The escalating crisis of water pollution necessitates the development of sustainable, low-cost, and globally accessible treatment technologies. Natural clay minerals have emerged as highly promising adsorbents due to their widespread availability, favorable physicochemical properties, and demonstrated effectiveness in removing a broad spectrum of aqueous pollutants. This review provides a comprehensive and critical assessment of the use of natural clay minerals for sustainable wastewater treatment. We first establish the fundamental structure-property-performance relationships of key clay types, including smectite, kaolinite, illite, vermiculite, and palygorskite. The review then outlines a rigorous framework for their characterization and critically evaluates the application of equilibrium and kinetic models to describe adsorption processes. A central focus is placed on the physicochemical modification strategies—such as acid/base activation, pillaring, organophilization, and composite formation—used to enhance adsorption capacity, selectivity, and regeneration. We synthesize performance data for the removal of heavy metals, anions, and organic pollutants, critically analyzing the underlying mechanisms and the influence of environmental factors. Finally, we identify persistent challenges for real-world deployment and propose a translational roadmap from laboratory research to pilot-scale application. This includes a critical discussion of regeneration, end-of-life options, and the need for transparent techno-economic and life-cycle assessments benchmarked against incumbent technologies. This review concludes that natural clays represent a viable and scalable platform for water remediation, provided that key challenges in material processing, regeneration, and data standardization are systematically addressed.

In this research, Hydroxyapatite-Cellulose (HAp/Cellulose) bio-composites were synthesized using Moroccan natural phosphate and cotton-derived cellulose to remove hexavalent chromium Cr(VI) from aqueous solutions. The materials were structurally characterized by SEM, XRD, and TGA, and their adsorption performance was systematically investigated under varying conditions. A factorial experimental design using Design Expert 11 optimized key variables including Cr(VI) concentration, contact time, and adsorbent mass. Under optimal conditions (0.102 g adsorbent dose, 164.88 min contact time, and 138.15 ppm initial concentration), the PC5 composite achieved a removal efficiency of 77.96%, while batch experiments showed removal rates exceeding 95% at equilibrium. Kinetic modeling revealed pseudo-second-order behavior (R² > 0.97), while Freundlich isotherms (R² = 0.9884) confirmed heterogeneous multilayer adsorption. Notably, Density Functional Theory (DFT) and Fukui function analysis were employed to probe the molecular-level interactions between Cr(VI) and the composite surface. DFT results demonstrated a narrow HOMO–LUMO gap (0.377 eV) and strong non-covalent interactions, corroborated by RDG/NCI visualization. The integration of computational insights with experimental validation highlights the high affinity of the HAp–Cellulose composite for Cr(VI), offering a promising, green, and cost-effective adsorbent for water remediation.

The isostructural hybrid phosphites (C2H10N2)[Mn(H2PO3)2Cl2] and (C2H10N2)[Ni(H2PO3)2Cl2] were synthesized as corrosion inhibitors using wet chemical methods and characterized through single-crystal X-ray diffraction, infrared spectroscopy, and thermal stability analysis via TGA-DTA. Their corrosion inhibition performance for C38 in 1 M HCl solution was assessed using electrochemical impedance spectroscopy (EIS) and the potentiodynamic polarization technique. Both isostructural hybrids revealed significant anti-corrosion activity with inhibition efficiencies of 84 and 73

This work describes the eco-friendly synthesis and multifunctional performance of hydroxyapatite/cellulose (HAp@Cell) bio-films prepared from Moroccan natural phosphate and cotton-derived cellulose through a solvent-free, low-temperature (< 100 °C) route. Structural (XRD) and morphological (SEM) analyses confirmed nanocrystalline HAp homogeneously dispersed in a semi-crystalline cellulose matrix, creating a rough and porous network favorable for molecular interactions. The optimized film (PC5) exhibited outstanding adsorption toward methylene blue (qₑ,max ≈ 85 mg g⁻¹) and natural indigo (~ 95% removal). Kinetic data fitted the pseudo-second-order model, while the Freundlich isotherm best described multilayer adsorption, indicating a heterogeneous surface with high affinity for cationic dyes. At the molecular scale, non-covalent interactions such as hydrogen bonding, electrostatic attraction, and π–π coupling between dye molecules and surface hydroxyl/phosphate groups dominate the adsorption process. The same surface chemistry governs the antibacterial mechanism, where the controlled release of Ca²⁺ and PO₄³⁻ ions combined with electrostatic contact destabilizes bacterial membranes, producing inhibition zones of 25 mm for S. aureus and 20 mm for E. coli. The films maintain over 85% adsorption efficiency after five reuse cycles, demonstrating high stability and regeneration potential. These results position the HAp@Cell composite as a sustainable, dual-function material for wastewater decolorization and antimicrobial protection within Morocco’s eco-circular strategy.

