The use of Sulfidated nano zero-valent iron (S-nZVI) for stabilzation of soil contaminant- implication on plants.

Omolola Elizabeth Ojo

Disertační práce

Abstract:

Nanoparticles have shown promise in metal (loid) stabilization; however, risks associated with using engineered nanoparticles cannot be neglected. The main aim of the thesis was to evaluate the influence of sulfidated nano zero-valent iron (S-nZVI) with or without the co-application of sewage sludge in stabilizing metal (loid) in soil and simultaneously investigate its influence on plants grown on such soil. Sewage sludge has been commonly used as a fertilizer and a source of organic matter in soils, and its use could be beneficial during the stabilization process; nevertheless, it may also include several contaminants, including leachable metals. The study's first phase investigated how the co-application of S-nZVI and sewage sludge can reduce the leaching of Cd, Pb, Fe, and Zn. Two leaching procedures (SPLP and TCLP) were used with five treatments (control, 1% Fe grit, 1% composted sludge, 1% S-nZVI, 1% composted sludge, and 1% S-nZVI). Samples were incubated for 1 week, 1 month, 3 months, and 6 months. The combination of composted sludge and S-nZVI was the most effective in reducing the leachability of metals in the column systems. S-nZVI alone was the most efficient in reducing approximately 80% of the Zn concentration in soil solution. Iron grit was the most effective in reducing the concentration of extractable metals in the batch experiment. Therefore, the most practical combination of two amendments for decreasing metal leaching and potentially minimizing the related dangers was S-nZVI combined with composted sewage sludge and Fe grit. The second phase of the experiment investigated the role of the co-application of S-nZVI and sewage sludge on plant performance in terms of growth, plant pigment, antioxidant enzymes, and metal uptake using two plant species (Arrhenatherum elatius L. and Festuca rubra L.). Six different amendments (control, 1% S-nZVI, 2% S-nZVI, 3% composted sludge, 1% S-nZVI + 3% sewage sludge, and 2% S-nZVI+ 3% sewage sludge) were used, and plants were grown for a total of 75 days, after which plants were harvested and analyzed. Applying S-nZVI with or without sewage sludge effectively improved plant height and above-ground biomass, and increased plant pigment was also observed. 1% S-nZVI alone promotes the reduction of about 45% Pb in Festuca rubra roots. The coapplication of S-nZVI with sewage sludge did not significantly influence the growth and biomass of both plants, while the co-application of 2% S-nZVI with 3% sewage sludge was the best in stabilizing Pb and Cd in the soil, thus reducing its uptake by plants. Variations were observed in pigments in both plants, with most amendments resulting in increased plant pigments. There was little to no influence of antioxidant enzymes in most variants across treatments for both plants; Festuca rubra is the most tolerant plant. Thus, the co-application of S-nZVI and sewage sludge is a promising amendment. However, additional studies are still needed to evaluate its full potential and eliminate the risks associated with its usage

Keywords

Antioxidant enzymes, Stabilization, Sulfidate nano zero-valent iron

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 22. 5. 2024

Obhajoba závěrečné práce

• Vedoucí: prof. RNDr. Michael Komárek, Ph.D.
• Oponent: Aleš Vaněk, Ph.D., doc. RNDr., Ondřej Lhotský, externi, Diego Baragaño Coto, externi

Česká zemědělská univerzita v Praze

Fakulta životního prostředí

Doktorský studijní program:
Applied and Landscape Ecology