In recent years, nanotechnology has introduced novel nanomaterials that can have promising outcomes in environmental cleanup and remediation. Particularly, modified magnetic nanoparticles are being intensively studied as new types of adsorbents for removal of toxic pollutants from aquatic systems. This extraordinary interest stems from their unique morphology, nanosized scale and novel physicochemical properties. Water pollution is a matter of great concern. It's quality is equally important for both domestic purposes and industrial needs. Thus, in this book we focus on the use of magnetic nanoadsorbent for the removal of organic pollutants. Recently, magnetic nanoparticles and their modified forms have been used as adsorbents, due to their large specific surface area, excellent physical and chemical stability, and other advantageous structural and surface properties. The main outcome of reading this book will be that the reader is going to have a holistic view of the immense potential and ongoing research in organic pollutants removal by green chemistry, and its close connection with modern research and applications.