A novel, environmentally sustainable spectrofluorimetric method was developed and validated for sensitive determination of ganciclovir in rabbit plasma following valganciclovir administration. The method is based on fluorescence quenching of Erythrosin B probe through static complex formation with ganciclovir, as confirmed by comprehensive spectroscopic characterization using UV-visible absorption and fluorescence spectroscopy. Furthermore, temperature-dependent Stern-Volmer analysis revealed static quenching mechanism with Stern-Volmer constants decreasing from 3.77 × 105 to 2.79 × 105 M− 1 upon temperature increase from 298 to 313 K. Moreover, thermodynamic studies demonstrated spontaneous, exothermic interactions with negative Gibbs free energy and enthalpy changes, while positive entropy indicated favorable complex formation. Additionally, Job’s method confirmed 1:1 stoichiometry, while semiempirical PM3 quantum mechanical calculations identified halogen bonding and electrostatic interactions as primary binding mechanisms. Experimental conditions were systematically optimized to achieve maximum quenching efficiency at pH 5.0 with 10 µg/mL Erythrosin B concentration and 5-minute reaction time. The method demonstrated excellent analytical performance with good linearity (r2 = 0.9991) over 0.05–3.0 µg/mL range and adequate sensitivity for therapeutic monitoring applications. Furthermore, comprehensive validation according to ICH M10 guidelines confirmed method reliability with accuracy ranging from 96.04% to 104.76% and precision below 4.61% RSD across all quality control levels. Subsequently, successful pharmacokinetic application in New Zealand white rabbits provided key parameters including Cmax of 4.25 µg/mL, half-life of 2.94 h, and AUC₀₋∞ of 21.6 µg·h/mL, consistent with published clinical data. Finally, environmental sustainability assessment using four complementary evaluation tools confirmed favorable green analytical chemistry and analytical practicality traits with scores of 0.71, 76%, 70.0, and 65% for AGREE, MoGAPI, BAGI, and CACI, respectively. In conclusion, the developed spectrofluorimetric method offers significant advantages including cost-effectiveness, minimal waste generation, and elimination of derivatization steps, positioning it as an attractive alternative to conventional methods.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-32405-z.

A bstract We establish the connection between thermodynamic and dynamical instabilities in relativistic hydrodynamics with multiple flavours of conserved U(1) charges. In theories with positive hydrodynamic entropy production, where the underlying perfect fluid has a positive speed of sound squared and satisfies the null energy condition, we show that hydrodynamic instabilities can arise only through negative diffusion coefficients associated with the U(1) charges. The onset of such instabilities is governed by the eigenvalues of the thermodynamic Hessian matrix, while the flavour-space polarisations of the unstable diffusion modes are determined by the corresponding eigenvectors. We illustrate this connection using strongly coupled 𝒩 = 4 supersymmetric Yang-Mills theory at finite densities of the three U(1) R-charges. In the dual holographic description, the five-dimensional STU black brane exhibits unstable quasinormal modes precisely at the onset of thermodynamic instability. We derive analytic expressions for the R-charge diffusion coefficients in several representative cases, including the configuration with three equal chemical potentials.

The adsorption of adenine on montmorillonite (MMT) clay, both in its natural form and exchanged with divalent cations (Ca²⁺, Mg²⁺, Ni²⁺), was investigated under varying pH, temperature, and concentration conditions to gain insights into the role of mineral surfaces in prebiotic molecular organisation. Adsorption isotherms, thermodynamic parameters, and the influence of cations were examined. The presence of divalent cations enhanced adsorption by neutralising the negatively charged clay surface, promoting electrostatic interactions. Thermodynamic analysis revealed that the adsorption process was spontaneous (ΔG°:–2.96 to –3.71 kJ·mol⁻1), driven by weak intermolecular forces, with enthalpy values ranging from 5.46 to 7.09 kJ·mol⁻1 and positive entropy contributions. These findings suggest that montmorillonite (MMT) clay could have acted as an effective adsorbent for concentrating and stabilising biomolecules like adenine under early Earth conditions, potentially facilitating the emergence of complex organic compounds and self-replicating systems. The study highlights the importance of mineral–organic interactions in prebiotic chemistry and provides mechanistic insights into the possible role of clay minerals in the chemical evolution of life.

