Density Of Receptor Sites Research Articles

A statistical physics-based physicochemical study of L-phenylalanine adsorption on activated carbon.

In this comparative study of the adsorption of L-phenylalanine (L-Phe) on two modified low-activated carbons (ACK and ACZ) at four temperatures (293-313K), steric and energetic characteristics of adsorption were investigated. An advanced statistical physics multilayer model involving single-layer and double-layer adsorption scenarios was developed to interpret the L-Phe adsorption phenomenon. Modeling results indicate that two and three L-Phe layers were arranged depending on the tested adsorption systems. The estimated number of L-Phe molecules per leading adsorption site varied from 1.71 to 2.09 and from 1.76 to 1.86 for systems L-Phe-ACK and L-Phe-ACZ, respectively. The results show that a multimolecular adsorption mechanism might connect this amino acid molecule on ACZ and ACK surfaces in a non-parallel location. These parameters changed as follows, according to the adsorbed quantity at saturation analysis: Qasat (L-Phe-ACK) ˃ Qasat (L-Phe-ACZ). This indicates that ACK material was more efficient and valuable for L-Phe adsorption than ACZ. It was also shown that the adsorption capacity decreases as the temperature increases, proving the exothermicity of the adsorption process. This analytical substantiation is confirmed by calculating the binding energies, suggesting the occurrence of physical bonds between L-Phe amino acid molecules and ACK/ACZ binding sites and among L-Phe-L-Phe molecules. Pore size distribution was interpreted and calculated by applying the Kelvin theory to data from single adsorption isotherms. All used temperatures depicted a distribution of pores below 2nm. The docking analysis involving L-Phe and the ACZ and ACK adsorbents reveal a significant resemblance in how receptors detect ligands. Consequently, the findings from the docking process confirm that the calculated binding affinities fall within the spectrum of adsorption energy. This study analyzed the adsorption capacity of the L-Phe through a model proposed by statistical physics formalism. Molecular docking was used to determine the various types of interactions between the two activated carbons. Two aspects, including orientation of L-Phe on the site, number of molecules per site n, interaction energy, density of receptor site, and adsorption capacity, were discussed to elucidate the influence of activation on the two adsorbents.

Statistical physics of azo reactive dye adsorption by metal hydroxide sludge for water remediation

We performed a theoretical investigation of azo reactive red (RR-120) on metal hydroxide sludge (MHS) using five advanced statistical physics models to interpret thermodynamic equilibrium data for potential water remediation applications. Each model incorporates multiple physicochemical parameters to comprehensively describe the microscopic process through empirical data fitting. The thermodynamic functions (entropy, internal energy and Gibbs free energy) were analyzed using the grand canonical formalism. Our analysis indicated that the single-energy monolayer model represents the most realistic scenario. The adhesion of RR-120 onto MHS was endothermic with an adsorption energy below 40.0 kJ/mol suggesting that Van der Waals interactions and hydrogen bonding are the predominant driving forces. The stereographic analysis demonstrated that as the density of receptor sites (Nm) incremented, there was a corresponding decline in the number of anchored entities per site (n). Moreover, thermodynamic assessment revealed that the disorder increased before half-saturation and decreased after half-saturation while negativity of Gibbs free energy indicated a spontaneous process of RR-120 adsorption in all tested temperatures. The exceptional adsorption capabilities of MHS will open up new avenues in wastewater treatment, soil remediation and air purification.

Statistical physical modeling insights for urinary analgesic drug adsorption on carbon nanomaterial derivative.

The presence of phenazopyridine in water is an environmental problem that can cause damage to human health and the environment. However, few studies have reported the adsorption of this emerging contaminant from aqueous matrices. Furthermore, existing research explored only conventional modeling to describe the adsorption phenomenon without understanding the behavior at the molecular level. Herein, the statistical physical modeling of phenazopyridine adsorption into graphene oxide is reported. Steric, energetic, and thermodynamic interpretations were used to describe the phenomenon that controls drug adsorption. The equilibrium data were fitted by mono, double, and multi-layer models, considering factors such as the numbers of phenazopyridine molecules by adsorption sites, density of receptor sites, and half saturation concentration. Furthermore, the statistical physical approach also calculated the thermodynamic parameters (free enthalpy, internal energy, Gibbs free energy, and entropy). The maximum adsorption capacity at the equilibrium was reached at 298 K (510.94 mg g-1). The results showed the physical meaning of adsorption, indicating that the adsorption occurs in multiple layers. The temperature affected the density of receptor sites and half saturation concentration. At the same time, the adsorbed species assumes different positions on the adsorbent surface as a function of the increase in the temperature. Meanwhile, the thermodynamic functions revealed increased entropy with the temperature and the equilibrium concentration.

