两性复配修饰黏土对苏丹草修复Cu2+污染紫色土的影响

为了探索添加吸附材料对植物修复Cu²⁺污染土壤的影响，选取不同十二烷基二甲基甜菜碱 （BS-12）和十四烷基磺酸钠 （STS）复配修饰比例（50%BS-12+25%STS、50%BS-12+50%STS和50%BS-12+100%STS）的膨润土作为吸附材料，将其分别以1%的质量比加入到紫色土（PS）中，形成PS（对照）、PBS₂₅（50%BS-12+25%STS修饰膨润土混合紫色土）、PBS₅₀和PBS₁₀₀四种混合土样。采用盆栽实验对比苏丹草在0（CK）、50、100、200和500 mg/L Cu²⁺污染混合土样中的发芽率、株高、地上部和根系生物量，并分析混合土样和苏丹草对Cu²⁺污染的修复效果。结果显示，随着Cu²⁺处理浓度的增加，苏丹草在PS上的种子发芽率逐渐降低，而在各PBS土样上的发芽率基本保持先增加后稳定的趋势；不同Cu²⁺污染混合土样上的苏丹草株高均随生长时间的增加而增加。苏丹草地上部、根系干重和鲜重在PBS₂₅、PBS₅₀土样上均随Cu²⁺处理浓度的增大而降低，而在PS和PBS₁₀₀土样上均随Cu²⁺处理浓度的增加先增加后降低，峰值分别出现在200和100 mg/L的Cu²⁺处理。Cu²⁺污染处理下苏丹草各生理指标之间均保持中度以上正相关关系，且相关系数表现为PBS₁₀₀最高、PBS₂₅和PBS₅₀次之、PS最低的趋势。各混合土样对Cu²⁺的吸附能力表现为PBS₂₅ > PBS₅₀ > PBS₁₀₀ > PS，苏丹草对Cu²⁺的富集含量表现为PS > PBS₁₀₀ > PBS₅₀ > PBS₂₅的趋势，苏丹草联合两性复配黏土修复Cu²⁺污染紫色土的修复率达99%以上。

Effect of Adding Amphoteric-anionic Modified Clay on the Remediation of Cu2+ Polluted Purple Soil by Sudan Grass

To explore effects of adding sorbents on the remediation of Cu²⁺ polluted soil by hyperaccumulator, we selected BS-12 (dodecyl dimethyl betaine) and STS (sodium tetradecyl sulfate) to modify bentonite as the sorbent material, mixed the sorbent material with a mass ratio of 1% in a purple soil (PS) to prepare 4 batches of target soil, PS (control experiment), PBS₂₅ (50% bentonite was modified by BS-12 and 25% bentonite was modified by STS), PBS₅₀ (50% bentonite was modified by BS-12 and 50% bentonite was modified by STS) and PBS₁₀₀ (100% bentonite was modified by STS). The pot culture experiments of Sudan grass growing in these four kinds of soil polluted with different concentrations Cu²⁺ (0, 50, 100, 200 and 500 mg/L) were carried out to investigate germination rate, plant height, biomass of aboveground and root. The results showed that:with increasing of Cu²⁺ concentration, the germination rate of Sudan grass in PS soils decreased gradually but increased firstly and then maintained stable in other cases; the height of Sudan grass increased with growth time no matter different soils nor different concentrations of Cu²⁺; the above-ground and root biomass of Sudan grass decreased with increasing Cu²⁺ concentration in PBS₂₅ and PBS₅₀ soils, but decreased firstly and then increased with peaks occurring at 200 and 100 mg/L of Cu²⁺, respectively, in PS and PBS₁₀₀ soils; positive correlations (above medium degree) among physiological indexes of Sudan grass were found under all levels of Cu²⁺ contamination, and the correlation coefficient values showed a trend of PBS₁₀₀ > PBS₅₀~PBS₂₅ > PS; sorption abilities of Cu²⁺ on different soils were PBS₂₅ > PBS₅₀ > PBS₁₀₀ > PS, and accumulation abilities of Cu²⁺ in leaves of Sudan grass were PS > PBS₁₀₀ > PBS₅₀ > PBS₂₅. The removal rate of Cu²⁺ from the amphoteric-anionic modified purple soil by Sudan grass could be more than 99%.