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: Cu/Co催化阴极活化过硫酸盐强化光电催化降解有机物研究
作者: 刘珊珊1
学位类别: 硕士
答辩日期: 2017-06
授予单位: 中国科学院大学
授予地点: 北京
导师: 赵旭
关键词: 光电催化氧化,过硫酸盐,过硫酸氢盐,有机物去除,阴极还原 ; Photoelectrocatalysis, Persulfate, Peroxymonosulfate, Organic removal, Cathodic reduction
其他题名: Enhancement of Photoelectrocatalytic Degradation of Organics with Persulfate Activated by Cu/Co Catalytic Cathode
学位专业: 环境工程
中文摘要: 水中难降解有机污染物的高效去除一直是水处理领域的研究热点与难点。半导体光电催化氧化技术通过外加偏压有效提高了光催化效率,也克服了催化剂需后续分离的问题。光电催化系统中,有关阴极的研究相对较少,阴极并未得到有效利用。本文建立了具有催化功能的铜和四氧化三钴阴极,与具有可见光催化活性的钼酸铋阳极构成光电催化系统,选取了双氯芬酸钠和苯酚两种目标污染物分别代表水体中的PPCPs和常见化工生产原料污染物,利用催化阴极活化添加在光电系统中的过硫酸盐,与光阳极的光电催化作用耦合,开展了催化降解有机污染物的研究。主要研究内容和结果如下: (1)首先开展了Cu做光电催化系统阴极,投加过二硫酸盐(PS)时对双氯芬酸钠(DCF)的强化降解研究。实验发现与单独光电催化体系(PEC)相比,PS的加入可以强化DCF的去除率。反应2小时后,DCF的去除率由19.4%(0 mM PS)提高到了86.3%(10 mM PS),一级动力学速率常数由0.1112 h-1提高到了1.0498 h-1。条件实验结果显示,较高的PS投加量、较高的外加偏压和较低的初始pH值有利于DCF的降解。ESR结果显示,SO4•−和HO•两种自由基共存于体系中,主要集中在阴极附近;与惰性Ti片阴极相比,Cu阴极产生的自由基强度明显较高,证明本体系中主要是由铜材料自身活化了PS。通过FE-SEM、GI-XRD、XPS和原位拉曼技术的表征分析,确认了反应后电极表面生成了Cu2O。根据以上表征分析,提出了阴极Cu(0)−Cu(I)−Cu(II)−Cu(0)的变价过程,PS从阴极Cu得到一个电子被活化,产活性自由基强化了DCF的光电催化降解;电化学还原作用同时抑制了铜离子的溶出过程。对双氯芬酸钠降解过程中产生的中间产物进行了检测,分析了可能的降解路径。 (2)采用一步水热合成法制备了Co3O4负载的碳纸电极(Co3O4@CFP),将其用于阴极,开展了其活化过一硫酸盐(PMS),耦合光电催化过程强化降解苯酚的研究。实验发现与单独的PEC过程相比,PMS的加入对苯酚去除有强化作用。施加1.5 V电压时,2小时降解效率从6%(0 mM PMS)增至100%(2mM PMS),一级动力学速率常数从0.0005 min-1提高至0.0496 min-1。条件实验显示,随着PMS投加量的增加、外加偏压的增加和溶液初始pH值的降低,苯酚的去除率变高。ESR结果显示,SO4•−和HO•两种自由基共存于体系中且主要集中在阴极附近。反应后,碳纸电极表面没有发生明显变化,通过FE-SEM、XRD、XPS等技术表征发现负载的Co3O4颗粒尺寸有所变大但晶型仍保持稳定。推测其反应机理为光生电子促进了阴极Co3+向Co2+的还原反应,加速了PMS的活化过程;阴阳极同产自由基强化了苯酚在体系中的降解去除。 本实验结合了两种高级氧化技术来共同强化有机物的降解,为工程水处理过程提供了基本理论依据和技术支撑。
英文摘要: The effective removal of organic pollutants in water is considered as a research hotspot and difficulty in water treatment field. Semiconductor photoelectrocatalytic oxidation process increases the efficiency of photocatalytic process by applying bias potential and overcomes the problem of catalyst separation. In previous studies, the cathode in the system is not fully exploited. In this paper, we constructed a photoelectrocatalytic system with a γ-Bi2MoO6 anode and Cu/Co3O4@CFP cathodes with catalytic function. Diclofenac (DCF) and phenol were chosen as two representative organics to be removed in our new system. The cathodic activation of persulfate (PS) /peroxymonosulfate (PMS) and photoelectrocatalytic oxidation process were combined in our system. The main contents and results are exhibited below: (1) Firstly, we investigated the enhancement of PS addition in the process of PEC degradation of DCF. Compared with the single PEC process, significant enhancement of DCF degradation efficiency was observed in the combined system under visible light irradiation. At an applied bias of 1.5 V and initial solution pH of 5.62, the removal efficiency of DCF was increased from 19.4% in the PEC process to 86.3% in the PEC process with 10 mM PS addition. The pseudo-first-order kinetic rate constant of DCF degradation was increased from 0.1112 h-1 (R2=0.993) to 1.0498 h-1 (R2=0.987). High PS concentration, high