Search Results (1,474)

Sustainable management of industrial solid waste is critical for a circular economy. This study presents a novel approach for valorizing blast furnace slag (BFS) into NaA zeolite through selective acetic acid leaching followed by hydrothermal crystallization. The leaching step selectively extracts Ca²⁺ and Mg²⁺ while efficiently retaining silicon and aluminum in the solid residue, producing a reactive aluminosilicate precursor that facilitates zeolite nucleation and growth. The effects of the silicon-to-aluminum molar ratio (n(Si)/n(Al)), crystallization temperature, and duration on the phase evolution and morphology were systematically investigated. The results demonstrate that phase-pure NaA zeolite with high crystallinity and a uniform cubic morphology can be obtained from precursor gels with n(Si)/n(Al) ratios of 0.5–1.25. Optimal synthesis conditions were identified as n(Na):n(Si):n(Al):n(H₂O) = 6:1:1:240 at 373 K for 8 h. The resulting zeolites exhibit a BET specific surface area of 52.1 m²/g, a micropore volume of 0.016 cm³/g, an average adsorption pore size of 4.7 nm, and an external specific surface area of 12.8 m²/g. It achieved near-complete removal of Cu²⁺ and high adsorption efficiencies for Pb²⁺ (77.78%) and Ni²⁺ (71.79%) from 250 mg/L solutions at 298 K with a dosage of 4.0 g/L, following the affinity sequence Cu²⁺ > Pb²⁺ > Ni²⁺, with all pairwise differences statistically significant at p < 0.001, using one-way ANOVA and Tukey’s HSD tests. The adsorption of three metal ions was most accurately described by the Freundlich isotherm and pseudo-second-order kinetic models, indicating heterogeneous multilayer chemisorption. The theoretical maximum monolayer adsorption capacities (q_max) were 307.67 mg/g for Cu²⁺, 246.09 mg/g for Pb²⁺, and 173.79 mg/g for Ni²⁺, whereas the kinetic equilibrium adsorption capacities (q_e) reached 62.69, 48.85 and 41.69 mg/g, respectively. This study demonstrates a value-added strategy for valorizing BFS into a micro-mesoporous adsorbent, advancing both circular resource utilization and environmental remediation. Full article

This study presents the synthesis and use of a novel bamboo-derived magnetic activated carbon (BMAC) for the effective removal of cationic and anionic dyes, specifically methylene blue (MB), methyl orange (MO), and sunset yellow (SY), from aqueous solutions. The adsorbent was synthesized using thermal carbonization and subsequent inclusion of magnetic oxide, yielding a porous structure with improved adsorption and magnetic separation properties. Thorough characterization utilizing SEM, EDX, BET, FTIR, XRD, and TGA/DTA validated the creation of a highly porous material including uniformly dispersed magnetic particles and several surface functional groups. Batch adsorption tests were performed to examine the influences of contact time, adsorbent dosage, initial dye concentration, pH, and temperature. The findings indicated rapid adsorption kinetics, with equilibrium reached in around 60–70 min, and adsorption capacity ranked as MB > MO > SY. Augmenting adsorbent dosage enhanced removal efficiency but diminished adsorption capacity per unit mass due to site unsaturation. The maximum adsorption capacities (q_m) of BMAC were 58.9, 56.3, and 32.7 mg/g for MB, MO, and SY, respectively, as determined from the Langmuir isotherm model, indicating superior performance compared with other reported magnetic activated carbon. The adsorption process was determined to be exothermic and spontaneous, as evidenced by thermodynamic characteristics. The equilibrium data were optimally characterized by the Langmuir isotherm model, indicating monolayer adsorption, whereas the kinetic studies conformed to the pseudo-second-order model, signifying that chemisorption is predominant. The adsorption mechanism encompasses electrostatic interactions, π–π stacking, hydrogen bonding, van der Waals forces, pore filling, and surface complexation with magnetic oxides. The findings indicate that BMAC is an efficient, sustainable, and magnetically recoverable adsorbent for the elimination of both cationic and anionic dyes from wastewater. Full article

