壬基酚在污灌土壤中吸附行为研究

采用序批式室内实验研究了壬基酚(NP)在污灌土壤中的吸附行为,同时探讨了壬基酚在土壤中吸附行为的影响因素,包括pH、离子强度、黑炭和矿物质.水溶液中NP检测方法为液液萃取-高效液相方法(LLE-HPLC).研究结果表明,土壤中有机质含量在吸附过程中起决定作用,土壤自身矿物组成成分对NP吸附行为具有一定影响.NP在土壤中吸附反应6h后达到平衡,吸附动力学都符合准二级线性模式；吸附等温线符合线性模式.壬基酚在污灌和清灌土壤中有机质吸附系数(Koc)分别为3.1×104 L·kg-1和3.2 ×104 L·kg-1,在土壤中很难移动.pH改变对壬基酚在土壤中吸附行为影响程度要高于离子强度,碱性条件下影响结果更为显著.NP在土壤黑炭和矿物质中吸附行为均符合线性模式,分配系数都有所下降.

Adsorption behaviour of nonylphenol in wastewater irrigation soil

To study the adsorption behavior of nonylphenol (NP) in irrigation soil, the batch laboratory experiments were carried out including various factors such as pH, ionic strength, black carbon and mineral. The concentration of NP in water solution was determined using liquid-liquid extraction followed by high resolution liquid chromatography (LLE-HPLC). The results showed that the organic matter dominated over other influent factors, and mineral composition constituent of the soil had some influence on adsorption behavior for NP. The adsorbed NP by soil arrived at equilibrium in 6 h and the adsorption kinetics was fitted with linear pseudo-second-order model well. The adsorption isotherm could be described by the linear model well. The distribution coefficient of normalized organic carbon for wastewater irrigation soil and groundwater irrigation soil were 3.1×10⁴ L·kg^-1 and 3.2×10⁴ L·kg^-1, respectively, which limited the migration of NP in soil. Compared with ion strength, the change of pH value brought greater influence on adsorption behavior, especially under alkaline condition. The process of adsorption by black carbon (BC) and mineral were fitted by linear model but with lower coefficients than that by soil.