Controlling Small Particles for Two-Step Density Sorting of Simulated Microplastics: Overcoming Surface Tension Effects with Surfactants

Infrared spectrometers are commonly recommended for analyzing microplastics (MPs) in sediment samples. However, these instruments are costly and time consuming, limiting the scope of surveys and our understanding of the distribution and long-term variation of MPs....

Full description

Saved in:
Bibliographic Details
Main Authors: Md. Ariful Islam, Shamim AL Mamun, Kei Nakagawa, Ken-ichi Shimizu, Mitsuharu Yagi, Achara Ussawarujikulcha, Hiroshi Asakura
Format: Article
Language:English
Published: Mahidol University 2025-05-01
Series:Environment and Natural Resources Journal
Subjects:
Online Access:https://ph02.tci-thaijo.org/index.php/ennrj/article/view/256051/172067
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849718726426886144
author Md. Ariful Islam
Shamim AL Mamun
Kei Nakagawa
Ken-ichi Shimizu
Mitsuharu Yagi
Achara Ussawarujikulcha
Hiroshi Asakura
author_facet Md. Ariful Islam
Shamim AL Mamun
Kei Nakagawa
Ken-ichi Shimizu
Mitsuharu Yagi
Achara Ussawarujikulcha
Hiroshi Asakura
author_sort Md. Ariful Islam
collection DOAJ
description Infrared spectrometers are commonly recommended for analyzing microplastics (MPs) in sediment samples. However, these instruments are costly and time consuming, limiting the scope of surveys and our understanding of the distribution and long-term variation of MPs. Although it is challenging to determine MPs by floatation sorting, it is possible to estimate the ratio ofMPs that float and sink in seawater. The study employed floatation sorting to confirm whether MPs with densities lower than the liquid float and those with densities higher sink, even for MPs smaller than 1 mm. As expected, large MPs (1 to 4.75 mm in size) with densities higher than that of the liquid sank. Unexpectedly, small MPs (212 μm to 1 mm) with densities higher than the liquid’s density also floated. Assuming the unexpected floating was due to surface tension, we added a surfactant to lower it, causing MPs with densities higher than the liquid’s to either sink as expected or accelerate sinking. Thus, with the use of a surfactant, even small MPs can be sorted by density if a heavy liquid is used after water.
format Article
id doaj-art-641f5bfcd43348588c438a4137550a36
institution DOAJ
issn 1686-5456
2408-2384
language English
publishDate 2025-05-01
publisher Mahidol University
record_format Article
series Environment and Natural Resources Journal
spelling doaj-art-641f5bfcd43348588c438a4137550a362025-08-20T03:12:19ZengMahidol UniversityEnvironment and Natural Resources Journal1686-54562408-23842025-05-0123327928810.32526/ennrj/23/20240264Controlling Small Particles for Two-Step Density Sorting of Simulated Microplastics: Overcoming Surface Tension Effects with SurfactantsMd. Ariful Islam0 Shamim AL Mamun1Kei Nakagawa2 Ken-ichi Shimizu3 Mitsuharu Yagi4Achara Ussawarujikulcha5Hiroshi Asakura6Graduate School of Fisheries and Environmental Science, Nagasaki University, 1-14 Bunkyo machi, Nagasaki 852-8521, JapanSchool of Physical and Chemical Sciences, University of Canterbury, 20 Kirkwood Ave., Ilam, Christchurch 8041, New Zealand Institute of Integrated Science and Technology, Nagasaki University, 1-14 Bunkyo machi, Nagasaki 852-8521, JapanInstitute of Integrated Science and Technology, Nagasaki University, 1-14 Bunkyo machi, Nagasaki 852-8521, JapanInstitute of Integrated Science and Technology, Nagasaki University, 1-14 Bunkyo machi, Nagasaki 852-8521, JapanFaculty of Environment and Resource Studies, Mahidol University, 999 Puttamonthon 4 Rd. Salaya, Puttamonthon, Nakornpathom 73170, Thailand Institute of Integrated Science and