地学前缘 ›› 2019, Vol. 26 ›› Issue (6): 19-27.DOI: 10.13745/j.esf.sf.2019.7.1

• 土壤污染环境监测 • 上一篇    下一篇

微塑料对水中甲基橙的吸附特征分析

宋欢，罗锡明，张莉，何宝南，李佳蔚，王一鹏   

  1. 1. 中国地质大学(北京) 海洋学院, 北京 100083
    2. 水资源与环境工程北京市重点实验室; 中国地质大学(北京) 水资源与环境学院, 北京 100083
  • 收稿日期:2019-06-14 修回日期:2019-07-08 出版日期:2019-11-30 发布日期:2019-11-30
  • 通讯作者: 罗锡明(1967—)， 男， 教授， 博士生导师， 主要从事地下水污染和土壤重金属污染治理研究。
  • 作者简介:宋欢(1994—)， 男， 硕士研究生， 海洋科学专业。E-mail：412480960@qq.com
  • 基金资助:
    国家重点研发计划项目(2018YFC1800405)；中国地质调查局项目(DD20190323)

Characteristic analysis of methyl orange adsorption on microplastics in water

SONG Huan，LUO Ximing，ZHANG Li，HE Baonan，LI Jiawei，WANG Yipeng   

  1. 1. School of Ocean Sciences, China University of Geosciences(Beijing), Beijing 100083, China
    2. Beijing Key Laboratory of Water Environmental Engineering; School of Water Resources and Environment, China University of Geosciences(Beijing), Beijing 100083, China
  • Received:2019-06-14 Revised:2019-07-08 Online:2019-11-30 Published:2019-11-30
  • Supported by:
     

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摘要： 以甲基橙(MO)为目标污染物，微塑料为载体，通过吸附动力学和等温吸附实验，比较通用塑料聚丙烯(PP)、通用工程塑料尼龙(PA)、聚甲醛(POM)和特种工程塑料聚四氟乙烯(PTFE)4种典型材质吸附MO的能力，并采用扫描电镜(SEM)、比表面积测试(BET)、显微拉曼光谱(Raman)、Zeta电位及傅立叶变换全反射衰减红外光谱(ATR-FTIR)技术手段对吸附前后PA进行表征，考察微塑料材质和PA粒径对MO吸附的影响，从而探究其可能存在的吸附机理。结果表明不同材质微塑料对MO的吸附能力具有明显差异性。其中，PA对MO的吸附量最大，可达7.39 mg/g，PA吸附MO的动力学过程包括起始的快速反应阶段和随后的慢速反应阶段，吸附过程符合二级动力学方程；等温吸附实验结果表明MO在PA上属于非均质化学吸附。静电作用及氢键的形成是造成不同材质微塑料吸附能力差异的主要原因，微塑料粒径大小与其对MO的吸附量呈显著负相关关系(R2=0.995, P<0.05)，这与微塑料可提供的有效吸附位点息息相关。本研究可以为科学评价微塑料复杂的环境行为以及作为载体协同迁移污染物的能力提供依据。

 

关键词: 微塑料, 尼龙, 甲基橙, 吸附

Abstract: Taking methyl orange (MO) as target pollutant and microplastics as carrier, we compared the adsorptive capacities of four typical plastic materials including common plastic polypropylene (PP), common engineering plastic nylon (PA), polyformaldehyde (POM) and special engineering plastic polytetrafluoroethylene (PTFE) in adsorption kinetics and isothermal adsorption experiments. We characterized PA before and after adsorption by scanning electron microscopy (SEM), specific surface area testing (BET), micro-Raman spectroscopy (Raman), and Zeta potential and attenuated total reflection Fourier transform infrared spectrum (ATR-FTIR). We investigated the effects of plastics materials and PA particle size on MO adsorption to explore likely adsorption mechanisms. The adsorptive capacities of microplastics for MO were obviously different for different plastic materials, among which PA had the largest adsorptive capacity of 7.39 mg/g. The adsorption process for PA included initial fast and subsequent slow reactions following two-stage second order kinetics. The results of isothermal adsorption experiments showed heterogeneous chemical adsorption of MO on PA. For different kinds of microplastics, the adsorptive capacity differences were mainly due to electrostatic effect and formation of intermolecular hydrogen bond. The particle size of microplastics was negatively correlated with the adsorptive capacity for MO (R2=0.995, P<0.05), which was closely related to the effective adsorption sites provided by microplastics. This study provided a basis for the scientific evaluation of the complicated behavior of microplastics and their capabilities, as carriers, of removing pollutants from the environment.

Key words: microplastics, nylon, methyl orange, adsorption

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