Nanomaterials and nanostructured materials have been a great deal of interest in various field due to their enhanced performance over their bulk phase. Based on the understanding their size and structure-dependent properties, we have worked on 1) novel absorbents and nanostructures for waste removal, 2) solar cell recycle process using nano absorbents, 3) semiconductor nanoparticles, and 4) bio-mineral nanocomposites. In particular, we are interested in improving the physical, electrical, and thermal properties of nanomaterials to suit each application through material complexation, surface modification, and shape and size control.