基于微塑料分离分析的甘蔗地土壤有机质去除方法研究

Study on the Removal of Organic Matter for Separation and Analysis of Microplastics in Sugarcane Soil

甘蔗地大量使用地膜(塑料),导致了甘蔗地土壤的白色污染。微塑料作为塑料垃圾的一种类型,其来源、分布、生态影响等已被广泛研究和报道,但微塑料种类繁多复杂,目前仍未有高效准确的方法,可以将其从土壤中分离出来,这严重制约着微塑料污染有关研究的深入开展。本文从氧化剂类型、氧化时间等方面,探索甘蔗地土壤中有机质去除的条件,并结合饱和氯化钠溶液浮选法,构建甘蔗地土壤中微塑料的分离分析方法。实验表明:0.4 mol/L高锰酸钾与(1︰3)硫酸等量混合,常温静置氧化24 h,甘蔗地土壤有机质的去除率达到90.90%;经过有机质去除以后,微塑料的检出率有很大的提高,最高甚至达到74.5%。

Large quantities of plastic mulching have been used in sugarcane field, which caused serious white pollution in sugarcane soil. Studies on source, distribution and ecological impacts of microplastics that act as one type of plastic waste have been widely carried out. Due to their multiple types, however, there are no efficient and accurate methods that separate microplastics from the soil, which would limit the further study. In this study, removal methods of organic matter in sugarcane soil were investigated by considering the factors such as oxidants types and oxidation time. Combined with flotation method using NaC1 saturated solution, the separation and analysis methods for separating microplastics from the sugarcane soil have been established. Results showed that the removal rate of organic matter in sugarcane soil could reach 90.90% after samples were pretreated with a mixture of equal volumes of 0.4 mol/L potassium permanganate solutions and sulfuric acid （1 ： 3） dissolution at room temperature for 24 h under stationary condition. Finally, the detection rate of microplastics from the sugarcane soil has been improved with the highest detection rate of up to 74.5%.