Clay Minerals, Surface Chemistry of Clays and Organoclays, and the Mechanisms of Organoclay Synthesis

2015 ◽  
pp. 87-190
Keyword(s):  
Surface Chemistry ◽  
Clay Minerals

scholarly journals Probing the nanoscale architecture of clay minerals

Clay Minerals ◽  
2010 ◽  
Vol 45 (3) ◽  
pp. 245-279 ◽  
Author(s):  
C. T. Johnston
Keyword(s):  
Surface Chemistry ◽  
Clay Minerals ◽  
Active Sites ◽  
Spatial Scales ◽  
Functional Materials ◽  
Molecular Size ◽  
Molecular Probes ◽  
Length Scale ◽  
Organic Solute ◽  
Reporter Group

AbstractIn recent years, experimental and theoretical methods have provided new insights into the size, shape, reactivity, and stability of clay minerals. Although diverse and complex, the surface chemistry of all clay minerals is defined spatially on a common scale of nanometres. This review is organized around the nanoscale architecture of clay minerals examined at several different length scales. The first, and perhaps most important, is the length scale associated with Hbonding in clay minerals. Hbonding interactions define the size and shape of 1:1 phyllosilicates and dominate the surface chemistry of many clay minerals. Structural and surface OHgroups contained within and on the surface of clay minerals provide a type of ‘molecular reporter group’ and are sensitive to subtle changes in their local environment. Examples of OH-reporter group studies in clay minerals, and the spatial scales at which they provide diagnostic information, are examined. The second length scale considered here is that associated with clay–water and clay–organic interactions. Inorganic and organic solutes can be used to explore the surface chemistry of clay minerals. Similar to the use of reporter groups, molecular probes have diagnostic properties that are sensitive to changes in their molecular environment. Clay–water interactions occur at a length scale that extends from the size of the H2O molecule (~0.3 nm) to the larger scales associated with clay-swelling (>10 nm). Similarly, clay–organic interactions are also defined, in part, on the basis of their molecular size, in addition to the type of chemical bonding interactions that take place between the organic solute and the clay surface. Examples illustrating the use of clay–water and clay–organic solute interactions as molecular probes are presented. The largest scale to be considered is that of the particles themselves, with scales that approach micrometres. Recent developments in the synthesis and characterization of ultrathin hybrid films of clay minerals provide complementary information about the nature and distribution of active sites on clay minerals, as well as providing new opportunities to exploit the surface chemistry of clay minerals in the design of functional materials.

The impact of structural Fe(III) reduction by bacteria on the surface chemistry of smectite clay minerals

1999 ◽  
Vol 63 (22) ◽  
pp. 3705-3713 ◽  
Author(s):  
Joel E. Kostka ◽  
Jun Wu ◽  
Kenneth H. Nealson ◽  
Joseph W. Stucki
Keyword(s):  
Surface Chemistry ◽  
Clay Minerals ◽  
Smectite Clay ◽  
The Impact

The Surface Chemistry of Clay Minerals

2019 ◽  
pp. 281-301
Author(s):  
Patrick V. Brady ◽  
James L. Krumhansl
Keyword(s):  
Surface Chemistry ◽  
Clay Minerals

Dynamics of carbohydrate strands in water and interactions with clay minerals: influence of pH, surface chemistry, and electrolytes

Nanoscale ◽  
2019 ◽  
Vol 11 (23) ◽  
pp. 11183-11194 ◽  
Author(s):  
Tariq Jamil ◽  
Jacob R. Gissinger ◽  
Amanda Garley ◽  
Nabanita Saikia ◽  
Arun K. Upadhyay ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Clay Minerals ◽  
Design Principles ◽  
Interaction Mechanisms ◽  
Clay Platelets ◽  
Influence Of Ph

We describe the dynamics of gellan strands in solution, the interaction mechanisms with clay platelets of different composition, and design principles to tune the attraction.

scholarly journals Surface Chemistry of Halloysite Nanotubes. As investigated by adsorption reactions and imaging analysis

2021 ◽  
Author(s):  
◽  
Nia B. Gray-Wannell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Chemistry ◽  
Clay Minerals ◽  
External Surface ◽  
Halloysite Nanotubes ◽  
Interlayer Water ◽  
Adsorption Sites ◽  
Transmission Electron ◽  
Microscopy Techniques

