Sunlight Assisted Degradation of Toxic Phenols by Zinc Oxide Doped Prussian Blue Nanocomposite

Abstract Aromatic phenols, found in various industrial effluents, are categorized as priority pollutants and seeking attention owing to their life threatening effects. In present study, nanocomposite of zinc oxide coupled with prussian blue (ZnO@FeHCF) was synthesized by green method using Azadirachta indica leaf extract. Nanocomposite was characterized by relevant techniques and found crystalline as well as nanosized. Fabricated nanocomposite was employed for the eradication of various phenols under Sunlight. Photocatalytic degradation of phenol, 3-aminophenol (3-AP) and 2,4-dinitrophenol (2,4-DNP) was performed at different parameters of pollutant-concentration, catalyst-amount, pH, contact-time and exposure of Sunlight. Obtained results showed the maximum removal of 3-AP (97%) followed by phenol (95%) and 2,4-DNP (93%) that is attributed to their basicity differences. Compared to ZnO and FeHCF, the nanocomposite was found more effective in degrading the phenols and lowered the t1/2 value of 3-AP (4.04 h), phenol (4.405 h) and 2,4-DNP (4.68 h) to a greater-extent. Effect of different foreign-anions was also studied to verify nanocomposite’s efficiency under natural conditions. Better photocatalytic activity of the nanocomposite as compared to ZnO and FeHCF might be due to longer-life-span of charge-carriers as revealed by photoluminescence study. Mechanism of the photocatalysis was investigated by using radical-scavenger to understand the steps involved in removal process. It was found that OH was the main species promoting the degradation of phenols. Sunlight active nanocomposite found to show excellent catalytic reusability up to 10 cycles. Overall, green synthesized nanocomposite is cheap, reusable, high-surface-activity, low band gap with charge separation recommended for bright future of environment.