赤泥改性生物炭修复铅污染土的电化学阻抗响应及其曲线重构OA

[Purposes]Biochar and its modified materials have shown certain application potential in the remediation of heavy metal-contaminated soils.However,the electrochemical response charac-teristics during the remediation of lead-contaminated soil by using red mud-modified biochar(RMBC)require further clarification.[Methods]Electrochemical impedance spectroscopy(EIS)was used to measure the impedance of soil specimens with different RMBC dosages and curing ages.The evolu-tion of impedance spectra was analyzed by using equivalent circuit model,low-field nuclear magnetic resonance,and machine learning.[Results]The results show that RMBC increases the radius of the capacitive arc in the Nyquist plots,which first increases and then tends to stabilize with increasing RM-BC dosage.With prolonged curing age,the diffusion feature in the low-frequency region gradually weakens,and the charge-transfer process becomes dominant.The equivalent circuit parameters indi-cate that RMBC affects the conductivity of the pore solution,interfacial charge transfer,and diffusion impedance.Low-field nuclear magnetic resonance results show that RMBC reduces the proportion of micropores and increases the proportions of small and mesopores.A data-driven model is developed by dividing the training and testing sets at the level of complete Nyquist curves.The model captures the overall trend of impedance spectra,although deviations remain in the high-impedance and low-fre-quency region.[Conclusions]These results indicate that EIS can characterize the impedance response of RMBC-remediated lead-contaminated soil,and machine learning can serve as an auxiliary tool for rapid estimation of Nyquist curves.