Graphene-based materials have received significant attention due to their exceptional properties in water treatment applications. Among these, three-dimensional graphene offers distinct advantages over its two-dimensional form, particularly in addressing nanosafety concerns, which have specific implications for environmental and health-related applications. This chapter explores the synthesis, characterization, and applications of 3D graphene-based adsorbents, focusing on their unique structural features, high porosity, and tunable properties that ensure outstanding performance in water purification. It presents the main methods for synthesizing 3D graphene-based materials, examining their impact on structural and chemical properties, alongside challenges in characterizing these complex macrostructures and their interactions with contaminants. Applications of 3D graphene in water treatment are also discussed, with an emphasis on adsorption strategies, including hierarchical structuring and surface functionalization, to enhance efficiency. Key challenges, such as developing scalable and eco-friendly synthesis methods and accessing the intricate features of 3D graphene, are analyzed. Finally, conclusions and perspectives are provided, highlighting pathways to optimize material design and uncover interaction mechanisms to create efficient, sustainable solutions tailored to water treatment needs.