Soil Remediation Using Zero-Valent Iron Nano-Particle Modified with Spondias Mombin Leaves Extract

Abstract

Zero-valent iron nano-particle (nZVI) was modified with Spondias mombin (Sm) leaves extract (Sm-nZVI) for the removal of total petroleum hydrocarbons (TPH), total hydrocarbon content (THC), and polycyclic aromatic hydrocarbons (PAHs) from contaminated soil. Advanced analytical tools such as Fourier Transform Infra-Red (FT-IR) Spectrophotometer, Scanning Electron Microscope(SEM) and X-ray diffractometer (XRD) were used to characterize the biosynthesized zero-valent iron nano-sorbent. The Fourier Transform Infra-Red analysis confirmed that the bioactive molecules such as alkaloids, polyphenols, flavonoids, etc. in Spondias mombin leaves extract were responsible for the zero-valent iron nanoparticle synthesis and stabilization. The peaks at 2  equal to 44.9^o confirmed zero-valent iron (Fe⁰) in Sm-nZVI. The micrograph showed an average particle size ranging from 13 nm to 158 nm in Sm-nZVI revealing the micro-porosity of the sorbent. The application of Sm-nZVI for the removal of organic pollutants with varied effects of experimental parameters such as dosage, contact time and pH were successful. The result showed that the pH value for optimum removal efficiency (%) of THC (77.99%), TPH (75.61%) and PAHs (96.98) was 3.0. The adsorbent dosage for optimum removal efficiency (%) was 0.8 g for THC (79.15%), TPH (80.36%) and PAHs (97.31%) and contact time was 45 min for PAHs (97.86%) and 120 min for THC (83.98%) and TPH (85.54%). The biosynthesized zero-valent iron nano-particle showed higher removal efficiency (%) for PAHs (97.29%). This study reveals Spondias mombin zero-valent iron nano-sorbent (Sm-nZVI) as an effective and efficient sorbent for remediation of soil ladened with organic pollutants and the likes.