Producing fragmented micro- and nano-plastics from expanded polystyrene with an accelerated mechanical abrasion experiment

Abstract

Fragmented secondary microplastic particles account for the majority of microplastics and have various origins,which makes proper control difficult. Photo-oxidation and mechanical abrasion on beaches and (or) sea surfaceare thought to be major weathering and fragmentation process for generating secondary microplastic particles.None of scientific information is, however, available where and how secondary microplastics are produced.Fragmentation of expanded polystyrene (EPS), one of top three polymer types in marine debris monitoring studywas done with an accelerated mechanical abrasion experiment in a laboratory. Forty EPS spherules detached froma EPS float were placed in an amber bottle with glass bead (3 mm in diameter) or natural sand (pre-combusted at450°C), respectively. The bottles were rotated with a tumbler for a month at 113 rpm. Fragmented EPS particleswere extracted by density separation with deionized water and identified with microscopic FT-IR, SEM andfluorescence microscope after Nile Red staining. After mechanical abrasion, apparent surface damage of EPSspherules was observed by SEM analysis. The hundreds of micron scale EPS particles were identified with FTIR.The EPS particles were selectively stained with Nile Red and subsequently identified and quantified under afluorescent microscope. EPS particles obviously outnumbered the control and were quantifiable. Number of EPSpartie major weathering and fragmentation process for generating secondary microplastic particles.None of scientific information is, however, available where and how secondary microplastics are produced.Fragmentation of expanded polystyrene (EPS), one of top three polymer types in marine debris monitoring studywas done with an accelerated mechanical abrasion experiment in a laboratory. Forty EPS spherules detached froma EPS float were placed in an amber bottle with glass bead (3 mm in diameter) or natural sand (pre-combusted at450°C), respectively. The bottles were rotated with a tumbler for a month at 113 rpm. Fragmented EPS particleswere extracted by density separation with deionized water and identified with microscopic FT-IR, SEM andfluorescence microscope after Nile Red staining. After mechanical abrasion, apparent surface damage of EPSspherules was observed by SEM analysis. The hundreds of micron scale EPS particles were identified with FTIR.The EPS particles were selectively stained with Nile Red and subsequently identified and quantified under afluorescent microscope. EPS particles obviously outnumbered the control and were quantifiable. Number of EPSparti