Evaluation Health Risks and Sorption of Hexavalent Chromium (Cr(VI) by Biochar and Iron Doped Zinc Oxide Modified Biochar (Fe-ZnO@BC) Using Trifolium: A Green Synthesis Technique.

Contamination of aquatic and terrestrial environment with hexavalent chromium Cr(VI) is one of the major hazards worldwide due its carcinogenicity, persistency and immobility. Different research techniques have been adopted for Cr(VI) remediation present in terrestrial and aquatic media, while adsorption being the most advance, low cost, environmentally friendly and common method. The present study discussed the mechanisms of Parthenium hysterophorus derived biochar, iron-doped zinc oxide nanoparticles (nFe-ZnO) and Fe-ZnO modified biochar (Fe-ZnO@BC) involved in Cr(VI) mobility and bioavailability. Pot experiments were conducted to study the effect of Parthenium hysterophorus derived biochar, nFe-ZnO and Fe-ZnO@BC application rates (2%, 2 mg/kg, 10 mg/kg, respectively). The results indicated that the addition of soil amendments reduced Cr(VI) mobility. The findings revealed that the reduction in chromium mobility was observed by P. hysterophorus BC, and Fe-ZnO@BC but nFe-ZnO application significantly (p = 0.05) reduced Cr(VI) and Cr uptake as compared to the control treatments. The results of SEM coupled with EDS showed a high micropores and channel, smooth surface which helped in adsorption, and may enhance soil conditions. The concentration index (CI) by different amendments in trifolium plant was followed the descending order as: nFe-ZnO > Fe-ZnO@BC > P. hysterophorus BC after 30, 60 and 90 days of harvesting, respectively. In addition, human health risk index was found less than one (H1 < 1.0) in amended soils as compared to control treatments.