Breakthrough in soil remediation: Biochar-encapsulated nano iron for heavy metal cleanup
Mississippi State University researchers develop an efficient method for heavy metal removal using biochar and nanoscale zero-valent iron
image: Mississippi State University researchers develop an efficient method for heavy metal removal using biochar and nanoscale zero-valent iron.
Credit: Department of Sustainable Bioproducts, Mississippi State University, Mississippi State, MS 39762, USA Corresponding author.
In a significant advancement for environmental remediation, researchers at Mississippi State University have unveiled a new composite material capable of effectively removing heavy metals from polluted water and soil. The study, published in the Journal of Bioresources and Bioproducts, details the synthesis and evaluation of BC-G@Fe0, a material derived from soybean stover-based biochar (BC) and nanoscale zero-valent iron (nanoFe0).
The research team, led by Dr. Xuefeng Zhang, utilized carbothermal reduction to synthesize the BC-G@Fe0 composites. The process involved the pyrolysis of biochar, which created a reduced atmosphere that converted iron oxides/salts to nanoFe0 particles. The resulting graphene shells encapsulating the nanoFe0 particles were formed due to gaseous carbon evolved from biomass carbonization reacting with iron oxides/iron salts.
The study revealed that increasing the biochar's surface area decreased the average diameters of nanoFe0 particles, reducing their aggregation and enhancing their heavy metal uptake capacity. The BC-G@Fe0 composite demonstrated remarkable uptake capacities for Cu2+, Pb2+, Ag+, and As3+, with values reaching up to 124.4, 121.8, 254.5, and 48.0 mg/g, respectively, at pH 5 and 25°C.
Furthermore, the BC-G@Fe0 composite showed high stability in fixed-bed continuous flow for Cu2+ removal, capable of treating 28.6 L of Cu2+ contaminated water continuously over 120 hours. The potential of BC-G@Fe0 for immobilizing bioavailable As3+ from contaminated soil was also explored, with 5% (w/w) of the composite addition immobilizing up to 92.2% of bioavailable As3+.
This research not only highlights the potential of biochar and nanoscale zero-valent iron in environmental remediation but also underscores the importance of surface area in the performance of such materials. The findings suggest that BC-G@Fe0 composites could be a viable solution for treating heavy metal contamination in water and soil, offering a sustainable and cost-effective alternative to traditional remediation methods.
See the article:
DOI
https://doi.org/10.1016/j.jobab.2023.10.001
Original Source URL
https://www.sciencedirect.com/science/article/pii/S2369969823000427
Journal