Types of Dyes and Their Effects on the Environment and Their Removal: A Review

Abstract

Dyes are extensively used in textile, leather, paper, plastic, cosmetic, and food industries, and during the staining process a large amount of dye components is discharged into the environment through industrial effluents. Because of their complex aromatic structures and high chemical stability, many dyes resist biodegradation and persist for long periods in natural ecosystems. Their contamination in water bodies reduces light penetration, which disrupts the photosynthesis process and alters dissolved oxygen levels, ultimately affecting aquatic biodiversity. Some types of dyes, especially azo and anthraquinone dyes, can degrade under environmental conditions and produce carcinogenic and mutagenic secondary compounds that pose serious risks to aquatic life, soil quality, and human health. This review emphasizes the major classes of dyes, the pollutants generated from dye-based industries, their environmental impacts, and associated health hazards. Moreover, the paper highlights various dye removal techniques using both conventional and advanced technologies, and discusses their advantages, limitations, and future prospects for developing sustainable, eco-friendly, and economical methods to mitigate the effects of dye pollutants on the environment.