We investigate the stability of maximizing measures for a penalty function of a two-dimensional subshift of finite type, building on the work of Gonschorowski et al. [Support stability of maximizing measures for shifts of finite type, Ergodic Theory Dyn. Syst. 41(3) (2021), pp. 869–880]. In the one-dimensional case, such measures remain stable under Lipschitz perturbations for any subshift of finite type. However, instability arises for a penalty function of the Robinson tiling, which is a two-dimensional subshift of finite type with no periodic points and zero entropy. This raises the question of whether stability persists in two-dimensional subshifts of finite type with positive topological entropy. In this paper, we address this question by studying a nearest-neighbor subshift of finite type satisfying the single-site fillability property. Our main theorem establishes that, in contrast to previous results, a penalty function of such a subshift of finite type remains stable under Lipschitz perturbations.

The current study examines the solute–solvent and solute solute interactions of three substituted pyrazole ligands (BCHPP, CNHPP, and CCHPP) at different concentrations and temperatures in a 70% dioxane–water mixture. A pyknometer and an Ostwald viscometer were used to measure densities and viscosities, respectively. The Jones-Dole equation was used to analyze the data and determine the A- and B-coefficients. Increased solute–solvent interactions were confirmed by the relative viscosity rising with increasing ligand concentration. All ligands exhibit structure-breaking behavior in the mixed solvent system when their B-coefficients are negative. Thermodynamic parameters (ΔG, ΔH, and ΔS) that shed light on the energetics of ligand–solvent interactions were determined through temperature-dependent viscosity measurements. The results indicate that because of the nitro group's strong electron-withdrawing properties, CNHPP has the largest free energy change. Positive entropy values indicate spontaneous processes that are dominated by solvent structural reorganization. The type and degree of molecular interactions in substituted pyrazole ligand systems are generally revealed by viscosity and thermodynamic analyses.

Abstract The rapid advancement of the Medical Internet of Things (MIoT) technology has enabled remote monitoring, real-time data exchange, and personalized treatment; however, it has also introduced critical security challenges that demand efficient, robust frameworks to safeguard sensitive data. One-dimensional (1D) discrete chaotic maps provide a simple yet effective approach for securing low-end applications. However, their limited dynamics and narrow control parameter ranges significantly restrict their practical usability. The paper proposes a Golden π-Ratio Scaling Chaotification Model (GPRS-CM) that extends the control parameter range of any 1D discrete chaotic map to infinity. The model has been tested for six maps, including Cubic Logistic, Chebyshev, Cubic, Logistic, Renyi, and Sine maps. The enhanced maps have been evaluated for chaos complexity in terms of bifurcation diagram, Lyapunov exponent, time sensitivity analysis, 0–1 test, cobweb plots, approximate and sample entropies, and 2D and 3D phase plots. The results show that the enhanced maps exhibit chaotic behavior with no blank regions, persistently positive Lyapunov exponents, larger approximate and sample entropy values, near ideal 0 - 1 test indicator values, linear $$\:M-T$$ and random $$\:P-Q$$ plots, intricate cobweb plots, and 2D and 3D plots that fill the entire phase space. Additionally, a fast, operationally efficient Pseudo-Random Bit Generator (PRBG) is designed, leveraging the GPRS-CM-based enhanced chaotic maps. The PRBG demonstrates small operation count, high speed, and large throughput in addition to qualifying the fifteen NIST4statistical tests for randomness. Performance efficiency of the PRBG is compared on an ARM Cortex-M4-based LPC4357 IoT platform, with and without Floating Point Unit (FPU) usage. The FPU version outperforms the non-FPU version, showing improvements of 5.749%, 20.421%, 2.231%, and 25.438% in memory, time, power, and energy consumption, respectively. Overall, the results confirm that the proposed GPRS-CM chaotification model and the enhanced map-based PRBG offer a highly robust and resource-efficient security solution for MIoT systems.