Background: Thrombotic disorders remain one of the leading causes of global mortality, necessitating the discovery of anticoagulants with broader therapeutic windows and multi-target efficacy. This study aimed to identify FDA-approved drugs capable of simultaneously inhibiting three critical nodes of the coagulation cascade: Factor X (F10), Proteinase-activated receptor 1 (PAR1) and Prothrombin (F2). Methods: High-confidence 3D structures of coagulation cascade proteins were established using AlphaFold2 and validated via MolProbity (Favored regions > 91%). A library of 1657 compounds from the Zinc database was screened using PyRx, followed by rigorous ADMET profiling to evaluate pharmacokinetic viability. The structural integrity and binding kinetics of the top candidate drugs were further analyzed through Molecular Dynamics simulation for 100 ns. Results: Virtual screening and downstream analysis identified 30 multi-target drugs. Avodart and Naldemedine were observed to have superior pharmacokinetic equilibrium. Compared to the other two drugs (Digoxin and Ledipasvir), Avodart and Naldemedine showed high affinity, higher adherence to drug likeness, lower metabolic inhibition risks and lack of acute toxicity, and were therefore the most suitable candidates. The 100 ns MD simulations revealed Avodart and Naldemedine to have the highest level of interaction stability and favorable MM-GBSA energies with Factor X, whereas Ledipasvir and Digoxin exhibited significant structural instability. Conclusions: The study proposes Avodart and Naldemedine as promising candidates for drug repurposing in antithrombotic therapy. This study provides a computational blueprint for the development of next-generation, broad-spectrum anticoagulants. Full article

Accurate and efficient modeling of laminar premixed flames is essential for chemical mechanism validation and parametric studies in combustion science. For this purpose, CombF was developed—a semi-analytical computational framework for one-dimensional (1D) laminar premixed flames—offering flexible control over nodal distributions and optional incorporation of experimental temperature data. Unlike conventional fully coupled solvers, CombF explicitly separates the initialization and solution stages, enabling structured control over intermediate structure and temperature constraints while preserving physical consistency. The methodology employs linear interpolation between pre- and post-reaction equilibrium states, adaptive grid refinement, and finite-difference solutions of species and energy conservation equations, with radiation heat transfer optionally included. CombF was validated for ethylene–air premixed flames by comparison with experimental data under varying equivalence ratios and inlet velocities using the YARC-AF kinetic mechanism, and for methane–air premixed flames by additional benchmark comparisons with Cantera, employing the DRM22 mechanism. CombF predictions were further validated against methane and propane–air flames under varying inlet compositions and velocities using the Diego mechanism and evaluated using the curve matching (CM) score, L₂ norms, and phase shift alignment via a nonparametric bootstrap approach. The results demonstrate strong agreement for major species (CO₂, H₂O), while intermediate species (CO, CH₂O) show higher sensitivity to temperature profile choice and nodal resolution, providing a more discriminating assessment of model fidelity. Incorporating experimental temperature fields substantially improves species distribution accuracy and structural alignment. Thus, CombF provides a reliable, flexible, and experimentally adaptive framework that is capable of accurately capturing flame structures, offering a practical tool for preliminary analyses, parametric exploration, and instructional applications in combustion research. Full article

Urea is the most widely used nitrogen fertilizer worldwide, and its application leads to soil acidification, which can potentially change the behavior of agrochemicals such as glyphosate and its main degradation product, aminomethylphosphonic acid (AMPA). This study assessed how urea-induced acidification influences the adsorption of glyphosate and AMPA in an Andisol. Batch equilibrium experiments were conducted to evaluate adsorption kinetics and isotherms with and without urea (200 kg N ha⁻¹), as well as under controlled pH conditions (pH 4, 5, and 6). Kinetic data were analyzed using pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models, while adsorption isotherms were described using the Freundlich model. Results showed clear differences in sorption behavior between both compounds. AMPA exhibited higher sorption capacity, faster equilibrium, and minimal effect from urea addition. In contrast, glyphosate adsorption was significantly reduced by urea, showing lower kinetic parameters. Mechanistic analysis indicated that AMPA retention is governed by chemisorption and intraparticle diffusion processes, whereas glyphosate adsorption is more influenced by surface interactions and competition with urea. Overall, urea application may increase glyphosate mobility in Andisols, while AMPA remains strongly retained, highlighting the role of fertilization in herbicide fate. Full article

