Literatura académica sobre el tema "Surface complexation structure"
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Artículos de revistas sobre el tema "Surface complexation structure"
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Maldonado-Valderrama, Julia, Yan Yang, Maykel Jiménez-Guerra, Teresa del Castillo-Santaella, José Ramos y Alberto Martín-Molina. "Complexation of DNA with Thermoresponsive Charged Microgels: Role of Swelling State and Electrostatics". Gels 8, n.º 3 (17 de marzo de 2022): 184. http://dx.doi.org/10.3390/gels8030184.
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Micro- and nanogels are being increasingly used to encapsulate bioactive compounds. Their soft structure allows large loading capacity while their stimuli responsiveness makes them extremely versatile. In this work, the complexation of DNA with thermoresponsive microgels is presented. To this end, PEGylated charged microgels based on poly-N-isopropylacrylamide have been synthesized, allowing one to explore the electrostatics of the complexation. Cationic microgels complexate spontaneously by electrostatic attraction to oppositely charged DNA as demonstrated by electrophoretic mobility of the complexes. Then, Langmuir monolayers reveal an increased interaction of DNA with swollen microgels (20 °C). Anionic microgels require the presence of multivalent cations (Ca2+) to promote the complexation, overcoming the electrostatic repulsion with negatively charged DNA. Then again, Langmuir monolayers evidence their complexation at the surface. However, the presence of Ca2+ seems to induce profound changes in the interaction and surface conformation of anionic microgels. These alterations are further explored by measuring adsorbed films with the pendant drop technique. Conformational changes induced by Ca2+ on the structure of the microgel can ultimately affect the complexation with DNA and should be considered in the design. The combination of microstructural and surface properties for microgels offers a new perspective into complexation of DNA with soft particles with biomedical applications.
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Sun, Yubing, Xiangxue Wang, Wencheng Song, Songhua Lu, Changlun Chen y Xiangke Wang. "Retracted Article: Mechanistic insights into the decontamination of Th(iv) on graphene oxide-based composites by EXAFS and modeling techniques". Environmental Science: Nano 4, n.º 1 (2017): 222–32. http://dx.doi.org/10.1039/c6en00470a.
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Varadachari, Chandrika, Tarit Chattopadhyay y Kunal Ghosh. "The crystallo-chemistry of oxide-humus complexes". Soil Research 38, n.º 4 (2000): 789. http://dx.doi.org/10.1071/sr99053.
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Complexation of humic substances with goethite, hematite, gibbsite, and boehmite has been explained from a viewpoint of crystal structure of the minerals. Theoretical analysis of crystal surface structures revealed the following. (i) Residual charge carried by O or OH on surfaces of gibbsite is –1/2; on boehmite it is –3/2 or –1/2; on goethite it is –4/3, –2/3, or –1/3; and on hematite it is –3/2, –1, or –1/2. Cations adsorbed to neutralise these charges can form bridging links with humic acid; higher charges form stronger links. (ii) Surfaces of goethite, hematite, and gibbsite also contain octahedral sites in which one O/OH position is vacant. These may provide centres for the formation of strong coordination bonds. (iii) Such vacant octahedral positions are absent in boehmite. It follows that in gibbsite, cation bridging links would be weak and vacant octahedral sites would be the dominant bonding sites; in goethite and hematite, both cation bridging and surface coordination sites would be present; in boehmite, cation bridging would be the only strong bonding mode. Derivations from crystallochemical analysis are supported by experimental observations. Infrared studies also show strong OH involvement in boehmite complexation in contrast to the weakness of OH involvement in gibbsite complexes.
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Hiemstra, Tjisse, Rasoul Rahnemaie y Willem H. van Riemsdijk. "Surface complexation of carbonate on goethite: IR spectroscopy, structure and charge distribution". Journal of Colloid and Interface Science 278, n.º 2 (octubre de 2004): 282–90. http://dx.doi.org/10.1016/j.jcis.2004.06.014.
