The performance and mechanism of cadmium availability mitigation by biochars differ among soils with different pH: Hints for the reasonable choice of passivators

文献类型： 外文期刊

第一作者： Jia, Yuehui

作者： Jia, Yuehui;Li, Jing;Liu, Jie;Li, Jing;Zeng, Xibai;Zhang, Nan;Jiku, Md Abu Sayem;Wu, Cuixia;Su, Shiming;Wen, Jiong

作者机构：

关键词： Acid and alkaline soil; Cd binding mechanism; Cd bioavailability; Cotton straw biochar; Soil cation competition

期刊名称：JOURNAL OF ENVIRONMENTAL MANAGEMENT （ 影响因子：8.91； 五年影响因子：8.549 ）

ISSN： 0301-4797

年卷期： 2022 年 312 卷

页码：

收录情况： SCI

摘要： The performances of passivation materials mitigating Cadmium (Cd) bioavailability considerably vary with the pH condition of Cd-contaminated soils. However, less information was available for the method of improving Cd passivation efficiency taking into account the pH of the targeted soil. Furthermore, the underlying mechanism of Cd availability mitigation in soils with different pH has not been clearly explored. In this study, cotton straw biochar (CSB) and its modified products using NaOH (CSB-NaOH) were prepared and applied in two kinds of Cdcontaminated soils with different pH. It was found that CSB-NaOH was more effective than CSB in regulating the Cd bioavailability in the acid soil, while the opposite tendency was observed in alkaline soil. The difference of the Cd passivation efficiency is correlated with contributions of various Cd-biochar binding mechanisms, which cation exchange mechanism is largely eliminated for CSB-NaOH. The interaction of Cd with CSB/CSB-NaOH was further evidenced through characterization results of Scan Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR) and X-ray Photoelectron spectroscopy (XPS). Characterization results proved that carboxyl, hydroxyl and ethyl groups were the key functional groups involved in Cd passivation. XPS results showed that Cd binding methods varied between CSB and CSB-NaOH, which Cd2+ and Cd-O were the main form of Cd binding to CSB while Cd-O was the main form on CSB-NaOH. In this work, it was demonstrated that in acid soil, pH change caused by biochar plays a more significant role in controlling the Cd bioavailability, while in alkaline soil, the strength of the Cd-biochar interaction is more decisive for the Cd passivation efficiency. This work provides information on how to select the suitable passivator to decrease the Cd bioavailability in terms of different soil pH and property.

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