Green mango peel-nanozerovalent iron activated persulfate oxidation of petroleum hydrocarbons in oil sludge contaminated soil

Abstract

Abstract One of the promising environmental applications of zero valent iron is its catalytic oxidation of various organic contaminants. In this study, to evaluate biologically synthesized nanozero valent iron (nZVI) as activator of persulfate oxidation of petroleum hydrocarbons in oil sludge contaminated soil, a series of batch experiments were conducted. Zero valent iron nanoparticles were synthesized using green mango peel extracts. Green mango peel-nanozero valent iron (GMP-nZVI) activated system showed a gradual increase in iron concentration over the three days treatment time. More or less similar effect was observed for C-nZVI and GMP-nZVI activated treatments after the 21st day treatment. TPH removal from the oil sludge contaminated soil using GMP-nZVI demonstrated >90% degradation over one week treatment. Surface capping of the synthesized material (GMP-nZVI) could enhance activation. The capping through controlled release of ferrous ion compared to C-nZVI might prevent scavenging of sulfate radicals. The inhibition of TPH degradation by mannitol demonstrated the role of hydroxyl radical in degrading TPH under GMP-nZVI activated persulfate oxidation system. In view of its TPH removal efficiency, low production cost and low environmental concerns, the GMP-nZVI has greater advantages over the chemically synthesized nanoparticles.