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TIWARY, AMIT S., PARTHA SARATHI SENGUPTA y ASOK K. MUKHERJEE. "MODELING THE GROUND STATE GEOMETRY AND ESTIMATING THE CHARGE TRANSFER TRANSITION ENERGY OF THE TOLUENE–ICl MOLECULAR COMPLEX BY AB INITIO AND DFT METHODS". Journal of Theoretical and Computational Chemistry 07, n.º 03 (junio de 2008): 331–46. http://dx.doi.org/10.1142/s0219633608003782.
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Out of several plausible isomeric structures of the toluene–ICl charge transfer (CT) complex, the most feasible one was determined by a detailed ab initio and DFT study at the HF, B3LYP, and mPW1PW91 levels using 6-31++G(d, p) basis set. Potential energy surface scans were performed with six possible structures ( I and Cl facing the o-, m-, and p-carbon atoms of toluene separately); the structures at the local minima of the surfaces were subjected to frequency calculation and the ones having no negative frequency were accepted as the real structure in the ground state. These structures were then subjected to full optimization. It was observed that the I – Cl bond, with its I atom oriented toward the aromatic ring, stands vertically above a C -atom at the ortho or para positions, being inclined at about 9° to the line perpendicular to the aromatic ring. Complexation increases the I – Cl bond length. After correction for basis set superposition error through a counterpoise calculation, we conclude from the binding energy that the preferred structure is the one with ICl above the ortho C atom. The calculated binding energy closely matches the experimental free energy of complexation. The electronic CT transition energy (hν CT ) with this structure in the ground state was calculated in vacuo by the restricted configuration interaction singlets method and in carbontetrachloride medium by the time dependent density functional theory method under the polarizable continuum model. The value of hν CT obtained from the ground-to-excited state transition electric dipole moments of the complex, is close to (somewhat underestimated) the reported experimental value.
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Zimmermann, C. J., N. Ryde, N. Kallay, R. E. Partch y E. Matijević. "Plasma modification of polyvinyltoluene and polystyrene latices". Journal of Materials Research 6, n.º 4 (abril de 1991): 855–60. http://dx.doi.org/10.1557/jmr.1991.0855.
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Polyvinyltoluene (PVT) latex particles were etched with O2 or CF4/O2 plasma and polystyrene (PS) latex by the O2 plasma. While the effect of these treatments on the surface topology and the specific surface area was minor, the electrokinetic measurements showed a significant change in the surface charge characteristics. The interpretation of the results in terms of a surface complexation model, taking the Stern–Gouy–Chapman structure of the interfacial layer into consideration, yielded the values of the corresponding equilibrium constants, which indicated that the chemical nature and the density of the surface charged groups were altered by plasma attacks.
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de Jonge, L. W., P. Moldrup y P. Schjønning. "Soil Infrastructure, Interfaces and Translocation Processes in Inner Space (''Soil-it-is''): towards a road map for the constraints and crossroads of soil architecture and biophysical processes". Hydrology and Earth System Sciences Discussions 6, n.º 2 (25 de marzo de 2009): 2633–78. http://dx.doi.org/10.5194/hessd-6-2633-2009.
