不同铵盐去除农田土壤重金属研究

Effect of Different Ammonium Salt on Metal-contaminant Removal from Field Soil

利用淋洗方法研究硝酸铵、磷酸二氢铵和草酸铵3种铵盐修复重金属污染土壤的效果。结果表明,随着淋洗次数的增加,淋洗液中Zn浓度下降,草酸铵在低浓度时下降幅度大,而高浓度下降较小;淋洗液中的Pb浓度随淋洗剂浓度及淋洗次数的增加而增加,其中,草酸铵处理的增加较大。草酸铵使土壤保持碱性状态,而硝酸铵和磷酸二氢铵则使土壤保持酸性状态。淋洗液的电导率随着淋洗剂浓度的增加而增加,其中,草酸铵处理的增加明显。玉米能够在经过铵盐修复过的土壤上发芽生长,草酸铵修复的植株生物量最高,且植株Zn含量最低;高浓度磷酸二氢铵修复的植株Pb含量最高,是中、低浓度修复的7.3和9.1倍,而不同浓度硝酸铵和草酸铵修复对植株Pb含量影响较小。3种铵盐均能修复重金属污染的土壤,以草酸铵效果为最好。

Effect of three ammonium salts（ ammonium nitrate, ammonium dihydrogen phosphate and ammonium oxalate ） on metal--contaminant removal from field soil using soil washing techniques was evaluated. The results indicated that Zn concentration of washing solutions decreased with the increase in washing cycles, with low concentrations ammonium oxalate substantially decreasing. The Pb concentration of washing solutions increased with the increase of concentration and washing cycles, with ammonium oxalate substantially increasing. Ammonium oxalate maintained alkaline soil,while ammonium nitrate and ammonium dihydrogen phosphate made soil acidic. Washing solution conductivity increased with increasing ammonium salt concentration, with ammonium oxalate increasing obviously. Corn could germinate and grow on the treated soils,with the biomass of plant growing on soils remediated by ammonium oxalate being the highost and plant Zn content being the lowest. The Pb content of plant growing on the soils washed with higher concentration was the highest, being 7.3 and 9.1 times to middle and lower concentration, respectively. Ammonium nitrate and ammonium oxalate of different concentrations had little effects on Pb content of plant. To conclude, the three ammonium salts can be used for remediation of the heavy metal-polluted soils, in which ammonium oxalate is the best choice.