Article
Chemistry, Applied
Nicoleta G. Apostol, Marius A. Husanu, Daniel Lizzit, Ioana A. Hristea, Cristina F. Chirila, Lucian Trupina, Cristian M. Teodorescu
Summary: The experiment investigates carbon monoxide adsorption and desorption on gold deposited on ferroelectric lead zirco-titanate, revealing the negative charge state of gold and the formation of gold nanoparticles. The neutral carbon adsorption is closely related to the polarization of the ferroelectric film, while carbon in molecular form is related to its bonding on metal nanoparticles. Desorbed carbon at higher temperature uptakes oxygen from the substrate.
Article
Chemistry, Physical
Frederic C. Meunier, Xianwei Wang, Thomas Buergi
Summary: The presence of negatively charged gold species on Au surfaces or supported Au nanoparticles has been widely reported based on the appearance of IR bands of adsorbed CO below 2090 cm-1. However, some researchers have suggested that these bands may be solely attributed to the presence of Ni-CO species contaminating the sample surfaces. In this study, CO adsorption was monitored using a CO supply, DRIFTS reaction cell, and lines that excluded nickel contamination. The results show that a band at 2067 cm-1 appeared without the involvement of Ni carbonyls, supporting the idea of CO adsorption on negatively charged Au surfaces. © 2023 Elsevier Inc. All rights reserved.
JOURNAL OF CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Shuai Zhang, Leilei Yin, Siyuan Wang, Jin-Cheng Liu, Yabin Zhang, Yongqing Wen, Qian Zhang, Yaping Du
Summary: In this study, ternary Pt3-xIrxSc nanoparticles were synthesized using a solid-phase synthesis strategy, and their excellent catalytic activity and stability in the hydrogen evolution reaction were demonstrated. This work provides a new approach for the design and synthesis of RE nanoalloys.
Article
Thermodynamics
Hussein Rasool Abid, Stefan Iglauer, Ahmed Al-Yaseri, Alireza Keshavarz
Summary: The study investigates the CO2 adsorption performance of coal after modification with methyl orange (MO), showing that MO-modified coal has higher CO2 adsorption capacity, which contributes to improving CO2 storage methods and mitigating the impact of climate change.
Article
Chemistry, Physical
Jason Tam, Peter M. Brodersen, Hiromichi Ohta, Uwe Erb
Summary: Rare earth oxide (REO) ceramics have potential as robust hydrophobic materials, but the origin of their hydrophobicity remains unclear. Two competing mechanisms suggest that airborne hydrocarbons adsorb on the surface or vacuum treatment is required for hydrophobic behavior. In this study, CeO2 epitaxial films were used to investigate the surface chemistry changes under ultra-high vacuum conditions. Accumulation of carbon and fluorine on the surface suggests caution in interpreting wettability data of REOs stored in vacuum.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2023)
Article
Chemistry, Physical
Aoyun Shen, Xinrong Liao, Yongqiang Li
Summary: PEI@cotton was functionalized with polyamine polymer by a facile and eco-friendly method, which showed superior adsorption performance for removing negatively charged organic dye pollutants compared to untreated cotton fiber. The adsorption of dyes by PEI@cotton followed the Langmuir model, and the pseudo-second-order kinetic model described the adsorption data well. The material can be regenerated multiple times without significant loss of performance, making it a promising candidate for rapid and efficient removal of negatively charged dyes from aqueous solutions.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2021)
Article
Chemistry, Multidisciplinary
Qiuxia Fu, Dandan Xie, Jianlong Ge, Wei Zhang, Haoru Shan
Summary: Novel negatively charged composite nanofibrous hydrogel membranes (NHMs) are obtained by a combination of electrospinning and surface coating modification. These NHMs have controllable morphologies and chemical structures, and exhibit high protein adsorption capacity, resistance to acid and solvents, good selectivity, and regenerability. They provide a new chromatography platform for protein purification in biopharmaceuticals and biochemical reagents.
Article
Polymer Science
Laura Fernandez-Pena, Eduardo Guzman, Francisco Ortega, Lionel Bureau, Fabien Leonforte, Dandara Velasco, Ramon G. Rubio, Gustavo S. Luengo
Summary: This study investigates the interaction of polymer mixtures in solution and their adsorption onto negatively charged surfaces. Experimental results suggest that the formation and composition of interpolymer complexes in solution play a crucial role in governing the deposition and tribological properties of adsorbed layers. The use of SCF calculations further confirms the experimental findings, providing insights into the distribution of polymer chains within the adsorbed layers.