Experimental and theoretical investigation of water sorption on lemon leaves: New perspectives with statistical physical modeling

A deeper analysis of the water sorption isotherms on lemon leaves (40, 50, and 60 °C) was carried out using statistical physical modeling to obtain information about the sorption mechanism and better understand the process. For this, a theoretical model was developed based on the grand canonical potential to describe the experimental data, and the isotherms were analyzed using the finite multilayer sorption model. The experimental sorption isotherms obtained for lemon leaves are Type II. The model used to analyze the process showed excellent predictive capacity, with coefficient of determination values above 0.97 and root mean square error below 0.08. The interpretation of the estimated parameters indicated that the water molecules are parallel to the surface of the lemon leaves, which allows the formation of finite layers of water. The system is directly affected by temperature, where increasing temperature decreases the density of receptor sites. The process occurs through physisorption since the calculated sorption energies are less than 50 kJ mol−1. The thermodynamic analysis of the process shows that water sorption on leaves is exothermic and spontaneous. This work contributes to a better understanding the drying process through the results obtained.

Understanding the adsorption of Reactive red 2 onto metal hydroxide sludge: analysis with physico-statistical steric and energetic perspectives.

This theoretical investigation delves into the analysis of Reactive red 2 (RR-2) adsorption isotherms on metal hydroxide employing a sophisticated double-layer model characterized by dual-energy levels within the realm of physical adsorption phenomena. An examination of five distinct statistical physics frameworks was undertaken to elucidate the modeling and interpretation of equilibrium data. Expression for the physico-chemical parameters involved in the adsorption phenomena was derived based on statistical physics treatment. Fitting experimental adsorption isotherms (308-333K) to a DAMTBS has revealed the number of anchored molecules per site, occupied receptor site density, and the number of adsorbed layers. The steric parameter n varies between 0.92 and 1.05. More importantly, it is evidenced that the adhesion mechanism of (RR-2) onto metal hydroxide as determined by the estimated adsorption energies (< 40kJ/mol) supports a spontaneous and exothermic physisorption process. Thermodynamic potential functions such as entropy, Gibbs free energy, and internal energy have been computed based on the most suitable model. This research advances our physical understanding of how metal hydroxide captures dye molecules RR-2 through adsorption reaction for water depollution treatment.

Thermodynamic interpretation of cationic dye adsorption onto untreated coffee residues as adsorbents via statistical physics approach

In this current paper, we perform a theoretical examination of adsorption systems undertaken through the application of statistical physics modeling to experimental data Remacryl Red TGL (BR) dye adsorption isotherms onto the untreated coffee residues (UCR) based adsorbents at 298–338 K range. The experimental values exhibited a strong agreement with the predicted values, and the developed model received high approval. Significant parameters are theoretically discussed such as thermodynamic, energetic, and stereographic factors which determine the (BR) adsorption onto UCR. In the pursuit of unraveling the adsorption mechanism, four different models are adopted: a monolayer with one energy (Model 1), a monolayer with two horizontal energies (Model 2), a monolayer with three energies (Model 3) and a double-layer with two vertical energies (Model 4). The analysis considered both steric and energetic parameters associated with the adsorption reaction, namely the number of adsorbed particles per site (n1 and n2), the receptor sites density (N1m and N2m), and the concentration at half-saturation. It appears that the experimental data aligns well with a monolayer model characterized by two energy states. The variations in these factors are examined in relation to the temperature of absorption isotherms. More importantly, the calculation of adsorption energies unequivocally pointed out that the adsorption process is of a chemisorptive nature. Our findings indicate that (UCR) could be utilized as a low-cost alternative adsorbent in wastewater treatment to eliminate the Remacryl Red TGL (BR) dye.

