Abstract
This review article examines various photolytic techniques and parameters for direct yellow 12 dye degradation. It has been thoroughly reviewed how a photocatalyst's structure and physio-chemical characteristics, particularly its absorption capacity and surface area correlate to its photocatalytic activities in the photo-degradation of dyes that contain azo group. The most widely used dye classes for adding color to cotton fabrics are direct dyes. Because of their degraded products, which include aromatic amines, which are thought to be extremely carcinogenic, reactive azo dyes pose a particular environmental and health risk. Because of its stability in both acidic and alkaline solutions, direct yellow 12 dye, also referred to as chrysophenine G, is used in a variety of industrial processes. Direct dye 12 is extremely toxic to both human and animals, and it can result in irreversible eye damage. Previously, effluents containing azo dyes were treated using chemical coagulation or adsorption onto activated carbon. However, conventional techniques primarily transfer pollutants from wastewater to solid waste. Thus, in order to degrade such dangerous dyes, cutting-edge, environmentally friendly techniques must be used. The photodegradation of direct yellow 12 dye by photocatalytic process is regarded as a promising methodology for industrial discharges treatment methods due to its low cost, non-toxic nature, and minimum pollution. Several operational parameters governing the photodegradation of harmful dyes are critical for determining the oxidation rates and efficiency of the photocatalytic system. Our findings revealed that a few fundamental factors influence photodegradation: substrate concentration, photocatalyst amount, pH of the solution, reaction medium temperature, light intensity and duration of irradiation, photocatalyst surface area, oxygen dissolution in the reaction medium, substrate and photocatalyst nature, doping of metal and non-metal ions, and substrate and photocatalyst structure. These outcomes will be useful in identifying the most practical and affordable solutions to degrade direct yellow 12 dye through photocatalytic based degradation processes.