Selective adsorbents were developed for removal and recovery of heavy metals from aqueous medium. As heavy metals interact with surface moieties differently depending on their chemical properties, tailor-made adsorbents were synthesized for metal separation from aqueous solution based on different adsorption mechanisms. This work is a comprehensive study in the design of adsorbent for selective adsorption of metal ions based on a nanostructured material, MCM-41. After the study of fundamental science governing adsorption selectivity of designed surface functionality, various applications of the selective adsorption are demonstrated in this book.