Environmental devices help in monitoring the collection of one or more measurements that are used to access the status of an environment. Today, environmental monitoring and analytical methods are among the most rapidly developing branches of analysis. The functionalization of nanomaterials in the field of environmental science has increasing importance with regards to the fabrication of devices. Functionalized nanomaterials reformulate new materials and advanced characteristics for improved application in comparison to old fashion materials and open an opportunity for the development of devices for introducing new technology and techniques for monitoring environmental challenges. The monitoring of these environmental challenges in advances have direct impact on health and sustainability. Functionalized nanomaterials have different mechanical, absorption, optical or electrical properties than original nanomaterials. In fact, major utilization of nanomaterials occurs in their functionalized forms, which are very different from the parent material. This handbook provides an overview of the different state-of-the-art materials, devices and environmental applications of functionalized nanomaterials. In addition, the information offers a platform for ongoing research in the field of environmental science and device fabrication. The main objective of this book is to cover the major areas focusing on the functionalization of nanomaterials, device fabrication along with different techniques and environmental applications of functionalized nanomaterials-based devices. This is an important reference source for materials scientists, engineers and environmental scientsts who are looking to increase their understanding of how functionalized nanomaterial-based devices are being used for environmental monitoring applications.