Co-application of biochar and titanium dioxide nanoparticles to promote remediation of antimony from soil by Sorghum bicolor: metal uptake and plant response

Abstract

Association of titanium dioxide nanoparticles (TiO2 NPs) and biochar (BC) to assist phytoremediation of Sb contaminated soil was investigated in this study. Seedlings of Sorghum bicolor were exposed to different regimes of TiO2 NPs (0, 100, 250 and 500 mg kg−1) and BC (0, 2.5% and 5%), separately and in combination, to investigate the effects on plant growth, Sb absorption and accumulation and physiological response of the plant in Sb contaminated soil. Co-application of TiO2 NPs and BC had positive effects on plant establishment and growth in contaminated soil. Greater accumulation of Sb in the shoots compared to the roots of S. bicolor was observed in all treatments. Application of BC increased immobilization of Sb in the soil. Using TiO2 NPs significantly increased accumulation capacity of S. bicolor for Sb with the greatest accumulation capacity of 1624.1 μg per pot achieved in “250 mg kg−1 TiO2 NPs+2.5% BC” treatment (P < 0.05). Association of TiO2 NPs and BC significantly increased chlorophyll a (Chl a) and chlorophyll b (Chl b) contents of S. bicolor compared to the TiO2 NPs-amended treatments. Results of this study presented a promising novel technique by combined application of TiO2 NPs and BC in phytoremediation of Sb contaminated soils. Co-application of TiO2 NPs and BC could reduce the required amounts of TiO2 NPs for successful phytoremediation of heavy metal polluted soils. Intelligent uses of plants in accompany with biochar and nanomaterials have great application prospects in dealing with soil remediation.

Keywords

• TiO2 NPs
• Biochar
• S. bicolor
• Phytoremediation
• Immobilization
• Antimony