Biochar-supported nano-scale zerovalent iron activated persulfate for remediation of aromatic hydrocarbon-contaminated  soil: an in-situ pilot-scale study

Abstract

Biochar supported nano-scale zerovalent iron (nZVI/BC) for persulfate (PS) activation has been studied extensively for the degradation of pollutants on the lab scale, but it was rarely applied in practical soil remediation in the field. In this research, we developed a facile ball-milling method for the mass production of nZVI/BC, which was successfully applied to activate persulfate for the remediation of organic polluted soil on an in-situ pilot scale. In-situ high-pressure injection device was developed to inject nZVI/BC suspension and PS solution into the soil with a depth of 0–70 cm. The removal efficiency of target pollutants such as 2-ethylnitrobenzene (ENB, 1.47–1.56 mg/kg), biphenyl (BP, 0.19–0.21 mg/kg), 4-(methylsulfonyl) toluene (MST, 0.32–0.43 mg/kg), and 4-phenylphenol (PP, 1.70–2.46 mg/kg) at different soil depths was 99.7%, 99.1%, 99.9% and 99.7%, respectively, after 360 days of remediation. The application of nZVI/BC significantly increased the degradation rates of contaminants by 11–322%, ascribed to its relatively higher efficiency of free radical generation than that of control groups. In addition, it was found that nZVI/BC-PS inhibited soil urease and sucrase enzyme activities by 1–61% within 55 days due to the oxidative stress for microbes induced by free radicals, while these inhibition effects disappeared with remediation time prolonged (> 127 days). Our research provides a useful implementation case of remediation with nZVI/BC-PS activation and verifies its feasibility in practical contaminated soil remediation. Graphical Abstract

Enhanced phenol removal by permanganate with biogas residue biochar: catalytic role of in-situ formation of manganese dioxide and activation of biochar

“…Previous studies have shown that ROS such as superoxide radical (O 2 • − ), hydroxyl radical (•OH), and singlet oxygen ( 1 O 2 ) might be involved in the oxidation process (Zeng et al 2022;Han et al 2022;Yao et al 2022). Tertbutanol (TBA) was found to be the scavenger for •OH and was used to reveal the role of •OH in phenol removal in the KMnO 4 /BRB system (Luo et al 2019).…”

Enhancing Biochar Impact on the Mechanical Properties of Cement-Based Mortar: An Optimization Study Using Response Surface Methodology for Particle Size and Content

“…To meet specific application requirements, BC produced via slow pyrolysis is typically subjected to milling and sieving, resulting in particle sizes ranging from 0.044 to 20 mm [22]. BC with a finer particle size boasts a larger specific surface area and an increased number of active sites, making it advantageous for applications such as soil remediation and heavy metal adsorption [23][24][25]. However, it is essential to determine whether fine particle size BC similarly benefits cementitious materials.…”