Water pollution has emerged as a critical threat to modern ecosystems. According to the United Nations Environment Program, approximately 80% of wastewater produced by human activity is discharged into the environment without treatment. This wastewater often carries a wide range of pollutants, from human and agricultural waste to industrial byproducts. Once these contaminants enter rivers, lakes, and oceans, they can cause severe ecological damage, including large-scale die-offs of aquatic life [1]. The few organisms that survive are often weakened, afflicted with diseases, or burdened with genetic mutations that can jeopardize future generations.These realities underscore the urgent need for cost-effective and efficient technologies capable of removing persistent pollutants—such as heavy metals and synthetic dyes—from contaminated water. One promising approach is the use of adsorbent materials, which bind pollutants and allow for their easier removal via conventional filtration methods [2–15]. However, most conventional adsorbents are expensive to produce and have low adsorption capacities, limiting their widespread use.Magnetic Mesoporous Organo-Silicate (MMOS) composites present a potential solution to these challenges, offering a combination of affordability, high adsorption performance, and reusability.In this study, the adsorption behavior of Cr(VI) ions, Congo Red (CR), and methylene blue (MB) dyes onto a Magnetic Mesoporous Organo-Silicate (MMOS) composite was investigated. The adsorption of Cr(VI) and MB was found to be spontaneous and exothermic, occurring with moderate to low energy barriers. Positive entropy changes for these adsorbates indicate increased randomness at the solid–liquid interface, further supporting the thermodynamic favorability of the process. In contrast, CR adsorption was non-spontaneous and endothermic, exhibiting highly unfavorable thermodynamic parameters, as reflected by positive ΔG values and a large negative activation energy. These results highlight the composite’s selective adsorption capabilities, with markedly superior performance for Cr(VI) and MB compared to CR. References Bishop, B.E., Savitzky, B.A. and Abdel-Fattah, T., Ecotoxicology and Environmental Safety, 73(4), pp.565-571 (2010).A Elmekawy, Q Quach, TM Abdel-Fattah, Nanomaterials 14 (13), 1143 (2024)SELME Mahmoud, TM Abdel-Fattah, ME Mahmoud, E Díaz, Environmental Nanotechnology, Monitoring & Management 22, 100977 (2024)SELME Mahmoud, D Ursueguia, ME Mahmoud, TM Abdel-Fattah, E Díaz, Biomass Conversion and Biorefinery, 1-1 (2023)A Elmekawy, Q Quach, TM Abdel-Fattah, Scientific Reports 13 (1), 12845 (2023)Omar H. Elsayed-Ali, Hani E. Elsayed-Ali and Tarek M. Abdel-Fattah, Journal of Hazardous Materials, 185 (2-3), 1550-1557 (2011)Alya Elsayed-Ali, Tarek Abdel-Fattah, Hani Elsayled-Ali, Hani, Journal of Chemical Education, 88(8), 1126-1129 (2011).TM Abdel-Fattah, ME Mahmoud, Chemical engineering journal 172 (1), 177-183 (2011)TM Abdel-Fattah, ME Mahmoud, MM Osmam, SB Ahmed, Journal of Environmental Science and health, part A 49 (9), 1064-1076 (2014)ME Mahmoud, TM Abdel-Fattah, MM Osman, SB Ahmed, Journal of Environmental Science and Health, Part A 47 (1), 130-141 (2012)TM Abdel-Fattah, B Bishop, Journal of Environmental Science and Health, Part A 39 (11-12), 2855-2866 (2004)ME Mahmoud, MM Osman, SB Ahmed, TM Abdel-Fattah, The Scientific World Journal 2012 (2012)ME Mahmoud, SS Haggag, TM Abdel-Fattah, Polyhedron 26 (14), 3956-3962 (2007)ME Mahmoud, AA Yakout, MT Abed El Aziz, MM Osman, TM Abdel-Fattah, Journal of Environmental Science and Health, Part A 50 (10), 1072-1081 (2015)H Namkoong, E Biehler, G Namkoong, TM Abdel-Fattah, ACS omega 7 (44), 39931-39937 (2022)

