•Obtaining thermodynamically consistent adsorption isotherms using PCP-SAFT DFT.•Predicting excess isotherms with a minimum number of representative pores.•The adsorbed region of the DFT density ...profiles is discriminated from the free fluid.•The DFT was directly coupled with the algorithm for obtaining the PSD.
Gravimetric measurements are often used to generate excess adsorption isotherms. However, adsorbed density and volume should be known to transform excess isotherms into absolute ones by considering buoyance effects. Depending on the strategy used, the results may present artifacts, especially at high pressures. A Density Functional Theory (DFT) augmented with the PCP-SAFT equation of state is applied to describe the experimental data of excess and absolute adsorption isotherms of CH4 and CO2 fluids on activated carbon slit pores. The representative pore size distribution (PSD) adequately predicted the excess adsorption isotherms at different temperatures. The absolute adsorption isotherms obtained using our approach are compared with the classic approaches as the triple point density of the liquid and the Ozawa expression (and extrapolated to the high-pressure regions). The classical methodologies underestimate the amount adsorbed while the proposed methodology provides thermodynamically consistent results even when condensation of CO2 occurs in the bulk phase.
Over the past few decades, the classical density functional theory (cDFT) models have gained importance in modeling inhomogeneous fluids. Notably, adsorption databases produced by non-local DFT ...(NLDFT), quenched solid DFT (QSDFT) and 2D-NLDFT approaches are used in different characterization methodologies to recover the pore size distribution (PSD) for a various nanoporous materials. This family of models has a much lower computational cost when compared to molecular simulation. However, it lacks formulations that use DFT for multidimensional-multicomponent systems with heterogeneous solids. In addition to the complexity of representing the interactions between confined molecules and their confined mixtures, it is challenging to represent surface heterogeneities. Here we study materials with equivalent external potential but presenting energy heterogeneities varying throughout the material using a multidimensional classical DFT approach consistent with the SAFT equation of state. For this purpose, we applied three external potentials to model three types of slit-like cavities. Among them, a classical slit-like pore was generated, in which the energy sites did not vary along with the material. In the other two cavities, the energy sites could vary along the cavity, simulating a cavity in which the external potential varies bidimensionally. Finally, we evaluate the effect of the energy heterogeneity of these cavities on the adsorption of Ar and Kr and their mixing. The results show that local heterogeneities can alter the shape of isotherm curves and adsorption selectivities. Solids with heterogeneity showed higher selectivity but lower capacity.
The density functional theory (DFT) has been applied to describe confined fluids with great success in the literature. However, the usual numerical methods to solve the Euler–Lagrange equations of ...the grand potential functional are inefficient, finding local minimum and making the convergence very costly for systems with high complexity. Therefore, we present new numerical methods to accelerate the search of equilibrium density distributions of confined fluids, making it possible to find the DFT solutions directly, even when the system is inside the hysteresis region (more than one local minimum) of a sorption isotherm. Here, we use the PC-SAFT-DFT to describe the confinement of simple molecules, molecules with chain effects, and mixtures. We show that the present methodology is convenient to describe the phase diagrams of confined fluids.
Density functional theory (DFT) models appear as tools for modeling the phenomenon of adsorption in nano-confinement environments. The challenges of DFT approaches are to take the acuity observed in ...molecular simulation with a notably lower computational cost. Therefore, the model has the advantage to take into account different contributions, which can become necessary depending on the system to be studied. Here, we present the PC-SAFT-QSDFT for a better evaluation of confined fluids properties in a wide pressure range, aiming its application in the analysis of the phase transitions, hysteresis loops, and isosteric enthalpy of adsorption. Accordingly, we tested the model in a system formed by mono-segmented species, and after in systems composed by multi-segmented substances. The results obtained for the latter show that the model adequately represents experimental data. The evaluation of the isosteric enthalpy of adsorption shows consistent results.
Considering the characterization of the pore size distribution, for mesoporous and microporous materials, the recommendation of IUPAC is the deconvolution of the integral adsorption equation, using a ...kernel calculated with the Non-Local Density Function Theory (NLDFT). However, we observed in the literature a lack of systematic studies about the impacts that experimental uncertainty has on the determination of the pore size distribution (PSD). Thus, in this paper, we study the influence of errors related to experimental gaseous adsorption data on the solid characterization, showing the importance of the statistical analysis on the PSD of two idealized materials. The result suggests that this methodology has a strong dependence on the experimental uncertainty of the data used, i.e. the fit of adsorption isotherm is not a self-sufficient hypothesis to reconstruct the pore size distribution.
Hydrotreating stands as a critical facet in oil refining to meet stringent environmental norms, facilitating the production of ultra-low sulfur fuels. This study delves into the concurrent ...hydrodesulfurization of DBT and 4,6-DMDBT utilizing a NiMoP/Al2O3 catalyst. Through 27 experiments, parameters such as temperature, pressure, concentrations, and WHSV were scrutinized to derive kinetic insights. Employing five power law (PL) models, encompassing both global and individual HDS variations, parameter estimation employed weighted least squares optimization techniques like particle swarm and Gauss-Newton methods. Rigorous statistical analyses underlined model performance nuances. While the ‘global HDS of 4,6-DMDBT’ model met the chi-squared test, the ‘global HDS of DBT’ revealed complexities beyond PL modeling. Notably, the negative hydrogenation order for DBT implied significant adsorption effects. Apparent activation energies, approximately 117 kJ mol−1 for DBT and 124 kJ mol−1 for 4,6-DMDBT, were discerned using global models.
•Deep hydrodesulfurization of DBT and 4,6-DMDBT was evaluated in fixed-bed reactor.•Estimation and statistical evaluation of kinetic parameters were performed.•A power-law model considering individual DBT routes fits the experimental data well.•The reparameterization technique and Arrhenius equation optimization reduced parametric correlation.
In recent years, major improvements in breast cancer treatments have led to a significant increase in survival. Despite that, this population's quality of life (QoL) information is lacking, ...especially real-world data.
This was a prospective, multicentre, observational study of female breast cancer patients, without prior systemic treatment, treated between 2012 and 2019 in private health care in Brazil. QoL was assessed by two questionnaires, the EQ-5D-5L and the EORTC-QLQ-BR23. Additional data were retrospectively collected.
The study comprised 1372 patients, most with early-stage disease (80.2% stages 0–II). At a median follow-up of 25.6 months, the estimated 3-year overall survival was 93.6%. Patients with locally advanced and metastatic breast cancer had the lowest visual analogue scale scores and the highest symptom burden in all dimensions of EQ-5D-5L, but with the most significant improvement after treatment. With the EORTC-QLQ-BR23 questionnaire, patients undergoing lumpectomy had a better perception of body image. Axillary dissection led to greater arm symptoms after 12 months, radiotherapy enhanced breast symptoms and patients treated with chemotherapy had significant worsening in the effects of systemic therapy compared with endocrine or HER2 therapy. Staging and immunohistochemical subtype correlated with survival and with several QoL parameters, but overall survival was not independently affected by patient-reported outcomes in this cohort.
Our results show that early diagnosis and access to treatments with fewer side-effects, such as endocrine or targeted therapy, and less aggressive surgeries are the best strategies to achieve a better QoL for breast cancer patients.
•Real-world patient-reported outcomes are promising tools for patient-centered care.•Advanced breast cancer leads to high symptom burden and worse perception of health.•Patients undergoing lumpectomy had a better perception of body image.•Adding radiation therapy to surgery increases symptoms in the breast.•Chemotherapy is the systemic treatment that most reduces quality of life.
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