石灰用量和培养时间对红壤镉形态转化的影响

石灰是酸性镉(Cd)污染土壤修复的主要钝化材料.通过室内培养试验,研究了石灰不同用量对镉污染红壤土壤pH、阳离子交换量和Cd赋存形态的影响,并探讨Cd形态间与土壤pH和阳离子交换量的关系.结果表明,与对照比,施用石灰显著提高了 土壤的pH和阳离子交换量,且随施入量的增加而效果明显.培养期间土壤Cd形态主要以可交换态为主...

Effects of lime dosage and cultivation time on forms transformation of cadmium in red soil

Lime is the main passivation material for remediation of acid cadmium (Cd) contaminated soil. Through indoor laboratory experiments, the effects of different application of lime on the pH, cation exchange capacity and Cd forms in Cd contaminated soil were studied, and the relationship between Cd forms, pH and cation exchange capacity was investigated. Compared with the control, lime significantly increased soil pH (43.86%-54.05%) and cation exchange capacity (7.57% -20.67%). And the effect was obvious with the increase of the amount of application. During the cultivation, the soil Cd forms was mainly exchangeable Cd, followed by carbonate-bound Cd and iron-manganese oxide bound Cd, and the organic-bound Cd and residue contents Cd were minimal. With the cultivation time, the forms of soil exchangeable Cd gradually decreased, and the other 4 forms of Cd increased. With the increase of the application of lime, the reduction ratio of soil exchange Cd gradually increased. After 120 days of cultivation, compared with the control, the exchangeable Cd in the soil contaminated with 0.5 mg·kg-1 Cd decreased by 29.74%, 43.99% and 47.61%. The exchangeable Cd in the soil contaminated with 1 mg·kg-1 Cd decreased by 37.47%, 38.09% and 54.28%. In the two Cd solubility, the other 4 forms of Cd increased. The correlation showed that soil pH and cation exchange amount were significantly positively correlated with carbonate-bound Cd and residual Cd, but significantly negatively correlated with exchangeable Cd. The exchangeable Cd was significantly negatively correlated with the other 4 forms of Cd. In general, lime can transform Cd from exchangeable to other 4 forms by affecting pH and cation exchange capacity in soil, thereby reducing the availability of Cd in soil.