This study examines the corrosion resistance of H13 tool steel exposed to ionic molten salt solution through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) techniques. H13 steel samples were produced via selective laser melting (SLM) with three different build orientations (0 deg, 45 deg, and 90 deg) using the Build Processor v3.2 machine. Nyquist and Bode plots, along with polarization curves, were used to assess the impact of orientation on corrosion resistance. The findings were supported by microstructure analysis of the corroded samples using optical and scanning electron microscopies. The phase angle and the impedance modulus increased with building orientation, with the 0 deg orientation showing the highest values. Polarization resistance values were 1704 Omega cm(2), 1540 Omega cm(2), and 1430 Omega cm(2) for 0 deg, 45 deg, and 90 deg, respectively, demonstrating superior corrosion resistance for the 0 deg orientation. Results highlight the critical impact of SLM build orientation on corrosion resistance, providing insights for future corrosion mitigation strategies for alloys.

Prickly pear seed oil (PPSO), extracted from the seeds of Opuntia ficus-indica, is increasingly attracting interest among researchers because of its unusual chemical richness and the diversity of its potential uses. The oil contains a mixture of unsaturated fatty acids, tocopherols, phytosterols, and various polyphenolic compounds, all of which contribute to its strong antioxidant properties and to its anti-inflammatory and antimicrobial effects. A number of recent reports have emphasized the interest of PPSO in cosmetics, particularly for skin hydration and anti-aging applications, where it is often considered a natural alternative to synthetic ingredients. Besides its cosmetic relevance, the oil is also being investigated for its possible nutraceutical uses. In this review, we provide a concise overview of what is currently known about the composition, biological properties, extraction techniques, and practical applications of PPSO. We also point out certain limitations that affect its broader use, including the relatively high cost of production and the need for standardized formulations supported by clinical testing. With the increasing demand for sustainable and natural bioactive ingredients, PPSO is likely to attract even more research attention in the coming years.

The increased demand for natural products within the agri-food sector has focused much research on the antifungal and antioxidant potentials of essential oils from aromatic plants. And by disrupting the cell membrane and fungi growth inhibition, these compounds have shown a great degree of antifungal activity on a wide variety of fungi and also stimulate plant immune systems. These substances have been reported to demonstrate activity against different pathogenic fungi. Essential oils such as those of Origanum vulgare, Thymus algeriensis, Eucalyptus globulus, and Rosmarinus officinalis with their major active principles such as thymol, carvacrol, eucalyptol, and eugenol represent the cluster of promising compounds due to their particular chemical composition. Additionally, they are high in antioxidants that protect cells from oxidative stress and help preserve food. Their application as natural antifungal agents presents several advantages, such as a broad spectrum of action, biodegradability and low toxicity for humans and the environment, which makes them a good candidate as food additives, in post-harvest treatment or in natural pesticide formulations.

In this study, zinc oxide (ZnO) nanostructures were successfully electrodeposited on two different substrates like carbon felt (CF) and titanium (Ti), to develop efficient photocatalysts for the degradation of the azo dye Reactive Blue 49 (RB49) under solar irradiation. The synthesis process was optimized using electrochemical techniques such as cyclic voltammetry and chronoamperometry, resulting in well-crystallized ZnO films confirmed by XRD and characterized morphologically via SEM-EDS analyses. The photocatalytic performance of ZnO/CF and ZnO/ Ti was evaluated through the degradation of RB49 dye solutions under natural sunlight. Results demonstrated that ZnO/FC exhibited superior photocatalytic activity, achieving up to 99% degradation efficiency within 160 min, compared to 92% for ZnO/Ti. The study also highlighted the influence of operational parameters such as initial dye concentration and solution pH, with optimal degradation occurring under acidic conditions (pH 3). Moreover, both photocatalysts showed promising reusability over five consecutive cycles, retaining significant degradation efficiencies, thus underlining their potential for sustainable wastewater treatment. This work supports the use of electrodeposited ZnO-based materials as eco-friendly and cost-effective alternatives for removing hazardous dyes from industrial effluents using solar energy.

