RCEES OpenIR  > 环境化学与生态毒理学国家重点实验室
水环境中含Ag纳米颗粒和纳塑料的分离、测定及表征研究
周小霞
Subtype博士后
Thesis Advisor江桂斌
2018-05-10
Degree Grantor中国科学院生态环境研究中心
Place of Conferral北京
Degree Discipline环境科学
Keyword含ag纳米颗粒,纳塑料,分离富集,分析测定,水环境 Ag-containing Nanoparticles, Nanoplastics, Separation And Enrichment, Analysis And Determination, Environmental Waters
Abstract

    金属纳米颗粒及塑料制品具有优异的理化性质,因此得到了大量的生产和广泛使用,应用领域涉及工业生产、医疗器械和日常生活用品等。这些产品在生产、使用和处理过程中不可避免地会释放到环境中,而释放后的大型塑料垃圾又会逐步分解形成粒径小于 5 mm的微塑料甚至  1000 nm以下的纳塑料。这些金属纳米颗粒和微纳塑料比表面积大,表面会吸附大量有害的共存污染物,并在生物体中累积和在食物链中传递,给环境生物和人体健康造成潜在的危害。因此,为了科学解析金属纳米颗粒和纳塑料的环境污染特征并评估其环境与生物安全性,迫切需要发展环境中金属纳米材料和纳塑料的分离、测定及表征方法。
    本文首先针对环境中普遍存在的含 Ag纳米颗粒的分析测定开展了相关研究工作。基于圆盘固相萃取技术和电感耦合等离子体质谱(ICP-MS)、紫外吸收光谱(UV-vis)、透射电子显微镜(TEM)、尺寸排阻与 ICP-MS联用(SEC-ICP-MS)技术相结合,发展了水环境中痕量含 Ag纳米颗粒的分离富集、测定和表征方法。其次,针对环境中广泛存在的纳塑料的表征进行了相关研究。基于表面增强拉曼光谱(SERS)技术,发展了水环境中痕量纳塑料组成表征的方法。论文主要包括以下内容:
     第一部分,首先概括介绍了环境中金属纳米颗粒的种类及其来源,重点综述了金属纳米颗粒的分离、检测及表征的相关方法。其次,简单介绍了环境中微纳塑料的来源,并重点总结了目前微纳塑料在分离、测定和表征方面的发展现状。
     第二部分,基于圆盘固相萃取技术,发展了水环境中痕量含 Ag纳米颗粒分离富集方法。研究表明,采用孔径为 0.45  m的聚偏二氟乙烯(PVDF)微孔膜为固相萃取圆盘,在 Ag+存在条件下,可选择性地萃取含Ag纳米颗粒。研究发现,纳米颗粒表面包裹剂和粒径对萃取效率影响不大,但环境中广泛存在的腐殖酸会降低含 Ag纳米颗粒的萃取率,而Ca2+能有效抑制腐殖酸的干扰。对萃取富集在PVDF微孔膜表面的含Ag纳米颗粒,可采用2%    (m/v) FL-70溶液高效洗脱,在优化的条件下,富集倍数可达 1000倍,对不同水样加标  5.6–58.0 ng/L测得含Ag纳米颗粒的回收率为  62.2–80.2%。此外,通过 TEM、UV-vis和   SEC-ICP-MS等技术表征发现,富集前后的含  Ag纳米颗粒的粒径分布和形貌基本保持不变,因此可通过表征洗脱液中含 Ag纳米颗粒便能获得实际水样中痕量含   Ag纳米颗粒的原始粒径和形貌特征,为环境中痕量含 Ag纳米颗粒的转化研究和风险评价提供了有效途径。
     第三部分,基于 SERS技术,首次成功发展了水环境中痕量纳塑料的表征方法。研究表明,在纳塑料周围包裹大量具有 SERS活性的纳米  Ag后,通过拉曼(Raman)二维扫描成像获得纳塑料在硅片上的大致分布,从而可以对纳塑料进行更加细致的分析。本方法可用于粒径小至~50  nm纳塑料的表征,充分证明了SERS在纳塑料鉴别方面具有很大的潜力。因此,本研究将有助于推动纳塑料的
表征发展,是纳塑料研究的重要一步。

