Novel Approaches to Design Eco-friendly Materials Based on Natural Nanomaterials

Book excerpt: Naturally available nanomaterials or those synthesized from natural resources become “new favorite” of material world due to their advantages of low cost, safety and environmental friendliness. They are honored as future “green materials” and widely used in fabricating various functional materials. Naturally available materials have been playing an increasingly important role in many fields such as environmental remediation, separation, catalysis, and polymer composites. This book collects latest research results on the new composites for environmental application, focusing on the study of fabricating functional composites using natural clay minerals. Naturally available materials or solid waste or minerals are good precursors for producing adsorbents. Composites based on sub-bituminous coal, lignite, and a blend of coal and Irvingia gabonensis seed shells, the Cl-type Mg-Al hydrotalcite (Cl-LDH), the hydroxyapatite decorated with carbon nanotube and Zirconium (Zr)-containing silica residue purification (ZSR-P) were proved to have good adsorption capability to Cd(II) and Pb(II) ions, antibiotic molecules, Cd(II), and fluoride, respectively. The nano-Mg(OH)2 loaded carbon cloth showed good separation effect for Eu(III), and the sodium-modified clinoptilolite showed good separation effect for CH4/N2 from coal bed gas. Also, natural nanoclay is an effective precursor for the preparation of inorganic-inorganic or organic-inorganic nano-hybrid materials. Using nano-kaolinite as a carrier, the inorganic-inorganic hybrid cobalt blue pigment with excellent color and stability can be obtained by surface co-precipitation and in-situ calcination crystallization process. The intercalation of 7-amino-4-methylcoumarin (AMC) molecules into the interlayer space of montmorillonite (MMT) can effectively inhibit fluorescence quenching and improve the detection effectiveness of Cr(VI) in water. The interlayer space of kaolinite can accommodate organic molecules to form an organic-inorganic hybrid composite. Natural clay minerals are also effective carriers for catalysts. Er3+:CeO2/palygorskite nanocomposites prepared by a facile precipitation method showed excellent desulfurization rate under visible light irradiation. The zero-valent iron-loaded nanoclays composite catalysts can degrade efficiently Rhodamine 6G (Rh 6G) under microwave irradiation. In addition, the polymer composites have been developed using natural palygorskite, montmorillonite nanosheets or silica nanoparticles as inorganic components, which are potential to be used in many fields such as packing, biomedicine, or rubber. With the increasing attention to clay minerals, research methods for the microstructure of clay minerals continue to receive attention. It is no doubt that natural materials have got a booming attention from researchers in mineralogy, materials science, chemistry, energy, biomedicine and other fields due to their advantages. However, there is still a long way to go to substitute traditional synthetic nanomaterials with natural ones, and there are still theoretical and technological limitation in the design and synthesis of new materials from natural materials. Related theoretical research and technological development require continuous exploration by researchers. This book has collected some recent advances in related research, and hopes to play a role in attracting more attention to the construction of functional materials from natural raw materials. It is also believed that through the unremitting efforts of all researchers, the dream of green materials and green preparation processes can be realized.