中文关键词
土壤镉磷柠檬酸干湿交替 | 英文关键词soilcadmiumphosphoruscitric aciddry and wet alternation |
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| 中文摘要 |
| 以武汉市棕红壤为研究材料，采用室内培养和等温平衡吸附实验，研究了磷和柠檬酸共存下对土壤吸附镉的影响；并模拟干湿交替实验，通过BCR连续提取，研究了不同剂量磷和柠檬酸处理后，经多次干湿交替后镉的形态变化.结果表明，经10 mg·L-1 CdCl2溶液处理后的土壤胶体，添加较低质量浓度（40 mg·L-1）的磷对其吸附镉的影响不明显，而添加磷质量浓度较高（80 mg·L-1）时可显著提高其对镉的吸附，吸附量较CK处理增加78 g·kg-1，吸附率提高7.89%；向经40 mg·L-1磷溶液处理过的土壤胶体中加入柠檬酸，可减弱其对镉吸附，且随柠檬酸浓度增高，抑制效果增加，而且对低剂量磷（40 mg·L-1）处理的土壤胶体抑制作用更明显，加入1 mmol·L-1与5 mmol·L-1柠檬酸后，土壤胶体对镉的吸附率分别降低了30.89%与40.97%；而当磷处理质量浓度较高时，柠檬酸的影响则不显著.周期性的干湿交替显著促进土壤中镉由弱酸提取态及可还原态向可氧化态及残渣态的转变，即磷钝化的镉在柠檬酸的影响下，随干湿交替次数的增加，镉的有效性降低. |
| 英文摘要 |
| In brown-red soil, the effect of phosphorus and citric acid co-existence on the adsorption of cadmium was studied using indoor experiments and isothermal equilibrium adsorption analysis. After treatment with different doses of phosphorus and citric acid, the fractions of cadmium were altered by varying dry and wet conditions. The results showed that:① Soil treated with 10 mg·L-1 of CdCl2 solution showed no notable effect on cadmium adsorption when a low concentration of phosphorus was added (40 mg·L-1); however, higher a concentration of added phosphorus (80 mg·L-1) significantly increased cadmium adsorption (an increase of 78 g·kg-1 and 7.89% compared to the control treatment); ② Using a 40 mg·L-1 phosphorus solution, the addition of citric acid proportionally reduced cadmium adsorption. This inhibition effect was more notable for the soil treated with low-dose phosphorus (40 mg·L-1) than the high-dose treatment with 1 mmol·L-1 and 5 mmol·L-1 citric acid (cadmium adsorption decreased by 30.89% and 40.97%, respectively). The effect of citric acid was not significant, however, at higher concentrations of phosphorus. When the concentration of citric acid reached 5 mmol·L-1, cadmium adsorption was only 1% lower than without citric acid treatment; ③ Periodic dry-wet alternation significantly promoted the transformation of cadmium from a weak acid extractable and reducible state to an oxidizable and residual state in the soil. That is, the availability of cadmium in soil subjected to the combined action of phosphorus and citric acid decreased with an increase in wet and dry alternations. |
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