直流电场对土壤中铅的定向迁移作用

Promotion Effect of DC Electric Fields on Directional Migration of Lead in Soil

电场作用下,土壤中铅的定向迁移机制与利用电场强化植物修复效率密切相关。通过施加电场强度为1 0 V/cm的直流电场于铅污染土壤中,研究了土壤中可溶性铅、有效性铅以及总铅的含量在时间和空间上的变化,分析了土壤中铅的定向迁移机制、影响因素及其对于植物修复的促进作用。结果表明,直流电场使水溶性铅含量在阳极区增加、阴极区降低,而中间区则呈现先降低后增加的变化趋势。运行12 h后,水溶性铅在阳极区的含量是阴极区的6.8倍。在直流电场作用下,土壤中铅的溶解性和移动性增加,总体上呈现向阴极区迁移和积累趋势;有效性铅含量增加,有利于提高铅的植物有效性。

The directional migration mechanism of lead in soil under the influence of electric fields is closely related to the efficacy of using electric fields to accelerate the process of phytoremediation.The effect of DC electric fields on the concentration of water-soluble lead,available lead and total lead were investigated through applying an electric field of 1.0 V/cm to lead-contaminated soil.The mechanisms and promotion influence of the directional migration were further analysed.The results showed that the concentration of water-soluble lead in soil would be increased in the anode area and decreased in the cathode area whilst decreased first and increased thereafter in between.After 12 hours,the concentration of water-soluble lead in the anode area would reach 6.8 times higher than in the cathode area.DC electric fields made the solubility and mobility of lead in soil increase.In general,lead tended to migrate toward cathode area and be accumulated.An increase in available lead content could enhance the availability of lead to plants.