{"title":"Additives and polymer composition influence the interaction of microplastics with xenobiotics","authors":"Darius Hummel, A. Fath, T. Hofmann","doi":"10.1071/EN21030","DOIUrl":null,"url":null,"abstract":"Environmental context The effects of the presence of polymer additives and polymeric structure on sorption of xenobiotics to microplastics remain unclear. Our results combined data from experimental sorption batch experiments using three environmentally relevant model sorbates with confocal microscopy. This provides clear evidence that both factors play a major role in sorption strength and the underlying sorption process, affecting sorption onto the particle surface and partitioning into the bulk polymer. Abstract Microplastics are particulate contaminants of global concern. Interactions of microplastics with organic contaminants are frequently studied with commercially available polymer materials as surrogates. The influence of the polymer structure (i.e. internal 3D polymer geometry and monomer chain length) and the presence of additives on their interactions with xenobiotics remains unclear. This work investigates sorption of three sorbates of environmental concern to two polyamide (PA) and two polyvinyl chloride (PVC) sorbents of different molecular composition and additive content, respectively. Sorption was studied using complementary data from sorption isotherms and confocal laser-scanning microscopy. The additives in PVC increased sorption affinity owing to an increased sorbent hydrophobicity and a higher void volume within the polymer. Surface area normalisation indicated surface adsorption for unplasticised PVC and absorption for 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH)-plasticised PVC, which were confirmed using confocal laser-scanning microscopy. The strong sorption to PA was mainly driven by hydrogen-bond interactions. The contribution depended on the molecular features of the sorbent and the sorbate. Confocal laser-scanning microscopy showed that PA6 was taking up more sorbate into its bulk polymer matrix than PA12, the two being different in their chemical composition. This difference could be attributed to the higher swelling capability of PA6. The results emphasise that the molecular structure of the polymer and the presence of additives have to be taken into consideration when sorption of organic substances to plastics is investigated.","PeriodicalId":11714,"journal":{"name":"Environmental Chemistry","volume":"212 1","pages":""},"PeriodicalIF":2.0000,"publicationDate":"2021-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"7","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Environmental Chemistry","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.1071/EN21030","RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, ANALYTICAL","Score":null,"Total":0}
引用次数: 7
Abstract
Environmental context The effects of the presence of polymer additives and polymeric structure on sorption of xenobiotics to microplastics remain unclear. Our results combined data from experimental sorption batch experiments using three environmentally relevant model sorbates with confocal microscopy. This provides clear evidence that both factors play a major role in sorption strength and the underlying sorption process, affecting sorption onto the particle surface and partitioning into the bulk polymer. Abstract Microplastics are particulate contaminants of global concern. Interactions of microplastics with organic contaminants are frequently studied with commercially available polymer materials as surrogates. The influence of the polymer structure (i.e. internal 3D polymer geometry and monomer chain length) and the presence of additives on their interactions with xenobiotics remains unclear. This work investigates sorption of three sorbates of environmental concern to two polyamide (PA) and two polyvinyl chloride (PVC) sorbents of different molecular composition and additive content, respectively. Sorption was studied using complementary data from sorption isotherms and confocal laser-scanning microscopy. The additives in PVC increased sorption affinity owing to an increased sorbent hydrophobicity and a higher void volume within the polymer. Surface area normalisation indicated surface adsorption for unplasticised PVC and absorption for 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH)-plasticised PVC, which were confirmed using confocal laser-scanning microscopy. The strong sorption to PA was mainly driven by hydrogen-bond interactions. The contribution depended on the molecular features of the sorbent and the sorbate. Confocal laser-scanning microscopy showed that PA6 was taking up more sorbate into its bulk polymer matrix than PA12, the two being different in their chemical composition. This difference could be attributed to the higher swelling capability of PA6. The results emphasise that the molecular structure of the polymer and the presence of additives have to be taken into consideration when sorption of organic substances to plastics is investigated.
期刊介绍：
Environmental Chemistry publishes manuscripts addressing the chemistry of the environment (air, water, earth, and biota), including the behaviour and impacts of contaminants and other anthropogenic disturbances. The scope encompasses atmospheric chemistry, geochemistry and biogeochemistry, climate change, marine and freshwater chemistry, polar chemistry, fire chemistry, soil and sediment chemistry, and chemical aspects of ecotoxicology. Papers that take an interdisciplinary approach, while advancing our understanding of the linkages between chemistry and physical or biological processes, are particularly encouraged.
While focusing on the publication of important original research and timely reviews, the journal also publishes essays and opinion pieces on issues of importance to environmental scientists, such as policy and funding.
Papers should be written in a style that is accessible to those outside the field, as the readership will include - in addition to chemists - biologists, toxicologists, soil scientists, and workers from government and industrial institutions. All manuscripts are rigorously peer-reviewed and professionally copy-edited.
Environmental Chemistry is published with the endorsement of the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the Australian Academy of Science.
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