贵州土壤重金属吸附解吸特性的研究

以贵州省典型土壤黄壤和石灰土为研究对象,采用野外调查和室内分析相结合的方法,对贵州土壤重金属吸附解吸特性进行研究。结果表明：贵州地区重金属超标率石灰土>黄壤；石灰土的pH缓冲性能大于黄壤,且碳酸钙含量增加到90g/kg时,黄壤的pH将不在增加,pH稳定在7.08,碳酸钙含量增加到120g/kg时,石灰土pH讲不再增加,稳定在8.26,而增加粘粒含量对土壤pH无明显作用；除了石灰土中的Cr和As,无论黄壤还是石灰土,复合污染土壤重金属的吸附固持的作用随碳酸钙含量的增加而增强,而随着粘粒含量的增加,黄壤和石灰土的吸附量都有所增加,但解吸量无明显促进或降低,即碳酸钙影响该地区土壤重金属蓄积的作用大于粘粒；黄壤和石灰土对重金属的吸附过程主要集中在前90min内,其后的吸附则进行得十分缓慢,且对重金属的最大吸附量石灰土>黄壤；三种动力学模型拟合中,伪二级动力学方程的拟合度最好,从动力学参数中可知,石灰土重金属平均吸附量大于黄壤重金属平均吸附量,黄壤重金属平均吸附速率大于石灰土重金属平均吸附速率。

Study of Adsorption Desorption Characteristics of Heavy Metals in Guizhou Province

Filed investigation and labratory analysis was used to research the effects of calcium carbonate and clay particle on accumulation capacity of heavy metals in contaminated soils.The results showed that the exceeding standard rate of heavy metals in contaminated soils is that lime soil>yellow soli.The cushioning property is that lime soil >yellow soli and when calcium carbonate content increased to 90g/kg,the pH of yellow soil is stable at 7.08,when calcium carbonate content increased to 120g/kg,the pH of lime soil is stable at 8.26 .while with increasing clay content on the soil pH has no obvious effect.The accumulation capacity of heavy metals in contaminated soils is with the increase of calcium carbonate content,that is calcium carbonate is one of the main effect of accumulation capacity of heavy metals in contaminated soils.Pseudo two order kinetic equation is the best one to fit the adsorption kinetics process and we will know that the average adsorption capacity of heavy metals is lime soil >yellow soil and the average adsorption rate is yellow soil>lime soil.