Despite the wealth of findings already available in the corrosion field, exploring the adsorption process of organic inhibitors onto steel surfaces remains an area of active research. This pursuit is particularly relevant in the context of sustainable development, where the use of environmentally friendly inhibitors is encouraged to minimize the environmental impact of industrial processes. In this work, two novel organic compounds, 4-oxo-2-(prop-2-yn-1-ylamino)-4H-chromene-3-carbaldehyde (OPC) and 2-(benzylamino)-4-oxo-4H-chromene-3-carbaldehyde (BOC), were synthesized and evaluated as corrosion inhibitors for mild steel in 1 M HCl solution. The electrochemical outcomes of OPC and BOC revealed the mixed-type characters, protecting anodic and cathodic reactions. In addition, they reached an inhibition efficiency of 97% for OPC and 95% for BOC at the 10−4 M. According to the Langmuir isotherm model, these molecules adsorb onto the steel surface, displacing water molecules and forming an inhibitor layer. This adsorption was confirmed by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, as well as by X-ray diffraction and UV–visible molecular analysis. On the other hand, DFTB and DM simulations confirmed the high reactivity of these molecular structures, especially for OPC, which contains triple-bond groups. The theoretical outcomes supply a thoughtful explanation for the inhibition behavior and confirm the experimental findings.

2-Benzyl(prop-2-yn-1-yl)amino-4-oxo-4H-chromene-3-carbaldehyde 2 abbreviated as PAC was successfully synthesized and fully characterized by different spectroscopic analysis (1H,13C-NMR, HRMS-ESI) and X-ray diffraction of a single crystal, showing an orthorhombic crystal system belonging to the Pbac space group. Furthermore, biological evaluation revealed remarkable activity against the following bacteria S. aureus and E. coli, yielding inhibition zones of 13.70 +/- 0.85 mm and a minimum inhibitory concentration (MIC) of 1.875 mg/mL against E. coli. Regarding its anticorrosion performance, electrochemical investigations confirmed that PAC acts as an effective anti-corrosion agent for mild iron in a 1 M HCl solution. Electrical impedance spectroscopy (EIS) and potentiodynamic revealed a maximum inhibition efficiency of 95.8% at 10-4 M. The observed improvement in load transferring resistance and decreased double layer capacitance indicate the formation of an adsorbed protection film on the metal surface. Adsorption behavior follows the Langmuir isotherm model with predominant chemisorption characteristics. To further elucidate the mechanism, molecular docking studies demonstrated favorable protein-ligand interactions and strong binding affinity, supporting the experimental antibacterial results. Additionally, DFT calculations provided deeper insight into the electronic properties and reactivity descriptors of PAC, corroborating its adsorption capability and multifunctional performance.

In this study, an innovative methodology was implemented to combine an isoxazole derivative (ARZ) with hydroxyapatite (HAp), varying several parameters to obtain three distinct composites (ARZ-Hap-1, ARZ-Hap-2 and ARZ-Hap-3). These composites (ARZ-Hap) were synthesized by a dissolution-recrystallization process, thereby facilitating enhanced interaction between ARZ and HAp. This approach promoted homogeneous dispersion of ARZ within the HAp matrix, consequently enhancing the stability and functionality of the resulting materials. The structural characterization of these composites was determined by FT-IR, XRD, BET, TGA, and NMR (¹³C, ³¹P) methods. Subsequently, the composites were subjected to a rigorous evaluation process to ascertain their antibacterial and antifungal activities. Among them, ARZ-HAp-3 exhibited noticeable antimicrobial activity against E. coli, S. aureus, and B. subtilis, demonstrating a measurable inhibitory effect on bacterial growth. In terms of antifungal activity, this composite demonstrated the best results, particularly against C. albicans and F. oxysporum, with minimal MIC and MFC values comparable to those of fluconazole. These results indicate the potential of the ARZ-HAp-3 composite as a promising bioactive material, demonstrating a combination of structural efficiency and targeted biological activity. The release of ARZ from the composites was monitored by UV-Visible spectroscopy, revealing a gradual and controlled profile. The quantity of the substance released is proportional to the initial content of ARZ, with a maximum observed for ARZ-Hap-3 ( 900 mg/L). This mechanism, based on slow diffusion, confirms the potential of these materials for sustained release of active ingredients. Furthermore, a molecular docking analysis was conducted to explore potential interactions between ARZ and biological targets associated with the pathogens studied. The results of the study indicated a high binding affinity of ARZ with certain enzymes that are essential for bacterial and fungal survival. This finding corroborates the experimental observations made in the study, thereby providing a scientific rationale for the observed effects.

