Article
Chemistry, Multidisciplinary
Yunhao Sun, Zhengxing Dai, Gulou Shen, Xiaohua Lu, Xiang Ling, Xiaoyan Ji
Summary: This study improves the efficiency of the ePC-SAFT-DFT calculation for confined systems by combining the Chebyshev pseudo-spectral collocation method with the Anderson mixing algorithm. The study systematically investigates the effects of temperature, pressure, pore size, and pore shape on CO2 solubilities in silica-nanopore-confined ionic liquids (ILs). The results suggest that using silica material with narrow spherical pores and selecting IL-anions that have a significant impact on absorption enhancement can achieve high CO2 solubilities.
FRONTIERS IN CHEMISTRY
(2022)
Article
Chemistry, Physical
Orest Pizio, Stefan Sokolowski
Summary: The wetting phase diagrams for model systems consisting of water and chemically modified graphite surfaces with grafted chain molecules were explored using the density functional approach. The topology of the phase diagram was found to depend on the amount and length of grafted chains.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Thermodynamics
Yuanjing Mao, Zhi Yang, Hao Guo, Ying Chen, Songping Mo, Xianglong Luo, Jianyong Chen, Yingzong Liang
Summary: In this study, the performance of four typical SAFT-type EoSs in predicting thermodynamic properties of fluids was evaluated. SAFT-VR Mie had the best accuracy in predicting vapor-liquid equilibria, while PC-SAFT showed satisfactory predictions for enthalpy of vaporization of alkanes. However, the description of liquid-phase derivatives was inaccurate. To improve the accuracy for associating fluids, a reasonable association scheme or incorporation of experimental data was suggested. SAFT-VR Mie also outperformed other models in predicting isobaric heat capacity, which could be further improved by optimizing universal constants or using higher-order perturbations.
INTERNATIONAL JOURNAL OF THERMOPHYSICS
(2023)
Article
Physics, Fluids & Plasmas
I. Ibagon, A. P. Furlan, T. J. Oliveira, R. Dickman
Summary: This study investigates the associating lattice gas (ALG) model introduced by Henriques et al., showing consistent results using transfer matrix calculations and Monte Carlo simulations. The critical point at the DF-HDL transition is found to be one end of a critical line separating phases, and the transition between DF and LDL phases is determined to be discontinuous, in contrast to previous simulation studies. The phase diagram observed in the simulations closely resembles that from the exact solution on a Husimi lattice, indicating limitations in reproducing key features of liquid water behavior.
Article
Engineering, Chemical
V. M. Sermoud, G. D. Barbosa, E. do A. Soares, L. H. de Oliveira, M. Pereira, P. A. Arroyo, A. G. Barreto Jr, F. W. Tavares
Summary: Gravimetric measurements are commonly used to study excess adsorption isotherms, but knowledge of adsorbed density and volume is necessary for transforming excess isotherms into absolute ones. The study applied Density Functional Theory (DFT) with the PCP-SAFT equation of state to describe the experimental data of CH4 and CO2 fluids on activated carbon slit pores. The proposed methodology provided thermodynamically consistent results, even in cases where CO2 condensation occurred in the bulk phase, which classical methodologies underestimated.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Chemistry, Physical
Orest Pizio, Stefan Sokolowski
Summary: In this study, the wetting of graphite-like substrates by water was investigated using a density functional approach. The theoretical results accurately described the wetting temperature and contact angle changes with temperature and fluid-substrate attraction, and were compared with experimental and simulation data. The study provides tools for easier investigation of the behavior of other associating fluids on solids of importance in chemical engineering.
Article
Chemistry, Physical
Debadutta Prusty, Alejandro Gallegos, Jianzhong Wu
Summary: The interfacial behavior of associating species is crucial for both fundamental physics and industrial applications. This study investigates the adsorption behavior of a mixture of nanoparticles and polymer chains, representing asphaltene and resin molecules, onto an attractive surface. The results provide insights into the effects of various characteristics of these molecules on the adsorption amount and reveal the interplay between different driving forces.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Engineering, Chemical
Ismail I. I. Alkhatib, Lourdes F. Vega
Summary: The study examines the phase equilibria and excess properties of binary mixtures of n-alkanes with various fluids, modeling them using polar soft-statistical associating fluid theory. The theory accurately predicts behavior of mixtures involving low to moderate dipolar molecules, implicitly considering the effects of very strong dipolar fluids by fixed polar parameters of pure components. The study systematically investigates the impact of asymmetric energy scales between polar and nonpolar fluids on vapor-liquid equilibria and excess properties.
Article
Physics, Fluids & Plasmas
Philipp Rehner, Thijs van Westen, Joachim Gross
Summary: In this study, a Helmholtz energy functional for systems consisting of hard heterosegmented chains is developed using hard-sphere fragments as monomers. The resulting equation of state can be used as a reference for developing statistical associating fluid theory models that accurately describe the thermodynamic properties of nonspherical molecules.
