Biological and Photocatalytic Degradation of Congo Red, a Diazo Sulfonated Substituted Dye: a Review

• Published in: Water, air, and soil pollution air, and soil pollution, 2022-11, Vol.233 (11), Article 468
• Main Authors: Khan, Rana Rashad Mahmood, Qamar, Hoorish, Hameed, Ayesha, Rehman, Aqmar ur, Pervaiz, Muhammad, Saeed, Zohaib, Adnan, Aqib, Ch, Ayoub Rashid
• Format: Article
• Language: English
• Subjects: Atmospheric Protection/Air Quality Control/Air Pollution; Azo compounds; Azo dyes; Bimetals; Biodegradation; Catalysts; Cell walls; Climate Change/Climate Change Impacts; Cobalt; Cobalt ferrites; Degradation; Dyes; Earth and Environmental Science; Environment; Environmental monitoring; Functional groups; Fungi; Gadolinium; Health aspects; Hydrogeology; Industrial wastes; Iron compounds; Iron constituents; Methods; Microorganisms; Nanoparticles; Phosphates; Photocatalysis; Photodegradation; Pollutants; Polycyclic compounds; Soil Science & Conservation; Textile industry; Textile industry wastewaters; Titanium dioxide; Wastewater; Wastewater management; Water pollution; Water Quality/Water Pollution; Zinc oxide
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/s11270-022-05935-9

The environment has undergone significant change because of technological advancement. Industries are releasing pollutants directly into the environment. Water pollution is a growing issue for humanity. Methods for managing wastewater generated by biological and industrial wastes are being developed. Textile industries are risking the health of living beings by contaminating water with dyes. Azo dyes are the major constituent of wastewater from textile industries. This review article focuses on the photodegradation of Congo red, the most prominent Azo dye. For Congo red degradation, both biological (via microorganisms) and chemical (via nanoparticles) methods are being investigated. The biological method primarily employs bacterial and fungal species. Bacterial species such as Bacillus sp ., Pseudomonas sp. , and Staphylococcus lentus sp. efficiently degrade Congo red dye. The presence of functional groups on the cell wall of fungi, such as phosphates and hydroxyl, promotes efficient dye degradation. The use of nanoparticles for photodegradation of dyes is preferable because it does not result in polycyclic compounds after degradation. Many bimetallic catalysts, such as ZnO and TiO 2 , have shown promising photocatalytic properties due to their large band gap. The use of nanoparticles that can be easily separated after photodegradation is preferred. As Gd 3+ doped cobalt ferrite nanoparticles have higher removed capabilities than undoped cobalt ferrite nanoparticles, doping improves the degrading capability of nanocatalysts. Graphical Abstract