Optimization of pre-treatment methods for density separation-digestion in the identification of microplastics in soil
To address the challenges of difficult separation in the pre-treatment methods for detecting microplastics in soil,which lead to low extraction efficiency and inaccuracy,a pre-treatment method based on density separation-oxidative digestion has been established and parameters of the steps were compared and tested.Experiments were conducted on various flotation liquids,ultrasonic mixing times,static settling times,and drying temperatures.The results indicate that an ultrasonic elution time of around 30 min～40 min is optimal.The dual-density flotation method using both NaCl and NaI shows an increased recovery rate for PE,PVC,and PET by 2.43％,69.10％,and 59.82％respectively,compared to the use of NaCl alone.Furthermore,to avoid thermal damage to microplastics,the drying temperature was determined to be between 50 ℃～60 ℃.The use of 30％H2O2 for 24 hours of oxidative digestion was selected to remove organic impurities,and a settling time of at least 24 hours was ensured to ef-fectively separate soil impurities from microplastics.The pre-treatment method based on density separation and oxidative digestion established in this study is simple to operate with high recovery rates,and can provide certain technical support for the study of the decomposition and detection of various microplastics in soil.
万方数据
维普