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Abstract. Soil functions and their impact on health, economy and the environment are evident at the macro scale but determined at the micro scale, based on interactions between soil micro-architecture and the transport and transformation processes occurring in the pore and particle networks and at their interfaces. Soil structure formation and its resilience to disturbance are highly dynamic features affected by management (energy input), moisture (matric potential), and solids composition and complexation (organic carbon, OC, and clay interactions). In this paper we review and put into perspective preliminary results of the newly started research program ''Soil-it-is'' on functional soil architecture. To identify and quantify biophysical constraints on soil structure changes and resilience, we claim that new paradigms are needed to better interpret processes and parameters measured at the bulk soil scale and their links to the seemingly chaotic soil inner space behavior at the micro scale (soil self-organization). As a first step, we revisit the soil matrix (solids phase) and pore system (water and air phases), constituting the complementary and interactive networks of soil infrastructure. For a field-pair with contrasting soil management, we suggest new ways of data analysis on measured soil-gas transport parameters at different moisture conditions to evaluate controls of soil matrix and pore network formation. Results imply that some soils form sponge-like pore networks (mostly healthy soils in terms of environmental functions), while other soils form pipe-like structures (poorly functioning soils), with the difference related to both complexation of organic matter and degradation of soil structure. The recently presented Dexter threshold (ratio of clay to organic carbon of 10 g g−1) is found to be a promising constraint for a soil's ability to maintain or regenerate functional structure. Next, we show the Dexter threshold may also apply to hydrological and physical-chemical interface phenomena including soil-water repellency and sorption of volatile organic vapors (gas-water-solids interfaces) as well as polycyclic aromatic hydrocarbons (water-solids interfaces). However, data for differently-managed soils imply that energy input, soil-moisture status, and vegetation (quality of eluded organic matter) may be equally important constraints together with the complexation and degradation of organic carbon in deciding functional soil architecture and interface processes. Finally, we envision a road map to soil inner space where we search for the main controls of particle and pore network changes and structure build-up and resilience at each crossroad of biophysical parameters, where, for example, complexation between organic matter and clay, and moisture-induced changes from hydrophilic to hydrophobic surface conditions can play a role. We hypothesize that each crossroad (e.g. between OC/clay ratio and matric potential) may initiate breakdown or activation of soil self-organization at a given time as affected by gradients in energy and moisture from soil use and climate. The road map may serve as inspiration for renewed and multi-disciplinary focus on functional soil architecture.
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Son, Yeongkyun, Tae-Hyun Kim, Daekeun Kim y Yuhoon Hwang. "Porous Clay Heterostructure with Alginate Encapsulation for Toluene Removal". Nanomaterials 11, n.º 2 (3 de febrero de 2021): 388. http://dx.doi.org/10.3390/nano11020388.
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A volatile organic compound adsorbent based on a porous clay heterostructure (PCH) with alginate biopolymer was successfully prepared. From N2 adsorption–desorption analysis, the specific surface area, pore volume, and pore size of bentonite were dramatically increased after introducing the porous structure. Following complexation with alginate (Alg-PCH), the pore volume and pore size were not significantly affected by pore structure. The thermal stability of Alg-PCH shows enhanced thermal stability compared to alginate and alginate beads. The morphology layered structure of Alg-PCH was carried out by transmission electron microscopy (TEM), suggesting the disorder and re-order of the c-axis layer stacking by porous structure and complexation with alginate, respectively, which was well-matched with X-ray diffraction results. To optimize the preparation of Alg-PCH, various reaction conditions (alginate, CaCl2 concentration, bead size, and weight ratio between alginate and PCH) were utilized. According to the toluene adsorption–desorption experiments, the preparation conditions for Alg-PCH were selected as a 2 mm extrusion tip, 0.5% of alginate, and 2% of CaCl2 solution with a 1:50 alginate:PCH weight ratio. Additionally, it shows 61.63 mg/g adsorption capacity with around 49% desorption efficacy under atmospheric temperature and pressure.
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Larsson, Maja A., Ingmar Persson, Carin Sjöstedt y Jon Petter Gustafsson. "Vanadate complexation to ferrihydrite: X-ray absorption spectroscopy and CD-MUSIC modelling". Environmental Chemistry 14, n.º 3 (2017): 141. http://dx.doi.org/10.1071/en16174.