In this study, a polyvinyl alcohol/carboxymethyl chitosan (PVA/CCTS) hydrogel was synthesized via free radical polymerization and employed for the adsorption of Rhodamine B (RhB) from aqueous solution. The hydrogel was systematically characterized by FTIR, SEM, XPS, and BET analyses, confirming its interconnected porous network and functional group composition. Under optimized conditions (adsorbent dosage = 0.1 g, pH = 6, RhB concentration = 65 mg·L⁻¹, and T = 298.15 ± 2 K), the maximum adsorption capacity reached 15.88 mg·g⁻¹. Kinetic analysis showed that the pseudo-second-order model best described the adsorption behavior under optimal conditions, indicating that the uptake of RhB is governed by multiple interaction mechanisms rather than simple physisorption alone. The equilibrium data were best fitted by the Freundlich isotherm (R² = 0.976), indicating surface heterogeneity of the hydrogel. Thermodynamic evaluation revealed an endothermic (ΔH = 28.38 ± 4.40 kJ·mol⁻¹), with adsorption efficiency improving at elevated temperatures. The hydrogel retained appreciable adsorption capacity after three adsorption–desorption cycles (5.78 mg·g⁻¹ at the third cycle). Density functional theory (DFT) calculations identified -COOH and -NH₂ groups as the primary active sites, and molecular electrostatic potential analysis confirmed that electrostatic interactions between the negatively charged hydrogel surface and cationic RhB drive the initial adsorption. Molecular dynamics (MD) simulations over 100 ns further demonstrated that van der Waals forces constitute the dominant driving force, supplemented by electrostatic interactions and hydrogen bonding, with the hydrogel’s cross-linked network stabilizing adsorbed RhB molecules. The integrated experimental computational approach provides a comprehensive mechanistic understanding of RhB adsorption on PVA/CCTS hydrogel, offering guidance for the rational design of polysaccharide-based adsorbents for dye-contaminated wastewater treatment. Full article

The complete removal of persistent aromatic organic pollutants from aqueous environments demands the development of sustainable and highly efficient filtration materials. In this study, novel bio-sourced mixed-matrix membranes (MMMs) were successfully fabricated by incorporating the highly porous metal–organic framework MIL-68(Al) into a biodegradable polylactic acid (PLA) matrix via a solvent-induced phase inversion method. The integration of MIL-68(Al) nanoparticles significantly tailored the membrane’s morphological structure, endowing the hybrid membranes with enhanced surface hydrophilicity (water contact angle reduced from 90.3° to 72.7°) and superior permeability. The pure water flux reached an optimal value of 42.2 L m⁻² h⁻¹ at a 15 wt.% MOF loading. Crucially, the hybrid membranes exhibited exceptionally high adsorptive removal performance for p-nitrophenol (PNP) and methylene blue (MB). Driven by the abundant accessible active sites of the MOF filler, the MIL-20/PLA membrane achieved a maximum equilibrium adsorption capacity of 121.03 μg/cm² (36.90 mg/g) for PNP, representing a remarkable 25.7-fold enhancement over the pristine PLA membrane. Kinetic analyses confirmed that the adsorption process is strictly governed by pseudo-second-order kinetics, indicating a chemisorption mechanism dominated by hydrogen bonding and π–π stacking interactions. Furthermore, the optimized membranes demonstrated outstanding dynamic filtration efficiencies (>80%) and robust regenerability over multiple continuous operating cycles. This work not only highlights the synergistic interfacial effects between MOFs and biodegradable polymers but also provides a highly effective, eco-friendly, and sustainable membrane platform for the advanced remediation of organic-contaminated wastewater. Full article

