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[Display omitted] • Preparation and characterization of three activated carbon different sources for the removal of naproxen. • Adsorption isotherms for the naproxen were carried out for all adsorbent at different temperatures. • All the adsorption systems were well described by the monolayer adsorption with two different energy sites. • Thermodynamic parameters shown that the adsorption of naproxen presents an endothermic nature despite of the system. In this work, physical statistical models were employed to provide reasonable information regarding the adsorption of naproxen onto different activated carbons. The activated carbons were prepared from different biomasses (pitaya peels, jabuticaba peels, or grape residues from the winery process) using ZnCl 2 as an activator. All the adsorbents were characterized regarding their functional groups and morphological surfaces. The maximum capacity obtained for the activated carbons (at 328 K) was found to be: 167.0 mg g−1 for jabuticaba peels at pH 4; 158.81 mg g−1 for pitaya peels at pH 6.7; and last., grape residues the capacity was 176.0 mg g−1 at pH 7. The equilibrium data of the three adsorbents were well fitted to the monolayer with two energy sites adsorption model, assuming that NPX adsorption on the carbon surfaces occurs via two different functional groups. This statistical physics model calculated the number of NPX molecules bound on the surface and the saturated adsorption capacity for both functional groups at different temperatures. The obtained results indicate that the naproxen molecules can be adsorbed in a parallel and horizontal manner according to the material employed. The receptor density tends to increase with the temperature evolution, indicating that thermal energy and solubility play an important role in adsorption. Configurational entropy indicates similar thermodynamic behavior for all materials where higher disorder is found at the early stages of the adsorption, followed by and decrease a possible organization of the molecules on the surface. The Gibbs free energy shows that adsorption of naproxen is spontaneous in all cases and internal energy is proportional to the adsorption capacity indicating that the system releases energy as the adsorption occurs. Therefore, this article reports new findings to understand the adsorption mechanism of naproxen molecules on activated carbons prepared from lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

• A novel adsorbent from Physalis peruviana chalice was developed. • The adsorbent was able to a successful adsorb 2,4-D. • Statistical physics models indicate that adsorption occurs due to physisorption. In this study, the chalice generated from the production of the Physalis peruviana fruit was subjected to a treatment with sulfuric acid and applied in the adsorption of 2,4-Dichlorophenoxyacetic acid (2,4-D). The precursor, and the treated material before and after the adsorption, were analyzed by different techniques. After the acid treatment, it was found that the surface was changed from a smooth to an irregular surface with the presence of cavities with irregular size. The adsorption was favored at pH = 2 and with a dosage of 0.8 g L−1. The pseudo-second-order model was the best to represent kinetic data. The isothermal experiments were well represented by the Langmuir and Tóth models, reaching a high capacity of 244 and 320 mg g−1, respectively. The computed thermodynamic values show that the 2,4-D adsorption was spontaneous and exothermic. Overall, this study indicates that the Physalis peruviana chalice treated with strong acid presents great potential as an alternative material for the adsorption/removal of 2,4-D herbicide from liquid effluents. [ABSTRACT FROM AUTHOR]

• Application of sta-phy modelling coupled to DFT calculations is essential for understanding the adsorption mechanisms. • The mono-layer model with one energy site (M 1:1) successfully represented the phenomena occurring on a microscopic level. • Changes in orientation with increased temperature decrease atrazine interaction with the AC by increasing self-repulsion. • The neutrality of the diuron can evenly balance the charges on the surface, increasing the adsorption efficiency. • Electrostatic mapping supplies a perspective to the interpretation and evolution of the modelled steric parameters. Atrazine and diuron are two pesticide compounds with very low surface interaction capacity, whose adsorption efficiency remains a challenge in environmental remediation applications. In this work, statistical physics (sta-phy) modelling and density functional theory (DFT) calculations have explored several still unveiled mechanisms involved. A model activated carbon (AC) sample was produced with Hovenia dulcis fruit residues, a local invasive tree species. The adsorption process was spontaneous and endothermic, and the adsorption capacities (Q m) increased as the temperature increased. The number of adsorbate molecules per site (n) decreased as the density of the receptor site (N m) increased, revealing that the temperature influences the geometry of the molecules during the surface interaction. According to the electrostatic mapping provided by the DFT calculations, it was possible to infer that the obtained Q m values for atrazine, between 42.54 and 73.20 mg g−1, can be a response caused by its own self-repulsion. For diuron, due to its increased neutrality, the potential balance of the electrostatic charges between adsorbate-adsorbent tends to be more effective, resulting in higher Q m values, ranging from 97.91 to 119.7 mg g−1. Therefore, the combination of sta-phy modelling with quantum mechanics calculations is a powerful tool for mechanism interpretation, capable of providing complementary insights into the adsorption process from both adsorbent and adsorbate perspectives. [ABSTRACT FROM AUTHOR]