Article
Thermodynamics
Elvis do A. Soares, Amaro G. Barreto Jr, Frederico W. Tavares
Summary: A self-consistent thermodynamic perturbation theory for excess Helmholtz free-energy in hard-core fluids is proposed, showing that the modified mean-field theory is a better option. This study offers a new approach to describe the thermodynamic and structural properties of hard-core fluids.
FLUID PHASE EQUILIBRIA
(2021)
Article
Materials Science, Biomaterials
Xinxin Li, Youzhi Wang, Yiming Zhang, Zhimou Yang, Jie Gao, Yang Shi
Summary: Enzyme-instructed self-assembly (EISA) strategy has important advantages in the preparation of supramolecular self-assembly materials for biomedical applications, facilitating the self-assembly and hydrogelation of hydrophobic and bioactive peptides. By designing phosphorylated precursors, supramolecular hydrogels can be formed through dephosphorylation by alkaline phosphatase (ALP). Furthermore, EISA can also occur on the surface of cells that overexpress ALP.
JOURNAL OF MATERIALS CHEMISTRY B
(2022)
Article
Energy & Fuels
Tianqi Liu, Ge Li, Nannan Shen, Marten S. G. Ahlquist, Licheng Sun
Summary: The study synthesized four catalysts with different hydrophobicities and found that hydrophobic complexes showed better water oxidation performance. The research indicates that the increase in activity is correlated with hydrophobicity.
Article
Chemistry, Multidisciplinary
Xiangyu Li, Ye Tian, Panpan Zhang, Na Liu, Huajun Zhai, Jiujiang Ji, Shuaiheng Zhao, Yue Liu, Dake Xu, Fuhui Wang, Yen Wei, Lin Feng
Summary: A bio-inspired lotus-petiole-mimetic microstructured graphene/poly(N-acryloyl glycinamide) solar evaporator is developed, achieving high evaporation rates and energy conversion efficiency using accurate control of supramolecular interactions. Molecular dynamics simulations provide insights into water evaporation behaviors, and the evaporator shows excellent performance in purifying complex contaminants in wastewater.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Engineering, Chemical
John Towne, Xiaodong Liang, Georgios M. Kontogeorgis
Summary: Thermodynamic models that take association into account are important for predicting multiphase equilibria. By considering the relationship between chemical and perturbation theories, this study proposes a method for estimating association parameters using quantum chemistry calculations and statistical mechanics. The estimated parameters can be used to reduce the number of adjustable model parameters for equations of state.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Engineering, Chemical
Ilias K. Nikolaidis, Romain Privat, Jean-Noel Jaubert, Ioannis G. Economou
Summary: The perturbed chain-statistical associating fluid theory (PC-SAFT) equation of state (EoS) is applied and evaluated using a thermodynamic database, including 200 non-electrolytic binary systems. The assessment is based on various properties, and deviations between model predictions and experimental data are calculated using a proposed methodology.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Engineering, Chemical
Amin Haghmoradi, Deepti Ballal, Wael A. Fouad, Le Wang, Walter G. Chapman
Summary: This contribution extends the SAFT model and perturbation theory to accurately model species with a combination of monovalent and divalent association sites, particularly for simulating water. The theory predictions are verified with Monte Carlo simulation results and show good agreement with experimental data.
Article
Energy & Fuels
Yash Khemka, Mohammed I. L. Abutaqiya, Caleb J. Sisco, Walter G. Chapman, Francisco M. Vargas
Summary: The study uses different methods to model the viscosity of light crude oils, finding that SARA-based methods predict viscosity with higher accuracy than the SCN method. Despite using the simpler PR EoS with SARA method, viscosity predictions are as good as those obtained using the advanced PC-SAFT EoS.
