Biochar Supported Ni/Fe Bimetallic Nanoparticles For In-situ Remediation Of 1,1,1-TCA From Groundwater

1,1,1-TCA is a typical organic pollutant and is widespread in groundwater. Nano scale zero-valent iron (nZVI) shows high removal efficiency due to its stronger electronegativity. However, bare nZVI particles are unstable in water. Both passivation and agglomeration would result in a dramatic decline in the reactivity of nZVI. In order to enhance the reactivity of ZVI, biochar supported Ni/Fe nanoparticles were prepared and their efficacy in removing 1,1,1-trichloroethane (1,1,1-TCA) from groundwater was evaluated. Degradation reactive wells were established by using biochar supported Ni/Fe nanoparticles as active fillers. And the effectivity of degradation reactive wells for in-situ remediation of 1,1,1-TCA was investigated by simulation experiments in laboratory. The result showed that surface modification of Ni/Fe nanaparticles by using biochar could highly enhance the reactivity. The removal of 1,1,1-TCA reached 92% within 30 min. The BC-Ni/Fe nanoparticles effectively degraded 1,1,1-TCA (40 mg/L) in the anaerobic medium, and could be reused up to 10 times. Biochar prevented the bimetallic nanoparticles from agglomeration and improved the stability. At the same time, biochar adsorbed 1,1,1-TCA. Simulation experiments in laboratory showed that 1,1,1-TCA removal efficiency maintained ratios at 85% in 20 days, which proved that using BC-Ni/Fe nanoparticles as active fillers to establish degradation reactive wells for in-situ remediation of 1,1,1-TCA was feasible.