Triton X-100对土壤中柴油的解吸特征及影响因素

Desorption Characteristics of Diesel from Soils in the Presence of Triton X-100 and the Factors Governing the Desorption

为考察非离子表面活性剂Triton X-100对土壤中柴油解吸特性及土壤理化性质对其解吸的影响,通过振荡平衡法研究Triton X-100对浙江水稻土、重庆紫壤、江西红壤、海南沙土、青海灰漠土和黑龙江黑土中柴油解吸行为及其影响因素.结果表明,Triton X-100对浙江水稻土、重庆紫壤、江西红壤、海南沙土、青海灰漠土和黑龙江黑土中柴油的解吸均符合先快后慢、最后达到解吸平衡的规律,平衡时解吸量分别1.61、1.85、1.80、2.29、2.01和1.13 mgg.其解吸动力学过程均符合准二级动力学模型(R^2>0.99);6种典型土壤中柴油的等温解吸特征可较好地用修正的米氏方程模型进行描述(R^2>0.92).Q_(max)(柴油最大解吸量)介于1.81~2.23 mgg之间,浙江水稻土、重庆紫壤、江西红壤、海南沙土、青海灰漠土和黑龙江黑土中ρ_(max)(柴油最大解吸率)分别为73.20%、78.06%、75.63%、90.36%、79.89%和62.92%;土壤各理化性质对Triton X-100解吸土壤中柴油的影响起综合作用,其中土壤w(砂粒)与ρ_(max)呈显著正相关(R^2=0.993 6,P<0.01),对Triton X-100解吸柴油的影响最大;而CEC(阳离子交换量)、w(OM)、w(黏粒)均与ρ_(max)呈显著负相关(P<0.05).研究显示,修正的米氏方程可用于描述柴油在土壤-水-表面活性剂Triton X-100系统中的解吸行为,w(砂粒)是影响不同土壤中柴油解吸的关键因子,可为应用Triton X-100修复柴油污染土壤提供理论基础.

In order to study the desorption characteristics of diesel from soils in the presence of Triton X-100 and the factors governing the desorption,the desorption of diesel from six soils including Zhejiang paddy soil,Chongqing purple soil,Jiangxi red earth,Hainan sandy soil,Qinghai gray desert soil and Heilongjiang black soil were investigated using batch equilibration technique and the factors governing the desorption were investigated.It was demonstrated that the desorption rate of diesel in Zhejiang paddy soil,Chongqing purple soil,Jiangxi red earth,Hainan sandy soil,Qinghai gray desert soil and Heilongjiang black soil were fast initially and then slowed down before reaching the desorption equilibrium.The equilibrium desorption capacity were 1.61,1.85,1.80,2.29,2.01 and 1.13 mg g,respectively.The desorption kinetics results can be satisfactorily described with the pseudo-second model(R 2>0.99).The desorption isotherms of diesel in six soils were found reasonably fitted to the modified Michaelis-Menten equation(R 2>0.92),and the maximum equilibrium desorption capacity(Q max)ranged from 1.81 mg g to 2.23 mg g.The maximum equilibrium desorption efficiency(ρmax)of diesel from Zhejiang paddy soil,Chongqing purple soil,Jiangxi red earth,Hainan sandy soil,Qinghai gray desert soil and Heilongjiang black soil were 73.20%,78.06%,75.63%,90.36%,79.89%and 62.92%,respectively.The soil physiochemical properties on diesel desorption were influenced by many factors.The linear correlation analysis indicated that theρmax was positively correlated with soil w(sand)(P<0.01),but negatively correlated with CEC,w(OM)and w(clay)(P<0.05).Therefore,soil w(sand)was the main factor that affected the desorption of diesel in the presence of Triton X-100.The results indicate that the modified Michaelis-Menten model can be used to describe the desorption performance of diesel in soil-water-Triton X-100 system,and reveal that the w(sand)is most important soil characteristic factor for influence of diesel desorption.To provide meaningful information for enhanced remediation from diesel contaminated soil by Triton X-100.