Other Abstract

     Because of their  unique chemical and physical properties,  metallic nanoparticles and plastics  are widely  applied in  consumer and  industrial products.  The increasing production  and  widespread   usage  of  nanoparticles  and   plastics  resulted  in  their increasing release  into the environment  during the production,  application, recycling and  disposal,   and  the   released  plastic   debris  will   gradually  degrade   into  tiny,
“secondary” microplastics  (< 5  mm) and even  nanoplastics (<1000  nm). Because  of their   high  surface   areas,   nanoparticles  and   nanoplastics   would  adsorb   various hazardous coexisting  pollutants, and  then bioaccumulate  and transport  through food chain, and therefore enhanced their exposure and risk  to ecosystem and human health.Therefore,  to exactly  understand  the distribution  of  nanoparticles and  nanoplastics, and   then  assess   the   environmental   risks  of   nanoparticles   and   nanoplastics  to environment  and organisms,  accurate analysis  and  characterization of  nanoparticles and nanoplastics in the environment is of great importance.
     This  dissertation  focuses   on  analysis  and   characterization  of  Ag-containing nanoparticles  and nanoplastics.  First, by  coupling  disc-based solid  phase  extraction (SPE)  with inductively  coupled  plasma mass  spectrometry  (ICP-MS),  transmission electron microscopy (TEM),UV-vis spectroscopy,and size-exclusion chromatography   coupled    with   ICP-MS    (SEC-ICP-MS)   techniques,    we   have developed a method  for preconcentration, characterization and  quantification of trace Ag-containing nanoparticles in environmental waters. Then, we presented the first use of  surface enhanced  Raman  spectroscopy  (SERS)  to  identify trace  nanoplastics  in environmental waters.
    In the  first  part, we  summarized  the category,  source and  release  pathways of metallic  nanoparticles, and  then  reviewed  the  update  methods used  for  extraction, separation, analysis  and characterization  of metallic  nanoparticles. In  additional, the source  of  nanoplastics  in  environment  is  briefly  introduced, and  then  the  current development  of  separation,  determination  and  characterization  of  nanoplastics  are summarized.
    In  the second  part,  we  report the  novel  application  of  disc-based solid  phase extraction (SPE) for separation and preconcentration of nanoparticulate Ag (NAg) in a large volume of  water samples (1 L).  Starting from real water  samples, namely, river water, lake  water, as  well as  the effluent  and influent  of wastewater  treatment plant (WWTP),  semi-automated enrichment  of  NAg  from  1 L  of  samples was  achieved within ~30  min using the  disc-based SPE  system, which  consists of a  syringe pump and  a  syringe  filter  holder  to   embed  the  filter  membrane.  While  polyvinylidene fluoride  (PVDF) membrane  can  selectively intercept  NAg  in  the presence  of  Ag+ ,aqueous solution of 2% (m/v) FL-70 (a  surfactant) was found to efficiently elute NAg without disturbing their  sizes and shapes.  Analysis of NAg was  performed following optimization of  filter membrane and  elution conditions  with an enrichment  factor of 1000.  Additionally, transmission  electron  microscopy (TEM),  UV-vis  spectroscopy, and  size-exclusion  chromatography coupled  with  ICP-MS  (SEC-ICP-MS)  analysis showed  that  no  size  and/or  shape  changes  occurred  after  extraction,  making  this method attractive  for  practical applications.  Furthermore, feasibility  of  the protocol was verified by applying it to extract NAg in four real  waters with recoveries of 62.2–80.2% at  0.056–0.58 g/L  spiked levels.  This  work will  facilitate robust  studies of trace NAg transformation and their hazard assessments in the environment.
     In the third part, the first use of surface enhanced Raman spectroscopy (SERS) to identify trace nanoplastics (1–999 nm  size range) is presented. When nanoplastics are surrounded by SERS-active silver nanoparticles (AgNPs), a set of Raman spectra with chemical  information  can  be   obtained  via  SERS  mapping.  This  map   shows  the potential distribution of  the nanoplastics on a  silicon wafer, allowing a  more detailed analysis of  the nanoplastics  to be  quickly performed. This  new method  can identify previously undetectable plastic particles as small as  ~50 nm, demonstrating the power of  SERS  to  probe  nanoplastics  and   study  their  formation.  Our  work  is  thus  an important step in nanoplastic research.

Document Type学位论文
Identifierhttp://ir.rcees.ac.cn/handle/311016/41596
Collection环境化学与生态毒理学国家重点实验室
Recommended Citation
GB/T 7714
周小霞. 水环境中含Ag纳米颗粒和纳塑料的分离、测定及表征研究[D]. 北京. 中国科学院生态环境研究中心,2018.
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