摘要
针对西部黄土高原地区油田开发引起的农田严重污染,讨论多环芳烃污染物在黄土介质中的迁移和滞留规律,采用室内实验方法,对比研究了菲和萘在天然黄土和十六烷基三甲基溴化铵(HDTMAB)改性的黄土的吸附动力学过程。结果表明,萘和菲在HDTMAB改性黄土上吸附速率比在天然黄土上至少快3倍。萘和菲在天然黄土和阳离子改性黄土上的吸附符合一级动力学方程,吸附速率与起始浓度、温度及黄土本身的性质有关;在温度25℃时,菲在120min内完全达到平衡,而萘在30min内即可完全达到平衡,萘和菲在天然黄土和阳离子改性黄土上的吸附速率由膜扩散过程控制;菲和萘的吸附速率常数k与温度T成负相关。该研究为如何采用土壤改性技术将石油类污染物滞留在表土层,防止污染物向土层深部淋滤迁移提供了理论基础,为进一步将石油污染物从土壤中去除创造了条件。
Due to the serious environmental situation resulted from oil field exploitation at the Loess Plateau of northwest China, the available countermeasures for preventing farm land from petroleum contamination and for the utilization of relevant remediation technologies have become a main concern. A laboratory study was executed to investigate the effect of surfactants on the sorption of polycyclic aromatic hydrocarbon （PAH） contaminants in loess soil. Phenanthrene and naphthalene were chosen as the organic contaminant indicators in both natural loess soil and the modified soil samples by using the cation surfactant hexadecyltrimethylammonium （HDTMA） bromide. The sorption characteristics of naphthalene and phenanthrene in a rapid equilibrium process and their kinetic behaviors in natural and modified loess soils were studied on the basis of changing temperatures, adding different amounts of the surfactant and initial concentrations of the organic contaminants. The sorption rate in the cation surfactant modified loess soils was at least 3 times faster than that of the natural soil. A first-order kinetics model fitted the sorption data well for both soils. The sorption rates of the two organic compounds were related to their primary residual quantity on the soils. The sorption amounts approached constant values approximately within 30 and 120 min for naphthalene and phenanthrene at 298-318 K, respectively. The temperature dependent sorption of the two organic compounds displayed a linear relationship on logKp and 1/T. The rate constants, however, displayed negative correlation with temperature. The activation energy was 6.196-1.172 kJ·mol^-1 for naphthalene and 28.86-15.70 kJ·mol^-1 for phenanthrene at 298-318 K. These results can be used to predict the sorption kinetics of phenanthrene and naphthalene in loess soils and better understand the transport of petroleum contaminants in the soil environment. Modifying loess soil by cation surfactants as an initial technique for restraining transport from the disposal sites can provide an effective approach to prevent soil contamination, crop uptake, and even further deterioration of groundwater aquifers from leaching petroleum pollutants.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2006年第4期958-963,共6页
Journal of Agro-Environment Science
关键词
吸附
菲
萘
黄土
表面活性剂
土壤污染
sorption
naphthalene
phenanthrene
loess soils
surfactant
