Highly effective adsorption and passivation of Cd from wastewater and soil by MgO- and Fe3O4-loaded biochar nanocomposites

Introduction: The application of Fe- (BC-Fe) and Mg-modified (BC-Mg) biochars for the remediation heavy-metal-contaminated soil has become a research hotspot in recent years. It is critical to select suitable biochar rejuvenation under same pollution condition. Methods: In this study, were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM). addition, adsorption passivation effects BC-Fe BC-Mg comprehensively evaluated through batch experiments incubation experiments, Cd-contaminated on plant growth also demonstrated pot experiments. Results: SEM, FTIR, XRD showed that MgO Fe 3 O 4 nanoparticles successfully loaded surface. maximum efficiencies Cd 52.63 66.23 mg g −1 , which was 9.05 7.19 times higher than original (7.32 ), respectively. Soil culture experiment 5% significantly reduced DTPA-Cd content 38.86% 50.85% at 120 days, promoted conversion acid-soluble oxidizable residual states. Pot revealed shoots maize 3.97 6.09 times, respectively, both increased dry fresh weights roots plants. Moreover, BC, BC-Fe, provided nutrients required activities dehydrogenase, urease, peroxidase. adsorption–passivation mechanism mainly included electrostatic attraction, while precipitation ion exchange. Discussion: Overall, results can be used as an efficient functional material heavy-metal remediation, study guidance selection passivator materials remediation.