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| Stabilization mechanism of non-metallic materials on cadmium in water-sediment environment |
| Received:September 24, 2024 |
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| KeyWord:non-metallic materials;biochar;lake sediments;cadmium;phosphorus |
| Author Name | Affiliation | E-mail | | YANG Daizong | Guangxi Colleges and Universities Key Laboratory of Environmental-friendly Materials and Ecological Restoration, Guangxi Key Laboratory of Advanced Structural Materials and Carbon Neutralization, School of Materials and Environment, Guangxi Minzu University, Nanning 530105, China
Chinese Research Academy of Environmental Sciences, Beijing 100012, China | | | YIN Cailiu | Guangxi Colleges and Universities Key Laboratory of Environmental-friendly Materials and Ecological Restoration, Guangxi Key Laboratory of Advanced Structural Materials and Carbon Neutralization, School of Materials and Environment, Guangxi Minzu University, Nanning 530105, China | | | YU Hui | Chinese Research Academy of Environmental Sciences, Beijing 100012, China | | | LI Xixi | Chinese Research Academy of Environmental Sciences, Beijing 100012, China | | | ZANG Longfei | Chinese Research Academy of Environmental Sciences, Beijing 100012, China | | | LUO Mingke | Chinese Research Academy of Environmental Sciences, Beijing 100012, China | luo.mingke@craes.org.cn |
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| Abstract: |
| In order to investigate the differences of typical non-metallic materials kaolin（KL）, activated carbon（AC）and biochar（BC）on the stabilization of Cd in water-sediment. This article studied the effects of three materials on the physicochemical factors（pH, ORP）, nutrients[total organic carbon（TOC）, total phosphorus（TP）, total nitrogen（TN）] and Cd（concentration, form, biological toxicity）in the system of“overlying water-interstitial water-sediment”. The results showed that the materials all enhanced the oxidation of the overlying water and depressed TOC and Cd（Ⅱ）concentrations in the aqueous phase, with AC causing the greatest degree of nutrient deposition and release from the system. Spearman correlation analysis proved that the specific surface area and total pore volume of the material were negatively correlated with pH and TOC, the TP concentration in the interstitial water was super-significantly positively correlated with Cd biological toxicity. Firstly, non-metallic materials change different physicochemical factors（such as pH, TP）at the sediment-water interface, indirectly reduce the migration of Cd（Ⅱ）, Secondly, the materials directly adsorb the unstable components of Cd in the overlying water, transforming it into a more stable oxidizable state. Among them, BC, due to its unique characteristic, promotes the transformation of reducible state Cd with P to more stable Cd1.25Ca0.75（P2O7）crystals. Furthermore, it enhances the residue state of Cd in the sediments by 12 percentage points, which has the best passivation effects. In summary, the adsorption, passivation and stability of Cd derive BC>AC>KL, AC has the greatest effect on physicochemical characteristics in the water-sediment environment. |
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