2 mg·g⁻¹ at 20 °C, with favorable separation factors (0 < r_L < 1), while Freundlich fitting indicated moderate surface heterogeneity. Thermodynamic analysis revealed that MB adsorption is spontaneous (ΔG° = −11.98 to −12.56 kJ·mol⁻¹), mildly endothermic (ΔH° = +5.26 kJ·mol⁻¹), and entropy-driven (ΔS° = +0.059 kJ·mol⁻¹·K⁻¹). FTIR evidence, combined with pH-dependent behavior, indicates that adsorption proceeds via synergistic electrostatic attraction, pore confinement within FAU domains, and partial ion-exchange interactions. Desorption efficiencies conducted under mild acidic, neutral, and alkaline conditions resulted in low MB release (1–8%), indicating strong dye retention and high framework stability. Overall, the results demonstrate that WWTP residual sands are an effective and scalable low-cost precursor for producing zeolitic adsorbents, supporting their potential application in sustainable water purification and circular-economy-based wastewater treatment strategies. Full article

A highly active Co/Beta catalyst was prepared via ion-exchange method, in which sodium cations in the beta zeolite framework were replaced by cobalt ions using an aqueous cobalt nitrate solution. Based on XRD, SEM, TEM, XPS, and nitrogen adsorption–desorption analyses, it was confirmed that cobalt species successfully took the place of sodium ions in beta zeolite, while the cobalt species diffused with a uniform dispersion. Strong electronic coupling between cobalt species and zeolite framework oxygen stabilizes Co²⁺ sites in the material. The catalysts perform high efficiency in dye Acid Orange II (AO7) degradation reactions, which gives more than 99.5% removal efficiency at room temperature and initial pH within 10 min under low catalyst dosage. The advantages of the Co/Beta catalyst are reasonably attributed to its maximized metal−zeolite synergistic efficiency. Full article

This study conducted a systematic investigation of the degradation pathway and process optimization of strong acid cation exchange resins subjected to SCWO. Controlled experiments evaluated the effects of operating temperature, oxidant stoichiometry, initial organic concentration, and residence time. RSM was utilized to refine the operating parameters, and a second-order regression model (R² = 0.9951) was established to predict COD removal (R_COD), valid within experimental ranges: reaction temperature 400–500 °C, oxidant stoichiometry 80–150%, initial COD 10,000–100,000 mg·L⁻¹, and residence time 1–10 min. COD-dependent NaOH addition could enhance degradation efficiency. The R_COD was sensitive to operating temperature, oxidant stoichiometry, and residence time. Under the optimized conditions of 472 °C, oxidant stoichiometry of 137%, initial COD of 77,216 mg·L⁻¹, and residence time of 4.9 min with the addition of 1.74 wt% NaOH, the R_COD reached 99.92%, which was in close agreement with model predictions. GC-MS analysis of intermediates revealed that sulfonic groups dissociated early, followed by aromatic compounds, particularly phenol, undergoing ring-opening and oxidation to small carboxylic acids and aliphatic species, which were ultimately mineralized to CO₂ and H₂O. These findings provide mechanistic insight into resin decomposition and offer a scientific basis for the safe treatment of radioactive waste resins using SCWO. Full article

Biochar (BC), a carbonaceous material derived from biomass pyrolysis, exhibits a wide range of physicochemical properties, including a high cation exchange capacity, porosity, and specific surface area, which make it a highly valuable amendment for soil enhancement and environmental sustainability. As BC has shown strong potential to remediate soils, enhance their fertility, and increase crop productivity, it can successfully be used as a soil remediation factor. Additionally, it can play a critical role in carbon sequestration and climate change mitigation, revealing a high sorption capacity, multifunctionality, and long-term persistence in soils, where it can remain stable for hundreds to thousands of years. The present systematic review aims at presenting the dynamics of BC when incorporated into a soil system, focusing on its pH, water-holding capacity, aeration, microbiota, and carbon and nutrient availability across various case studies, particularly in acid, saline/sodic, and heavy metal-contaminated soils. Given the variability in BC performance, robust, long-term field-based research is essential to validate the current findings and support the development of targeted and sustainable biochar applications. Full article