通过盆栽试验,采用太阳能供电方式,探究在干湿交替的水分条件下,水稻种植过程中极性交换电场辅助植物修复(EKPR)土壤重金属镉(Cd)污染的可行性.控制灌溉条件下,两电极板附近的土壤区域种植水稻作物,中间土壤区域种植水葱作富集植物.结果表明,交换电极使电解水反应产生的氢离子(H+)和氢氧根离子(OH-)不断被中和,有效避免了土壤pH值极化.土壤电流变化范围为0.08～0.36 A,说明极性交换和较高的土壤含水率有效确保土壤中的可迁移离子数量和离子流动性,能够驱动重金属迁移.与对照处理(CK)相比,EKPR处理水葱根部干物质量显著增加34.93％;水稻根部和稻谷干物质量显著降低17.21％～30.16％、16.18％～22.28％,叶片和茎部干物质量分别提高3.82％～13.17％、7.59％～30.91％.EKPR处理水葱根部、地上部Cd含量分别提高15.49％～22.45％、33.30％～35.45％;水稻根部、稻谷 Cd 含量分别降低 14.48％～35.06％、39.04％～57.43％.极性交换电场辅助植物修复技术可提高水葱对Cd的富集量,同时降低水稻对Cd的富集量,与CK处理相比,EKPR处理水葱Cd生物富集量显著增加46.48％,水稻Cd生物富集量显著降低24.75％.试验结束后,水稻根系附近的土壤Cd含量下降16.33％～19.14％.研究结果表明,在控制灌溉水稻种植过程中,极性交换电场辅助植物修复是一种可行的修复手段,在作物生产过程中利用电动修复和植物修复实现土壤净化,具有良好的应用前景和现实意义.
Electrokinetic-assisted Phytoremediation of Soil Cadmium Pollution in Paddy Fields under Polarity Exchange Technology
The feasibility of electrokinetic-assisted phytoremediation(EKPR)with polarity reversal to remove cadmium(Cd)contaminants from paddy soils under controlled irrigation was investigated.The experiments were carried out in cuboid pots powered by solar energy.The rice crops were planted near the electrodes under controlled irrigation,and the Scirpus tabernaemontani was planted as hyperaccumulator between two rows of rice plants.The results showed that H4 and OH-produced by electrolysis reactions could be directly neutralized by the polarity reversal operation,thus effectively avoiding the polarization of soil pH value.The soil current was varied from 0.08 A to 0.36A,indicating that polarity exchange and high soil water content effectively ensured the number and mobility of free-moving ions in soils,which could drive heavy metal migration.Compared with CK treatment,EKPR treatment significantly increased the root dry biomass of Scirpus tabernaemontani by 34.93％.EKPR treatment significantly reduced the root and brown rice dry biomasses by 17.21％～30.16％and 16.18％～22.28％respectively,while significantly increased the leaf and stem dry biomasses by 3.82％～13.17％and 7.59％～30.91％,respectively.EKPR treatment increased the Cd content in root and ground parts by 15.49％～22.45％and 33.30％～35.45％,respectively.The content of Cd in rice root and brown rice was decreased by 14.48％～35.06％and 39.04％～57.43％,respectively.The electrokinetic-assisted phytoremediation technology could increase the Cd enrichment of Scirpus tabernaemontani and decrease the Cd enrichment of rice crops.Compared with CK treatment,the bioenrichment of Cd in Scirpus tabernaemontani under EKPR treatment was significantly increased by 46.48％,and that in rice crops was significantly decreased by 24.75％.At the end of EKR experiments,the soil Cd content near rice roots was decreased by 16.33％～19.14％.The results showed that under controlled irrigation,the electrokinetic-assisted phytoremediation with polarity reversal was a feasible method for cadmium contaminants in paddy soils.It had a good application prospect and practical significance to use electrokinetic-assisted phytoremediation to achieve soil purification in crop production.
国家科技期刊平台
NSTL
万方数据