Interest in halloysite clay minerals has increased steadily over the last 20+ years, in part, due to their nanotubular shape and size, high aspect ratio and potential technological applications (Churchman et al., 2016). Throughout this thesis the surface chemistry of halloysite nanotubes is investigated by employing several analytical and advanced microscopy techniques to obtain a greater understanding of their internal and external surface features and surface adsorption reactions. This multifaceted analysis approach investigates a range of tubular halloysites of two morphologies, cylindrical and polygonal prismatic, where comparison of the two forms a framework for the presentation and discussion of the results. The results presented in Chapter 3 demonstrate the phosphate adsorption capacity of halloysite nanotubes is influenced by pH and maximum adsorptions of 1.3 mg/g and 0.5 mg/g were obtained for the cylindrical and polygonal prismatic morphologies respectively. Use of advanced microscopy techniques in Chapter 4 showed the external surface of the polygonal prismatic nanotubes have multiple steps and edges, which may act as additional adsorption sites, as has been shown for other clay minerals (Siretanu et al., 2016). In addition, use of cross-section transmission electron microscopy provided evidence of the link between the two morphologies, where the cylindrical nanotubes appear to be the template from which the larger polygonal prismatic nanotubes grow, as previously postulated by Hillier et al. (2016). In further novel work (Chapter 5), gold nanotags have been functionalised with a variety of anionic and neutral terminated linkers and used as nanoscale probes to study adsorption to the surface of halloysite nanotubes Here, transmission electron microscopy proved that the adsorption occurred primarily on the nanotube inner lumen and edges. The final technical chapter, Chapter 6, focuses on the structure and dynamics of interlayer water in halloysite through the use of neutron scattering techniques, where the initial results demonstrated that the interlayer water appears to move via both rotations and translations within the interlayer. The research presented ascertains that the surfaces of the halloysite nanotubes are more complex than often depicted for technological applications and that the specific tubular morphology is important in the functionality and behaviour of the nanotubes. This fundamental work contributes towards optimisation of halloysite nanotubes for technological applications.

The Surface Chemistry of Clay Minerals

2001 ◽  
pp. 281-301
Author(s):  
James Krumhansl ◽  
Patrick Brady
Keyword(s):  
Surface Chemistry ◽  
Clay Minerals

scholarly journals Characterization and Adsorption Applications of Composite Biochars of Clay Minerals and Biomass

2021 ◽  
Author(s):  
Lihui Gao ◽  
Jillian L. Goldfarb
Keyword(s):  
Methylene Blue ◽  
Hydrogen Bonding ◽  
Surface Chemistry ◽  
Clay Minerals ◽  
Organic Contaminants ◽  
Proximate Analysis ◽  
Surface Functional Groups ◽  
Relative Contribution ◽  
Adsorption Capacities ◽  
Oak Leaves

Abstract Composite mineral-biochars of a homogeneous biomass (cellulose) and heterogeneous biomass (oak leaves) were fabricated with either 5wt% or 10wt% minerals (montmorillonite (MMT), kaolinite, and sand), and then pyrolyzed at 600 °C for 60 min. Characterizations including proximate analysis, ultimate analysis, surface area and porosity, morphology and surface chemistry confirmed that minerals were present on the surface of biochar, and MMT/kaolinite-biochar composites showed a strengthening in the chars’ aromatic structures, as well as increases in oxygen-containing surface functional groups. Methylene blue adsorption isotherms indicated that the MMT/kaolinite-biochars had higher adsorption capacities than pure biomass or biomass-sand biochars (110 mgMB/gchar and 24 mgMB/gchar for MMT-cellulose char and cellulose char, respectively). A multilinear model relating adsorption capacity and adsorbent properties was developed to measure the relative contribution of biochar properties to adsorption behavior. The model indicates that pore volume and hydrogen bonding were the dominant properties in controlling the adsorption of methylene blue onto the biochars. Findings from this work indicate that composite biochars prepared from biomass and inexpensive clay minerals are a promising adsorbent for remediating organic contaminants from water.

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