Efficient photocatalytic degradation of Bisphenol A by metal ferrites nanoparticles under sunlight

Abstract

Abstract Bisphenol-A (BPA) is an alleged endocrine-disrupter and carcinogen compound. Due to this, complete removal of BPA from environment is highly imperative to protect living organisms. Metallic ferrites have been proven with excellent properties and efficiency in various commercial applications. Therefore, crystalline nanoparticles of size less than 50 nm, of cobalt (CoFe2O4) and zinc (ZnFe2O4) ferrites were fabricated employing leaf-extract of Azarachita indica and water. Both ferrites (20 mg) were found effective in Sunlight assisted photocatalytic removal of 50 mg L−1 of toxic BPA from water at neutral pH. Nanoparticles of ZnFe2O4 showed highest efficiency (92%) followed by CoFe2O4 (89%) than bared ones like Fe2O3 (70%), ZnO (68%) and Co3O4 (54%). Results obtained were in good agreement with uppermost BET surface-area and Zeta-potential value, of uniformly distributed nanoparticles of two ferrites. Calculated band gap energies of ZnFe2O 4 and CoFe2O 4 were, 2.14 eV and 2.42 eV, respectively. GC–MS analysis of reaction mixture revealed the formation of minor and non-toxic metabolites (mass below 100) that finally undergo mineralization. Proposed degradation pathways revealed the role of hydroxyl radical that led to subsequent oxidation and hydrolysis of the BPA. Total organic carbons and scavenger analysis indicated the 58% mineralization after 5 h and involvement of free radical mechanism under direct sunlight. Overall, green synthesized ferrites were found remarkable photocatalysts and reusable (n = 10) with significant retain of activity. Furthermore, such ferrites nanoparticles may be recommended for further treatment of noxious contaminants in view of their large surface area, high charge separation capacity.