中国科学院生态环境研究中心机构知识库
Advanced  
RCEES OpenIR  > 环境纳米材料实验室  > 学位论文
题名: 生物质基炭材料对水中复合污染物的吸附去除机理研究
作者: 赵楠1
学位类别: 博士后
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: 郝郑平 ; 张静
关键词: 酸处理生物炭,H3PO4 活化生物炭,Fe3C,Cr(VI),有机污染物,甲基橙,选择性吸附,共吸附,降解 ; acid treated biochar ; H3PO4 activated biochar ; Fe3C ; Cr(VI) ; organicpollutants ; methyl orange ; selective adsorption ; coadsorption ; degradation
学位专业: 环境工程
中文摘要: 水体及土壤中的大多数污染都是重金属、有机污染物或者其他污染物共存所造 成的复合污染,为污染物的处理带来了极大的困扰。本研究以水中重金属复合污 染物为研究目标,通过选择性吸附方法来处理高浓度盐溶液中以及有机污染物共 存下的重金属铬离子。利用高温裂解方法制备得到了三种生物质基炭吸附材料, 即酸改性生物炭,磷酸活化生物炭和碳化铁。运用多种分析手段对其结构特性进 行表征,建立生物质基炭材料的结构与功能之间的联系。通过研究生物质基炭材 料对重金属、有机物和染料的吸附和降解,重点阐述生物质基炭材料对重金属进 行选择性吸附,对重金属和有机物进行共吸附以及对染料进行吸附降解的机理, 为选择性吸附机制,共吸附机理以及染料降解机理研究提供理论依据,为解决工 业废水深度处理效率低,材料对离子选择性差,有机无机复合污染,染料的环境 污染等重要问题提供了新的思路。该研究有望在生物质基炭材料的应用、重金属、 有机物和染料等污染物的去除方面提出新的理论认识和提供可行的环保关键技术, 对环境污染物的处理具有重要意义。 (1) 利用玉米秸秆作为制备生物炭的来源,在300oC、500oC 及700oC 条件 下制备得到了三种生物炭(C300、C500、C700),并应用比表面积测定仪、扫描 电子显微镜、元素分析仪、显微红外光谱仪(IR)等仪器设备对生物炭的结构特 性进行分析。吸附等温线实验表明C300 对Cr(VI)的吸附能力最强,其最大吸附量 为33.33 mg/g。当Cl-浓度是Cr(VI)浓度的1000 多倍时,生物炭对Cr(VI)仍然具有 很好的选择性吸附能力。三种生物炭对Cr(VI) 的选择性吸附能力为 C300>C500>C700。开展HNO3 氧化生物炭实验,建立生物炭含氧官能团含量与生 物炭对Cr(VI)的选择性吸附能力之间的关系。生物炭对Cr(VI)的选择性吸附能力 随着HNO3 浓度的增加而增强。应用X 射线光电子能谱仪分析铬在生物炭上的存 在价态,生物炭上的Cr(VI)基本全部被还原为Cr(III)。最后利用电子自旋共振和自 由基淬灭实验解析生物炭对Cr(VI)的去除还原机理,中性条件下生物炭的可持久性自由基能够作为电子给体还原Cr(VI)生成Cr(III)。 (2) 利用H3PO4 对玉米秸秆进行活化,扩大其比表面积。元素分析和IR 结 果显示H3PO4 活化后的生物炭脂肪碳含量减少,芳香碳含量增多,含氧官能团的 含量下降。与C300 样品相比,H3PO4 活化后的生物炭对Cr(VI),双酚A(BPA) 和萘(NAP)的吸附能力均明显提高,IR 和高斯量化计算中的杂化密度泛函方法 表明H3PO4 活化生物炭对Cr(VI)主要通过表面配位的方式进行结合,羟基是其吸 附位点。BPA 主要通过H 键和π-π相互作用与生物炭进行结合,NAP 与生物炭之 间也形成了π-π相互作用。复合体系中双酚A 和萘的加入对Cr(VI)的去除效率影响 不大,Cr(VI)的去除效率降低~10%。随着Cr(VI)浓度的增大,H3PO4 活化生物炭对 NAP 的去除效率无影响,对BPA 的去除效率逐渐提高,说明CrO42-通过表面配位 的方式与生物炭进行结合后会进一步的与BPA 之间形成H 键,从而促进了生物炭 对BPA 的吸附。不同浓度盐溶液对复合体系中Cr(VI)和有机污染物的去除效率无 影响,说明Cl-不会与双溶液体系中的Cr(VI)和有机污染物产生竞争吸附,也说明 该材料具有很好的耐盐性。 (3)将生物炭与Fe(NO3)3 混合后通过高温裂解方法制备得到Fe3C。去除动 力学曲线显示达到平衡时,Fe3C 对甲基橙的去除效率可以达到99.62%,Fe0 对甲 基橙的去除效率为96.52%,生物炭对甲基橙的去除效率只有24.97%。Fe3C 与甲基 橙作用后的紫外谱图显示,Fe3C 对甲基橙具有吸附和降解双重功效,Fe0 对甲基橙 是降解作用,生物炭对甲基橙只有吸附作用。X 射线衍射分析结果显示,在与甲 基橙相互作用过程中,Fe3C 依然以Fe3C 的形式存在,Fe0 从160 min 后变成了氧 化铁。循环再生实验表明,使用3 次后的Fe3C 对甲基橙的去除效率仍然可以达到 99.42%,而Fe0 第二次使用时对甲基橙的去除效率已经降低到了77.05%。原位化 学还原实验进一步表明Fe3C 具有很好的稳定性。
英文摘要: Most of the water and soil pollution is caused by combined pollution with various coexisting pollutants, which brings difficulties for pollution control. In order to make the research on the treatment of Cr(VI) in the presence of high salt concentration and organic pollutants by selective adsorption technology. Acid treated biochar, H3PO4 activated biochar and Fe3C were prepared by high temperature pyrolysis method. A variety of analytical methods were used to characterize their structures and build the relationship between the structures and functions. The mechanisms for selective adsorption of heavy metals, coadsorption of heavy metal and organic pollutants, and adsorption and degradation of dyes on biochar based carbon materials were elucidated through the experiments of the adsorption and degradation of heavy metals, organic pollutants and dyes. This can build the theory basis for selective adsorption mechanism, coadsorption mechanism and the degradation mechanism of dyes. It can also propose new ideas for solving the low efficiency of advanced treatment for industrial wastewater, the bad ion selectivity of materials, combined pollution of organic and inorganic contaminants and the environmental pollution caused by dyes. This project is expected to build new theories and provide feasible key technologies on the application of biochar based carbon materials, and the removal of heavy metal, organic contaminants and dyes, which has significant importance on the treatment of environmental pollutants. (1) Biochars derived from corn