This study investigates the thermodynamic and kinetic features of chromium reduction from chromium ore using complex Fe–Si–Cr and Al–Si–Cr alloys as reducing agents for the refined ferrochrome production. The thermodynamic probability of Cr₂O₃ reduction by silicon and aluminum was evaluated using thermodynamic equilibrium calculations based on reference thermodynamic data, including determination of the standard Gibbs free energy change over the studied temperature range. The results showed that both reduction routes are thermodynamically feasible, while aluminum exhibits a higher affinity for oxygen and a greater reducing capacity. The thermal behavior of chromium ore and its mixtures with Fe–Si–Cr and Al–Si–Cr alloys was studied by differential thermal and thermogravimetric analysis. The use of Al–Si–Cr, especially in briquetted form, was found to shift several thermal transformation stages to lower temperatures and to reduce the apparent activation energy of the high-temperature interaction stages compared with Fe–Si–Cr-containing mixtures. The obtained results indicate that Al–Si–Cr alloy is a promising complex reductant for intensifying chromium recovery and improving process conditions in refined ferrochrome production. Full article

A new type of bio-based adsorbents thiamine-functionalized maleated chitosan (CSMA@TA) was prepared and tested to help the effective removal of methylene blue (MB) in water systems. Successful functionalization was confirmed using structural and surface analysis by FTIR, SEM, XRD, TGA, BET and XPS that revealed a mesoporous structure with a surface area of 50.61 m²/g, pore volume of 0.062 cm³/g and an average pore diameter of 2.65 nm, as well as incorporation of active sites containing nitrogen and sulfur. The best fit of the Langmuir model (R² ≈ 0.986; RMSE less than 1.0) demonstrated that the adsorption capacity of CSMA@TA was highly dependent on operation parameters, with an optimum adsorption capacity of about 230 mg/g and a removal efficiency of more than 93.4% under an initial MB concentration of 25 mg/L. Kinetic studies followed the pseudo-second-order model (R² ≈ 0.986), indicating that the uptake was dominated by chemisorption. Analysis of intraparticle diffusion indicated that the adsorption process involved three stages: diffusion in the boundary layer (k1d = 17.95 mg/g·min^−1/2), which controlled the first stage; gradual diffusion in the pore diffusion; and stabilization of the equilibrium. The thermodynamic parameters indicated the presence of strong adsorbate-adsorbent interactions and interfacial structuring. ∆G° values ranged between −24.85 and −23.56 kJ/mol, ∆H° = −44.08 kJ/mol, and ∆S° = −64.65 J/molK indicated strong adsorbate-adsorbent interactions and interfacial structuring. The adsorbent also exhibited good reusability, retaining more than 90% of its initial efficiency after five cycles, making it stable. The enhanced performance of CSMA@TA is due to the synergistic effect of carboxyl groups and heteroaromatic thiamine moieties, which enable electrostatic attraction, hydrogen bonding, and π–π interactions. These findings support the claim that CSMA@TA is a high-efficiency, sustainable, and reusable adsorbent with strong potential for practical wastewater treatment applications. Full article

