Sustainable Degradation of Organic Pollutants Using Various Treatment Processes: A Review

Organic pollutants, such as dyes and colorants, are water-soluble compounds produced by various industries, including textiles, food, cosmetics, pharmaceuticals, printing, paints, leather, and plastics. Dyes are of particular concern because their stable aromatic structures make them toxic, mutagenic, and carcinogenic to living organisms. Therefore, environmental scientists have focused on developing various physical, chemical, and biological treatment processes to remove these contaminants from wastewater. The conventional techniques, such as coagulation, flocculation, precipitation, photocatalytic degradation, ion exchange, and membrane filtration, have been widely adopted. More recently, biomass-based waste materials such as bagasse, green algal biomass, and household vegetable and agricultural residues have been investigated as promising, low-cost, and sustainable adsorbents for dye removal. In addition, nanomaterials such as zinc oxide, titanium dioxide, silica powder, carbon nanotubes, and well-structured biocomposite materials have also shown great potential in wastewater treatment. This review examines major treatment technologies and highlights their merits and limitations, supported by comparative tables and illustrative figures.