Ding Yuan, Wang Weiya, Ao Shiying
National-Local Joint Engineering Research Center of Heavy Metal Pollutant Control and Resource Utilization, School of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang, China.
PeerJ. 2021 Aug 9;9:e11921. doi: 10.7717/peerj.11921. eCollection 2021.
Arable land polluted by copper (Cu) and cadmium (Cd) is a widespread problem. The use of biochar and/or clay mineral as a soil amendment can effectively solidify heavy metals in the soil. We applied biochar (BC), iron modified biochar (Fe-BC), maifanite (MF, a kind of clay minerals), a combination of BC with MF (BC:MF), and Fe-BC with MF (Fe-BC:MF) at a 2 wt % dose as soil amendments to study their ability to prevent Cu and Cd from accumulating in ryegrass ( L.). We found that after 90 days of cultivation, the Cd and Cu content both significantly decreased in ryegrass shoots from 2.06 and 209.3 mg kg (control) to 1.44-2.01 and 51.50-70.92 mg kg, respectively, across treatments ( < 0.05). Similarly, the bioconcentration factor (BCF) for Cd/Cu was significantly smaller ( < 0.05) in all amendments versus control soil. This trend differed among the shoot, BCF, and transportation factor (TF). Combining BC:MF or Fe-BC:MF did not significantly improve the Cd/Cu stabilization in the soil compared to the corresponding single amendment ( > 0.05). Our adsorption balance experiment showed that BC, Fe-BC, and MF physically and chemically adsorbed Cd and Cu by complexation with functional groups (mesoporous nanomaterials) whose porosity measurements ranged from 0.68 to 78.57 m g. Furthermore, the amorphous crystalline iron oxide binding Cd and Cu was the key to immobilizing these metals in the soil. The amendments applied in our study show promise for enhancing immobilization of Cu and Cd in contaminated paddy soils.
受铜（Cu）和镉（Cd）污染的耕地是一个普遍存在的问题。使用生物炭和/或粘土矿物作为土壤改良剂可以有效固化土壤中的重金属。我们以2 wt%的剂量施用生物炭（BC）、铁改性生物炭（Fe-BC）、麦饭石（MF，一种粘土矿物）、BC与MF的组合（BC:MF）以及Fe-BC与MF的组合（Fe-BC:MF）作为土壤改良剂，研究它们防止Cu和Cd在黑麦草（Lolium perenne L.）中积累的能力。我们发现，种植90天后，各处理黑麦草地上部分的Cd和Cu含量均显著降低，从对照的2.06和209.3 mg/kg分别降至1.44 - 2.01和51.50 - 70.92 mg/kg（P < 0.05）。同样，与对照土壤相比，所有改良剂处理中Cd/Cu的生物富集系数（BCF）均显著更小（P < 0.05）。地上部分、BCF和转运系数（TF）的这种趋势有所不同。与相应的单一改良剂相比，BC:MF或Fe-BC:MF组合并没有显著提高土壤中Cd/Cu的稳定性（P > 0.05）。我们的吸附平衡实验表明，BC、Fe-BC和MF通过与孔隙率在0.68至78.57 m²/g范围内的官能团（介孔纳米材料）络合，对Cd和Cu进行物理和化学吸附。此外，结合Cd和Cu的无定形结晶氧化铁是将这些金属固定在土壤中的关键。我们研究中施用的改良剂在增强污染稻田土壤中Cu和Cd的固定方面显示出前景。
