Diclofenac sodium (DCF) is widely used and ends up in water bodies, posing a serious environmental threat. Carbon-based materials are effective adsorbents for removing contaminants from polluted waters. In this study, we synthesized monolayer molybdenum disulfide-doped carbon material (MoS2@CM) via a high-temperature process to assess its efficiency as an adsorbent for DCF adsorption from aqueous solution. The characterization data indicated that MoS2 doping significantly affected the physicochemical properties of the MoS2@CM structure. MoS2-nanoparticles enabled the formation of metal-sulfur-oxygen bonds, which boosted the adsorption of DCF molecules. The suitability of MoS2@CM as an adsorbent for DCF removal was investigated. The MoS2@CM exhibited much faster adsorption kinetics, with an adsorption capacity of 424 mg g-1 at 45 °C. Based on indirect evidence from pH effect, zeta potential, kinetic, and isotherm data, as well as literature on MoS2-doped carbons, we hypothesize that the following interactions may contribute to the adsorption of DCF onto MoS2@CM: pore filling, hydrogen bonding, π-π interactions, and possible electrostatic attractions. The adsorbents were subjected to regeneration, and the results indicated that both adsorbents could be reused for at least 5 consecutive cycles, with MoS2@CM exhibiting a higher reusability than @CM. The @CM and MoS2@CM adsorbents showed excellent performance in treating a synthetic effluent, with percentage removals of 78.7% and 80.2% of the total compounds, respectively, highlighting their potential for treating real effluents. This research provides new pathways for the preparation of biomass/metal/heteroatom materials for effective application in the removal of emerging contaminants from aqueous solutions, and beyond.

Managing exhausted adsorbents is a major challenge in water treatment. This study proposes a circular bioeconomy strategy by upcycling spent, organically loaded biochar into high-quality Regenerated Carbon (RC). The RC was created through co-pyrolysis of a mixture of three used biochars, microcrystalline cellulose, and ZnCl2 at 500 degrees C. Characterisation revealed a turbostratic carbon structure, a moderate surface area of 567 m2/g, and a highly oxygenated, amphiphilic surface. Despite having a moderate surface area, RC achieved a high maximum adsorption capacity of 460.2 mg/g at 20 degrees C for 2,4-dichlorophenol (2,4-DCP), showing that surface chemistry plays a significant role alongside textural properties. Adsorption kinetics fit the Fractal-PFO model (n approximate to 0.56), suggesting diffusion-limited transport on a rough, energetically diverse surface. Equilibrium data matched the Liu isotherm, and thermodynamic analysis indicated an entropy-driven [Delta S degrees = + 102.35 J/ (K & sdot;mol)], endothermic physical process mainly influenced by the hydrophobic effect. The adsorption mechanism combines it-it electron donor-acceptor interactions, hydrogen bonding, and halogen bonding. Practically, RC maintained over 94% removal efficiency in complex simulated industrial effluents and achieved about 40% reversible capacity across multiple regeneration cycles with a NaOH/ethanol eluent. This Waste-to-Wealth strategy effectively converts hazardous spent biochar into a sustainable, highly efficient material for removing persistent chlorinated aromatics.

Copper oxide-modified wollastonite (CaSiO3) was synthesized via a controlled coprecipitation route and assessed as a nano-ceramic adsorbent for malachite green (MG) removal from aqueous media. Adsorption behavior was evaluated using conventional kinetic and isotherm models coupled with statistical physics analysis to elucidate molecular-scale mechanisms. The adsorption process followed pseudo-first-order kinetics, while the Liu isotherm best described equilibrium data, yielding maximum capacities of 103.75-117.11 mg/g. Statistical physics modeling indicated a multi-docking adsorption mechanism, with steric parameter values (n = 0.39-0.78) suggesting predominantly horizontal alignment of MG molecules on the adsorbent surface. Increasing temperature enhanced both active site density and saturation capacity, confirming the endothermic nature of adsorption. Low adsorption energies (1.26-3.42 kJ/mol) demonstrated that physisorption dominated, driven mainly by electrostatic and van der Waals interactions. Thermodynamic parameters confirmed the spontaneous nature of MG uptake. The developed ceramic adsorbent exhibited excellent stability and reusability over five adsorption-desorption cycles.