applied bias and low pH0 were beneficial to DCF removal. Active free radicals involving SO4•− and HO• were produced in this process and concentrated near the cathode, which were confirmed by ESR analysis. Compared with other cathode materials (like Ti cathode), the radical intensity near the Cu cathode was much greater. Furthermore, the surface variation of Cu cathode was characterized by FE-SEM, GI-XRD, XPS and in situ Raman spectroscopy. It was demonstrated that Cu2O formed on the surface during the reaction with PS addition. According to above analysis, we proposed the surface Cu(0)−Cu(I)−Cu(II)−Cu(0) redox cycle of Cu cathode, which was responsible for the PS activation, leading to the generation of free radicals. The cathodic reduction also largely inhibited the Cu ions leaching. The intermediates generated in the degradation process were examined and we proposed the possible pathway of DCF. (2) The carbon fiber paper loaded Co3O4 particles (Co3O4@CFP) was prepared as the second cathode by a facile hydrothermal method and we investigated the influence of PMS addition into the PEC system. An enhancement was also observed in the new system. At an applied bias of 1.5 V, the removal efficiency of phenol was increased from 6% in the PEC process to 100% with 2 mM PMS addition into the PEC process. The pseudo-first-order kinetic rate constant of phenol degradation was increased from 0.0005 min-1 (R2=0.941) to 0.0496 min-1 (R2=0.970). High PMS concentration, high applied bias and low pH0 were proved to be favorable in degrading phenol process. Based on the ESR analysis, SO4•− and HO• were demonstrated to be the dominant oxidizing species for contaminant degradation in the combined system. After the reaction, the Co3O4@CFP did not show significant variation. The cathode was characterized by FE-SEM, XRD and XPS. It was proved that the loaded particles became larger but the main components were still the same. The cathodic Co3O4 activated PMS to form SO4•− radicals, in which photogenerated-electrons accelerated the cobalt cycle process on the cathode. The generated free radicals both on the anode and cathode were responsible for the enhanced phenol removal. In this paper, two representative advanced oxidation processes were combined to enhance the target contaminants degradation. This work may provide fundamental theoretical basis and technological support for the water treatment engineering in the future.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/38665
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
刘珊珊--CuCo催化阴极活化过硫酸盐强化光电催化降解有机物研究.pdf(3708KB)学位论文--限制开放 联系获取全文

作者单位: 1.中国科学院生态环境研究中心

Recommended Citation:
刘珊珊. Cu/Co催化阴极活化过硫酸盐强化光电催化降解有机物研究[D]. 北京. 中国科学院大学. 2017.
Service
Recommend this item
Sava as my favorate item
Show this item's statistics
Export Endnote File
Google Scholar
Similar articles in Google Scholar
[刘珊珊]'s Articles
CSDL cross search
Similar articles in CSDL Cross Search
[刘珊珊]‘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 © 2007-2018  中国科学院生态环境研究中心 - Feedback
Powered by CSpace