Pyrolytic synthesis and performance efficacy comparison of biochar-supported nanoscale zero-valent iron on soil polluted with toxic metals.

Toxic and hazardous metals such as cadmium (Cd) and Lead (Pb) can cause cancer in humans; hence, reducing their bioavailability in the soil is crucial for human health and environmental safety. In this study, biochar modified with nanoscale zero-valent iron (nZVI-BC) was synthesized from low-cost adsorbent waste materials and iron (iii) oxide (Fe₂O₃₎ via carbothermal reduction process for stabilization of Pb and Cd in the soil. Furthermore, an evaluation of treatment efficiency on exposure health hazards for both carcinogenic and non-carcinogenic risks was done. The results revealed that nZVI-modified eggshell biochar was able to reduce the concentration bioavailable of Pb and Cd in soil by (69–75%) and (62–65%), and reduce the toxicity leaching of Pb and Cd by (53–66%) and (68–75%), respectively. The treatments reduced carcinogenic risk (CR) and hazard index (HI) in children and adults by 35–47% for Pb and 25–36% for Cd, respectively. Hence, this study proposes a new way to reduce and modify environmental wastes to make nZVI-supported biochar that can remediate toxic metals from the soil, improve soil nutrients, reduce human exposure health risks, and enhance the environment's health. [ABSTRACT FROM AUTHOR]