Developing advanced carbonaceous adsorbents with engineered porosity is critical for addressing the global challenge of water contamination by persistent organic micropollutants (OMPs). In this study, we synthesized a series of 3D carbon nanostructure sponges (CS) derived from microcrystalline cellulose via a two-step carbonization and potassium hydroxide (KOH) activation process. By systematically varying the cellulose-to-KOH ratio from 1:1-1:4, we engineered the pore architecture from a strictly microporous framework to a highly hierarchical micro-mesoporous system. Extensive characterization using nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), and Transmission Electron Microscopy (TEM) revealed that the optimal material (CS4) exhibits an exceptional Brunauer-Emmett-Teller (BET) specific surface area of 3007 m(2) g(-1) and a total pore volume of 1.37 cm(3) g(-1). Structural analysis resolved a crystallographic paradox: while XRD indicated a loss of long-range order, Raman spectroscopy and TEM confirmed the preservation of local graphitic domains within a highly crumpled, exfoliated nanosponge morphology. This unique structure proved decisive in the adsorption of diverse OMPs, including pharmaceuticals, phenols, and dyes. Adsorption assays demonstrated a strong structure-function relationship governed by size exclusion; while all adsorbents effectively removed small phenolic compounds (capacities similar to 200 mg g(-1)), only the hierarchically porous CS4 could accommodate bulky dye molecules such as Direct Red 80 (60.6 mg g(-1)) and Reactive Green 19 (46.8 mg g(-1)), which were sterically hindered on the microporous CS1. The results establish cellulose-derived carbon nanosponges as sustainable, high-performance adsorbents with tunable porosity, offering a scalable solution for the remediation of complex wastewater matrices containing pollutants of varying molecular dimensions.

Background The widespread presence of diclofenac (DCF), a nonsteroidal anti-inflammatory drug, in aquatic environments emphasizes notable environmental concerns due to its persistence and ecotoxicity. Methods In this study, a new composite adsorbent (C16mim@cell) was developed by coating nanocrystalline cellulose with the ionic liquid 1-hexadecyl-3-methylimidazolium chloride (C16mim) using an ultrasonic-assisted impregnation method. The resulting composite was characterized using SEM, TEM, FTIR, XRD, TGA, and XPS analysis. The removal of DCF was investigated through batch adsorption experiments. Additionally, periodic density functional theory (DFT) simulations were employed to examine the interaction between DCF and the C16mim@cell surface. Significant Findings The C16mim@cell composite showed rapid DCF removal, reaching equilibrium in <10 min with a maximum adsorption capacity (Q(max)) of 78.37 mg. g(-1) at 20 degrees C. The kinetic data best matched the fractal-like pseudo-first-order (FPFO) model, indicating heterogeneous surface interactions. The Liu isotherm model provided the best fit for the equilibrium data. Thermodynamic analysis confirmed the process is spontaneous and exothermic (Delta H degrees= -20.74 kJ mol(-1)), driven by physical adsorption. DFT simulations showed that DCF binds to the surface of the adsorbent via pi-pi stacking, hydrogen bonding, and electrostatic interactions. The composite achieved over 95 % removal efficiency in simulated pharmaceutical effluents and can be fully regenerated using mild saline eluents, maintaining effectiveness through multiple cycles. These results demonstrate C16mim@cell's potential as a fast, reusable, and sustainable method for removing pharmaceutical pollutants from water.

