不同有机物料的Cd2+吸附特性及其对Cd污染土壤的修复效果研究

为探究经济有效的农田土壤重金属污染修复技术,首先通过等温吸附试验明确了废烟末、甘蔗滤泥和油菜籽油枯对Cd~(2+)的吸附特性,其次通过土培试验和盆栽试验研究了3种有机物料添加对土壤有效态Cd含量、小白菜Cd含量和小白菜生物量的影响。结果表明,3种有机物料对Cd~(2+)的吸附量大小顺序为:甘蔗滤泥油菜籽油枯废烟末,甘蔗滤泥的最大吸附量(Qmax)可达2 106.20mg·kg-1;废烟末、甘蔗滤泥、油菜籽油枯的施用均显著降低土壤有效态Cd含量,降幅分别为39.79%、48.81%、47.77%。施用甘蔗滤泥和油菜籽油枯可显著降低小白菜对Cd的吸收量,降幅分别为35.93%和34.43%。施用甘蔗滤泥和油菜籽油枯也可显著增加小白菜的鲜重和干重,鲜重分别增加了81.42%、96.88%,干重分别增加了131.75%、128.91%。因此,以甘蔗滤泥降低农田土壤有效态Cd含量的效果最好。

Effects of three organic materials on Cd2+ adsorption capacity and remediation of Cd contaminated soil

This research aimed to study economic and effective technologies for use in repairing farmland soil damaged by heavy metal contamination. Specifically, it focused on cadmium(Cd) adsorption capacity in three typical agricultural organic wastes in Yunnan Province of China:Tobacco waste(TW), bagasse sludge(BS), and rapeseed cake(RC) using an isothermal adsorption method. A soil culture and biological assay were carried out to investigate the available Cd in soil and the Cd uptake by pakchoi. The adsorption capacity of the three organic materials was ranked as BS > RC > TW. The maximum adsorption capacity(Q_max) of BS was 2 106.20 mg·kg^-1. Compared with the control, TW, BS, and RC significantly reduced Cd bioavailability in soils by 39.79%, 48.81%, and 47.77%, respectively. BS and RC application decreased the Cd concentration in pakchoi significantly when compared with the control, and the decrease was 35.93% and 34.43%, respectively. Compared with the control, BS and RC application increased the pakchoi fresh weight significantly by 81.42% and 96.88%, and increased dry weight by 131.75% and 128.91%, respectively. Thus, the effect of BS on reducing soil Cd contamination was the most effective among the three organic materials.