黑碳对沉积物和土壤中乙草胺吸附作用

Effect of black carbon on acetochlor sorption in soils and sediments

黑碳是自然界普遍存在的物质,它对持久性污染物的迁移转化有重要影响.研究了沉积物和土壤中的黑碳在农药乙草胺吸附行为中的作用.结果表明:乙草胺在黑碳上的初始吸附符合一级动力学模型.在黑碳与有机碳相对含量较低(fBC/fOC=0.02～0.09)时,非黑碳的有机碳对吸附起主要作用.在黑碳与有机碳的相对含量较高(0.30～0.61)时,黑碳对吸附起主导作用,黑碳相对含量越高,对KOC影响越大.同时,建立了乙草胺吸附体系中KOC与fBC之间的关系模型用于预测不同黑碳含量的天然吸附剂对乙草胺的吸附能力.

Black carbon （BC）, ubiquitous in environment, plays an important role in the fate of persistent organic substances. Sorption of acetochlor on BC in soils and sediments was investigated. The results show that initial sorption on BC is well fitted to the first order model. At the extent of low ratio of BC to organic carbon （fBC/fOC = 0. 02-0. 09） , organic carbon rather than BC is dominant in sorption of acetochlor. However, when fBc/foc is up to 0. 30-0. 61, BC has more influence on sorption of the target contaminant. The greater effect on Koc is observed at higher content of BC. A model describing the relationship between Koc and fBc is established to predict the capability of acetoehlor sorption on natural sorbent under various BC contents.