This study presents a comprehensive experimental and theoretical investigation of Catechol adsorption onto pinecone-derived activated carbon (PB600) for water remediation applications. Adsorption equilibrium data were modeled using four statistical physics-based isotherm formulations, systematically fitted to the experimental results. Convergence was evaluated through rigorous error analysis using reduced chi-square (χ2), residual sum of squares (RSS), coefficient of determination (R2), and adjusted R^2_adj . Among the tested scenarios, the monolayer adsorption model with a single energy level provided the best fit, revealing a maximum adsorption capacity (Qₘₐₓ) of 263.8 mg·g−1 at 298 K. The stereographic analysis showed that the occupation number (n) remained below unity across all temperatures, indicating a horizontal molecular orientation and a multi-point attachment mechanism on the adsorbent surface. The thermodynamic insights derived from the accurate model parameters revealed that surface accumulation is exothermic and spontaneous, as evidenced by the negative values of internal energy and Gibbs free energy. The adsorption energy values remained consistently below 40 kJ·mol−1, confirming that the process is driven by physisorption involving van der Waals forces, π–π interactions, and hydrogen bonding. Additionally, entropy increased with both temperature and concentration, suggesting enhanced molecular disorder at higher loading. A temperature-driven transition in adsorption behavior was observed around 302 K, beyond which the density of receptor sites (Nₘ) increased sharply, indicating thermally induced structural changes in the adsorbent and improved site accessibility. The outcomes demonstrate the potential of PB600 as a high-performance and renewable bio-adsorbent. Its strong adsorption capacity under moderate conditions, combined with low-energy binding characteristics, positions it as a promising material for scalable, eco-friendly treatment of phenolic pollutants. These findings support future development of hybrid or modular filtration systems tailored for real-world applications in industrial and decentralized water purification.

In this investigation, we deployed four advanced statistical physics models within the grand canonical ensemble to scrutinize the adsorption forces and thermodynamics governing the removal of hydroquinone (1,4-benzenediol, HYD) onto the biochar surface, contributing to advancements in water remediation. Our main findings demonstrated the effectiveness of a monolayer model with a single-site energy distribution for describing, at the molecular scale, the binding mechanism within biochar pores. By leveraging this framework, we successfully computed the key steric parameters and derived essential thermodynamic functions (molar entropy, molar internal energy, and Gibbs free energy). Thermodynamic analysis revealed that the microscopic docking of hydroquinone onto the adsorbent’s available sites is a spontaneous, endothermic (heat-consuming), and energetically favorable process. Furthermore, the magnitude of the internal energy confirms physisorption, in which weak physical interactions (van der Waals forces) primarily govern surface occupancy. Analysis of the pore size distribution (PSD) indicated that pine biochar is primarily composed of macropores, while the observed distribution of adhesion energies (AED) provided strong evidence supporting the physisorption mechanism.

Herein, Hydnophora coral waste was chemically treated and thermally processed to form calcium aluminate ceramic (CAC), which served as an efficient adsorbent for Cr(vi) remediation. The produced CAC biosorbent was characterized using SEM-EDX, XRD, FTIR, and TEM techniques. Adsorption behavior was systematically evaluated through kinetic, equilibrium, thermodynamic, and statistical-physics modeling. Regeneration tests were performed to evaluate stability and reusability over multiple adsorption-desorption cycles. The developed CAC principally included crystalline mayenite (Ca12Al14O33) and Ca4Al6O13 phases, confirming successful phase transformation during the fabrication process. Kinetic analysis indicated that the pseudo-first-order model provided the best fit for the adsorption process, while the Liu isotherm most effectively described the equilibrium data. The as-synthesized CAC biosorbent exhibited notable Cr(vi) adsorption capacity (148.65-304.62 mg g-1 across 25-55 °C), reflecting a strong dependence on solution temperature. Thermodynamic analysis confirmed a spontaneous uptake, as ΔG° ranged from -5.064 to -7.528 kJ mol-1 at 298-328 K, and an endothermic process, as ΔH° was +19.601 kJ mol-1. The low ΔE values ranging from 11.45 kJ mol-1 (25 °C) to 13.11 kJ mol-1 (55 °C) indicated that the adsorption system is mainly governed by a physisorption mechanism (ΔE < 15 kJ mol-1). Statistical physics analysis revealed a horizontal multi-docking adsorption configuration, and steric parameters emphasized the significance of the functional group density of CAC in enhancing uptake performance. Additionally, the prepared material exhibited excellent regeneration capability, maintaining high performance over multiple adsorption-desorption cycles. Overall, this work highlights a sustainable method for converting coral limestone waste into high-performance ceramic adsorbents. Additionally, the use of statistical physics theory offers valuable insight into the molecular-level mechanisms controlling Cr(vi) adsorption.

