This book highlights recent findings of membrane - based dye removal methods along with the application of photocatalytic, nanofiltration and ultrafiltration membrane including membrane – based fibers, metal-organic frameworks, polyethersulfone, ceramic, etc.  Among water and wastewater pollutants, dyes have been normally observed and detected in various aquatic solutions, including rivers and lakes. Aesthetic pollution, toxicity, persistent, and carcinogenicity are some of the adverse effects of dyes entering the ecosystem. Although dyes have brought a colourful world, their presence in the environment are responsible for adverse effects on the planet. Diverse physical, chemical and biological methods are available to treat dye contaminated water. This book presents membrane separation technology that has been developed in the past decade to treat different wastewaters, and owning to its effective performance, has garnered the attention of academia and industry alike.