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Environmental contextVanadium, a metal pollutant from fossil fuels and slags, may be toxic, thereby necessitating an understanding of its environmental chemistry. One important factor that controls the mobility and bioavailability of vanadium is its binding to iron oxides. This study focuses on the characterization and modelling of vanadium adsorption onto ferrihydrite. The new model can be used to simulate the transport and bioavailability of vanadium in the environment. AbstractThe mobility of vanadium in the environment is influenced by sorption to metal (hydr)oxides, especially those containing iron. The aim of this study is to understand the adsorption behaviour of vanadium on poorly ordered (two-line) ferrihydrite (Fh). A further objective was to determine the binding mechanism of vanadate(V) to ferrihydrite surfaces in aqueous suspension to constrain the CD-MUSIC surface complexation model. Vanadium adsorption to ferrihydrite was evaluated by batch experiments which included series with different Fh-to-V ratios and pH values. Vanadate(V) adsorption was also evaluated in the presence of phosphate to compete with vanadate(V) for the available surface sites on ferrihydrite. In agreement with earlier studies, vanadate(V) was strongly adsorbed to ferrihydrite and the adsorption increased with decreasing pH. In the presence of phosphate, less vanadate(V) was adsorbed. Analysis by X-ray absorption near-edge structure spectroscopy revealed that the adsorbed vanadium was tetrahedral vanadate(V), VO4, regardless of whether vanadate(V) or vanadyl(IV) was added to the system. Spectra collected by extended X-ray absorption fine structure spectroscopy showed that vanadate(V) is bound primarily as an edge-sharing bidentate complex with V⋯Fe distances around 2.8Å. Based on this information, a surface complexation model was set up in which three bidentate vanadate(V) complexes with different degrees of protonation were included. The model provided a satisfactory description of vanadate(V) adsorption over most of the pH and concentration ranges studied, also in the presence of competing phosphate ions.
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Colin-Garcia, M., A. Heredia, A. Negron-Mendoza, F. Ortega, T. Pi y S. Ramos-Bernal. "Adsorption of HCN onto sodium montmorillonite dependent on the pH as a component to chemical evolution". International Journal of Astrobiology 13, n.º 4 (12 de mayo de 2014): 310–18. http://dx.doi.org/10.1017/s1473550414000111.
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AbstractThe aim of this work is to study the behaviour of hydrogen cyanide (HCN) adsorbed onto mineral surfaces (sodium montmorillonite, a clay mineral) in different pH environments as a possible prebiotic process for complexation of organics. Our experimental results show that specific sites on the surface of the clay increased the concentration of HCN molecules dependent on the pH values. Moreover, this adsorption can occur through physical and chemical interactions enhanced by the channel structure of the sodium montmorillonite. The three-dimensional channelling structure of the clay accumulates the organics, hindering the releasing (desorption) of the organic molecules. A molecular model developed here also confirms the role of the pH as a regulating factor in the adsorption of HCN onto the inorganic surfaces and the possibility for further reactions forming more complex molecules, as an abiotic mechanism important in prebiotic chemical evolution processes.
Tesis sobre el tema "Surface complexation structure"
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Gao, Pengyuan. "Theoretical Studies of the Interaction between U(VI) and Mineral Surfaces". Electronic Thesis or Diss., Orléans, 2023. http://www.theses.fr/2023ORLE1074.
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L'étude des processus d'adsorption des radionucléides sur les surfaces minérales est fondamentale pour la conception et l'évaluation de la sûreté des futurs systèmes de stockage des déchets radioactifs, ainsi que pour les diagnostics environnementaux des milieux pollués par des radionucléides. Parmi ces radionucléides, l'uranium a une abondance relativement élevée dans les systèmes naturels et a un rôle central dans le cycle du combustible nucléaire. L’uranium peut se trouver sous plusieurs états d’oxydation. L'U(VI) est l'état d'oxydation le plus pertinent dans la plupart des eaux de surface et des eaux souterraines oxygénées. L'adsorption de l'U(VI) sur les surfaces de divers minéraux a été largement étudiée par des expériences en batch complémenté par des techniques spectroscopiques. Des sites de complexation possibles et des espèces de surface ont été proposés, mais il est encore difficile d'obtenir des informations précises sur les mécanismes moléculaires responsables des processus d’adsorption. Ces informations sont essentielles pour comprendre les mécanismes physico-chimiques impliqués dans les expériences et pour développer des modèles prédictifs pour les