Article
Chemistry, Multidisciplinary
Haojie Zhang, Miao Lv, Jianzhong Jiang, Zhenggang Cui, Wenshui Xia, Bernard P. Binks
Summary: By combining with negatively charged particles, bile salts with poor emulsifying ability can be transformed into highly efficient emulsifiers, which can synergistically co-stabilize oil-in-water emulsions at extremely low concentrations and be reversibly switched between stable and unstable triggered by CO2/N-2 at room temperature. This strategy is applicable to emulsions containing different oils and bile salts, offering a generic model for various bile salts with different molecular structures in extending their applications in more technical fields.
Article
Environmental Sciences
Wei Wang, Shiyi Wang, Mohammadtaghi Vakili, Yan Wang, Chang Sun, Haoru Yang, Guotao Xiao, Minjuan Gong, Shuangxi Zhou
Summary: In this study, novel composite materials were prepared by intercalating functional pillars into graphene oxide sheets, leading to improved adsorption behavior. The synthesized materials, GO-PFB and GO-PFBS, showed significantly higher adsorption capacities for sulfadiazine than GO alone, with GO-PFBS being the most effective adsorbent. The adsorption of sulfadiazine onto GO-PFBS decreased with increasing solution pH.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Chemistry, Physical
Jie Zeng, Minjia Yang, Huihui Xiong, Bin Zhang Revision, Zhifeng Nie
Summary: Density functional theory calculations were used to study the adsorption and diffusion of oxygen on different sites of Ta surface, and the effects of rare earth doping on the adsorption and diffusion behavior were investigated. The results show that rare earth doping enhances the adsorption ability and reduces the energy barrier of oxygen diffusion.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Akriti Mishra, Puspendu K. Das
Summary: The interaction between heme protein cytochrome c from equine heart and negatively charged gold nanoparticles was studied using second harmonic light scattering in solution. Noncovalent interactions play a significant role in the adsorption process, with the adsorption primarily driven by enthalpy change. The thickness of the protein layer on the surface, as well as the entropy change, indicates specific patterns in the adsorption process.
CHEMICAL PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Johannes Hunger, Jan Schaefer, Patrick Ober, Takakazu Seki, Yongkang Wang, Leon Praedel, Yuki Nagata, Mischa Bonn, Douwe Jan Bonthuis, Ellen H. G. Backus
Summary: Understanding the collective behavior of ions at charged surfaces is crucial for geological and electrochemical processes. In this study, sum-frequency generation (SFG) spectroscopy was used to investigate the symmetry-breaking of water molecules at a charged silica surface in contact with different alkaline metal chloride solutions. The results demonstrate that the water response varies with the cation, with LiCl showing a significantly enhanced SFG response compared to CsCl. Further analysis indicates that the effect of different salts on the optical response is indirectly mediated by the reorganization of interfacial water.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Engineering, Chemical
Xin Mi, Xiang Li, Chong-Chen Wang, Bo Wang
Summary: In this study, cerium-based UiO-66 and MOF-808 were used to preferentially remove harmful chemicals at trace amounts in water with high environmental risk. The results showed that cerium-oxygen clusters effectively adsorbed the target chemicals through both chemical and physical mechanisms. The study also found that the length of alkyl chains in perfluoroalkyl carboxylic acids strongly correlated with the adsorption capacity. Additionally, the study demonstrated the complete decomposition of aromatic NSAIDs under solar light irradiation using reactive species generated by the cerium-oxygen clusters.
SEPARATION AND PURIFICATION TECHNOLOGY
(2023)
Article
Physics, Multidisciplinary
Alexandre Vilquin, Vincent Bertin, Elie Raphael, David S. Dean, Thomas Salez, Joshua D. McGraw
Summary: This study focuses on the spatial distribution and dispersion of charged nanoparticles in near-surface shear flows under the influence of electrostatic repulsion and absorption. By varying electrolyte concentrations, the electrostatic repulsion between particles and the charged surface can be adjusted. The particles leaving the field of vision are excluded from further analysis, making the experimental ensemble equivalent to Taylor dispersion with absorption. These two factors significantly modify the particle distribution and lead to a tenfold reduction in the spreading dynamics compared to the noninteracting case.
