本文主要研究内容
作者张波（2019）在《层状双金属氢氧化物基杂化复合材料的制备及其吸附性能研究》一文中研究指出：随着社会的进步和人类活动的增加,各种工业废水和居民生活污水的排放量逐年增加。在这种情况下,水体中存在着不同类型、不同结构尺度的污染物,其中重金属、酚类以及油类污染物因具有难生物降解、毒性高、迁移速率快、处理难度大、处理成本高等特点,受到了环境工作者的高度关注。大量的工程实践以及研究表明,吸附法是处理上述难降解污染物的有效途径之一。因此开发性能优异、安全、经济的吸附材料并开展其应用性能研究在水污染防治领域有着重要意义。层状双金属氢氧化物(Layered Double Hydroxides,简称LDHs)是由两种或两种以上的金属阳离子组成的具有类水镁石层状晶体结构的氢氧化物。LDHs具有独特的二维层状纳米结构、较高的正电荷密度以及较强的离子交换能力,是一种开发潜力巨大的吸附材料。但LDHs在干燥之后层片易堆叠,颗粒之间易发生团聚,无法较好的分散于水溶液中。同时,采用常规方法制备的LDHs具有较强的亲水性,使其对疏水性有机污染物的亲和度较差,处理效率较低。此外,LDHs在实际应用时还存在固液分离困难,循环利用率低等问题。在吸附机理的探究方面,相关文献均基于对宏观实验结果的定性解释,对LDHs基吸附剂涉及到的离子交换反应、氢键作用等相互作用机理缺乏分子层面的系统理论分析。本文在综合国内外大量文献的基础上,针对LDHs在实际应用时出现的上述问题,使用不同的制备方法构筑具有独特纳米结构的LDHs杂化材料,提高LDHs的水分散性,增大其比表面,进而提高LDHs对重金属以及酚类的吸附性能,此外还将LDHs与碳纳米材料以及磁性颗粒进行复合,利用各组分性能之间的协同性和兼容性提升复合材料对乳化油类污水的油水分离性能。本文使用多种表征技术手段对所制备的LDHs基杂化复合材料的微观形貌结构和表面性质进行分析,并系统的研究了复合材料对水体中六价铬离子(Cr(Ⅵ))、2,4-二氯苯酚(2,4-DCP)以及不同类型的乳化油的吸附性能,对宏观实验以及微观理论计算结果进行分析探究吸附机理。本论文的研究成果将为LDHs基水处理吸附材料的研制开发以及实际应用奠定坚实的理论基础。主要研究内容与结果如下:(1)通过离子交换法合成了乳酸阴离子插层的LDHs(LCT-LDHs),并将其在水溶液中剥离形成LDHs的纳米层片(LDHNSs)。所得产物LDHNSs与常规LDHs相比具有更好的分散性,更多的吸附点位以及更大的接触面积,并有效降低了LDHs因结构效应所造成的对客体阴离子的扩散阻力,大大加快了离子交换速率,实验结果显示,LDHNSs对六价铬离子(Cr(Ⅵ))具有优异的吸附性能。当水中的Cr(Ⅵ)离子浓度为20-200 mg/L时,吸附过程均可在8 min内达到平衡状态。此外,LDHNSs在碱性条件下对Cr(Ⅵ)具有较好的去除效率,LDHNSs的最佳投加量为2.0 g/L,Langmuir等温模型可更好的描述其吸附过程,在288 K,298 K以及308 K条件下饱和吸附量分别为108.91 mg/g,116.47 mg/g以及125.97 mg/g。热力学参数分析表明LDHNSs对Cr(Ⅵ)的吸附过程是自发的,吸热反应。结合宏观实验结果以及密度泛函理论分析可知,LDHNSs对Cr(Ⅵ)的吸附机理主要是在静电引力驱动下所发生的离子交换反应,其次,在吸附过程中Cr(Ⅵ)离子与LDHs层板之间还存在氢键相互作用。(2)采用牺牲模板法制备了中空纳米壳结构混合金属氧化物(HNLDOs)。