Technology, Nagasaki University, 1-14 Bunkyo machi, Nagasaki 852-8521, JapanInfrared spectrometers are commonly recommended for analyzing microplastics (MPs) in sediment samples. However, these instruments are costly and time consuming, limiting the scope of surveys and our understanding of the distribution and long-term variation of MPs. Although it is challenging to determine MPs by floatation sorting, it is possible to estimate the ratio ofMPs that float and sink in seawater. The study employed floatation sorting to confirm whether MPs with densities lower than the liquid float and those with densities higher sink, even for MPs smaller than 1 mm. As expected, large MPs (1 to 4.75 mm in size) with densities higher than that of the liquid sank. Unexpectedly, small MPs (212 μm to 1 mm) with densities higher than the liquid’s density also floated. Assuming the unexpected floating was due to surface tension, we added a surfactant to lower it, causing MPs with densities higher than the liquid’s to either sink as expected or accelerate sinking. Thus, with the use of a surfactant, even small MPs can be sorted by density if a heavy liquid is used after water.https://ph02.tci-thaijo.org/index.php/ennrj/article/view/256051/172067microplasticfloatation sortingdensity sortingsurfactantsedimentheavy liquid
spellingShingle Md. Ariful Islam
Shamim AL Mamun
Kei Nakagawa
Ken-ichi Shimizu
Mitsuharu Yagi
Achara Ussawarujikulcha
Hiroshi Asakura
Controlling Small Particles for Two-Step Density Sorting of Simulated Microplastics: Overcoming Surface Tension Effects with Surfactants
Environment and Natural Resources Journal
microplastic
floatation sorting
density sorting
surfactant
sediment
heavy liquid
title Controlling Small Particles for Two-Step Density Sorting of Simulated Microplastics: Overcoming Surface Tension Effects with Surfactants
title_full Controlling Small Particles for Two-Step Density Sorting of Simulated Microplastics: Overcoming Surface Tension Effects with Surfactants
title_fullStr Controlling Small Particles for Two-Step Density Sorting of Simulated Microplastics: Overcoming Surface Tension Effects with Surfactants
title_full_unstemmed Controlling Small Particles for Two-Step Density Sorting of Simulated Microplastics: Overcoming Surface Tension Effects with Surfactants
title_short Controlling Small Particles for Two-Step Density Sorting of Simulated Microplastics: Overcoming Surface Tension Effects with Surfactants
title_sort controlling small particles for two step density sorting of simulated microplastics overcoming surface tension effects with surfactants
topic microplastic
floatation sorting
density sorting
surfactant
sediment
heavy liquid
url https://ph02.tci-thaijo.org/index.php/ennrj/article/view/256051/172067
work_keys_str_mv AT mdarifulislam controllingsmallparticlesfortwostepdensitysortingofsimulatedmicroplasticsovercomingsurfacetensioneffectswithsurfactants
AT shamimalmamun controllingsmallparticlesfortwostepdensitysortingofsimulatedmicroplasticsovercomingsurfacetensioneffectswithsurfactants
AT keinakagawa controllingsmallparticlesfortwostepdensitysortingofsimulatedmicroplasticsovercomingsurfacetensioneffectswithsurfactants
AT kenichishimizu controllingsmallparticlesfortwostepdensitysortingofsimulatedmicroplasticsovercomingsurfacetensioneffectswithsurfactants
AT mitsuharuyagi controllingsmallparticlesfortwostepdensitysortingofsimulatedmicroplasticsovercomingsurfacetensioneffectswithsurfactants
AT acharaussawarujikulcha controllingsmallparticlesfortwostepdensitysortingofsimulatedmicroplasticsovercomingsurfacetensioneffectswithsurfactants
AT hiroshiasakura controllingsmallparticlesfortwostepdensitysortingofsimulatedmicroplasticsovercomingsurfacetensioneffectswithsurfactants