PHYSICAL REVIEW LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Srikanth Nayak, Raju R. Kumal, Zhu Liu, Baofu Qiao, Aurora E. Clark, Ahmet Uysal
Summary: Liquid-liquid extraction is an effective technique for separating precious and rare metals, with the organizational structure of the organic phase being correlated with different local hydration effects that are independent of metal concentration.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Physical
Michael J. Servis, Srikanth Nayak, Soenke Seifert
Summary: Liquid-liquid extraction is a chemical separation technique where the efficiency is limited by third phase formation; the organic phase structure and behavior are fundamentally connected with critical phenomena theory.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Raju R. Kumal, Srikanth Nayak, Wei Bu, Ahmet Uysal
Summary: Ion adsorption and transfer at charged interfaces are crucial in industrial and environmental processes. This study investigates SeCN- adsorption on a floating charged monolayer, revealing that the orientation and coverage of SeCN- ions change with increasing KSeCN concentration. The reorganization of interfacial ions and water is important for chemical separations of heavy metals.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Physics, Condensed Matter
Amanda J. Carr, Sang Soo Lee, Ahmet Uysal
Summary: In this paper, the electrical double layer (EDL) formed near graphene in dilute aqueous YCl3 solution is characterized using in situ high resolution x-ray reflectivity and resonant anomalous x-ray reflectivity techniques. The study reveals that yttrium ions (Y3+) readily adsorb to the negatively charged graphene surface to form an ion profile, and a molecular-scale gap is observed in the adsorbed Y3+ profile. Controlled adsorption and increasing cation coverage with increasing negative potential are also demonstrated. This experimental description provides important insights into the application of graphene-based systems for enhanced and selective ion separations.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Chemistry, Physical
Raju R. Kumal, Michael J. Servis, Pubudu N. Wimalasiri, Ahmet Uysal
Summary: Anions play important roles in the separation of lanthanides and actinides, but their behavior at aqueous interfaces is not well understood. This study used simulations to investigate the interfacial structure and behavior of thiocyanate anions at a charged interface, and found the emergence of a new population of thiocyanate ions at high concentrations.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Srikanth Nayak, Raju R. Kumal, Ahmet Uysal
Summary: This article investigates the ion-dependent reaction transformation process in rare earth metal separation technology. It is found that the introduction of specific ions can lead to the transformation of a monolayer into an inverted bilayer, providing insights for the development of new separation technologies. The study also reveals that temperature and the nature of background anions affect the transformation kinetics.
Article
Chemistry, Physical
Amanda J. Carr, Raju R. Kumal, Wei Bu, Ahmet Uysal
Summary: This study investigates the distribution of metal ions and water near graphene oxide films using interface-specific techniques. The results reveal that trivalent yttrium ions preferentially adsorb to graphene oxide and affect its structure, while divalent strontium and monovalent cesium ions have different effects. These findings provide fundamental information about the organization of ions and water at the interface and have relevance for improving graphene oxide membranes and applications downstream.
Article
Nanoscience & Nanotechnology
Amanda J. Carr, Seung Eun Lee, Raju R. Kumal, Wei Bu, Ahmet Uysal
Summary: Graphene oxide (GO) membranes are excellent candidates for separation applications, and understanding the interaction between water, ions, and the GO interface is critical. Experimental results show that solution conditions significantly impact water organization and lanthanide adsorption, which is connected to GO membrane performance.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Srikanth Nayak, Raju R. Kumal, Seung Eun Lee, Ahmet Uysal
Summary: We investigated the adsorption of trivalent neodymium on floating arachidic acid films using two surface specific probes, sum frequency generation spectroscopy and X-ray fluorescence near total reflection. Our findings showed that neodymium ions can compensate for the surface charge of the arachidic acid film without charge reversal. However, changes in the bulk concentration of neodymium ions affected the interfacial water structure. Additionally, the presence of a high concentration of NaCl led to overcharging at a certain Nd3+ concentration.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Brittany L. L. Bonnett, Dina Sheyfer, Pubudu N. N. Wimalasiri, Srikanth Nayak, Jyotsana Lal, Qingteng Zhang, Soenke Seifert, G. Brian Stephenson, Michael J. J. Servis
Summary: Extractant aggregation in liquid-liquid extraction organic phases affects energetics and the formation of a third phase, limiting the efficiency. Small angle X-ray scattering reveals that structural heterogeneities in binary mixtures of malonamide extractants and alkane diluents are well described by Ornstein-Zernike scattering, suggesting that the structure originates from the liquid-liquid phase transition. Molecular dynamics simulations confirm this mechanism. The molecular structure of the extractant and diluent modulate these critical concentration fluctuations, enabling the design of more efficient separation processes.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Xiaoyu Wang, Srikanth Nayak, Richard E. Wilson, L. Soderholm, Michael J. Servis
Summary: The design of extractants in liquid-liquid extraction (LLE) is an important aspect of metal ion separations. This study focuses on the role of solvent in the extractant phase and proposes a new mechanism for enhancing the energetics of metal-complexant interactions using nanostructured solvents. Molecular dynamics simulations reveal that the organic solvent can reshape the energetics of the extractant's conformational landscape, and specific solvents can ameliorate the unfavorable step of metal separation by promoting extractant reorganization. The formation of charge alternating nanodomains in ionic liquids is particularly effective in reducing the free energy penalty associated with the extractant's conformational change.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)