Water contamination by arsenic(V) [As(V)] and Congo red (CR) dye poses concurrent threats to public health and aquatic ecosystems, particularly in regions where metallurgical and textile industries coexist. Developing a single adsorbent capable of simultaneously addressing these chemically distinct pollutants, while recovering value from the spent material remains an open challenge in sustainable water treatment. This study reports the synthesis and evaluation of a novel ternary MgZnFe-LDH/1,2,4-triazole composite (TM-LDH/TZ), engineered for the concurrent adsorptive removal of As(V) and CR, and the subsequent repurposing of the pollutant-loaded material as an electrocatalyst for the urea oxidation reaction (UOR). The composite was prepared via co-precipitation and triazole surface grafting, then characterized by FTIR, XRD, BET, TGA, FESEM, and HRTEM. Batch adsorption experiments examined the influence of pH, adsorbent dose, initial concentration, and temperature, with equilibrium data modeled through Langmuir, Freundlich, Temkin, and the statistically grounded Advanced Monolayer Model (AMM); kinetics were assessed using pseudo-first/second-order and Elovich models. Maximum Langmuir adsorption capacities reached 204.75 mg g⁻¹ for As(V) and 499.72 mg g⁻¹ for CR simultaneously at pH 5 and 25 °C, surpassing the majority of previously reported single-pollutant adsorbents. Elovich and pseudo-second-order kinetics confirmed chemisorption as the governing pathway for As(V) and CR, respectively, while AMM thermodynamic analysis verified spontaneous adsorption across all experimental conditions. The spent composite delivered a UOR peak current density of 184.67 mA cm⁻² that is nearly twice that of the fresh material, with a reduced charge-transfer resistance of 1.19 Ω, and removal efficiency remained above 85% through three successive regeneration cycles. The bifunctional design, coupling high-capacity dual-pollutant removal with catalytic valorization of waste, positions TM-LDH/TZ as a circular-economy-aligned platform for advanced water remediation. Full article

Surfactant adsorption on reservoir rock is a major limitation in chemical enhanced oil recovery (EOR) because it reduces effective surfactant concentration and increases chemical loss. In this study, a sodium lignosulfonate (SLS)-silica nanoparticle (SNP) system was investigated on Buff Berea Sandstone (BBS) at different temperature mitigations to evaluate its potential for adsorption. Residual surfactant concentration was determined by UV-Vis spectrophotometry at 208 nm, yielding excellent linearity R² = 0.9948. Adsorption equilibrium was analyzed using Langmuir and the Freundlich isotherm models, while kinetics were evaluated using pseudo-first-order (PFO) and pseudo-second-order (PSO) models. At 30 °C, adsorption was best described by the Langmuir model (R² = 0.9619, SSE = 2.09, whereas at 60 °C, the Freundlich model gave the best fit (R² = 0.8220, SSE = 0.36). The optimum SNP concentration increased from 1000 to 1500 mg/L at 30 °C to 2000–2500 mg/L at 60 °C, likely due to elevated temperature, which enhanced molecular mobility and interfacial heterogeneity, thereby requiring more SNPs to cover or shield active adsorption sites on BBS. Kinetic results consistently favored the PSO model. These findings show that SNPs effectively reduce SLS adsorption and modify the adsorption behavior in a temperature-dependent manner, providing useful insight for the design of more efficient chemical-enhanced oil recovery formulations. Full article

The widespread presence of pharmaceutical residues, particularly emerging antibiotics such as levofloxacin (LVX) and amoxicillin (AMOX), in aquatic environments poses serious risks to ecosystems and public health. In this study, magnetically modified biochar was synthesized from orange peel waste and evaluated for the percentage removal of LVX and AMOX from synthetic wastewater. The biochar was chemically modified with iron to enhance its adsorption capacity and facilitate magnetic separation. The physicochemical properties of raw and iron-modified biochar were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Batch adsorption experiments were conducted to investigate the effects of temperature, contact time, adsorbent dosage, pH, and initial antibiotic concentration on removal efficiency. Antibiotic concentrations were quantified using UV–Vis spectrophotometry. Batch adsorption experiments revealed that iron-modified biochar (FeMBC) significantly outperformed raw biochar (RBC) in antibiotic removal. Optimal removal efficiencies of 90% for AMOX and 92% for LVX were achieved at an adsorbent dosage of 0.1 g, antibiotic concentration of 10 mg L⁻¹, contact time of 120 min, and temperature of 30 °C. Equilibrium data were best described by the Langmuir isotherm model, indicating monolayer adsorption, with correlation coefficients of 0.98 for AMOX and 0.97 for LVX. Kinetic analysis showed that the pseudo-second-order model provided the best fit, suggesting that chemisorption dominated the adsorption process. Thermodynamic studies confirmed that the adsorption was spontaneous and exothermic. Overall, the results demonstrate that iron-modified orange peel biochar is an efficient (90% better removal efficiency than RBC), low-cost, and environmentally sustainable adsorbent for the removal of emerging antibiotics from pharmaceutical wastewater, offering strong potential for practical water treatment applications. Full article

