A pragmatic review on photocatalytic degradation of methyl orange dye pollutant using greenly biofunctionalized nanometallic materials: A focus on aquatic body

Water is the source of life. But unfortunately, 80% of wastewater is discharged into the aquatic body untreated globally, of which industry is responsible for 70% of such water abstraction through the discharge of pollutants like methyl orange. According to the WWAP, water pollution kills 100 million individuals, 2 million marine animals, and seabirds yearly, and by 2025, it is forecasted that similar to 1000 million inhabitants in arid zones will experience severe water crisis, and thus, the security of water has become focal outcry due to daily environmental pollution escalation caused by rapid growth in industries and population. Recently, biosynthesized nanoparticles as photocatalysts have answered the call for sustainable treatment of methyl orange dye effluent through photodegradation because of their efficient photoactivity, inexpensiveness, and eco-benignness. In this review, photocatalytic-degradation mechanism and pathways of methyl orange in the aquatic environment in the presence of (OH-)-O-center dot and O-center dot(2)- using green nanoparticles were mechanistically discussed. The highest degradation efficiency was found to be 100%, the final mineralization products were H2O and CO2, and the least degradation time taken was 2 min with silver nanoparticles being the most commonly used degrader and plant extracts being the most commonly employed bioreductant for the biosynthesis of nanoparticles.