Statistical physics investigation on the simultaneous adsorption mechanism of Cd2+ and Pb2+ on amino functionalized activated carbon derived from coal gasification fine slag

In this study, a novel surface amino-functionalized activated carbon (T-AC) was synthesized from coal gasification fine slag (CGFS) and used as an adsorbent for heavy metal ions. T-AC exhibits excellent adsorption capacity for Cd2+ and Pb2+. The adsorption process of Cd2+ and Pb2+ onto T-AC was found to be spontaneous. The dominant adsorption process was chemisorption, primarily involving chelation and covalent bonding. In binary systems, as the initial concentration increases, the independent adsorption effect of Pb2+ and Cd2+ gradually becomes a competitive adsorption effect. Statistical physical models revealed that the adsorption of T-AC for Cd2+ and Pb2+ in single systems followed a multi-molecular adsorption process, whereas in binary systems, it involved a multi-anchorage process. The adsorption capacity was primarily influenced by the number of ions attached to the receptor sites and the density of the adsorbent receptor sites. Moreover, elevating temperature enhanced the thermal movement of heavy metal ions within the pore structure of the adsorbent, reducing their tendency to aggregate at the active sites. This work provides insights into the microscopic-level adsorption process of heavy metal ions by carbon-based materials and contributed to understand of the adsorption behavior.

Adsorption of ciprofloxacin from aqueous solution and fresh synthetic urine by graphene oxide: Conventional and statistical physics modeling approaches

This work uses conventional and statistical physics modeling approaches to address ciprofloxacin (CIP) adsorption by graphene oxide (GO) from aqueous solution and fresh synthetic urine. Instrumental techniques such as FTIR, XRD, SEM, TGA, BET, and EDS were employed to characterize the adsorbent material. The adsorption experiments were performed in a typical batch using different initial concentrations of CIP, adsorbent dosage, pH, and temperatures. Besides, the statistical physics approach was employed to investigate the CIP adsorption onto GO. Five models based on mono, double, and multilayers were used to describe the equilibrium isotherms. Steric and energetic parameters such as the number of adsorbed molecules per site, receptor site density, and half-saturation were considered. The kinetic data were adjusted using three conventional models (pseudo 1st order, pseudo 2nd order, and general order). The pH effect and influence of adsorbent dosage on adsorption performance were also investigated and discussed. In addition, adsorption mechanisms hypotheses were proposed based on experimental data and adsorption modeling using a statistical physics approach. Furthermore, the current work reports the removal of CIP at concentrations commonly found in urine considering factors such as fraction excreted in unmetabolized form, daily defined dose, and average daily urine volume excreted. The adsorption capacity values in aqueous medium and fresh synthetic urine were were 354.24 and 291.39 mg g−1, respectively.

Interpreting of the carbon dioxide adsorption on high surface area zeolitic imidazolate Framework-8 (ZIF-8) nanoparticles using a statistical physics model

The objective of this paper was to study CO2 adsorption on the extremely porous ZIF-8 (Zn(mIm)2 with mIm = 2-methylimidazolate). The ZIF-8 was characterized via X-ray diffraction, scanning electron microscopy, TGA analysis and N2 adsorption-desorption isotherms. The adsorption isotherms were generated at different temperatures, namely, 273 K, 298 K, 323 K, and 353 K. Based on the experimental result, a new model was simulated and interpreted using a multilayer model with saturation. The physicochemical parameters that described the CO2 adsorption process were determined by physical statistical formalism. The characteristic parameters of the CO2 adsorption isotherm such as the number of carbon dioxide molecules per site (nCO2), the receptor site densities (DZIF-8), and the energetic parameters (ΔE1a, ΔE2a) were investigated. In addition, the thermodynamic functions that governed the adsorption process such as the internal energy (Eint), entropy (Sad) and Gibbs free energy (Gad) were determined by a statistical physics model. Thus, the results showed that CO2 adsorption on ZIF-8 was spontaneous and exothermic in nature.

