Book excerpt: This book presents comprehensive chapters on the latest research and applications in wastewater treatment using green technologies. Topics include mesoporous materials, TiO2 nanocomposites and magnetic nanoparticles, the role of catalysts, treatment methods such as photo-Fenton, photocatalysis, electrochemistry and adsorption, and anti-bacterial solutions. This book will be useful for chemical engineers, environmental scientists, analytical chemists, materials scientists and researchers.