environnements concernés. Les calculs théoriques à l’échelle moléculaire se sont avérés être un outil efficace pour étudier les processus d’adsorption des radionucléides à l'interface minéral-eau. Dans cette thèse, les caractéristiques structurales et les mécanismes d'adsorption des espèces d'U(VI) sur les surfaces des principaux minéraux constitutifs du granite (orthoclase et quartz) et des matériaux tampons/remblais (montmorillonite) des futurs systèmes de stockage en couche géologique profonde ont été obtenus à l'aide de calculs de dynamique moléculaire ab initio. Les mécanismes de polymérisation des espèces d'U(VI) en solution aqueuse et sur les surfaces minérales ont été étudiés. En outre, l’influence de la variabilité des sites d’adsorption des minéraux argileux de type montmorillonite sur les réactions d'adsorption a également été étudiée de manière systématiqueStudies of the adsorption characteristics of key radionuclides in the host rock and buffer/backfill materials of deep geological repositories for high-level waste (HLW) are fundamental to the designand safety assessment. Uranium is a radionuclide of widespread interest due to its relatively high abundance in nature and its central role in the nuclear fuel cycle, while U(VI) is the most relevant oxidation state in most surface waters and oxygenated groundwater. The adsorption of U(VI) on the surfaces of various minerals has been extensively investigated by conventional batch experimentsand spectroscopic techniques. Possible complexation sites and surface species have been proposed,but it is still challenging to able to obtain mechanistically precise insights at the microscopic level.Information at the molecular level is essential to understand the physicochemical mechanisms involved in the experiments and to develop predictive models for the relevant environments.Theoretical computations have been proven to be an effective tool for studying the chemical processesof radionuclides at the mineral-water interface. In this thesis, the structural characteristics and adsorption mechanisms of U(VI) species on the surfaces of the main component minerals of granite(orthoclase and quartz) and buffer/backfill materials (montmorillonite) of the deep geological repository were calculated by first-principles calculations. The polymerization mechanisms of U(VI) species in aqueous solution and on mineral surfaces were investigated. In addition, the effect of local structural changes of montmorillonite on the nature of the adsorption reaction on the surface was also systematically investigated
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Fedi, Baptiste. "Etude multi-échelle des mécanismes d'élaboration de revêtements d'alliage zinc-nickel à base d'électrolytes alcalins : germination, complexation et structures cristallines". Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2078.
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Les travaux présentés dans ce mémoire ont pour but d’approfondir la compréhension des mécanismes d’élaboration de revêtements électrolytiques de zinc-nickel obtenus à partir d’électrolytes alcalins. Les dépôts de zinc-nickel contenant entre 12% et 16%de nickel, connus pour leur performances anti-corrosion, nécessitent l’utilisation d’agents complexants afin de d’obtenir des formes solubles et réductibles du nickel dans un électrolyte à base de zincates à haut pH. Une étude des mécanismes de complexation a permis d’améliorer la compréhension du rôle respectif des agents complexants et de leurs interactions sur la stabilité des mélanges, ainsi que sur la morphologie de la structure cristalline des revêtements obtenus. Les phases cristallines d’alliages de zinc-nickel électro déposés,contenant entre 1% et 20% de nickel ont été quantifiés par déconvolution de courbes d’oxydation potentio dynamique et par DRX. Cette approche donne accès à une cartographie précise des phases d’alliages obtenus en fonction de la teneur en nickel du dépôt. La stabilité thermique des différentes phases à également pu être évaluée et quantifiée par cette méthode. La formulation des électrolytes ainsi que les paramètres des procédés peuvent modifier les cinétiques de germination des revêtements. Une étude fondamentale des mécanismes de germination par chrono ampérométrie couplée à des méthodes d’identification paramétrique a permis de quantifier l’évolution de certains paramètres de germination d’éléments simples en fonction du potentiel d’électrodéposition. L’étude de la germination d’alliage a mis en évidence que des réactions de décomplexation d’espèces modifient les cinétiques de nucléation, sans permettre d’aboutir à un modèle descriptif completThe present work aims to deepen the understanding of the mechanisms of zinc-nickelelectrodeposition in alkaline baths. Zinc-nickel deposits containing between 12% and 16%nickel known for their anti-corrosion performance. Complexing agents are required toobtain soluble and reactive nickel forms, and to stabilize the electrolytes. A study ofthe complexing mechanisms has improved the understanding of