Utilization of red clay brick waste in the green preparation of an efficient porous nanocomposite for phenol adsorption: Characterization, experiments and statistical physics treatment

Red clay brick waste was utilized, for the first time, in the green preparation of nanoscale zero-valent iron (nZVI) to impregnate with activated charcoal (ACh). The as-synthesized nZVI@ACh composite was characterized via X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrometry, thermogravimetric analysis (TG) and its derivative thermogravimetry (DTG), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). This novel material was employed for phenol remediation at 25, 35, and 45 °C and pH 7. The results indicated that the prepared ZVI nanoparticles could be either trapped or distributed on the ACh structure. Experimental studies and their modeling with statistical physics theory were applied to analyze the phenol adsorption performance and mechanism using the nZVI@ACh. The phenol adsorption data fitted well to the Langmuir model, with maximum adsorption capacities of 122.85, 137.46, and 152.22 mg/g at 25°, 35°, and 45 °C, respectively. Theoretical calculations via statistical physics indicated that phenol molecules were removed on the nZVI@ACh following the hypothesis of the advanced monolayer model. The number of molecules adsorbed per site (n) ranged from 1.13 to 1.26 suggesting the involvement of vertical geometry and multi-molecular mechanism at all temperatures. The increment of the receptor sites density (NM) from 83.47 to 121.40 mg/g and the adsorption capacity at saturation (Qsat) from 104.75 to 137.19 mg/g with increasing temperature suggested the endothermic behavior of this removal process. Energetically, the phenol adsorption was directed by physical forces with adsorption energies (ΔE) ranging from 13.85 to 16.45 kJ/mol. Macroscopically, phenol adsorption onto nZVI@ACh was spontaneous according to the calculated thermodynamic functions. The developed nZVI@ACh adsorbent can be easily regenerated and reused preserving its competitive adsorption performance. Overall, these results offer a new approach that takes the Fe-rich solid wastes to the next standard in the design of outstanding and low-cost adsorbents for wastewater remediation. Also, the experimental study supported by the theoretical analysis generated new insights of the adsorption system at the micro- and macroscopic scales.

Utilization of Foamed Glass as an Effective Adsorbent for Methylene Blue: Insights into Physicochemical Properties and Theoretical Treatment

This study reports a potential approach for the valorization of glass waste (GW) that is mainly composed of amorphous silica to prepare lightweight foamed glass (FG). The preparation of FG was achieved by mixing sodium hydroxide with GW powder followed by sintering at a temperature of 800 °C. As-synthesized FG was characterized and applied as an effective adsorbent for the removal of hazardous organic water contaminants, in particular, methylene blue (MB) dye. FG exhibited porosity of 91%, bulk density of 0.65 g/cm3, compressive strength of 4 MPa, and thermal conductivity of 0.27 W/m·K. Theoretical treatment indicated that a monolayer model with one energy site was the best in fitting the removal of MB molecules. The number of MB molecules per active site (n) ranged from 2.20 to 1.70, suggesting vertical orientation and a multi-molecular adsorption mechanism. The density of FG receptor sites (DM) increased with the temperature, and this parameter played a vital role in the adsorption process. The adsorption capacity (Qsat) increased from 255.11 to 305.58 mg/g, which signifies endothermic interactions. MB adsorption on FG was controlled by physical forces such as electrostatic interactions (i.e., the adsorption energies were <20 kJ/mol). The results of this study prove the feasibility of glass waste as an effective and low-cost adsorbent for water remediation.

Synthesis and physicochemical characterization of new calcined layered double hydroxide Mg Zn Co Al-CO3; classical modeling and statistical physics of nitrate adsorption

This research focuses on the study of a new material, a layered double hydroxide, which was synthesized using a co-precipitation method at pH constant and, then, tested for its retention of nitrate anions. The LDH was prepared from four metal cations Mg-Zn-Co-Al to produce the quadratic material mentioned, Mg Zn Co Al-CO3, which was calcined to obtain metal oxides. Different techniques of characterization were considered, namely FTIR, X-ray diffraction, BET, SEM and EDX. Adsorption experiments for nitrate were carried out to test the effect of contact time, adsorbent mass, pH values, mass effect, and initial surfactant concentrations. When equilibrium was reached after 300 min (R2 = 0.998), the Pseudo-second order model was found to fit accurately the kinetic data. The intraparticle diffusion model recorded a rate constant of between 0.277 and 0.757 (g/mg. min−0.5) and the Sips adsorption isotherm best fitted the experimental data obtained. Maximum adsorption capacity for nitrate was found to be 55.97 mg g−1 which was in accordance with the experimental results. Thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic. The values of ΔH˚ and ΔS˚ of the adsorption process were 14.81 and 59.04 kJ mol−1, respectively. The low value of ΔH˚ (<40 kJ mol−1) indicated that the adsorption process was associated with physical forces. Finally, for a deeper insight into the nitrate adsorption mechanism, the statistical physics model was considered to quantify the number of adsorbed nitrate molecules per site, the anchorage number, the receptor sites density, the adsorbed quantity at saturation, the concentration at half saturation and the molar adsorption energy. A statistical physics model, with two binding sites, proved to be the best option to characterize and interpret the removal of nitrate on the tested LDH.