Propyl-paraben (PrP) is a common preservative found in cosmetics and pharmaceutical products. It is classified as a category 1 endocrine-disrupting compound, which highlights the importance of efficiently removing it from water during treatment processes. This study investigates the potential of using Leptolyngbya sp. dominated cyanobacterial biomass residues, in both their raw and hydrothermally treated (hydrochar) forms, for the removal of PrP from aqueous media. Batch and fixed-bed column experiments were carried out under varying conditions to assess adsorption kinetics and equilibrium behavior. Both raw biomass and hydrochar exhibited satisfactory PrP removal, achieving maximum adsorption capacities of 224.58 and 258.55 mg/g respectively, at 10 mg/L initial PrP concentration and 23.33 mg/L adsorbent dosage. Equilibrium data were best described by the Freundlich isotherm model, indicating a heterogeneous surface and multilayer adsorption. The kinetic analysis revealed that the adsorption behavior, for both adsorbents, was best described by the pseudo-second-order model, while the thermodynamic evaluation revealed negative ΔH° and ΔS° values, confirming an exothermic, physisorption-driven process. The adsorption mechanism was further investigated through surface characterization techniques, including Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, N₂ physisorption, and zeta potential analysis. The findings demonstrate the potential of microalgal biomass as a low-cost, sustainable biosorbent, for emerging contaminants, reinforcing its role in advanced water treatment and circular economy strategies. Full article

Emerging compounds in water, ranging from dyes to pharmaceuticals, negatively impact living organisms and challenge the industries responsible for their release. These pollutants exhibit chemical persistence and resistance to conventional treatment processes. Adsorption is considered an effective and accessible approach, particularly when low-cost and renewable materials are employed. The Problem-Intervention-Comparison-Outcome (PICO) framework and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines were followed. A structured search of Scopus was conducted to identify English-language original peer-reviewed articles published between 2016 and 2025 addressing the use of fruit waste (FW)-derived adsorbents for water decontamination. After independent screening, 528 studies were included. Risk of bias was assessed qualitatively. Due to substantial heterogeneity in materials, contaminants, and experimental designs, findings were synthesized narratively. FW-derived adsorbents were evaluated in terms of synthesis routes, physicochemical characteristics, adsorption mechanisms, kinetic and equilibrium behavior, process optimization and regeneration performance. Correlations were observed between surface functionalization, material properties and contaminant-specific removal efficiency, while limitations were noted for multi-component systems, regeneration stability, standardization and scale-up. By integrating material design with process-level considerations, this review outlines priorities for advancing FW valorization toward practical and sustainable water treatment applications. Full article

This study investigates a novel biocomposite material developed by immobilizing sawdust within a calcium alginate matrix (SDA 5%) for the removal of dyes from aqueous solutions. The material was synthesized and comprehensively characterized using FTIR, SEM, and EDS analyses and the pH_pzc drift method. Laboratory-scale experiments were performed to evaluate its performance in removing Malachite Green (MG) under varying operational conditions, including initial dye concentration (10–50 mg/L), pH (3–6), and biosorbent dosage (1–6 g/L). At pH 6 and a biosorbent dose of 3 g/L, under constant agitation (130 rpm), SDA 5% achieved removal efficiencies exceeding 95% across all tested MG concentrations. Furthermore, the biosorption capacity increased with increasing initial dye concentration, reaching a maximum value of 15.93 mg/g at an initial MG concentration of 50 mg/L. Nonlinear kinetic modelling revealed that the pseudo-second-order model best described the biosorption process, while equilibrium analysis showed that the Hill and Sips nonlinear isotherm models, followed by Temkin, provided the most accurate fit to the experimental data. These results demonstrate the high biosorption capacity and favorable interaction between MG molecules and the biocomposite surface. Overall, the study highlights sawdust-alginate biocomposites as sustainable, low-cost, and environmentally friendly biosorbents with significant potential for practical wastewater treatment applications. Full article