Remediation of Lead and Nickel Contaminated Soil Using Nanoscale Zero-Valent Iron (nZVI) Particles Synthesized Using Green Leaves: First Results

Nimita Francy,Subramanian Shanthakumar,Fulvia Chiampo,Yendaluru Raja Sekhar

doi:10.3390/pr8111453

Nimita Francy, Subramanian Shanthakumar + Show 2 more

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https://doi.org/10.3390/pr8111453

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Abstract

Nanoscale zero-valent iron (nZVI) particles have proved to be effective in the remediation of chlorinated compounds and heavy metals from contaminated soil. The present study aimed to analyze the performance of nanoparticles synthesized from low-cost biomass (green leaves) as chemical precursors, namely Azadirachta indica (neem) and Mentha longifolia (mint) leaves. These leaves were chosen because huge amounts of them are present in the region of Vellore. These nanoparticles were used to remove lead and nickel from contaminated soil. Characterization of nZVI particles was conducted using the Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and Brunauer–Emmett–Teller isotherm (BET) techniques. Remediation was performed on two different soil samples, polluted with lead or nickel at an initial metal concentration around 250 mg/kg of soil. The results revealed that after 30 days, the lead removal efficiency with 0.1 g of nZVI particles/kg of soil was 26.9% by particles synthesized using neem leaves and 62.3% by particles synthesized using mint leaves. Similarly, nickel removal efficiency with 0.1 g of particles/kg of soil was 33.2% and 50.6%, respectively, by particles using neem and mint leaves. When the nanoparticle concentration was doubled, Pb and Ni removal improved, with similar trends obtained at a lower dosage (0.1 g of particles/kg of soil). These first results evidenced that: (1) the nZVI particles synthesized using green leaves had the potential to remove Pb and Ni from contaminated soil; (2) the neem-derived particles gave better Ni removal efficiency than Pb one; (3) the mint-derived particles showed better Pb removal efficiency than Ni one; (4) the highest removal efficiency for both metals was achieved with the mint-derived particles; (5) double higher dosage did not greatly improve the results.

Highlights

The discharge of industrial waste into the environment causes the accumulation of heavy metals in water and soil
Fertilizers used for supplying nitrogen–phosphorous–potassium (NPK) to soil contain lead and cadmium (Cd) as component elements [6]
Nanoscale zero-valent iron particles were chemically synthesized using neem and mint leaves to remove lead and nickel from two soils. These leaves were chosen because huge amounts of them are present in the region of Vellore

Summary

Introduction

The discharge of industrial waste into the environment causes the accumulation of heavy metals in water and soil. Lead (Pb) and nickel (Ni) are two heavy metals present in the environment due to industrial activities. The presence of Pb in high concentrations can affect joints of the human body and lead to miscarriage in pregnant women [4]. The primary sources of Pb discharge into the environment are mostly fertilizer, biosolids, metal mining, battery, and paint industries [5]. Fertilizers used for supplying nitrogen–phosphorous–potassium (NPK) to soil contain lead and cadmium (Cd) as component elements [6]. Pb concentration in soil equal to 300 μg/kg of soil is evaluated as a threshold without substantial risk for intake by humans [7]

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