Investigation of the Hydrogen Absorption by the LaNi5 and LaNi4.75Pb0.25 Alloys Using a Statistical Physics Model

A theoretical model was selected among three potentially applicable models and then used to analyze the absorption isotherms of the hydrogen storage alloys LaNi5 and LaNi4.75Pb0.25 at three different temperatures (T = 303 K, 313 K, 323 K). The theoretical expressions of the model were based on the statistical physics formalism and simplifying hypotheses. The model selected was the one with the highest correlation with the experimental data. The model had six adjustable parameters: the number of hydrogen atoms per site nα, nβ, the receptor site densities Nα, Nβ and the energy parameters Pα, Pβ. The fitted parameters obtained for the Pb-doped and nondoped alloys were compared and discussed in relationship to the absorption isotherms. Finally, the fitted parameters or the model were further applied to calculate thermodynamic functions, such as entropy, Gibbs free energy and internal energy, which govern the absorption mechanism.

Synthesis of cellulose II-based spherical nanoparticle microcluster adsorbent for removal of toxic hexavalent chromium

Since natural cellulose is mostly cellulose I and has a fibrous form, most cellulose-based adsorbents are fibrous/rod-shaped and exhibit the cellulose I crystal structure. This study reports a cellulose II-based spherical nanoparticle microcluster adsorbent (SNMA), synthesized from biomass by a bottom-up approach, for removing toxic hexavalent chromium (Cr(VI)). The basic structure of SNMA was investigated. Notably, the prepared adsorbent was a microcluster composed of spherical nanoparticles, while exhibiting cellulose II crystal structure, resulting in higher thermal stability and significantly enhanced adsorption performance. The adsorption process and mechanism of SNMA on Cr(VI) were studied in detail. The SNMA achieved a high adsorption capacity (225.94 mg/g) and receptor site density. The SNMA is expected to be used as a bio-based spherical nanoparticle microcluster adsorbent platform for the adsorption of different toxic substances by changing the surface functional groups of its components, spherical nanoparticles.

CO2 adsorption by molecular sieve 10A°, experimental and theoretical examination via statistical physics: modeling macroscopic and microscopic investigation

ABSTRACT In order to monitor the greenhouse gases, there is a new focus on substances that can distinguish between no harmful gases rejected to the atmosphere and capture those that must be decreased. The physico-chemical parameters involved in the expression of analytical model are obtained from the adjustments of the experimental data. We observed that this model can be used to characterize the complicated process by the steric parameters. Samples of these parameters are as follows: The number of CO2 molecules captured per binding site of the adsorbent (nCO2). The density of receptor sites of the adsorbent (FM) through the adsorption energies (ΔEa) associated for the adsorption of CO2 on the molecular sieves, which are related to Ps1 parameters. The modulus of the obtained adsorption energies from fitting data ranged between 3.99 and 4.38 kJ/mol, confirming that the adsorption in this system is exothermic and it is founded on physisorption process. Furthermore, a meticulous study of the main intrinsic characteristics of the adsorbent to the temperature impact application and ensuring the compatibility between practical and theoretical statistical physics to find the pore size was carried out.

Adsorption of SO2 and NH3 onto copper/graphene nanosheets composites: Statistical physics interpretations, thermodynamic investigations, and site energy distribution analyses