• The functionalization of Physalis peruviana biomass with H 2 SO 4 is reported. • The surface chemistry of this modified biomass was characterized. • Adsorption of ketoprofen and 2,2-dichlorophenoxyactic acid is studied. • Application of physical model on adsorption isotherms. In this research, a functionalization of Physalis peruviana biomass with H 2 SO 4 and its application in the adsorption of ketoprofen and 2,2-dichlorophenoxyactic acid is reported. In particular, the adsorption properties of this biomass were improved through a sulfuric acid treatment to enhance its removal performance of organic molecules. Surface chemistry of this modified biomass was also characterized. Experimental adsorption isotherms of these organic pollutants were determined at 298 – 328 K and pH 2. A multilayer statistical physics model was used in the data modeling to analyze the corresponding adsorption mechanism. Results showed that the endothermic multilayer adsorption of ketoprofen was a multi-molecular process where molecular aggregation could be expected. On the other hand, the adsorption of 2,2-dichlorophenoxyactic acid on this functionalized biomass was multi-anchoring. Adsorption energies (ΔE 1) varied from 4.13 to 5.53 kJ/mol for KTP and from 7.54 to 7.96 kJ/mol for 2,4-D herbicide. These results showed that physical adsorption forces were involved in the removal of these organic molecules with this functionalized biomass because the adsorption energies < 40 kJ/mol. [ABSTRACT FROM AUTHOR]

[Display omitted] • The combined simulations are valuable tools for a thorough mechanism unveiling. • 2,4-D accommodates itself to the sites under its highest steric hindrance. • Adsorption is translated to the full occupation of first receptor sites. • Thermal effects and electrostatic repulsion play a key role in efficiency. In this study, six statistical physics (sta-phy) models were used to further describe and enlighten the mechanisms behind the adsorption of a low interaction model molecule through the interpretations of the real and ideal gas. Density functional theory (DFT) was employed for the simulation of electronic structure and reactivity parameters (E g , η, μ, and ω). Experimental assays were carried out with a representative activated carbon sample and 2,4-dichlorophenoxyacetic acid (2,4-D) pesticide as a base for the modeling and simulation. According to the classical interpretations, the adsorption was a monolayer exothermic process dependent on temperature. From the sta-phy perspective, the Hill model for monolayer adsorption with two energies best described the process. According to the estimations, the number of molecules adsorbed increases with increasing temperature, yet the number of primary adsorption sites (n) decreases with increasing temperature. The concentrations at a half-saturation (C i), in turn, increase with the increase in temperature. At last, by combining the sta-phy estimations with the DFT interpretations, it was possible to infer that, in addition to the thermal effects, electrostatic repulsion is a possible contribution that increases as the primary receptor sites are occupied. Therefore, the combination of simulations can provide answers to unclear mechanistic steps and help predict the contribution of the adsorbate to the estimated sta-phy parameters, with a very high degree of precision as statistically validated. [ABSTRACT FROM AUTHOR]

[Display omitted] • New insights into glyphosate adsorption on modified carbon nanotubes; • Steric and energetic interpretations based on statistical physics models; • The adsorption occurs through the formation of a monolayer; • Intermolecular interactions between glyphosate molecules can be neglected; • Glyphosate adsorption occurs at MPNs-Fe present on the adsorbent. The present work used a statistical physics approach to present new insights into the adsorption of the pesticide glyphosate on modified carbon nanotubes via green synthesis (MWCNT/MPNs-Fe). The experimental equilibrium curves obtained for this system under pH 4 at temperatures 298, 308, 318, and 328 K were simulated from monolayer, double layer, and multilayer models, with 1 and 2 energies, considering real and ideal fluid approaches. Taking into account the statistical indicators and the physical meaning of the parameters, exploring simplifying hypotheses, the Hill model with 1 energy and ideal fluid approach (M1) presented the best prediction of the experimental data, indicating that glyphosate adsorption occurs by the formation of a monolayer and that pesticide interaction with MWCNT/MPNs-Fe are characterized by only one energy. Based on this approach, to assess the steric aspects of the system, the number of molecules adsorbed per site (n), the density of receptor sites (N m), adsorption capacity at saturation (Q sat), and concentration at half-saturation (W) were interpreted. As for the energetic aspects, the adsorption energy (ΔE) was inferred. The combination of parameters to its evolution with temperature and the magnitude of ΔE indicated an exothermic process involving a physical interaction mechanism. Finally, the new insights showed that the MWCNT/MPNs-Fe adsorbent favored pesticide adsorption by interacting glyphosate molecules with the metallic iron nanoparticles present on the adsorbent surface. [ABSTRACT FROM AUTHOR]