交流电场联合有机物料强化东南景天修复重金属镉污染土壤

AC electric field combined with organic materials enhancing Sedum alfredii Hance phytoremediation of cadmium-contaminated soil

针对土壤重金属污染植物修复效率低的问题,采用盆栽实验,通过施加多种强度的交流电场(0、0.5、1.0 V·cm^-1)和不同种类的有机物料(黄腐酸钾、紫云英),研究了交流电场及其与有机物料联合对重金属超积累植物东南景天修复重金属镉污染土壤效率的作用。结果表明,交流电场促进了东南景天的生长和对重金属的吸收,以0.5 V·cm^-1作用最佳,在电场处理组20 d后东南景天地上部Cd积累量比不施加电场的处理组提高了48.1%。交流电场和有机物料联用可以进一步提升东南景天对土壤镉的累积,施加黄腐酸钾处理组有利于土壤酸可提取态Cd的提高,比对照组提高了16.35%。在交流电场为0.5 V·cm^-1条件下,以0.3%施用效果最佳,施加黄腐酸钾和紫云英分别是对照组(施加交流电场,不施加有机物料)的3.65倍和1.73倍。有机物料和交流电场的共同作用极大地促进了东南景天镉的积累。

To improve the phytoremediation efficiency of heavy metals contaminated soils,soil pot experiments were carried out to study the effect of alternating current(AC)electric field combining with organic materials on Sedum alfredii(hyper-accumulator)remediation efficiency of cadmium(Cd)-contaminated soil.Different AC electric field gradients(0,0.5 and 1.0 V·cm^-1)and different organic materials(potassium fulvate and milk vetch)(with application rates of 0.1%,0.3%,0.5%)treatments were tested.The results showed that the AC electric field could promote the growth of Sedum alfredii and its uptake of heavy metals,and 0.5 V·cm^-1 AC electric field presented the best effect.After 20 d AC electric field treatment,the Cd accumulation in the aboveground part of Sedum alfredii was 48.1%higher than that without AC electric field enhancement.The combination of AC electric field and organic materials further enhanced the absorption of soil heavy metals by Sedum alfredii.The application of two organic materials(potassium fulvate and milk vetch)had positive effects on the soil heavy metal availabilities.Potassium fulvate application elevated the soil acid-extractable Cd concentration,which was 16.35%higher than that of the control.At AC electric field of 0.5 V·cm^-1 and 0.3%organic material of potassium fulvate or milk vetch,the greatest enhancement on Cd accumulation in plant shoots of Sedum alfredii Hance occurred,which was 3.65 and 1.73 times higher than that of control(only with AC electric field enhancement),respectively.Consequently,heavy metal accumulation in plant shoots of Sedum alfredii was greatly promoted by the combined application of organic materials and AC electric field.