**Meet the editor**

Dr. Gustavo Morari do Nascimento is working as Professor at Federal University of ABC. He has experience in many fields related to characterization of nanomaterials. He obtained his doctoral degree from University of São Paulo (USP) with thesis about the spectroscopic characterization of nanocomposites of conducting polymers in clays. He received a Post doctoral Fellowship at MIT in the Raman

study double-walled carbon nanotubes doped with halogens. At his third Post doctoral fellowship he studied carbon nanotubes modified with molecular magnets. His current research focus is on molecular characterization of modified carbon nanostructured materials and polymer nanocomposites by using different spectroscopic techniques. Resonance Raman and SERS (surface enhanced Raman spectroscopy) coupled to microscopy techniques added to X-ray absorption techniques at National Synchrotron Light Laboratory have been the main techniques employed in his research.

## Contents

## **Preface XI**


## Chapter 7 **Ceramic Materials Based on Clay Minerals in Cultural Heritage Study 159**

Rodica-Mariana Ion, Radu-Claudiu Fierăscu, Sofia Teodorescu, Irina Fierăscu, Ioana-Raluca Bunghez, Daniela Ţurcanu-Caruţiu and Mihaela-Lucia Ion

## Preface

Chapter 7 **Ceramic Materials Based on Clay Minerals in Cultural**

Rodica-Mariana Ion, Radu-Claudiu Fierăscu, Sofia Teodorescu, Irina Fierăscu, Ioana-Raluca Bunghez, Daniela Ţurcanu-Caruţiu and

**Heritage Study 159**

Mihaela-Lucia Ion

**VI** Contents

This book brings a broad review of recent state-of-the-art results related to clays, clay minerals and ceramic materials based on clay minerals. The main goal of this work is to contribute to rationalization of some important results obtained in the open area of clays and clay materials characterization. Moreover, this book also provides a comprehensive account on polymer and biopolymer-clay nanocomposites, clay usage as adsorption materials for industrial pollutants, physical-chemistry aspects of clay and clay minerals aqueous dispersions, and finally archeo‐ logical investigation of clays used as ceramic materials in cultural heritage. This book will be beneficial for students, teachers and researchers of many areas who are interested to expand their knowledge about clays and its derivates in the field of Nanotechnology, Biotechnology, Environmental Science, Industrial Remediation, Cultural Heritage, etc.

This book starts with an opening chapter that discuss the new X-ray characterization techni‐ ques applied to clay materials. The physical-chemistry aspects of clays are then discussed in the next two chapters. Afterwards the synthesis and characterization of hybrid materials are analyzed through three chapters, and as closing chapter the use of clays as ceramic materials in cultural heritage is studied.

Hence, in the first chapter the use of X-ray absorption techniques (XAS) for elucidating clay structures and its composites is discussed. A typical X-ray absorption (XAS) spectrum enables the determination of crystallographic parameters, oxidation state, and also the types of chemi‐ cal bonds in the solid. Theoretical calculations are essential to verify the differences between the oxygen and silicon sites in clays and also other atomic aspects in layer and/or interlayer spaces. Polymer-clay nanocomposites can also be studied by XAS; this technique permits the study of both clay and polymer in different atomic edges.

The second chapter deals with properties and applications of clay mineral water dispersions and clay minerals as flame retardant additives for polymers. A direct method to prepare clay mineral polymer composites is through dispersion in water. Water dispersions of clay exhibit some interesting flow phenomena such as yield stress; i.e., the material behaves as a solid until a critical force applied on the material forces it to flow. The flame retardant properties of many composites have also been reported.

The third chapter discusses the charging behavior of clays and clay minerals in aqueous elec‐ trolyte solutions. Clay platelets can exhibit different charging mechanisms on various surfaces. Basal planes have a permanent charge, whereas the edge surfaces exhibit the amphoteric be‐ havior and pH-dependent charge that is typical for oxide minerals. This chapter tries to under‐ stand the influence of different parameters (i.e. pH and background salt composition and concentration) over the clay surfaces and how to measure each parameter independently. The problem is depicted by discussing in detail the literature data on kaolinite obtained with crys‐ tal face specificity. Some results from similar experiments on related substrates are also dis‐ cussed.

Fourth chapter studies the adsorption of pollutants present in aqueous media on different nat‐ ural clays after acid or base modifications. The adsorption processes taking place in aqueous solutions containing formaldehyde, acetic acid, and ammonium chloride on the surface of nat‐ ural and activated aluminosilicates, are also considered. The activating effect of a number of inorganic acids and bases on adsorption equilibrium is compared. The adsorption mechanism of electrolytes and polar molecules from aqueous media may comprise hydrogen bonding, chemisorptions, or ion exchange reactions.

The fifth chapter presents the study of a new synthetic material labeled metanacrite; the mate‐ rial was analyzed by X-ray diffraction, infrared spectroscopy, transmission electron micro‐ scope, and electrochemical impedance spectroscopy. The intercalation of lithium chloride salt leads to a stable hybrid material that after calcination under inert atmosphere at 723–873 K induces an amorphous hybrid. Finally, the resulting amorphous hybrid shows a superionic behavior with high ionic conductivity up to 10 -2 S.cm -1, good electrochemical stability, and can be used as an innovative solid electrolyte in lithium batteries and other electrochemical devices.

Sixth chapter deals with the electrorheological (ER) properties of biodegradable chitosan (CS) and natural bentonite (BNT). BNT/CS composites were synthesized by the in situ method and their structure and morphology were characterized using X-ray diffraction, thermo-gravimet‐ ric analysis, and scanning electron microscopy techniques. According to ER results, BNT/CS composites were found to be sensitive to external electric field strength, exhibiting a typical shear thinning non-Newtonian viscoelastic behavior.

In the closing chapter, the archeological studies of ceramic materials produced from clays are discussed. The ceramic heritage is mostly based on clay types used by humans over the histo‐ ry. Characterization of raw materials and ceramic objects based on clays is leading to some results about the production technology, provenance, authentication, etc. The chemical com‐ position of ancient ceramics and its pigments, excavated from different Romanian archaeologi‐ cal sites, suggested a chemical composition of ceramic based on clay minerals (kaolinite, illite, and smectite), while the red pigments are hematite or ocher, manganese oxides (are the brown pigments, and magnetite or carbon of vegetable origin form the black-pigmented layers.

I really hope that this book brings a good contribution in the field of clays characterization and all related materials. These complex materials are used in different industrial areas, with inter‐ face between nanotechnogy, biotechnology, earth and environmental sciences, and archaeo‐ logical investigation. Finally, I would like to give special thanks to all authors that contributed for this book (in alphabetical order): Abdesslem Ben Haj Amara, Ahmed Abdelmonem, Ale‐ jandro Rivera-Gonzaga, Antonio Sanchez-Solis, Daniela Ţurcanu-Carutiu, Fausto Calderas, Gilles Montavon, Guadalupe Sanchez-Olivares, Hafsia Ben Rhaiem, Ioana-Raluca Bunghez, Irina Fierăscu, Johannes Luetzenkirchen, Larisa Belchinskaya, Liudmila Novikova, Luis Medi‐ na-Torres, Mehmet Cabuk, Mihaela-Lucia Ion, Nouha Jaafar, Octavio Manero, Radu-Claudiu Fierăscu, Rodica-Mariana Ion, Sofia Teodorescu, and Tajana Preocanin.

> **Gustavo Morari do Nascimento** Federal University of ABC São Bernardo do Campo, Brazil
