Modeling and Thermodynamic Study of Water Vapor Desorption Isotherms of Orange Peel and Leaves using Statistical Physics Treatment

The shelf life and safety of food products is related to the water content, in particular to the water activity (aw). This is important to predict the physical, chemical and biological processes that take place during food storage. Analytical expression for modeling water desorption isotherms of food is developed using the grand canonical ensemble in statistical physics. The model is further applied to fit and interpret the desorption isotherms of water vapor on the orange peel and leaves at three different temperatures. In the developed model we introduce essentially six parameters such as the number of adsorbed water molecules per site, the number of adsorbed layers, the energy of desorption and receptor sites density. We interpret the results of fitting then we apply the model to calculate thermodynamic functions which govern the desorption mechanism such as internal energy and entropy

Water vapor molecule adsorption onto 'Ajwa' dates: Analytical investigation via infinite multilayer statistical physics model

A gravimetric technique was used to examine the water activity onto the ‘Ajwa’ dates. The equilibrium adsorption isotherms of water molecules were carried out at three temperatures (between 303 K and 323 K). A theoretical method was developed using statistical physics treatment to describe the experimental data at the ionic scale. The date’s isotherms were analyzed via the infinite multilayer adsorption model (formation of a high number of adsorbed layers) which is established based on the ideal gas law (there are no lateral interactions influences on the adsorption mechanism). The chosen model gave significant interpretation of the adsorption of water on the Ajwa dates based on the physicochemical model’s parameters (the density of binding sites (Dm), the number of water molecules per site (n) and the energetic parameters (a1) and (a2)). The physicochemical interpretation of the appropriate model indicated that the adsorption of water on the Ajwa dates occurred via a multi-anchorage process since the n values are lower than 1 for the three tested temperatures. The Ajwa dates adsorption was found typical to an exothermic process by the intermediate of the steric parameter Dm (Dm (303 K) = 0.58 kg/kg˃ Dm (323 K) = 0.33 kg/kg). Moreover, the energies values |−ε1| and |−ε2|, which varied from 27.8 KJ/mol to 51.2 KJ/mol, confirmed that the ‘Ajwa’ dates adsorption was a chemical process presenting covalent bonds between the water molecules and the dates’ sites

Evaluation and analysis of the adsorption mechanism of three emerging pharmaceutical pollutants on a phosphorised carbon-based adsorbent: Application of advanced analytical models to overcome the limitation of classical models

The double layer adsorption of sulfamethoxazole, ketoprofen and carbamazepine on a phosphorus carbon-based adsorbent was analyzed using statistical physics models. The objective of this research was to provide a physicochemical analysis of the adsorption mechanism of these organic compounds via the calculation of both steric and energetic parameters. Results showed that the adsorption mechanism of these pharmaceuticals was multimolecular where the presence of molecular aggregates (mainly dimers) could be expected in the aqueous solution. This adsorbent showed adsorption capacities at saturation from 15 to 36 mg/g for tested pharmaceutical molecules. The ketoprofen adsorption was exothermic, while the adsorption of sulfamethoxazole and carbamazepine was endothermic. The adsorption mechanism of these molecules involved physical interaction forces with interaction energies from 5.95 to 19.66 kJ/mol. These results contribute with insights on the adsorption mechanisms of pharmaceutical pollutants. The identification of molecular aggregates, the calculation of maximum adsorption capacities and the characterization of thermodynamic behavior provide crucial information for the understanding of these adsorption systems and to optimize their removal operating conditions. These findings have direct implications for wastewater treatment and environmental remediation associated with pharmaceutical pollution where advanced adsorption technologies are required

Effective adsorption of metals on porphyrins: Experiments and advanced isotherms modeling

In this article, the investigation of the adsorption process of six metal compounds (aluminum chloride, aluminum sulfate, iron chloride, iron sulfate, indium chloride and indium sulfate) on the promising macromolecule named porphyrin was performed to prove new insights about the metals-porphyrin complexes. The experimental adsorption data of the six complexation systems were controlled at four reaction temperatures using the well-known microbalance apparatus (QCM). In fact, the experimental outcomes and the physical modeling treatment indicated that the complexation process of aluminium and iron should be analyzed via the mono-layer adsorption model whereas; the interaction between the two indium compounds and the porphyrin was described via the double-layer model. Actually, the physicochemical description showed that the three metals were adsorbed via a multi-docking mechanism. The fitted values of the paramount parameter density of the adsorbent sites showed the endothermic character of the studied processes. Thus, some porphyrin sites were activated only at high temperature. The down trend of the iron isotherms was explained through the van der Waals parameters which describe the lateral interactions influences. The calculation of the adsorption energies which describe the interactions between the adsorbates and the adsorbent showed that chemical bonds were carried out between the aluminum and the porphyrin. The thermodynamic study, through the two thermodynamic functions (the configurational entropy and the free enthalpy), showed that the disorder of the six processes is maximum at the level of the energetic parameters and that the six complexation mechanisms advanced spontaneously towards saturation. For the iron, the behavior of the enthalpy indicated that the lateral interactions between the adsorbates disfavored the adsorption of iron chloride and iron sulfate at high concentration. The double-layer process of the indium was confirmed by the trends of the free enthalpies which showed two stability states for the two indium compounds

