中国科学院生态环境研究中心机构知识库
Advanced  
RCEES OpenIR  > 环境水质学国家重点实验室  > 学位论文
题名: 金属有机骨架(MOFs)材料的制备及其去除 PFOS的研究
作者: 徐毅
学位类别: 硕士
答辩日期: 2016-05
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 赵长伟
关键词: 金属有机骨架,吸附,全氟辛烷磺酸,共存离子 ; MOFs,adsorption,PFOS,coexisting ions
其他题名: Synthesis of Metal-Organic Frameworks(MOFs) and its removal performance of PFOS
学位专业: 环境工程
中文摘要:     全氟辛烷磺酸(PFOS)作为持久性有机污染物,对环境和人体健康具有潜在危害,寻找有效去除 PFOS的方法十分重要。本文选择具有规则易修饰的孔结构以及丰富主客体作用的金属有机骨架(MOFs)材料作为吸附剂,首先进行了系列 MOFs材料的制备,并将其用于吸附去除水中的  PFOS应用研究,系统研究了 MOFs材料与 PFOS吸附之间的构效关系,筛选出吸附效果较好的  MOFs材料,并进行吸附实验的深入研究,通过吸附等温线、吸附动力学、不同因素对吸附的影响以及红外等表征手段,探讨 MOFs吸附去除  PFOS的机理,并研究了在共存物质存在下,吸附剂对 PFOS的吸附效果。取得的主要研究成果如下:
       1、制备了十种 MOFs材料并对其进行表征,探讨了  MOFs材料对  PFOS吸附的构效关系。研究发现,改变金属核心粒子、改变不同长度的有机配体和改性官能团都会对吸附产生影响。上述因素会导致 MOFs材料一维孔道结构以及孔道窗口的改变,从而影响 PFOS进入  MOFs一维孔道的难度。孔道越宽,孔道窗口越大,吸附剂对 PFOS的吸附效果越好。经过对比,同系列的  MIL-53(Al)-BPDC、MIL-53(Al)-NDC和   MIL-53(Al)效果较好,因此选取这三种材料作为去除  PFOS的较优的吸附剂进行后续试验。
      2、以  MIL-53(Al)-BPDC、MIL-53(Al)-NDC和   MIL-53(Al)这三种材料作为吸附剂,研究了三种材料对 PFOS在不同  pH值时的吸附等温线,并对其进行了Langmuir模型、Freundlich模型和    Temkin模型拟合。结果表明,三种材料在酸性条件下吸附量更高。拟合结果表明,三种材料的吸附等温线更符合   Langmuir模型,当 pH为  4时,等温线与  Temkin模型的拟合度升高。通过  Langmuir模型得到 MIL-53(Al)-BPDC、MIL-53(Al)-NDC和  MIL-53(Al)在不同 pH值时对 PFOS的理论最大吸附量(pH=4/pH=7)分别为384.615/304.878mg/L,322.581/170.94mg/L和    66.533/66.181mg/L。吸附动力学表明,三种材料在最初80min-100min内可以完成总吸附量的 80%以上,吸附在 200min内基本达到平衡。三种材料更符合准二级动力学模型,拟合度均达到  0.999,这说明吸附速率主要有化学吸附控制。以吸附动力学曲线为基础进行内扩散模型拟合,发现拟合度较差,说明材料扩散速度受液膜扩散影响为主。
      3、考察了 pH、温度和离子强度以及再生对 MOFs吸附  PFOS的影响。结果表明,MOFs材料对水中  PFOS的去除受溶液   pH的影响,酸性条件下吸附效果更高;三种材料对 PFOS的吸附量随温度升高而升高,说明吸附过程是吸热过程;在实验浓度范围内,离子强度对吸附效果没有明显影响;材料随吸附 -再生循环次数增加吸附量有所下降,其中 MIL-53(Al)下降不明显。在循环三次后,材料对PFOS的吸附量能保持到初次吸附量的  85%以上。
      4、考察了腐殖酸、Ca2+、Pb2+和 AsO43-存在时,对 MOFs吸附  PFOS的影响,结果表明,腐殖酸在水中带负电,可与 PFOS发生竞争吸附,当腐殖酸浓度达到40mg/L时,会使三种吸附剂对  PFOS的吸附量减小;一定浓度的   Ca2+存在,对吸附剂吸附 PFOS起到促进作用;一定浓度的      Pb2+存在,对吸附剂吸附  PFOS起到促进作用;一定浓度的 AsO43-存在,对吸附剂吸附 PFOS起抑制作用。

 
 