Graphite-based adsorbents provide a sustainable and eco-friendly alternative to conventional metal-based adsorbents, yet their performance in removing pharmaceutical pollutants remains underexplored. In this study, a phenylboronic acid-functionalized magnetic expanded graphite (EG/Fe3O4-PBA) nanocomposite was developed as a novel adsorbent for the treatment of acetaminophen (ACT)-contaminated hospital wastewater. The functionalization endowed the composite with a porous structure, rapid magnetic separation, and strong affinity toward ACT molecules. The experiments were designed using a central composite design (CCD) and analyzed with response surface methodology (RSM) to assess the combined influence of operational parameters on adsorption performance and to optimize conditions for maximizing ACT removal efficiency. Adsorption behavior was systematically investigated through isotherm, kinetic, and thermodynamic studies. The equilibrium data fitted well to the Langmuir model, confirming monolayer adsorption with a high maximum capacity of 451.30 mg g-1 achieved within 20min. Kinetic analysis revealed that the process followed the pseudo-second-order model, highlighting chemisorption as the main mechanism. Thermodynamic evaluation showed negative Gibbs free energy values (-1.21 to - 15.67kJ mol-1), a positive enthalpy change (100.6kJ mol-1), and a positive entropy change (360.3J mol-1 K-1), confirming that adsorption was feasible, spontaneous, and endothermic. The nanocomposite also exhibited excellent reusability, maintaining 80.5% efficiency over seven adsorption-desorption cycles with only a minor decline from the initial 98.8%. These findings demonstrate that EG/Fe3O4-PBA combines high adsorption capacity, rapid removal efficiency, and good recyclability with environmental compatibility. This work highlights the significance of functionalized graphite-based nanocomposites as a promising and sustainable solution for the treatment of pharmaceutical-contaminated wastewater.

A molecular-level understanding of amino acid and small-molecule adsorption onto gold nanosurfaces is essential for designing nanomaterials with tailored biointerfacial properties. Till now, the interactions of gold nanoparticles (GNPs) with complex biomolecules such as peptides, proteins, and nucleic acids have been extensively studied under varying physicochemical conditions (including particle size, surface charge, functionalization, pH, and ionic strength). However, the fundamental mechanistic pathways governing the adsorption of their molecular building blocks─amino acids─onto GNP surfaces remain inadequately understood. Herein, we investigate the thermodynamics and mechanistic aspects of small molecule and amino acid adsorption on citrate-capped gold nanoparticles (cit-GNPs, ∼15 nm) using a combination of Dynamic Light Scattering (DLS), Zeta-potential analysis, and UV-Vis spectroscopy. Amino acids representing four distinct chemical classes─positively charged, negatively charged, polar neutral, and sulfur-containing─were selected to dissect the contributions of Coulombic forces, van der Waals interactions, and hydrogen bonding. Adsorption isotherms fitted using a modified Langmuir model yielded equilibrium constant (Keq) surface coverage and standard Gibbs free energy changes (ΔG°), which ranged from -37 to -50 kJ mol-1, consistent with physisorption-dominated binding. The cationic amino acids exhibited the highest affinity toward negatively charged cit-GNPs, while sulfur-containing residues (e.g., cysteine and others) showed exceptional binding strength due to thiol-gold interactions and sulfur's polarizability. Further temperature-dependent adsorption studies revealed exothermic, enthalpy-driven behavior with a positive entropy change indicative of increased configurational freedom at the nano-bio interface. These findings offer fundamental insights into amino acid-nanoparticle interactions, with implications for the rational design of gold-based nanostructures in nanomedicine.

‏A direct comparison was made between raw banana peel waste (RBPW) and acid-treated banana peel waste (ABPW), under identical conditions, for adsorption of crystal violet (CV). Sorption kinetics, isotherms, and thermodynamics were considered to reveal the underlying mechanisms. The effects of contact time, pH, initial CV concentration, temperature, and adsorbent dosage were evaluated. The sorption process obeyed a pseudo-second-order kinetic model, while the Langmuir isotherm model best explained the equilibrium data with maximum adsorption capacities. The Dubinin–Radushkevich model supported the potential of ion-exchange mechanisms for the acidified sample. Adsorption was spontaneous and endothermic, as revealed by negative Gibbs free energy, positive enthalpy (+16.4 kJ/mol for RBPW and +53.5 kJ/mol for ABPW) and positive entropy (RBPW = 6.79 J/mol·K and ABPW = 14.65 J/mol·K) values. The lower ΔH for the raw peel is more consistent with physisorption, while higher ΔH of the acid-treated peel suggests stronger interactions consistent with chemisorption/ion-exchange. The FT-IR analysis confirmed that functional groups such as –OH, –COOH, C=O, C-O, and possibly aromatic moieties on banana peel waste are involved in the sorption of CV. The enhanced performance of ABPW is attributed to acid-induced surface modifications that increased porosity, making the functional groups available for sorption process.

