Comparison of EDTA, Citric Acid and TiO2 Nanoparticles to Support Cd Phytoaccumulation in Spiked Soil

Abstract

Chelating agents can increase the bioavailability of cadmium (Cd) which is an important factor in phytoremediation. Current study aimed at comparing potential of organic and inorganic ligands for improving phytoextraction of Cd in soil. The greenhouse experiment was carried out to investigate the impacts of ethylenediaminetetraacetic acid (EDTA), citric acid and titanium dioxide nanoparticles (TiO 2 NPs) on the Cd accumulation and growth of Pelargonium hortroum. For this purpose, soil was spiked with different levels of Cd. One month old seedlings of P. hortorum were transplanted in each pot and different concentrations of EDTA, citric acid and TiO 2 were applied. After harvesting, plant biomass was measured and plant parts were digested in mixture of acid for the determination of Cd in root and shoot. The results revealed that the dry biomass of P. hortorum decreased by 46.5% with increasing levels of Cd and EDTA. However, the dry plant biomass increased with increasing levels of citric acid and TiO 2 NPs. The maximum dry plant biomass was observed in soil amended with TiO 2 NPs followed by citric acid and EDTA. The maximum accumulation of Cd in root (350, 260, 238 mg Cd kg-1) and shoot (997, 650, 450 mg Cd kg-1) was observed at 4 mmol kg-1 EDTA followed by 10 mmol kg-1 citric acid and 100 mg kg-1 TiO 2 NPs, respectively. Our results demonstrated that citric acid and TiO 2 NPs had affirmative effect on the Cd uptake in the artificially Cd-contaminated soil.