A metal oxide nanoadsorbent was synthesized using a straightforward, cost-effective procedure and evaluated for its effectiveness in removing a phenolic contaminant from water. The as-prepared material exhibited a hexagonal crystal arrangement, alongside a specific surface area of approximately 80 m²/g and a pore volume of 0.3 cm³/g. Scanning electron microscopy revealed predominantly hexagonal grains and lamellar fibers, containing about 43.3

Methylene blue is a textile dye widely used as a reference probe in laboratory studies to set optimal removal conditions, yet reported physical properties of methylene blue are often erroneous. Here we review methylene blue properties with emphasis on erroneous or confusing literature data. We present molecular, biological, water solubility, spectroscopic, physicochemical and degradation properties, with focus on medicinal effects, lipophilicity, sorption, X-Ray diffraction, computed molecular structure, specific surface area, ultraviolet–visible, molar absorptivity, solvatochromism, pH, infrared, self-association, acid/base and redox behaviours, photocatalytic degradation, oxidative degradation, and biodegradation.

Herein, a mixture of naturally carbonized limestone (BL) and rutile nanoparticles (TiO2) was modified with sodium alginate (SA) to produce a novel biosorbent (SA-AATiO2/BL) for methylene blue (MB) uptake. The physicochemical characterization data suggested a unique SA-AATiO2/BL properties rich in surface functionalities with improved adsorptive properties. The adsorption experiments suggested that pseudo-first-order (PFO) and Langmuir models offered the best fit for the kinetic and equilibrium studies, respectively. The maximum adsorption capacity was 263.40 mg/g at 25 °C, and it enhanced to 283.42 mg/g when the temperature increased to 55 °C. The statistical monolayer model's physicochemical parameters were used to understand MB adsorption per functional group, active site density of SA-AATiO2/BL interaction energies, and sorption capacities at saturation. Theoretically, the adsorption process across all temperatures involves a multi-molecular adsorption mechanism and vertical positioning. The thermodynamic studies indicated an endothermic and spontaneous adsorption, in which the MB molecules adsorption was governed by physical forces such as hydrogen bonds and electrostatic interactions, with energies ranging from 16.80 to 17.53 kJ/mol. According to the regeneration results of up to six rounds, the SA-AATiO2/BL demonstrated stability and suitability for reusing in actual wastewater treatment.

Activated carbon (AC)/CoFe2O4 nanocomposites, MAC-1 and MAC-2, were prepared by a simple pyrolytic method using a mixture of iron(III)/cobalt(II) benzoates and iron(III)/cobalt(II) oxalates, respectively, and were used as efficient adsorbents for the removal of amoxicillin (AMX) and paracetamol (PCT) of aqueous effluents. The synthesized nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The sizes of cobalt ferrite nanoparticles formed from benzoates of iron(III)/cobalt(II) and oxalates of iron(III)/cobalt(II) precursors were in the ranges of 5–80 and 6–27 nm, respectively. The saturation magnetization (M s), remanence (M r) and coercivity (H c) of the MAC-2 nanocomposites were found to be 3.07 emu g−1, 1.36 emu g−1 and 762.49 Oe; for MAC-1, they were 0.2989 emu g−1, 0.0466 emu g−1 and 456.82 Oe. The adsorption kinetics and isotherm studies were investigated, and the results showed that the as-prepared nanocomposites MAC-1 and MAC-2 could be utilized as an efficient, magnetically separable adsorbent for environmental cleanup. The maximum sorption capacities obtained were 280.9 and 444.2 mg g−1 of AMX for MAC-1 and MAC-2, respectively, and 215.1 and 399.9 mg g−1 of PCT using MAC-1 and MAC-2, respectively. Both adsorbents were successfully used for simulated hospital effluents, removing at least 93.00 and 96.77% for MAC-1 and MAC-2, respectively, of a mixture of nine pharmaceuticals with high concentrations of sugars, organic components and saline concentrations.

