|
| Heavy metal passivation effect and mechanism of ferrihydrite-synthetic humic-like acid composite in farmland |
| Received:February 07, 2023 Revised:May 29, 2023 |
| View Full Text View/Add Comment Download reader |
| KeyWord:synthetic humic-like acid;ferrihydrite;heavy metal;passivation;mechanism |
| Author Name | Affiliation | E-mail | | SUN Yucan | College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China | | | FANG Mingzhi | College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China | | | ZHANG Bing | College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China | | | LIU Yifei | Technical Centre for Soil, Agriculture and Rural Ecology and Environment, Ministry of Ecology and Environment, Beijing 100012, China | | | YANG Ting | College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China | boayang113@126.com | | CHEN Tan | College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
Beijing Engineering Research Center of Food Environment and Health, Minzu University of China, Beijing 100081, China | chentan05@tsinghua.org.cn |
|
| Hits: 1034 |
| Download times: 1079 |
| Abstract: |
| Ferrihydrite-natural humic acid composite(FH-NHA)has been widely used in the remediation of heavy metal pollution in soil. However, the active sites of natural humic acid from different sources vary, resulting in uncontrollable passivation effect and limited practical application. In this study, synthetic humic-like acid(SHLA)with controllable structure and properties was synthesized based on the optimized abiotic humification process. Ferrihydrite-synthetic humic-like acid composite(FH-SHLA)was further prepared. A soil simulation experiment, combined with the change in the contents of DTPA-extractable and BCR extractable heavy metals from the soil, were used to study the heavy metal passivation effect of FH-SHLA application. Furthermore, the impacts of FH-SHLA on physical and chemical properties of the soil were explored, and its heavy metal passivation mechanism was assessed using scanning electron microscopy, Fourier transform-infrared spectroscopy, and X-ray photoelectron spectroscopy. The results showed that FH-SHLA significantly changed physical and chemical properties of soil, such as pH, cation exchange capacity, conductivity, and organic carbon content. These properties improved to varying degrees. After 30 days of incubation with FH-SHLA, the content of DTPA-extracted lead(Pb), cadmium(Cd), and zinc(Zn)in soil decreased by 65.98%, 29.68% and 60.89%, respectively. These reductions exceeded those obtained using FH and FHNHA. FH-SHLA significantly promoted the transformation of soil Pb, Cd, and Zn from the effective fraction(acid-soluble fraction+reducible fraction)to stable fraction(oxidizable fraction+residue fraction). The passivation effect with FH-SHLA was better than the effect with FH and FH-NHA. The reduced partition index and stabilization efficiency were significantly increased, and metal bioavailability factor and ecological risk index were significantly reduced. FH-SHLA effectively reduced the ecological risk of heavy metal contaminated soil. The soil heavy metal passivation mechanism of FH-SHLA involves surface complexation, precipitation, and cation- π interaction. Thus, the FH-SHLA composite has significant implications in the remediation of heavy metal contaminated soil. |
|
|
|