This study presents the development of a novel adsorbent based on hydroxyapatite (CaHAp) grafted with sodium benzoate (SB) at varying proportions (5%, 10%, 15%) via a double decomposition method. Structural and chemical characterizations (XRD, FTIR, SEM, TGA/DTA) confirmed the successful integration of SB, with noticeable improvements in crystallinity (+ 10%), porosity, and thermal stability compared to pristine CaHAp. Adsorption experiments using methylene blue (MB⁺) as a model pollutant showed that the CaHAp-(SB)15 composite achieved an adsorption efficiency of 90%. The adsorption process followed Langmuir isotherm (R² > 0.96) and pseudo-second-order kinetics (R² > 0.99), indicating monolayer chemisorption as the dominant mechanism. Increasing SB content correlated with a significant rise in adsorption capacity from 5.41 to 9.42 mg·g⁻¹, demonstrating the role of –CO2⁻ groups in enhancing electrostatic interactions with cationic MB⁺. DFT simulations supported the experimental findings, showing favorable interactions between SB and CaHAp at both molecular and atomic levels, particularly through non-covalent forces such as van der Waals and electrostatic interactions. This combined theoretical–experimental approach highlights CaHAp-(SB)15 as a promising, low-cost, and eco-friendly adsorbent for dye-contaminated wastewater, offering high efficiency, reproducibility, and environmental compatibility.

Catalysis plays a crucial role in the chemical industry by enhancing reaction efficiency, reducing production costs, and minimizing environmental impact. With their unique properties, metal complexes can direct chemical reactions toward specific products, thereby improving selectivity and reducing waste. They also enable reactions to occur under milder conditions, thereby reducing energy consumption and associated costs. In this context, the synthesis and characterization of new complexes from various metal salts and pyrazole ligands are the main objectives of this work. The primary aim is to explore the potential of these compounds as catalysts for the oxidation of 2,6-dimethylphenol. The complexes were systematically synthesized and characterized using various spectroscopic and analytical methods, such as infrared (IR) with NMR, ultraviolet-visible (UV-Vis) absorption, X-ray diffraction (X-DR) analysis, and density functional theory (DFT) calculations. These techniques have allowed elucidating the molecular structures and electronic properties of the complexes. The catalytic activity of the complexes was evaluated through kinetic analysis, demonstrating their effectiveness as catalysts for the oxidation of 2,6-dimethylphenol (DMP). The results show that these new catalysts exhibit exceptional performance. The catalysts developed in this study offer significant potential for various industrial applications, providing more sustainable and economically viable solutions for oxidation processes. Furthermore, this research paves the way for optimizing existing processes and exploring new chemical reactions, thereby expanding the potential applications for these catalysts.

The current research focused on assessing the corrosion process of a new aluminium alloy in a 3.5 wt ^∘ , 45 ^∘ , and 90 ^∘ orientation using laser powder bed fusion additive manufacturing techniques. Moreover, the fabrication used three levels of laser power: scan speed, hatch spacing, and constant layer thickness, according to the Taguchi L9 experimental plan. Thereafter, the corrosion process of these samples was assessed in a 3.5 wt