Lead (Pb²⁺) contamination in aquatic environments represents a serious global threat due to its toxicity, persistence, and non-biodegradable nature. In this study, hydroxyapatite (HA) was synthesized from equine scapula bone and investigated as a low-cost, sustainable adsorbent for Pb²⁺ removal from aqueous media. HA was thermally treated at 100°C, 500°C, and 900°C to assess the effect of calcination on physicochemical and adsorption properties. Characterization techniques including XRD, FTIR, SEM/EDX, TGA and XRF confirmed structural and compositional evolution with temperature. Among the samples, HA-500 exhibited the highest adsorption performance, achieving 99% Pb²⁺ removal and a maximum capacity of 50mg/g under optimal conditions (0.25g dose, 20mg/L initial Pb²⁺ concentration). Kinetic studies followed a pseudo-second-order model (R² > 0.999), and equilibrium data were best described by the Freundlich isotherm (R² = 0.9839), indicating multilayer adsorption on heterogeneous surfaces. Thermodynamic analysis revealed that Pb²⁺ adsorption is spontaneous and exothermic, with negative Gibbs free energy values and positive entropy changes, confirming increased randomness at the solid-liquid interface. Furthermore, regeneration studies showed that HA-500 retained 73% of its efficiency after three cycles. These findings demonstrate the potential of equine bone as a novel bio-based source of hydroxyapatite for efficient and sustainable heavy metal remediation.

Photophysical studies on the interaction of small molecules with various forms of nucleic acids are attracting attention nowadays in order to delineate the molecular level mechanism of various biological processes occurring in vivo. Herein, we employed vivid steady-state and time-resolved spectroscopic techniques to elucidate the detailed characterization of the binding interaction of a biologically active cationic dye thioflavin T (ThT) with double and triple helical forms of RNA - A.U duplex and U.A*U triplex respectively. In both the cases, binding was accompanied by bathochromic and hypochromic shifts of absorption maxima of ThT along with significant regaining of fluorescence intensity which was intrinsically lost due to rapid transition from a locally excited state to nonradiative twisted intramolecular charge-transfer state through torsional rotation of BZT and DMAB rings around the C-C single bond. The binding constant was found to be greater with U.A*U triplex (Kb ∼ 105 M-1) than A.U duplex (Kb ∼ 104 M-1) at 293.15 K. However, steady-state absorption study, steady-state and time-resolved spectrofluorimetric and anisotropic study, anionic quenching study, circular dichroism study, and fluorescence contact energy-transfer analysis unveiled that the binding mode was partial intercalation in both the cases and the extent of intercalation was stronger in A.U duplex. Apparent anomaly in the binding affinity and intercalation strength probably lies in the interplay of two factors, namely, nonplanar structure of ThT and Columbic relaxation on binding. In both the cases, the binding was driven by a negative enthalpy change and a positive entropy change, and the van der Waals interaction together with H-bonding interactions are the major governing forces underlying the complexation. We also observed that the systematic addition of orange-emitting ethidium bromide to cyan-emitting ThT-RNA complex led to bright white light emission through Forster-type resonance energy-transfer mechanism, and this energy transfer was more feasible in the interstrand condition. This work renders the utility of ThT as a potential prerequisite for its application in pharmacological and optoelectronics industries.