Statistical Physics Modeling of Sorption Isotherms of Aluminum, Iron, and Indium on Tetraphenylporphyrin (H2TPP) and Tetrakis(4-tolylphenyl)porphyrin (H2TTPP): Phenomenological Investigation of Metalloporphyrins at the Molecular Level

A quartz crystal adsorbent functionalized with two promising porphyrins (the 5,10,15,20-tetrakis(4-tolylphenyl)porphyrin and the 5,10,15,20-tetraphenylporphyrin) was applied for the investigation of the adsorption phenomenon of aluminum chloride, iron chloride, and indium chloride. The aim is to prove new insights about the appropriate adsorption materials for metalloporphyrin fabrication. The equilibrium isotherms were measured at five adsorption temperatures (from 290 to 330 K) through the microbalance (QCM) method. The discussion of the experimental observations indicated that the adsorption of the aluminum chloride and the iron chloride was performed via a monolayer process. On contrary, the participation of the chloride ions in the double-layer adsorption of the indium chloride was explained by the layer-by-layer process. Overall, the statistical physics modeling of the experimental curves indicated that the number of ions per adsorbent site n was found inferior to 1 for all the adsorption systems (multi-interaction process for the three ions). Interestingly, the physicochemical investigation of the three adopted models showed that the complexation mechanism of the tested porphyrins was an endothermic process since the two steric parameters (n and PM) increased with the rise of the temperature. The FeCl3 curves were discussed via a monolayer adsorption model which includes the parameters a and b (lateral interaction description), indicating the lowest stability of the formed iron-porphyrin complex. The energetic study showed that the adsorption energies ∣−ΔE1/2∣ of AlCl3 on H2TTPP and H2TPP are superior to 40 kJ/mol (chemical adsorption mechanism), whereas the adsorption mechanisms of FeCl3 and InCl3 took place via a physical process since they presented adsorption energy values lower than 40 kJ/mol

Selective Extraction and Determination of Hydrocortisone and Dexamethasone in Skincare Cosmetics: Analytical Interpretation Using Statistical Physics Formalism

Molecularly imprinted polymers (MIPs), as magnetic extraction adsorbents, are used for the selective, rapid determination and extraction of dexamethasone and hydrocortisone in skincare products. Therefore, in this paper, magnetic molecularly imprinted polymers (MMIPs) and magnetic non-molecularly imprinted polymers (MNIPs) were utilized as adsorbents to describe the adsorption phenomena of dexamethasone and hydrocortisone. This interpretation, based on a statistical physics theory, applies the multilayer model with saturation to comprehend the adsorption of the drugs. Results obtained via numerical simulation revealed that dexamethasone and hydrocortisone adsorption happens via a non-parallel orientation on the surfaces of MMIPs and MNIPs, and they also showed that the adsorption amount of the MMIPs for the template molecule was notably greater than that of the MNIPs at the same initial concentration. The adsorption energy values retrieved from the data analysis ranged between 7.65 and 15.77 kJ/mol, indicating that the extraction and determination of dexamethasone and hydrocortisone is a physisorption process. Moreover, the distribution of a site’s energy was calculated to confirm the physical nature of the interactions between adsorbate/adsorbent and the heterogeneity of the surfaces of the MMIPs and MNIPs. Finally, the thermodynamic interpretation confirmed the exothermicity and spontaneous nature of the adsorption of these drugs on the tested adsorbents

Application of physical statistical modeling in the adsorption of the drug ketoprofen and the 2,4-d herbicide using the bark campomanesia guazumifolia forest species modified with H2SO4 as an adsorbent