straw biomass were prepared at 300oC、500oC and 700oC (C300, C500 and C700). BET surface area analyzer, scanning electron microscope, elemental analysis and micro Infrared spectroscopy (IR) were applied to characterize their structural characteristics. Adsorption isotherm experiment showed that C300 had the strongest adsorption capacity for Cr(VI), the maximum adsorption capacity is 33.33 mg/g. When the concentration of Cl- was 1000 times higher than that of Cr(VI), the biochars still had a good selective adsorption capacity. This selective adsorption capacity followed the order of C300>C500>C700. HNO3 treatment experiment was conducted to study the relationship between the surface oxygen groups of biochars and the selective adsorption capacity. The selective adsorption capacity will increase with the increase of HNO3 concentration. X-ray photoelectron spectra was used to analyze the valence state of chromium on biochar. Almost all the Cr(VI) was reduced to Cr(III). At last, electron spin resonance and free radical quenching studies were used to elucidate the removal and reduction mechanisms. Environmental persistent free radicals of biochars can be used as electron donor to reduce Cr(VI) in the neutral solutions. (2) H3PO4 was applied as the activation agent to modify the corn straw to increase the surface area. Elemental concentrations and IR spectra showed that the contents of aliphatic carbon and oxygenated functional groups decreased, aromatic carbon content increased. As compared with C300, H3PO4-C300 had an enhanced adsorption capacity for Cr(VI), NAP and BPA. IR spectra and hybrid density functional method suggested that biochar bind Cr(VI) mainly via surface complexation, where hydroxyl groups were the adsorption sites. Bisphenol A (BPA) interacted with biochar by π-π and hydrogen bond interactions. Naphthalene (NAP) could also bind biochar by π-π interaction. The presence of organic pollutants caused a limited decrease ~10% of removal efficiency of Cr(VI). The addition of Cr(VI) had little effect on the removal efficiency of NAP. But, the addition of Cr(VI) increased the removal efficiency of BPA via hydrogen bond interaction between CrO42- and BPA. In the binary systems, the removal efficiencies of Cr(VI), NAP, and BPA were not affected by different concentrations of NaCl. This further revealed that Cl- will not produce competitive adsorption with Cr(VI) and organic pollutants. H3PO4-C300 had a good salt resistance. (3) Fe3C was prepared by high temperature pyrolysis method after mixing biochar with Fe(NO3)3. The removal kinetics of methyl orange (MO) on biochars indicated that 99.62%, 96.52% and 24.97% of the MO were removed by Fe3C, Fe0 and biochar at equilibrium state. The UV-vis spectra showed that Fe3C had a dual effect of adsorption and degradation on MO, Fe0 could degrade MO directly and biochar had the adsorption capacity for MO only. X-ray diffraction spectra indicated that after the interaction with MO, Fe3C still exist in the form of Fe3C, Fe0 became iron oxide after 160 min. Regeneration studies suggested that the removal efficiency of MO on Fe3C was 99.42% after the third usage. But for Fe0, the removal efficiency reduced to 77.05% after the second usage. In situ chemical reduction showed that Fe3C had a good stability.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/38751
Appears in Collections:环境纳米材料研究室_学位论文

Files in This Item:
File Name/ File Size Content Type Version Access License
赵楠--生物质基炭材料对水中复合污染物的吸附去除机理研究.pdf(7430KB)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:
赵楠. 生物质基炭材料对水中复合污染物的吸附去除机理研究[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
[赵楠]'s Articles
CSDL cross search
Similar articles in CSDL Cross Search
[赵楠]‘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