ABSTRACT In this study, a novel composite adsorbent, Alg@Na-ZW, was successfully synthesised by embedding sodium zeolite (Na-ZW) into a sodium alginate matrix via a dispersion technique followed by thermal drying. The integration of Na-ZW into the biopolymer framework was confirmed through comprehensive characterisation using FTIR, XRD, SEM-EDX, XPS, and BET analyses, which revealed the formation of a porous structure favourable for adsorption. The composite was evaluated for its ability to remove methyl orange (MO) dye from aqueous solutions. Optimisation of key process parameters using response surface methodology (RSM) resulted in a high maximum adsorption capacity of 226.16 mg g−1, as determined by the Langmuir isotherm model (R2 = 0.987), indicating monolayer adsorption. Kinetic studies demonstrated that the adsorption process followed a pseudo-first-order model (R2 = 0.991), suggesting physical adsorption as the dominant mechanism. Thermodynamic analysis further supported this, with a positive enthalpy change (∆H° = 74.92 kJ mol−1) and entropy change (∆S° = 340.52 J mol−1 K−1), indicating that the process is endothermic and entropy-driven. Importantly, the composite exhibited good selectivity in the presence of competing ions and showed excellent reusability over multiple adsorption – desorption cycles with minimal efficiency loss. These results underscore the novelty and practical potential of Alg@Na-ZW as a cost-effective, sustainable, and recyclable adsorbent for dye-contaminated wastewater treatment.

In black hole thermodynamics, entropy is non-extensive. This entropy obeys the composition rule which coincides with the composition rule in the non-extensive Tsallis–Cirto $$\delta = 2$$ statistics. Here we extend this approach to the thermodynamics of white holes. The entropy of the white hole is negative as follows from the rate of macroscopic quantum tunneling from black hole to white hole. The white hole entropy is with the minus sign the entropy of the black hole with the same mass, S WH(M) = –S BH(M). This reflects the anti-symmetry with respect to time reversal, at which the shift vector in the Arnowitt–Deser–Misner formalism changes sign. This symmetry allows one to extend the Tsallis–Cirto entropy by adding a minus sign to the Tsallis–Cirto formula applied to white hole. As a result, the composition rule remains the same, with the only difference being that instead of entropy it contains the entropy modulus. The same non-extensive composition rule is obtained for the entropy of the Reissner–Nordström black hole. This entropy is formed by the positive entropy of the outer horizon and the negative entropy of the inner horizon. The model of the black hole formed by black hole atoms with Planck-scale mass is also extended to include the negative entropy of white holes.

Cannabinoids are increasingly recognized for their therapeutic potential, yet their pharmacokinetics remain poorly understood due to their high hydrophobicity and complex interactions with plasma proteins. Human serum albumin (HSA), the principal drug carrier in blood, critically influences the distribution, bioavailability, and efficacy of lipophilic compounds. In this study, we comprehensively investigated the binding interactions between HSA and six major cannabinoids (THC, CBD, CBC, CBG, THCV, and CBDV) using fluorescence spectroscopy, synchronous fluorescence scanning (SFS), circular dichroism (CD) spectroscopy, and molecular docking simulations. Fluorescence quenching analysis revealed a static quenching mechanism, supported by quenching rate constants (K b) exceeding diffusion limits. Temperature-dependent studies and van’t Hoff analysis indicated that the interactions were driven primarily by hydrophobic forces, as evidenced by positive entropy and enthalpy changes. CD spectral analysis showed that most cannabinoids induced minimal or stabilizing effects on HSA’s α-helical structure, with the exception of CBDV and CBG, which caused more pronounced, concentration-dependent secondary structure changes. Molecular docking localized the binding sites predominantly within Sudlow’s sites I, involving key hydrophobic residues such as Ile, Leu, Val and Ala. Together, these findings provide new molecular insights into the transport properties of cannabinoids and highlight the role of albumin in modulating their pharmacokinetic profiles, offering valuable guidance for therapeutic drug design and delivery strategies.

Due to their cost-effectiveness and high surface area, activated carbons are commonly used for the adsorption of dyes from aqueous solutions. In this study, activated carbon was synthesized from walnut shell waste via KOH activation (1:3 ratio), yielding a surface area of 2347.4m²/g. Reactive Blue 19 and Reactive Red 195 adsorption behavior were studied under varying experimental conditions. These included natural pH values (6.8-7.2), dye concentrations between 50 and 1250mg L⁻¹, and adsorbent dosages ranging from 0.1 to 1.0g. Adsorption equilibrium was achieved within 150min. The maximum adsorption capacities were found to be 1227.17mg g⁻¹ for RB 19 and 235.74mg g⁻¹ for RR 195. Isotherm modeling was conducted using Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models, with Freundlich providing the best fit for both dyes, indicating multilayer adsorption on heterogeneous surfaces. Thermodynamic analysis revealed that the adsorption processes were spontaneous and endothermic, with negative Gibbs free energy (ΔG°), positive enthalpy (ΔH°), and positive entropy (ΔS°) values. These results highlight the high adsorption performance and practical potential of walnut shell-derived activated carbon for dye removal from wastewater.