Copper/graphene nanosheets composites (CGCs) were adopted as multi-gas adsorbents to remove two harmful gases (i.e., ammonia and sulfur dioxide) in the atmospheric environment, respectively. Methods such as N2 adsorption/desorption, scanning electron microscopy, and X-ray diffraction were selected to fully characterize CGCs. Under laboratory conditions, the adsorption isotherms of NH3 and SO2 onto CGCs at three different temperatures (298.15 K, 308.15 K, and 318.15 K) and different pressures (0 ∼ 1.8 bar) were quantitatively tested. A multilayer model with saturation (M5) was adopted as the best suitable model to explore the adsorption mechanism for SO2-CGCs and NH3-CGCs adsorption systems from a molecular level. The numerical simulation results demonstrated that the adsorption of NH3 by CGCs is a multi-anchorage process and a pure parallel adsorption position (298.15 K), a multi-linking process and a mixed adsorption orientation (308.15 K and 318.15 K). In contrast, SO2-CGCs adsorption system at 298.15 K, 308.15 K, and 318.15 K, there will be a multi-molecule process and a pure non-parallel adsorption position. Overall, from statistical physical, thermodynamic and SED analyses, the adsorption mechanism of SO2 and NH3 on CGCs, which was mainly governed by the density of receptor sites (Dm), was a spontaneous exothermic reversible adsorption process driven by physical interaction forces for which van der Waals interactions were responsible, while the high temperature is detrimental to the occurrence of high adsorption capacity.

Statistical and physical interpretation of dye adsorption onto low-cost biomass by using simulation methods

In this work, statistical physics approach has been developed to investigate the adsorption of Basic Blue 3G dye onto low-cost biomass (coffee residues). Thermodynamic, energetic, and stereographic parameters controlling the dye adsorption were theoretically determined. Five models have been suggested as monolayers, double layers and three layers. Additionally, steric and energetic factors related to the adsorption process, such as the number of adsorbed molecules per site (n1, n2, n3), the receptor sites density (N1m, N2m, N3m), and the concentration at half-saturation have been taken into account. Thermodynamic potential functions such as internal energy Eint, entropy S and Gibbs free energy G have been analyzed and the selection of the models is coherently based on assumptions in good correlation with experimental conditions/findings. All the investigated parameters were deduced by using an adequate numerical fitting method. A detailed exploration of adsorption isotherms at microscopic scale was presented. The steric study explained the increase of the amount adsorbed at saturation as function of temperature. The discussion about energies showed that the adsorption was physical and exothermic, where the interactions are mainly of Debye and London type. The entropy quantification clearly demonstrated that the disorder increased before half-saturation and decreased after half-saturation, while the findings of free enthalpy and internal energy confirmed exothermicity and spontaneity.

Efficient Cr(VI) and phosphate removal from contaminated water using MnTiFeO nanoflakes: Statistical modeling and interpretation

MnTiFeO nanoflakes (NF) have been prepared and used to remove Cr(VI) and phosphate from an aqueous solution. The optimum potentials for adsorption of Cr(VI) and phosphate occur at acidic pH and are primarily due to ionic interactions. Langmuir monolayer adsorption is observed. The active sites of NF show some selectivity for Cr(VI) due to various putative interaction modes. The adsorption of Cr(VI) and phosphate are dominated by a multi-docking process, as implied by steric parameters in applied advanced statistical models. The observed selectivity of NF is primarily due to a higher receptor site density for Cr(VI) ions than for phosphate anions. Statistical modeling yields the best fitting of the experimental data for a double-layer in the binary system. MnTiFeO NF can be regarded an effective, competitive, and low-cost adsorbent for the removal of hexavalent Cr and phosphate. The maximum adsorption capacities of MnTiFeO NF for Cr(VI) and phosphate adsorption were evaluated as 166.66 and 163.93 mg/g, respectively.

New insights into glyphosate adsorption on modified carbon nanotubes via green synthesis: Statistical physical modeling and steric and energetic interpretations

• 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.

Statistical modeling and interpretation of Sono-assisted adsorption mechanism of Crystal Violet dye on FeTiPbO Nanocomposite

In this study, Crystal Violet (CV) adsorption isotherm on FeTiPbONC was simulated and interpreted using the conventional methods as well as statistical physics two energies double layer model. This model was formalized based on the statistical physics. The following parameters are added in this pattern: steric and energy-sensitive parameters relevant to the adsorption mechanism. The findings of the mathematical model at temperatures 298, 308 , and 318 K givethe values of receptor site density (Nm) as 355.85, 50.91 and 26.815 mg/g, which reveals that maximum adsorption was achieved at lower temperature. The adsorption energies ε1 (from 16.95 to 30.39 kJ/mol) and ε2 (from 7.98 to 13.02 kJ/mol) increases as temperature rises, showing that the CV-FeTiPbONC contact is stronger than the CV-CV interaction. The results showed that FeTiPbONC might be employed as a nanoadsorbent for the removal of organic contaminants from an aqueous matrix.