硅藻土负载羟基铁对土壤镉污染的控制效应

Control effects of diatomite supported iron carbonyl on soil cadmium pollution

以人工模拟的镉污染土壤为研究对象,利用羟基铁对硅藻土实施负载改性;通过进行土壤培养试验,研究铁与土质量比和硅藻土负载羟基铁(Hy Fe-De2)投加量对改良镉污染土壤效果的影响,并使用扫描电镜(SEM)和红外吸收光谱(FTIR)分析改性前、后硅藻土微观形貌与活性基团的变化。结果表明:当铁与土质量比为2∶1时,Hy Fe-De2对土壤镉控制效果最好,土壤可交换态镉含量较对照组减小了27. 2%;随着Hy Fe-De2投加量的增加,土壤可交换态镉含量逐渐减小,土壤p H值逐渐减小,含水率先增大后减小,有机质无明显变化,有效铁和有效锰含量不断提升;当Hy Fe-De2投加量为1. 5%时,Hy Fe-De2对土壤镉的控制效果最好;SEM和FTIR分析表明,羟基铁以絮状体的形式覆盖在硅藻土表面,填充了硅藻土孔隙,大量羟基的引入有效地改善了硅藻土的表面性能;Hy Fe-De2使得土壤可交换态镉含量较对照组减小了34. 4%,较天然硅藻土增加了65. 4%,改良效果显著;Hy Fe-De2通过硅藻土与羟基铁耦合后的吸附作用实现了对土壤中镉的有效固定。

Using the simulated cadmium-polluted soil as research object,the diatomite was modified by hydroxyl iron.Through soil culture test,the influence of iron and soil mass ratio and diatomite load of hydroxyl iron( Hy Fe-De2) on the effect of improving cadmium contaminated soil were studied,and the changes of micromorphology and active groups of diatomite before and after modification were analyzed by SEM and FTIR. The results show that when the iron and soil mass ratio is 2 ∶ 1,Hy Fe-De2 has the best control effect on soil cadmium,and the content of exchangeable soil cadmium decreases by 27. 2% compared with the control group. With the increase of the dosage of Hy Fe-De2,the content of exchangeable cadmium in the soil gradually decreases,the p H value of the soil gradually decreases,and the water content rises first and then decreases. There is no obvious change in the organic matter,and the content of available iron and effective manganese continuously increases. When the dosage of Hy Fe-De2 is 1. 5%,Hy Fe-De2 has the best effect on soil cadmium control. SEM and FTIR analysis show that the surface properties of diatomite are effectively improved by the introduction of a large number of hydroxyl groups. Compared with the control group,the content of exchangeable cadmium in Hy Fe-De2 soil decreases by 34. 4% and increases by 65. 4%,indicating significant improvement effect. Hy Fe-De2 can effectively fix cadmium in soil by adsorption of diatomite coupled with hydroxyl iron.