The aim of this study was to investigate the thermodynamic properties of modified activated carbon developed from periwinkle shell carbon (PSC) for the adsorption of heavy metals (Fe+ and Pb) from waste water .Metalsadsorption from aqueous solutions unto periwinkle shell carbon was prepared (carbonized at 650oC and activated with phosphoric acid) and characterized to determine its physicochemical properties. Batch adsorption experiments were conducted to investigate the effects of process parameters (contact time, particle size, carbon dosage and initial concentration) on adsorption rate. Adsorption isotherms were analyzed using the Langmuir, Freudlich andTemkin isotherms while thermodynamic parameters such as enthalpy change (ΔHo ) , entropy change (ΔS o ) and Gibbsenergy change (ΔGo ) were determined. Results showed that adsorption rate increase with increase in contact time, adsorbent dosage and decreased with increase in particle size. Isotherm data showed that theFreudlich isotherm accurately described the adsorption data indicating that adsorption has a heterogeneous adsorbent surface. Thermodynamic parameters results showed that adsorption process was endothermic with enthalpy change (ΔHo ) of 96.38KJ/mol; a positive entropy change (ΔSo ) of 35.11 KJ/mol, indicating an increase in the degree of freedom (or disorderliness) of the adsorbed specie and a negative Gibbs-energy change (ΔGo ) at all temperature indicating that the adsorption process was spontaneous and favourable at high temperature. The study has showed PSC is a good adsorbent and it is effective enough for waste water treatment, as such it is recommended for integration with existing technologies to explore compatibilities with current water treatment systems and scale-ip studies should be conducted to evaluate performance in continuous flow system.

Abstract The binding behavior of U(VI) ions onto nano-Kaolin (NK) and nano-Kaolin/MnFe2O4 composite (NK-MF) adsorbents was systematically investigated, focusing on the influence of pH, adsorbent mass, temperature, and contact time. Kinetic analysis, utilizing the pseudo-second-order model, revealed that both NK and NK-MF composites reach their maximum capacity of adsorption (qm) at pH 3. The maximum adsorption capacities were found to be (8.6) mg g−1 for NK and (14.79) mg g−1 for NK-MF at 25C°, indicating a significant enhancement due to the incorporation of MnFe2O4. The adsorption isotherms were examined using Langmuir, Freundlich, and Dubinin-Radushkevich models to characterize the adsorption mechanisms. The Langmuir and Freundlich models provided the best fit (R2 > 0.9), indicating monolayer and multilayer adsorption. Thermodynamics parameters, including enthalpy change (ΔH°), Gibbs free energy change (ΔG°), and entropy change (ΔS°), were derived from adsorption data across different temperatures. The values at 25 °C of ΔH° were (49.67) for NK and (70.97) for NK-MF; ΔG° values were (−5.06) kJ mol−1 for NK and (−7.39) kJ mol−1 for NK-MF; and ΔS° values were 187.36 J (mol·K)−1 for NK and (263.70) J (mol·K)−1 for NK-MF. The results indicate that the adsorption process is endothermic, with conditions that favor adsorption and a positive entropy change. These findings demonstrate the effectiveness and potential of NK and NK-MF composites as viable adsorbents for the uptake of U(VI) ions from water-based solutions. The incorporation of MnFe2O4 into NK improves adsorption capacity, making NK-MF a novel and practical material for uranium removal in environmental applications.

Polypyridyl-based bridging corrosion inhibitors: A critical review on interface and ligands properties.

Sustainable cobalt (II) removal from wastewater using an electrospun Ag-MOF/polycaprolactone-chitosan nanofiber membrane: Optimization and regeneration performance.