Study On Polyacrylamide Adsorption And Migration Regularity In Daqing Soil

A large area of soil and water are contaminated to various degrees with the developmentand utilization of Daqing oilfield in recent50years, but the pollution is more severer in someareas. Soil is the material basis and environmental conditions for human survival anddevelopment. If soil is contaminated or pollution load exceeds its self-purification capacity, itssurvival ability would decrease, even all disappear. Pollutants in the soil are harmful to plants,animals and human life and health.Then they damage the structure and function of socialeconomy and ecosystem. When Daqing oilfield is developed and drilled, the importantcomponents of oil displacement agents which is used extensively is polyacrylamide, whichmakes application of polyacrylamide very large. However, during the process of production,transportation, utilization and discharge, the destination of polyacrylamide is soil. Therefore,the study of polyacrylamide in the soil adsorption and migration patterns has importantpractical significance for soil environment of oil and gas field development and construction.In this paper, through simulation experiments of static adsorption and dynamic adsorption inthe Daqing soil of polyacrylamide, systematically studied the adsorption and migrationpatterns of polyacrylamide in soil of Daqing feature.Primary research contents and results as follows: Static adsorption experiments ofpolyacrylamide in the Daqing characteristic soil. Experiments examined the adsorptionsituation of polyacrylamide whose average molecular is3million in Daqing characteristic soil:chernozem soil and saline alkali soil. In the experiments, there are equilibrium concentrationand the adsorption time on which polyacrylamide in different concentration reach theadsorption equilibrium respectively in the chernozem and saline-alkali soil. Thus we canreceive payload type static adsorption isotherm, parametric equation and the isothermal curveequations. Dynamic adsorption experiments of polyacrylamide in the Daqing characteristicsoil. Through the dynamic soil adsorption column which is self-designed, the experimentsstudied adsorption and migration patterns of polyacrylamide in different concentrations inDaqing soil, and continuously dynamic test and intermittent dynamic adsorption test. Then wecan receive absorption/desorption curve of polyacrylamide in Daqing soil. Thus understandthe migration rule of polyacrylamide in the Daqing soil. In the dynamic adsorptionexperiments, we introduce inert tracer, bromide ions, to study adsorption and migrationpatterns of polyacrylamide.The static adsorption experiment indicated the static adsorption rule of PAM in theChernozem and saline-alkali soil of Daqing. It showed that adsorption ratio of PAM in the twokinds of soils increased with the addition of equilibrium concentration. And both of the ratiosincreased significantly within a range. Then the rate of increase of this ratio decreased as theaddition of the equilibrium concentration, and became gently. When the adsorption ofdifferent concentration of PAM in the chernozem and saline-alkali soil reached saturation state, the adsorption amount ratio approached a certain value unlimitedly, and there is aextreme value; however, when equilibrium concentration in a relatively low concentrationregion, the increase of adsorption ratio enlarged fast, and the increase of adsorption ratioenlarged slowly in the relatively high concentration region. By studying the data of staticadsorption test, we got PAM in different soil adsorption isotherm. The curve equation isein chernozem soil, the curve equation is ein saline soil. Bystudying the data of dynamic adsorption test, we find the adsorption and migration rule ofdifferent flows of PAM in Daqing Chernozem and saline-alkali soil using the soil adsorptioncolumn. In the adsorption stage, volume of the mixed solution required by the PAM reachinga saturated adsorption state in the soil adsorption column decreased as the flows increased; inthe parsing stage, clean water volume required by PAM reaching full elution in the soiladsorption column decreased as the flows increased.