Ubiquitous photoaging of microplastics: Potential challenges to air flotation

IF 6.3 2区工程技术 Q1 ENGINEERING, CHEMICAL

Journal of water process engineering Pub Date : 2025-05-17 DOI:10.1016/j.jwpe.2025.107953

Zhengkai Wang , Liuyuan Xue , Yanting Zhang , Jinhui Xu , Xinyu Wang , Lupeng Huang , Chang Liu , Guojiang Xia , Xiancheng Ren , Jing Zhang

{"title":"Ubiquitous photoaging of microplastics: Potential challenges to air flotation","authors":"Zhengkai Wang , Liuyuan Xue , Yanting Zhang , Jinhui Xu , Xinyu Wang , Lupeng Huang , Chang Liu , Guojiang Xia , Xiancheng Ren , Jing Zhang","doi":"10.1016/j.jwpe.2025.107953","DOIUrl":null,"url":null,"abstract":"<div><div>The effect of photoaging on microplastic removal by air flotation and its potential mechanisms are unclear and deserve further investigation. Five common microplastics in nature (PP, PE, PET, PVC, and PS) were subjected to simulated photoaging, and the experimental data revealed that the air flotation efficiency of microplastics gradually decreased with the increase of the degree of light aging. Although photoaging has adverse effects, the densities of PP and PE are lower than water. Their air flotation efficiencies decreased only marginally by 2.3 % and 5.3 % respectively compared to their non-photoaged counterparts. In contrast, the air flotation removal rates of PS, PVC, and PET decreased to 25.7 %, 13.7 %, and 7.3 %, respectively, after 72 h of light exposure. Mechanistic analysis via SEM, FTIR, zeta potential, and contact angle measurements revealed increased fragmentation and disintegration of the five microplastics with increased photoaging severity, alongside significant physicochemical changes: reduced zeta potential, enhanced electronegativity, increased oxygen-containing functional groups, and lowered surface contact angle. Overall, the surface hydrophilicity of the five microplastics increased significantly, which led to the deterioration of the flotation performance of microplastics and the reduction of air flotation removal rate. The effects of ultraviolet light on the aging of the five microplastics were in the following order: PE < PP < PS < PET < PVC. This study reveals the adverse effects of light aging in nature on the removal of microplastics by air flotation, and provides theoretical guidance for the evaluation and optimisation of microplastic air flotation removal processes.</div></div>","PeriodicalId":17528,"journal":{"name":"Journal of water process engineering","volume":"75 ","pages":"Article 107953"},"PeriodicalIF":6.3000,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of water process engineering","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2214714425010256","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}

引用次数: 0

Abstract

The effect of photoaging on microplastic removal by air flotation and its potential mechanisms are unclear and deserve further investigation. Five common microplastics in nature (PP, PE, PET, PVC, and PS) were subjected to simulated photoaging, and the experimental data revealed that the air flotation efficiency of microplastics gradually decreased with the increase of the degree of light aging. Although photoaging has adverse effects, the densities of PP and PE are lower than water. Their air flotation efficiencies decreased only marginally by 2.3 % and 5.3 % respectively compared to their non-photoaged counterparts. In contrast, the air flotation removal rates of PS, PVC, and PET decreased to 25.7 %, 13.7 %, and 7.3 %, respectively, after 72 h of light exposure. Mechanistic analysis via SEM, FTIR, zeta potential, and contact angle measurements revealed increased fragmentation and disintegration of the five microplastics with increased photoaging severity, alongside significant physicochemical changes: reduced zeta potential, enhanced electronegativity, increased oxygen-containing functional groups, and lowered surface contact angle. Overall, the surface hydrophilicity of the five microplastics increased significantly, which led to the deterioration of the flotation performance of microplastics and the reduction of air flotation removal rate. The effects of ultraviolet light on the aging of the five microplastics were in the following order: PE < PP < PS < PET < PVC. This study reveals the adverse effects of light aging in nature on the removal of microplastics by air flotation, and provides theoretical guidance for the evaluation and optimisation of microplastic air flotation removal processes.

查看原文本刊更多论文

微塑料无处不在的光老化：空气浮选的潜在挑战

光老化对气浮去除微塑料的影响及其可能的机制尚不清楚，值得进一步研究。对自然界中常见的5种微塑料（PP、PE、PET、PVC和PS）进行了模拟光老化实验，实验数据表明，微塑料的气浮效率随着光老化程度的增加而逐渐降低。虽然光老化有不利影响，但PP和PE的密度低于水。他们的气浮效率仅下降2.3%和5.3%，分别相对于他们的非光老化的同行。光处理72 h后，PS、PVC和PET的气浮去除率分别降至25.7%、13.7%和7.3%。通过扫描电镜（SEM）、红外光谱（FTIR）、ζ电位（zeta potential）和接触角（contact angle）测量的机理分析显示，随着光老化严重程度的增加，五种微塑料的破碎和解体程度增加，同时发生了显著的物理化学变化：ζ电位降低、电负性增强、含氧官能团增加、表面接触角降低。总体而言，5种微塑料的表面亲水性显著提高，导致微塑料的浮选性能恶化，气浮去除率降低。紫外光对五种微塑料老化的影响顺序为：PE <；页& lt;PS & lt;宠物& lt;PVC。本研究揭示了自然界光老化对气浮去除微塑料的不利影响，为气浮去除微塑料工艺的评价与优化提供理论指导。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Journal of water process engineering Biochemistry, Genetics and Molecular Biology-Biotechnology

CiteScore

10.70

自引率

8.60%

发文量

846

审稿时长

24 days

期刊介绍： The Journal of Water Process Engineering aims to publish refereed, high-quality research papers with significant novelty and impact in all areas of the engineering of water and wastewater processing . Papers on advanced and novel treatment processes and technologies are particularly welcome. The Journal considers papers in areas such as nanotechnology and biotechnology applications in water, novel oxidation and separation processes, membrane processes (except those for desalination) , catalytic processes for the removal of water contaminants, sustainable processes, water reuse and recycling, water use and wastewater minimization, integrated/hybrid technology, process modeling of water treatment and novel treatment processes. Submissions on the subject of adsorbents, including standard measurements of adsorption kinetics and equilibrium will only be considered if there is a genuine case for novelty and contribution, for example highly novel, sustainable adsorbents and their use: papers on activated carbon-type materials derived from natural matter, or surfactant-modified clays and related minerals, would not fulfil this criterion. The Journal particularly welcomes contributions involving environmentally, economically and socially sustainable technology for water treatment, including those which are energy-efficient, with minimal or no chemical consumption, and capable of water recycling and reuse that minimizes the direct disposal of wastewater to the aquatic environment. Papers that describe novel ideas for solving issues related to water quality and availability are also welcome, as are those that show the transfer of techniques from other disciplines. The Journal will consider papers dealing with processes for various water matrices including drinking water (except desalination), domestic, urban and industrial wastewaters, in addition to their residues. It is expected that the journal will be of particular relevance to chemical and process engineers working in the field. The Journal welcomes Full Text papers, Short Communications, State-of-the-Art Reviews and Letters to Editors and Case Studies