their respective role andbehavior, and their influence on the stability and the morphology and crystalline structureof the coatings obtained. The crystalline phases of electroplated zinc-nickel alloys in therange from 1% to 20% nickel content were quantified by deconvolution of potentiodynamicoxidation curves and XRD. This approach has led to a precise mapping of the alloyphases obtained as a function of the nickel content. The thermal stability of the differentphases has also been evaluated and quantified by this method. The formulation of theelectrolytes and the process parameters may modify the kinetics of coating germination. Afundamental study of the mechanisms of germination by chronoamperometry coupled witha parametric identification allows the quantification of parameter evolution in relation tonucleation phenomenon of simple elements. The study of alloy germination has shownthat decomplexing reactions are able to modify nucleation kinetics, without achieving acomplete comprehensive modeling
Capítulos de libros sobre el tema "Surface complexation structure"
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Sposito, Garrison. "The Spectroscopic Detection of Surface Species". En The Surface Chemistry of Natural Particles, 43–78. Oxford University PressNew York, NY, 2004. http://dx.doi.org/10.1093/oso/9780195117806.003.0002.
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Abstract Surface complexation models have been applied successfully to soil colloids to bring matters full circle; but, like their predecessors, they rely solely on prior molecular concepts and are tested only by goodness-of-fit to adsorption data. Since the model assumptions are so different and the models so plausible, one is left to wonder what physical truth they bear. One fears that the fog will lift only to reveal a Tower of Babel. It is inevitable that methodologies not equipped to explore molecular structure will produce ambiguous results in the study of surface speciation. The method of choice for investigating molecular structures is spectroscopy. Surface spectroscopy, both optical and magnetic, is the way to investigate surface species, and thus to verify directly the molecular assumptions in surface speciation models.
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Manju, Megha Jain, Sanjay Kumar, Ankush Vij y Anup Thakur. "Metal-Organic Frame Works (MOFs) for Smart Applications". En Synthesis and Applications of Semiconductor Nanostructures, 144–81. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815080117123040012.
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Metal-organic framework (MOF) is a class of materials, which is formed by combining metal/inorganic and organic linkers, resulting in the formation of a framework with high surface area and permanent porosity. The freedom to vary inorganic and organic linkers stimulated the synthesis of thousands of MOF structures, for their utility in various applications. The presence of high porosity, high surface area and high free volume made these materials a perfect choice among the class of solid adsorbents. The metal nodes, tunable pore, versatile structure and functionalized surface allow various types of chemical interactions, viz. electrostatic interactions, π complexation, H-bonding, coordination bonding, van der Waals interactions, hydrophobic/hydrophilic interactions. All these features made MOF a customizable material to be utilized for targeted applications. This chapter involves a discussion about the usage of versatile MOFs in smart applications, such as gas storage, gas separation and drug delivery, along with a brief discussion about the synthesis of MOFs.
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Brezonik, Patrick L. y William A. Arnold. "Surface Chemistry and Sorption". En Water Chemistry, 493–548. 2a ed. Oxford University PressNew York, 2022. http://dx.doi.org/10.1093/oso/9780197604700.003.0012.
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Abstract This chapter focuses on how surfaces on suspended particles, nanoparticles, and sediments affect solute behavior and concentrations. The molecular structures of solids that yield various kinds of surfaces and interfaces are described, along with features of surfaces themselves. Forces that attract/repel solutes to/from surfaces are described with emphasis on electrical charge and excess surface energy, called surface tension. A major focus is on sorption, i.e., the accumulation of solutes onto surfaces. The Freundlich and Langmuir models that quantify this process are described along with more complicated models developed to overcome their limiting assumptions. Mechanistic models that consider the physics of the electrical double layer at solid-solution interfaces, e.g., the Gouy-Chapman double layer model, are developed, along with modern extensions. Surface complexation models that combine double-layer physics with a chemically oriented approach to quantify the interactions between ionic solutes and surfaces are described and examples of their use are given.