英文摘要:       Perfluorooctane sulfonate  (PFOS) as  one class  of  emerging pollutants  detected from water has drew great attention in recent years.How to remove PFOS  from waters and ensuring the security of drinking water for human beings is very important. In this study, a series of Metal-Organic Frameworks (MOFs) were prepared and  were used to adsorb PFOS  from water.  Structure-property relationship  between MOFs  and PFOS adsorption was systematically  investigated. Meanwhile, MOFs with  better adsorption effect  were chosen  for further  research.  Mechanism of  PFOS  adsorption on  MOFs was  studied by  discussing  adsorption  kinetics  and  isotherm, influence  of  different environmental   factors   and   characterization   results  of   adsorbents.   Additionally,influence of coexisting substance in  water was discussed.The main conclusions are as follows:
      1. Ten kinds of  MOFs were synthetized and characterized  and they were used to investigate  structure-property relationship  between  MOFs  and  PFOS adsorption.  It turned out that different  central metal paticles, length of organic  linker and functional groups had influence on PFOS adsorption. Factors  mentioned above led to the change of  structure  of  one  dimensional   channel  and  channel  window  of  MOFs,which influenced the accessibility  of PFOS to enter  the channel. The wider  the channel and the  larger   the  window  is   ,  the  better   the  effect   of  PFOS  adsorption   is.  After comparison, MIL-53(Al)-BPDC, MIL-53(Al)-NDC and MIL-53(Al) awere chosen for further study because of their better results.
      2.   MIL-53(Al)-BPDC,   MIL-53(Al)-NDC    and   MIL-53(Al)   were   used    as adsorbents for batch experiment. The  adsorption isotherms of PFOS on three kinds of materials at  different  pH were  studied, and  the Langmuir  model,  Freundlich model and  Temkin model  fitting  were carried  out.  The  result showed  that  the  adsorption amount of  PFOS was  higher under the  acidic condition;  the adsorption isotherms  of the three materials were more  consistent with the Langmuir model; when the  pH is 4, the fitting  degree of  the isotherm  with the  Temkin model  increased. The  theoretical maximum adsorption amount (pH=4/pH=7) of  MIL-53(Al)-BPDC, MIL-53(Al)-NDC and   MIL-53(Al)  obtained   by   the   Langmuir  model   was   384.615/304.878mg/L, 322.581/170.94mg/L and 66.533/66.181mg/L. According to the adsorption kinetics of three adsorbents,  80% of the total  adsorption amount was  adsorbed within the  initial 80min-100min;   Adsorption  basically   reached   the   balance   within  200min.   The Second-order kinetic fitted the  kinetics well and the correlation coefficient  was above 0.999.  The   result   means  that   the  adsorption   rate   was  controlled   by  chemical adsorption. The intrapaticle diffusion fitting was also carried out, which showed a low fitting digree. That  means the diffusion rate was  mainly influenced by the  liquid film diffusion.
      3.  The   influence  of   pH,  temperature,  ionic   strength  and   regeneration  was investigated. It turned out  that the effect of adsorption  removal of PFOS using MOFs was affected by the solution pH, and the adsorption efficiency was higher under acidic condition; the adsorption  amount of PFOS on  three kinds of materials increased  with the   increase  of   temperature,   which  indicated   that   the  adsorption   process   was endothermic;  in  the  experimental  concentration   range,  the  ionic  strength  had  no obvious effect  on the  adsorption amount;  the adsorption  amount decreased  with the times  of  regeneration  increased,   and  the  amount  kept   above  85%  of  the  initial adsorption amount after three cycls.
        4. The effet of humic acid,  Ca2+, Pb2+ and AsO43- on the adsorption of PFOS was investigated.  It  proved  that humic  acid  and  AsO43-  had  negative  influence on  the adsorption of PFOS;  whereas, Ca2+ and Pb2+ had positive influence  on the adsorption of PFOS.

 
 
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/37032
Appears in Collections:环境水质学国家重点实验室_学位论文

Files in This Item:
File Name/ File Size Content Type Version Access License
徐毅--金属有机骨架( MOFs)材料 的制备及其去除PFOS的研究.pdf(3332KB)学位论文--限制开放 联系获取全文

Recommended Citation:
徐毅. 金属有机骨架(MOFs)材料的制备及其去除 PFOS的研究[D]. 北京. 中国科学院研究生院. 2016.
Service
Recommend this item
Sava as my favorate item
Show this item's statistics
Export Endnote File
Google Scholar
Similar articles in Google Scholar
[徐毅]'s Articles
CSDL cross search
Similar articles in CSDL Cross Search
[徐毅]‘s Articles
Related Copyright Policies
Null
Social Bookmarking
Add to CiteULike Add to Connotea Add to Del.icio.us Add to Digg Add to Reddit
所有评论 (0)
暂无评论
 
评注功能仅针对注册用户开放,请您登录
您对该条目有什么异议,请填写以下表单,管理员会尽快联系您。
内 容:
Email:  *
单位:
验证码:   刷新
您在IR的使用过程中有什么好的想法或者建议可以反馈给我们。
标 题:
 *
内 容:
Email:  *
验证码:   刷新

Items in IR are protected by copyright, with all rights reserved, unless otherwise indicated.

 

 

Valid XHTML 1.0!
Copyright © 2007-2017  中国科学院生态环境研究中心 - Feedback
Powered by CSpace