生物炭负载纳米零价铁对湖泊底泥镉污染的修复效果

制备了生物炭负载纳米零价铁(nZVI/BC)复合材料，采用SEM、TEM、FTIR、EDS、XPS等手段对其表面形貌、粒径大小、官能团结构、表面元素及化学形态进行了表征和分析。通过镉(Cd)形态、浸出毒性、生物可利用性、上覆水中溶解态Cd质量浓度及底泥理化性质等指标评价了nZVI/BC对湖泊底泥中Cd的修复效果。结果表明，相比于对照组，经56 d修复后nZVI/BC处理组中Cd的残渣态质量分数增加了29.73%，有效降低了Cd的移动性；Cd的浸出质量浓度从4.65 μg·L^?1降至0.38 μg·L^?1，Cd的生物可提取态质量浓度从5.08 μg·L^?1降至2.13 μg·L^?1，其浸出质量浓度和生物可提取态质量浓度分别下降了91.83%和58.07%。同时，经过56 d的修复，nZVI/BC使上覆水中溶解态Cd的质量浓度比对照组降低了67.53%。此外，nZVI/BC的添加提高了底泥的pH和有机质，根据这2个指标的变化进一步分析了nZVI/BC复合材料对Cd的稳定机制。以上研究结果可为重金属污染底泥的修复提供参考。

Remediation effect of cadmium pollution in lake sediment by biochar-supported nanoscale zero-valent iron

Biochar-supported nano zero-valent iron (nZVI/BC) composites were prepared, and its surface morphology, particle size, functional group structure, surface elements and chemical morphology were characterized and analyzed by SEM, TEM, FTIR, EDS and XPS. The remediation effect of cadmium (Cd) in lake sediment by nZVI/BC was evaluated by Cd speciation, leaching toxicity, bioavailability, dissolved mass concentration of Cd in overlying water and physical and chemical properties of sediment. The results showed that after 56 d remediation, the residual mass speciation of Cd in nZVI/BC treatment group increased by 29.73% in comparison with the control group, which effectively reduced the mobility of Cd. The Cd leaching mass concentration decreased from 4.65 μg·L?1 to 0.38 μg·L?1, and the Cd bioextractable mass concentration decreased from 5.08 μg·L?1 to 2.13 μg·L?1, and the leaching mass concentration and bioextractable mass concentration of Cd decreased by 91.83% and 58.07%, respectively. At the same time, after 56 d remediation, nZVI/BC reduced the mass concentration of dissolved Cd in the overlying water by 67.53% in comparison with the control group. Besides, the addition of nZVI/BC increased the pH and organic matter of the sediment. According to the changes of these two indexes, the stability mechanism of nZVI/BC composites to Cd was further analyzed. The above results can provide a reference for remediation of heavy metal contaminated sediment.