低分子量有机酸对制革污泥污染土壤中铬的活化及植物提取效应

CHELATE-ASSISTED Cr(III) PHYTOEXTRACTION IN TANNERY SLUDGE APPLIED SOIL

通过盆栽试验研究了乙二胺四乙酸(EDTA)、柠檬酸和草酸在Cr与有机酸摩尔比为1∶1和1∶5情况下对制革污泥污染土壤中Cr(III)的活化作用以及铬的植物提取效应。研究结果表明,有机酸对土壤中Cr(III)的活化作用显著,其中,EDTA处理的土壤中Cr(III)的溶解性提高了6～11倍;柠檬酸处理的土壤中Cr(III)的溶解性提高了2～8倍;草酸处理在Cr与有机酸摩尔比为1∶5时才表现出较明显的活化作用,为对照的2.8倍。小麦幼苗地上部分Cr的吸收量与土壤中Cr的溶解态呈显著相关性,稳定性络合物显著地促进了植物地上部分对Cr(III)的吸收。有机酸施用量在20mmol/kg以内时,小麦幼苗的生长未受影响,用量达50mmol/kg时,小麦幼苗生长明显受抑,其中EDTA最为显著,其次为柠檬酸和草酸。

Pot experiments were conducted to investigate the effect of oxalic acid, citric acid and EDTA on the phytoextraction and translocation of Cr(III) by wheat seedling in tannery sludge polluted soils. Statistically significant increases of Cr in soil water solution and the seedlings suggested the existence of Cr(III)-organic acid ligands. However, oxalic acid had less effective compared with citric acid. Among them, organic acids showed more effective compared with dissolvable organic matter in soils. Significant correlationships were found between Cr content of the wheat seedling and dissolved in soils.