Emerging pollutants are a widespread environmental concern, andadsorption represents one of the choices available for the removal of suchcompounds from polluted waters. However, the set-up of a new adsorption system requiresthe experimental determination of adsorption isotherms and their thoroughmodelling, for the sake of a convenient optimization. In this work, the Campomanesia guazumifolia biomass is adopted as precursor for the synthesis of anew adsorbent and then tested for the adsorption of KTP and 2,4-D. Theadsorption performances of this biomass are significantly improved through atreatment with sulfuric acid, which allows obtaining higher removal efficiency ofthe target organic molecules. The experimental isotherms are measured at 298 – 328 K and pH 2. An ETAM model is employed for amodeling analysis of the experimental data, for the comprehension of theoccurring adsorption mechanism. Results demonstrated that adsorption of KTP isendothermic and occurs in multilayer with a multimolecular process, in whichthe molecular aggregation can be predicted. On the contrary, the adsorption of 2,4-D on this functionalized biomass is exothermic. The adsorption energiesresulted to be < 40 kJ mol−1, indicating that physical adsorption forces are involved inthe removal of these organic molecules

Adsorption of CO₂ on ZSM-5 Zeolite: Analytical Investigation via a Multilayer Statistical Physics Model

In this paper, a synthesized zeolite (ZSM-5) is used as an adsorbent to analyze the adsorption phenomenon of carbon dioxide. This investigation, based on the statistical physics treatment, applied the multilayer model with saturation to understand the CO2 adsorption on four samples, namely M-ZSM-5 (M = Na+, Mg2+, Zn2+, La3+), at various temperatures T = 0 °C, 30 °C and 60 °C. The modeling results indicated that CO2 adsorption occurred via a non-parallel orientation on the ZSM-5 surface. The CO2 adsorption capacities varied from 26.14 to 28.65 cm3/g for Na-ZSM-5, from 25.82 to 27.97 cm3/g for Mg-ZSM-5, from 54.82 to 68.63 cm3/g for La-ZSM-5 and from 56.53 to 74.72 cm3/g for Zn-ZSM-5. Thus, Zn-ZSM-5 exhibits the highest adsorption amount. The analysis of the adsorption energies shows that the adsorption of CO2 on ZSM-5 zeolite is a physisorption phenomenon that could be controlled thanks to the energy parameters obtained via the numerical findings using the multilayer statistical model. Finally, the distribution of site energy was determined to confirm the physical character of the interactions between adsorbate/adsorbent and the heterogeneity of the zeolite surface

Enhanced efficiency of flexible organic polymer solar cells by incorporation of titanium dioxide nanoparticles

Solar power has quickly become one of the most effective forms of renewable energy today as it provides a clean solution to the growing demand for energy. Most solar panels in the market are rigid as they are made up of metals; therefore, organic polymers provide a flexible alternative. Nanotechnology provides the synthesis of nanoparticles by simple approaches suitable for applications in various fields. Nanoparticles of titanium dioxide (TiO2) were synthesized and characterized in this paper (NPs), which were further incorporated in the construction of a novel, organic polymer solar panel (OPSC) that is flexible and portable; it is made from thylakoid (chloroplast) extract of chard (B. vulgaris subsp. cicla) combined with polystyrene polymer matrix. Insertion of TiO2 NPs in the OPSC improved the current generation compared to the reference devices (OPSC) without TiO2 NPs. Therefore possible uses for the constructed solar panel were suggested. The prepared films were tested for the current generation. Under illumination, the solar panels generated a current of −140 µAp, and −213 µAp without and within TiO2 NPs, respectively. This study opens windows for manufacturing flexible, efficient, and stable organic polymer solar panels

Techno-economic case study of applying heat recovery and CO2 capture systems on a gas turbine power plant; 4E analysis

Produced CO2 from fossil fuel-based transportation vehicles and energy systems can have a direct impact on people who live in adjacent of the power plants. So, in the present work, we proposed and modeled an integrated system comprising a gas engine, a carbon dioxide capturing unit, an absorption chiller, and a greenhouse. The greenhouse uses directly the CO2 produced in gas engine through the carbon dioxide capturing unit to mitigate the emitted CO2 into the atmosphere. Besides that, the produced heating in gas engine could be exerted in a cycle to render the greenhouse space in cold weather condition. In warm seasons this thermal energy could also be delivered to an absorption chiller for producing required cooling for inside space of the greenhouse. Herein, the generated electricity is sold to grid, and an economic analysis is brought about. To evaluate and estimate the system performance and interest of selling electricity, a mathematical function was applied. The results show that, during cold seasons, the maximum possible net interest is 800,000 $, and for warm seasons is 2,500,000$. The maximum COP is also achieved by 1.007. Finally, the amount of CO2 emission rate is mitigated at least 50%