The organoarsenical compounds, such as p-arsanilic acid (p-ASA) and roxarsone (ROX), are commonly used as veterinary drugs to control intestinal parasites in poultry and swine farms. Because of this, environmental contamination by organoarsenical compounds can occur, primarily affecting water sources, which has raised widespread concern. Metal-organic frameworks (MOFs) are emerging as promising materials for water purification because of their varied crystal structures, extensive surface areas, adjustable pore sizes, and excellent chemical stability. In this study, a zirconium-based MOF (UiO-66) was synthesized, and its structural properties were analyzed using XRD, SEM, TGA, NMR, and BET surface area measurements. The performance of Zr-MOF was evaluated for removing the organoarsenical compound (p-ASA) from natural and drinking water. Batch adsorption experiments were carried out to assess the effects of pH, adsorption time, analyte concentration, and potential interferences. The adsorption efficiency did not significantly change across the pH range of 4-8. The isotherm studies showed that the adsorption mechanism was best described by the Langmuir model (R 2 0.9880), with a maximum adsorption capacity of 542.6 mg g-1. This indicates the presence of uniform adsorption sites and the formation of a monolayer. The adsorption kinetics studies revealed that the Avrami model fitted the data well (R 2 0.9971), suggesting a complex adsorption mechanism primarily based on physisorption (k AV 1.33). The proposed method demonstrates that UiO-66 is highly effective at removing p-ASA from natural and drinking water, even in the presence of coexisting ions, providing a sustainable approach to remediating contaminated water sources.

In the original publication [...].

Ouricuri endocarp was utilized as a biosorbent for the recovery of europium (Eu(III)) from aqueous solutions and rare earth elements (REEs) from authentic leachate derived from phosphogypsum, which encompasses various REEs. Various characterization techniques were applied to analyze the physicochemical and adsorptive properties of the biosorbent. The results indicate that the adsorption kinetic data conform well to the pseudo-first-order model, while the Liu model describes the equilibrium data well. Ouricuri endocarp and Eu interactions are favorable and spontaneous. The maximum adsorption capacity for Eu(III) is determined to be 22.9 mg/g according to the Liu model. Based on experimental results and adsorbent characteristics, the proposed adsorption mechanisms between ouricuri endocarp and Eu include ion exchange and electrostatic interactions as the primary mechanisms. The Eu(III) recovery is also feasible as a continuous flow process demonstrating inclined breakthrough curves and lower values of the length of the mass transfer zone. Ouricuri endocarp demonstrates its selectivity for recovering various REEs from authentic phosphogypsum leachate. It achieves a 98% recovery rate for Eu and approximately 60% for Ce, La, and Nd, affirming its efficacy under real-world conditions. Finally, concentration of REE was done by ashing loaded ouricuri endocarp, and a solid with around 34% (in weight) of REE is obtained.