Article
Chemistry, Physical
Shun Xi, Yiwei Zhu, Jinxin Lu, Walter G. Chapman
Summary: This paper examines the self-assembly behavior of block copolymer melts and solutions with two-dimensional density inhomogeneity using modified inhomogeneous statistical associating fluid theory (iSAFT). It proposes a real-space combinatorial screening method to map out phase diagrams and studies the effects of compressibility, solvent selectivity, and block copolymer molecular architecture on self-assembly behavior.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Editorial Material
Chemistry, Physical
Arjun Valiya Parambathu, Thiago J. Pinheiro dos Santos, Walter G. Chapman, Dilipkumar N. Asthagiri
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Engineering, Chemical
Mohammed M. Alajmi, Caleb J. Sisco, Mohammed I. L. Abutaqiya, Francisco M. Vargas, Walter G. Chapman
Summary: The cubic-plus-chain (CPC) equation of state combines the classical cubic equation of state with the chain term from statistical associating fluid theory, allowing it to model both short-chain and long-chain compounds. The model can be modified and has been successfully used to simulate the phase equilibria of various mixtures.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Engineering, Chemical
Ahsan Kamil, Wael A. Fouad, Sumnesh K. Gupta, Walter G. Chapman
Summary: In this study, the Polar PC-SAFT and UNIQUAC models were used to model the VLE and excess properties of solvating mixtures. While UNIQUAC struggled in capturing the highly nonlinear function of activity coefficient curves, Polar PC-SAFT successfully predicted the distribution of hydrogen bonds and excess properties in the systems studied.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Engineering, Chemical
Carl T. Lira, J. Richard Elliott, Sumnesh Gupta, Walter G. Chapman
Summary: Association and complex formation are important factors in nonidealities of phase equilibrium modeling. Models based on Wertheim's association theory offer advantages and can overcome limitations of current models. Infinite dilution activity coefficients provide insights into liquid phase nonidealities. A systematic procedure is needed to characterize association parameters for broader implementation of these models.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Editorial Material
Engineering, Chemical
Sumnesh Gupta, J. Richard Elliott, Andrejs Anderko, Jacob Crosthwaite, Walter G. Chapman
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Engineering, Chemical
Walter G. Chapman, Wael A. Fouad
Summary: This paper presents a general relationship for the excess chemical potential to develop activity coefficient models from free energy perturbation theory. The Flory-Huggins theory is explained and the accuracy of the approach when there is a volume change on mixing is discussed. The result has implications in coarse-graining strategies for mesoscale modeling. Corrections for molecular size and shape, multiple association sites, multiple polar functional groups, and polarizability are also presented. The activity coefficient model is applicable to mixtures containing polar, polarizable, and associating components, and has several advantages such as known accuracy and smooth transition to the fugacity coefficient approach when necessary.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Engineering, Chemical
Jinxin Lu, Andres Gonzalez de Castilla, Simon Mueller, Shun Xi, Walter G. Chapman
Summary: Alcohols are commonly used additives in surfactant self-assembling systems and their effect on these systems is complex. They can act as cosolvents by altering solvent properties and as cosurfactants by coaggregating with surfactants. Two molecular theories, iSAFT and COSMOplex, can accurately predict the effect of different alcohols on micellar structure and critical micelle concentration.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Physical
Rohan S. Adhikari, Arjun Valiya Parambathu, Walter G. Chapman, Dilipkumar N. Asthagiri
Summary: Calculating the hydration free energy of macromolecules has always been a challenge, but with the development of molecular quasi-chemical theory (QCT), it is now possible to calculate it within all-atom simulations. This study compares the results obtained using QCT with predictions from implicit solvent models and reveals the importance of cooperativity in hydration. The deviations between implicit and explicit solvent results highlight the limitations of additive models.
JOURNAL OF PHYSICAL CHEMISTRY B
(2022)
Article
Chemistry, Physical
Arjun Valiya Parambathu, Walter G. Chapman, George J. Hirasaki, Dilipkumar Asthagiri, Philip M. Singer
Summary: In this study, atomistic MD simulations were used to investigate the effects of nanoconfinement on the 1H NMR relaxation times T1 and T2 of heptane in kerogen. The results show that confinement plays an important role in reducing T1 by -3 orders of magnitude, in agreement with experimental measurements. For T2, confinement breaks spatial isotropy and gives rise to residual dipolar coupling, leading to a -5 orders of magnitude reduction compared to bulk heptane. Using the simulated T2, the surface relaxivity was calibrated to predict the pore-size distribution of organic nanopores in kerogen without additional experimental data.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Review
Engineering, Chemical
Sumnesh Gupta, J. Richard Elliott, Andrzej Anderko, Jacob Crosthwaite, Walter G. Chapman, Carl T. Lira
Summary: This paper reviews and updates the status of thermophysical property needs in the chemical industry, with reference to similar observations made 20 years ago. It draws on a series of symposia held in conjunction with the American Institute of Chemical Engineers (AIChE) national meetings and incorporates the authors' experiences and references from a recent special issue of Ind. Eng. Chem. Res. It discusses the trend towards more rigorous molecular methods and the continued use of empirical methods through sophisticated correlations. The paper also highlights gaps in experimental data, the need for estimation methods and model validation, and the identification of new needs in estimation, modeling, and measurements.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Chemistry, Physical
Arjun Valiya Parambathu, Walter G. Chapman, George J. Hirasaki, Dilipkumar Asthagiri, Philip M. Singer
Summary: This study investigates the effects of nanoconfinement on the 1H NMR relaxation times (T1 and T2) of heptane in kerogen using atomistic MD simulations. The results show that confinement plays an important role in reducing T1 by three orders of magnitude, in agreement with experimental measurements of heptane dissolved in kerogen. In addition, confinement breaks spatial isotropy and gives rise to residual dipolar coupling, leading to a five orders of magnitude reduction in T2. The simulated T2 is used to calibrate the surface relaxivity and predict the pore-size distribution of the organic nanopores in kerogen.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Thiago J. Pinheiro J. dos Santos, Arjun Valiya Parambathu, Carla C. Fraenza, Casey Walsh, Steve G. Greenbaum, Walter G. Chapman, Dilip Asthagiri, Philip M. Singer
Summary: In this study, the effects of temperature and concentration on r(1) of the Gd3+-aqua complex were investigated using molecular dynamics simulations and measurements. By expanding the autocorrelation function and determining the thermal activation energies, new insights into the molecular-scale physics of r(1) were revealed.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)