Introduction:Gout is the most common inflammatory arthritis, characterized by hyperuricemia, tophus formation, joint disease, and kidney stones. Uric acid, the final byproduct of purine catabolism, is eliminated via the kidneys and digestive system. Xanthine oxidase (XO) catalyzes the conversion of hypoxanthine and xanthine into uric acid, making XO inhibitors crucial for treating hyperuricemia and gout. Currently, three XO inhibitors are clinically used, showing significant efficacy. A molecular modeling study on triazole derivatives aims to identify novel XO inhibitors using 3D-QSAR, molecular docking, MD simulations, ADMET analysis, and DFT calculations. These computational approaches facilitate drug discovery while reducing research costs. Methods:Our work focuses on a series of synthesized anti-xanthine oxidase inhibitors, aiming to develop new inhibitors. A computational study was carried out to identify the xanthine oxidase inhibitory structural features of a series of triazole inhibitors using computational method. Results:A model based on CoMFA and CoMSIA/SEA has been built to predict new triazole derivatives. Discussion:The optimal model established from CoMFA and CoMSIA/SEA was successfully evaluated for its predictive capability. Visualization of the contour maps of both models showed that modifying the substituents plays a key role in enhancing the biological activity of anti-gout inhibitors. Molecular docking results for complexes N°8-3NVY and N°22-3NVY showed scores of -7.22 kcal/mol and -8.36 kcal/mol, respectively, indicating substantial affinity for the enzyme. Complex N°8-3NVY forms two hydrogen bonds with SER 69 and ASN 71, three alkyl bonds with ALA 70, LEU 74, and ALA 75, and one Pi-Pi T-shaped bond with PHE 68. Complex N°22-3NVY forms three hydrogen bonds with HIS 99, ARG 29, and ILE 91, and one halogen bond with LEU 128 at 3.60 Å. A MD study revealed that the N°22-3NVY complex remained highly stable throughout the simulation. Therefore, we proposed six new molecules, their anti-gout inhibitory activities were predicted using two models, and they were evaluated for Lipinski's rule, and ADMET properties. The results show that both Pred 4 and Pred 5 have better pharmacokinetic properties than the height potent molecule in the studied series, making these two compounds valuable candidates for new anti-gout drugs. Subsequently, using DFT study to evaluate the chemical reactivity properties of these two proposed compounds, the energy gap results revealed that both molecules exhibit moderate chemical stability and reactivity.

Water contamination is caused by numerous environmental pollutants from human and natural actions. In the current work, we created a novel cellulosic derivative with high chelating efficiency for metal ions. The polymer is designed to have an aryl pendant group with amino and mercapto functionalities at positions 1 and 2 (CellOMA). Cellulose extracted from the waste of the olive industry was used in this study, it was oxidized with sodium periodate to create dialdehyde functionality, then converted to Schiff base by reacting it with 2-mercaptoaniline, which was reduced with sodium borohydride to generate the target polymer. The Cell-OMA structure and thermal stability were confirmed by FT-IR and DSC analysis, respectively. Cell-OMA quantitatively removed mercury, and more than twenty metal ions were present in a real sample of wastewater. The maximum experimental Qe values for Hg(II) removal by Cell-OMA was about 75.5 mg/g. The regeneration cycles showed good reproducibility of Cell-OMA. Thermodynamic studies showed spontaneous adsorption of Hg(II) by Cell-OMA at room temperature. The equilibrium isotherms study revealed a fit to the Langmuir model. DFT calculations were conducted to enable QTAIM analysis, unveiling moderate to strong interaction between Hg(II) and Cell-OMA binding sites. Utilizing NCI plots and RDG versus sign(lambda)rho plots robustly validated the strong adsorption interaction, thereby yielding significant insights into molecular interactions. The natural based origin and adsorption efficiency of Cell-OMA in addition to simple synthetic methods make it feasible for commercial use as a chelating material for various toxic metal ions.

This study investigated the effectiveness of two piperidine-based compounds, piperidine-2-carboxylic acid (PPC) and piperazine-2-carboxylic acid (PPR) derivatives, as corrosion inhibitors in a 15 % hydrochloric acid (HCl) solution. To assess their performance, experiments on weight loss, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) were conducted at 313 K. In the EIS tests, the maximum values of 95 % for PPR and 88 % for PPC derivatives revealed that the inhibition efficiency increased with increasing inhibitor concentration. According to the PDP analysis, both inhibitors behaved as mixed-type agents, impacting both anodic and cathodic processes. SEM examination revealed the production of a compact, homogeneous protective coating on the steel surface, and the adsorption behavior was consistent with the Langmuir isotherm. To obtain a deeper understanding of the molecular mechanisms underlying corrosion inhibition, complementary theoretical investigations utilizing computational techniques such as density functional theory (DFT), density functional tight binding (DFTB), and molecular dynamics (MD) simulations were performed. These investigations primarily focused on the analysis of molecular orbital energies and adsorption behavior on the N80 steel surface.

