Multifunctional Oxide-Based Materials: From Synthesis to Application

The book deals with novel aspects and perspectives in metal oxide and hybrid material fabrication

Advanced Hybrid Materials Based on Titanium Dioxide for Environmental and Electrochemical Applications

Constant technological progress, as well as the pursuit of “friendly” technologies, leads to intensive work on the development of a new generation of advanced products with strictly defined, unique physicochemical properties dedicated to specific applications. This group of materials includes hybrids based on titanium dioxide and its derivatives, characterised with specific, well-defined physicochemical and structural properties, chiefly determined during their synthesis. Different properties of titania nanoparticles depend on their morphology, crystallite size, and crystalline structure. Nanocrystalline titanium dioxide can be synthesised via different methods, among which chemical precipitation, microemulsion method (inversed micelles), sol-gel process and hydrothermal crystallisation are the most important ones. That is why, a crucial part of the following chapter will be paid to characterisation of synthesis routes used for titanium dioxide and titania-based hybrid production. Furthermore, application of TiO2-based materials, including mixed oxide systems as well as graphene oxide–based hybrids, in electrochemical (electrode material) and environmental (photocatalysis) aspects, will be described in detail

Enzyme immobilization by adsorption : a review

Endowed with unparalleled high catalytic activity and selectivity, enzymes offer enormous potential as catalysts in practical applications. These applications, however, are seriously hampered by enzymes’ low thermal and chemical stabilities. One way to improve these stabilities is the enzyme immobilization. Among various tested methods of this process that make use of different enzyme-carrier interactions, immobilization by adsorption on solid carriers has appeared most common. According to these findings, in this review we present a comparative analysis of the literature reports on the recent trends in the immobilization of the enzymes by adsorption. This thorough study was prepared in order to provide a deeper understanding of the process. Both carriers, carrier modifiers and procedures developed for effective adsorption of the enzymes are discussed. The review may thus be helpful in choosing the right adsorption scheme for a given enzyme to achieve the improvement of its stability and activity for a specific application

Depolymerization and Activation of Lignin: Current State of Knowledge and Perspectives

A very important topic in present-day research is the depolymerization of lignin, meaning the multi-parametric decomposition of the biopolymer into low-molecular-weight products (monomers) by breaking of the intermolecular bonds. Depolymerization can occur under many different factors, such as high temperature or catalysts, which determine the mechanism of disintegration. In the case of lignin, this process is carried out in order to obtain many valuable low-molecular-weight compounds. It is becoming more and more popular as a result of the use of ionic liquids, but methods using alkaline, acidic, and metallic catalysts, as well as pyrolysis and supercritical fluids, are also known. All of these methods will be described in detail in this chapter

Modified and unmodified zinc oxide as coagent in elastomer compounds

The aim of this work was to study the activity of unmodifi ed and modifi ed ZnO in the peroxide crosslinking of hydrogenated acrylonitrile-butadiene elastomer (HNBR) and ethylene-propylene copolymer (EPM). In the first step, zinc oxide was obtained by emulsion precipitation. Maleic acid was introduced onto the surface of ZnO using an in situ method. The unmodifi ed and modifi ed zinc oxide was characterized using dispersive and morphological analysis, BET surface area analysis, and elemental, spectroscopic and thermal analysis. In the second stage of the research, the ZnO/MA systems were incorporated into the structure of elastomer compounds improving the kinetic and mechanical properties of vulcanizates. The proposed modifi cation method had a favorable effect on the physicochemical properties of the zinc oxide and on the kinetic and mechanical properties of the vulcanizates. This study demonstrated that modifi cation of zinc oxide by maleic acid is a promising technique

Lignosulfonate as a byproduct of wood pulp production: A potential precursor for the preparation of functional hybrid materials

Functional hybrid materials based on magnesium lignosulfonate and silica were obtained and characterized. Magnesium lignosulfonate is a common waste product of the wood pulp industry, while silica is a well-known inorganic material with exceptional physicochemical properties. In this study, silicas with a spherical particle shape were synthesized using a sol-gel method and alternatively in a nonpolar medium. Silica was found to improve the thermal and electrokinetic properties of the final products. The resulting lignosulfonate/silica hybrid materials were analyzed with the use of advanced techniques and measuring methods: scanning electron microscopy, a laser diffraction method enabling particle size measurements, Fourier transform infrared spectroscopy, elemental analysis, thermogravimetry, electrophoretic light scattering, zeta potential measurements, low-temperature nitrogen sorption, and colorimetric analysis. The results enabled the hybrid materials to be characterized from the point of view of potential applications in various branches of industry (for example as polymer fillers, electroactive blends and biosorbents). We additionally indicate new methods for the utilization of waste products, a category to which lignosulfonate certainly belongs

EMULSION SYSTEMS USED TO OBTAIN SYNTHETIC SILICATES BY HIGHLY DISPERSED PIGMENTS

The studies pertained to production of highly dispersed green pigments, precipitated in the form of chromium(III) and nickel(II) silicates. The experiments were conducted at four various temperatures (20, 40, 60 or 80 o C), using distinct emulsion systems and precipitating agents, so that appropriately selected parameters of the process would permit to obtain pigments of optimum utilitary properties. The obtained silicates were subjected to studies on principal physicochemical properties, such as capacity to absorb water, dibutyl phthalate, paraffin oil and bulk density. The pigments were characterised also using modern investigative techniques: SEM to study morphology and DLS (dynamic light scattering) technique to examine particle size and tendency to form agglomerates

Additives for Abrasive Materials

The overarching objective of the chapter is to acquaint the readers with the topic associated with the production of abrasive tools and presentation of the most significant research results regarding the determination of the most important functional properties of selected additives (described in the literature and established on the basis of authors’ own scientific experiences). The studies regarding various additives, which were characterized in detail in the literature, were mainly based on thorough physicochemical and microstructural analysis as well as the determination of basic strength and thermos-mechanic parameters. The attempt to implement alternative cross-linking agents, which would result in the limited release of volatile organic compounds, is also of great importance in terms of production of environmentally friendly final products. A subsequent aim is to attract the attention of a wide range of readers and popularize the topic associated with conventional abrasive materials and next-generation abrasive compositions

EFFECT OF INORGANIC OXIDES TREATMENT ON THE TITANIUM DIOXIDE SURFACE PROPERTIES

Studies were conducted involving evaluation of titanium white, surface-coated with inorganic oxides. The studies aimed at determining dispersion properties, i.a. particle size distribution and polydispersity index. Moreover, microscopic observation allowed to evaluate surface morphology of the modified TiO 2 particles. Colourimetric data of titanium white was measured and the specific surface area was estimated using BET method. Effect of the surface modification with oxides on electrokinetic properties and zeta potential were appraised. Increased amounts of aluminium oxide and silicon dioxide used for modification of titanium dioxide surface deteriorate uniform character of the sample and results in an increase in diameter of pigment particles. The titanium white pigments belong to mesoporous adsorbents. Value of the isoelectric point (IEP) depends on the amounts of aluminium oxide and silica used for surface processing of titanium white