Nitazoxanide (NTZ) is a broad-spectrum antiparasitic pharmaceutical widely used off-label for SARS-CoV-2 prophylaxis and treatment. This drug has been on the market since 2002, but there is a lack of studies investigating its environmental fate and effects. Furthermore, conventional wastewater treatment plants fail to remove this type of compound. The present study investigated, for the first time, the use of a solar photo-Fenton (SPF) process to degrade NTZ in distilled water (DW) and hospital wastewater (HWW). Different experimental conditions were applied, using both classical pH (2.8) and near-neutral pH (5.0). The initial SPF conditions were (i) pH 2.8 and (ii) pH 5.0, both with a single addition (SA) of iron at the start of the treatment (0 min), and (iii) pH 5.0, with multiple addition (MA) of iron at 0 and 20 min. At pH 2.8, primary elimination of NTZ of over 90 % was obtained after t 30W = 29 min in DW and after t 30W = 59 min in HWW, with the process following pseudo-first order kinetics. At pH 5.0, the degradation rates obtained were 93.7 % and 90.1 % (t 30W = 104.5 min in DW), and 50 % and 46 % (t 30W = 109.5 min in HWW), using the MA and SA approaches, respectively. In this case, both processes followed two steps with pseudo-first order kinetics. Analysis by LC-QTOF MS enabled the identification of five transformation products (TPs) during the NTZ degradation process. The degradation mechanism involved thiazole ring opening reactions, further oxidation of the moiety, and reactions with NaHSO3 (used to quench residual H2O2). Different in silico endpoints predicted by (Q)SAR models were evaluated, resulting in concerns regarding some of the proposed TPs, especially TP5, which was predicted to be highly mobile, persistent, and potentially carcinogenic. On the other hand, TP1 was being predicted to be less persistent, biodegradable, nonmutagenic, and possibly non-carcinogenic.

Water pollutants such as synthetic dyes can cause significant problems for human health and ecosystems due to their chemical properties and environmental interactions. Contamination of surface and underground water caused by the discharge of synthetic dyes is a widespread problem that arises primarily from industrial activities such as textile manufacturing, leather processing, paper production, and plastics industries. Since adsorption is one of the most efficient and reliable methods to remove pollutants from water, in this work, pine tree logging residues (LR) were used to produce boron/sulfur chemically modified biochars with superior adsorption performance and recyclability. The biochars were produced using a two-step pyrolysis procedure with potassium hydroxide as a chemical activator. The specific surface areas (B.E.T.) of the biochars were 2645 m2 g-1 for the boron-treated biochar (LR-Boron), 2524 m2 g- 1 for the sulfur-treated (LR-Sulfur), and 3141 m2 g- 1 for the control biochar (LR-Control, without boron or sulfur), respectively. The LR-Boron biochar showed an exceptional degree of graphitization of (ID/IG=0.45), while the LR-Sulfur biochar displayed an ID/IG= 1.02; for comparison, the LR-Control exhibited an ID/IG= 0.81, showing that the sample subjected to boron treatment created carbon- rich in graphitic structures. The three biochars were evaluated as adsorbents for removing reactive black-5 azo dye (RB-5) from water and mixtures of several dyes in synthetic aqueous effluents. The adsorption data showed that all carbons exhibited outstanding RB-5 removal performance. Kinetic measurements were well fitted by the Avrami fractional order model, and the LR-sulfur carbon displayed the fastest adsorption kinetics. Isotherm measurements were well fitted by the Liu model, with a theoretical Qmax of around 1419 mg g- 1 (LR-Control), 1586 mg g-1 (LR-Boron), and 1766 mg g-1 (LR-Sulfur) at 316 K. The presence of sulfur-functional groups on the LR-Sulfur biochar surface was probably the reason for the superior adsorption performance of this biochar. Both sulfur and boron-treated biochars exhibited higher regeneration potentials, maintaining around 60-67 % removal capacity after 7 cycles compared to 35 % for the LR-Control biochar. Thermodynamic adsorption studies showed that the adsorption process was endothermic, favorable, and compatible with physical adsorption. All produced biochars were highly efficient for removal of pollutants from concentrated synthetic effluents.