In this study, we report a new class of spiranic junction heterocycles; 1,3,4-triphenyl-7-oxa-1,2-diazaspiro[4.4] non-2-en-6-one (3a), 1,3-diphenyl-4-(p-tolyl)-7-oxa-1,2-diazaspiro[4.4]non-2-en-6-one (3b), and 4-(4-methoxyphenyl)-1,3-diphenyl-7-oxa-1,2-diazaspiro[4.4]non-2-en-6-one (3c); as effective corrosion inhibitors for carbon steel (CS) in 1.0 M hydrochloric acid. These compounds were synthesized in high yields (83 %-88 %) by ultrasonic-assisted cyclization of diphenylnitrilimine dipole with alpha-arylidene-gamma-butyrolactone and were fully characterized using IR, 1H NMR, and 13C NMR techniques. Weight loss (WL) measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) tests all indicated significant corrosion inhibition efficiencies of 84.17 %, 86.17 %, and 88.12 % at 10-3 M for 3a, 3b, and 3c, respectively. PDP studies confirmed their role as mixed-type inhibitors, while activation energy evaluations suggested both chemisorption and physisorption mechanisms. Scanning electron microscopy (SEM) imaging further demonstrated that these inhibitors effectively protect the CS surface from acid-induced damage. To complement the experimental findings, conductor-like screening model for realistic solvation (COSMO-RS) and density functional theory (DFT) calculations revealed insights into compounds' solvation properties and a direct correlation between minor structural modifications in the spiranic heterocycles and enhanced adsorption on the metal surface, respectively. The synergy between experimental and theoretical approaches underscored the potential of these newly synthesized heterocyclic structures as efficient corrosion inhibitors, providing valuable guidance for designing effective corrosion inhibitors.

The adverse effects of corrosion on industrial metals, particularly N80 carbon steel under acidic conditions, call for developing effective corrosion inhibitors. Due to their structural and electrical properties, isatine-hydrazones have emerged as possible corrosion inhibitors. This study investigates the corrosion inhibition capabilities of two specific Isatin-hydrazones, (E)-1-octyl-3-(2-(5-oxo-4,4-diphenyl)-4,5-dihydro-1H-imidazol-2-yl)hydrazono)indolin-2-one (OPHIHI) and (E)-3-(2-(5-oxo-4,4-diphenyl)-4,5-dihydro-1H-imidazol-2-yl)hydrazono)indolin-2-one (OIHIHI), on N80 carbon steel in a highly acidic medium. The study assessed the corrosion inhibition efficacy of OIHIHI and OPHIHI using both computational and experimental approaches. Weight loss measurements, potentiodynamic polarization, and electrochemical impedance spectroscopy were used in the experiments. In contrast, density functional theory (DFT), molecular dynamics (MD), and tight-binding density functional theory (DFTB) were used in the computational analyses to elucidate the interaction mechanisms between the inhibitors and metal surfaces. The experiment demonstrated that both OPHIHI and OIHIHI effectively reduce corrosion rates in a 15 wt.% HCl solution at 303 K, achieving an inhibition efficiency of 96% and 92%, respectively, at an optimal 5×10−3 mol/L concentration. These inhibitors were discovered to form protective layers on the N80 carbon steel surface, offering mixed protective qualities (cathodic and anodic protection) with a preponderance of cathodic protection against carbon steel corrosion in 15 wt.% HCl. Computational studies supported the experiment's findings by demonstrating that isatin-hydrazones' superior electrical properties enabled them to form robust covalent bonds with the Fe (110) surface. Based on these results, OPHIHI and OIHIHI could be used as corrosion inhibitors in the oil and gas industry, particularly under highly acidic conditions.

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 50 mg/g under optimal conditions (0.25 g dose, 20 mg/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.