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Bunker, Bruce C. y William H. Casey. "Bio-inspired Synthesis of Oxide Nanostructures". En The Aqueous Chemistry of Oxides. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780199384259.003.0015.
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Nature is capable of building magnificently intricate and detailed structures out of otherwise boring materials such as calcium carbonate and silica. Anyone who has taken their children to see dinosaurs at a Natural History museum or visited natural wonders such as the Petrified Forest in Arizona are familiar with the natural process called fossilization by which the tissues of dead organisms are eventually replicated by objects of stone. Most living organisms (including humans) are critically dependent on more deliberate and controlled biomineralization phenomena that lead to the production of all hard tissues, including our teeth and bones, seashells and diatom skeletons, egg shells, and the magnetic nanoparticles that provide homing devices from bacteria to birds. All these processes are nothing more than specific examples of highly controlled nucleation and growth phenomena such as those described in generic terms in Chapter 7. At a molecular level, these processes are controlled by the same reaction mechanisms involving oxide surfaces, which were outlined in Chapter 6. However, biomineralization is orders of magnitude more sophisticated than standard nucleation and growth processes. The unique features of biomineralization involve the interplay between organic biomolecules and the nucleation and growth of inorganic phases such as oxides. This interplay is of critical importance in both biology and emerging nanotechnologies, providing specific examples that illustrate many of the concepts of oxide chemistry introduced in Chapters 5 through 7. In this chapter, we highlight the key concepts of biomineralization and provide examples of how researchers can now produce complex nanostructured oxides via biomimetic nucleation and growth strategies that replicate some of the key features used to make hard tissues in living systems. These strategies include the use of (1) molecular complexation and compartmentalization to control supersaturation levels, (2) specific ligands and surface structures to mediate nucleation phenomena, (3) hierarchical self-assembled organic architectures as templates for oxide formation, (4) functionalization to stimulate desired heterogeneous nucleation and growth processes on those templates, and (5) organic surfactants to manipulate both crystal-phase preferences and growth habits.
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Grabowski, Sławomir J. "Hydrogen Bonds and Halogen Bonds – A Comparative Study". En Intermolecular Interactions in Crystals: Fundamentals of Crystal Engineering, 478–515. The Royal Society of Chemistry, 2017. http://dx.doi.org/10.1039/bk9781782621737-00478.
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The halogen and hydrogen bonds are analyzed and compared. These interactions may be classified as σ-hole bonds steered by electrostatic forces since the arrangement of the units forming complexes or greater aggregates is determined by the distribution of electrostatic potential at the molecular surfaces. However, for both interactions the effects connected with the electron charge density shifts as a result of complexation are also pronounced. Numerous common properties for the A–H⋯B hydrogen bond, HB, and the A–X⋯B (X is the halogen atom) halogen bond, XB, may be exhibited; the directionality of those interactions, the increase of the positive charge of H and X atoms after the formation of the bond; the simultaneous decrease of the H or X-atom volume and the increase of the negative charge of A-atom. In general, both interactions are ruled by the same mechanisms; hyperconjugation and the rehybridization process. There are also distinct properties of hydrogen and halogen bonds that partly result from the differences in the volumes of H and X-atoms. The most important is that the halogen atoms may act at the same time as the Lewis acid and as a Lewis base but an H-atom possesses one of these properties – it may act as the Lewis acid centre in hydrogen bonds or the Lewis base in hydride bonds. The theoretical results on HBs and XBs in this chapter are supported by numerous experimental results – mostly examples of crystal structures.
Informes sobre el tema "Surface complexation structure"
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Myneni, Satish, C. In-situ Evaluation of Soil Organic Molecules: Functional Group Chemistry Aggregate Structures, Metal & Surface Complexation Using Soft X-Ray. Office of Scientific and Technical Information (OSTI), noviembre de 2008. http://dx.doi.org/10.2172/942132.
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