The invention relates to a method for separating micro-plastics from
sediment rich in organic matters in
mangrove forest, which comprises the following steps:
sediment pretreatment: freeze-
drying a sample, sieving, and oscillating and dispersing by using an alkaline
buffer solution with the pH value of 9.0-10.0; performing
density gradient centrifugation: sequentially performing step-by-step
centrifugation by using a NaI solution with the concentration of 1.1-1.3 g / cm < 3 > and a ZnCl2 solution with the concentration of 1.5-1.7 g / cm < 3 >;
enzymatic hydrolysis purification: digesting a centrifugal product with a compound
enzyme solution at 35-40 DEG C for 4-8 hours; and vacuum
filtration: collecting the micro-plastics by using a filter membrane with the aperture of 0.2-0.8 mu m. According to the method for separating the micro-plastics from the sediments rich in the organic matters in the
mangrove forest, the density range of all common plastics is accurately covered by dual-
density gradient centrifugation, the average
recovery rate of 0.1-5mm micro-plastics in the sediments in the
mangrove forest reaches 90.2 + / -3.5%, the degradation efficiency of typical organic matters in the mangrove forest by adopting
organic matter interference elimination and
cellulase and
protease combination reaches 92.4%, and the degradation rate of the typical organic matters in the mangrove forest reaches 92.4%. Therefore, the separation efficiency is effectively improved, the contact ratio of
particle size distribution curves of 1 mu m-5 mm before and
after treatment reaches 98.2%, and the integrity of the micro-plastic can be effectively guaranteed.