HNLDOs具有较低的密度,较好的水分散性,丰富的孔隙度,较大的比表面积以及较好的表面渗透性,因此,HNLDOs对2,4-二氯苯酚(2.4-DCP)具有优越的吸附能力。实验结果证实在293 K,303 K,和313 K温度条件下HNLDOs对2.4-DCP的最大吸附量分别是566.08 mg/g,490.44 mg/g,和451.44 mg/g。与不同类型的吸附剂比较,HNLDOs在吸附容量上占据优势。此外当溶液初始pH值为7.0时,HNLDOs对2.4-DCP具有较高的吸附容量。当2,4-DCP的初始浓度范围在5-300 mg/L之间时,吸附均可在480 min内达到平衡。经过拟合发现吸附等温线数据更加符合Langmuir吸附等温模型。计算所得热力学参数显示吸附反应是自发的,放热过程。最后通过分子动力学模拟确定了吸附产物2,4-DCP/LDHs层间的最优水化状态,在此结果的基础上,通过密度泛函理论计算出吸附能,并明确了反应过程中存在着化学吸附,同时证实了2.4-DCP与LDHs层板之间还存在着氢键相互作用。综合分析宏观实验以及理论计算的结果可知,HNLDOs对2,4-DCP吸附反应的主要机理为在静电引力的驱动下所发生的“结构记忆效应”以及氢键相互作用。最后通过吸附-解吸附实验发现,HNLDOs在对2.4-DCP的吸附反应中具有较好的再生能力,因此,此类型吸附剂具有处理实际氯酚类废水的应用潜力。(3)以氧化石墨(GO)作为基底,通过两步反应制得不同LDHs:MGO质量比的MGO/LDHs复合材料。由于复合材料各组分之间性能的协同作用,使其展现出了优异的油水分离性能。实验结果表明当LDHs:MGO质量比为1:1时,复合材料对原油水包油乳液具有最高的油水分离效率,当LDHs:MGO质量比为1:3时,复合材料对白油和癸烷的水包油乳液具有最高的油水分离效率。在最佳投加量以及LDHs:MGO质量比的情况下,复合材料对乳化油滴的去除率均可达99%以上。实验数据显示,复合材料对乳液中乳化油滴的吸附过程符合伪二级动力学方程。随着温度的升高,复合材料对三种乳液的油水分离效率均降低,随着离子强度的升高,复合材料的油水分离效率均升高。结合对动态界面张力的分析以及光学显微镜的观察发现MGO/LDHs复合材料对乳化油滴的吸附包括两个过程:(1)复合材料通过自身的两亲性以及与油滴之间的静电引力吸附于油水界面,期间与表面活性剂SDBS发生相互作用,油滴发生聚并;(2)在外加磁场的作用下包裹着油滴的复合材料得以富集,完成油水分离的过程。最后吸附-解吸附实验证实MGO/LDHs复合材料在经过4次循环使用后仍具有较高的油水分离效率。(4)以羧基化碳纳米管(CNTs)作为前驱体,通过两步反应制备5种不同LDHs:MCNTs质量比的MCNTs/LDHs复合材料。由于羧基化CNTs的存在使得复合材料具有了一定的界面活性,LDHs的存在使得复合材料具有较高的正电荷密度,抵消了复合材料与乳化油滴之间的静电斥力。因此,MCNTs/LDHs复合材料具有优异的油水分离性能,实验结果显示,当LDHs:MCNTs质量比为1:1时,复合材料对原油的水包油乳液具有最高的油水分离效率,当LDHs:MCNTs质量比为1:5时,复合材料对石蜡油和十六烷的水包油乳液具有最高的油水分离效率。在最佳投加量以及LDHs:MCNTs质量比的情况下,复合材料对乳化油滴的去除率均可达99%以上。复合材料对乳液的油水分离过程为吸热反应,乳液的pH值对油水分离过程没有太大的影响,随着乳液中离子强度的增高,复合材料对乳液的油水分离效率提高。动态界面张力以及光学显微镜的表征证实,MCNTs/LDHs复合材料的油水分离过程可分为颗粒向油水界面的迁移、颗粒在油水界面上的吸附以及最后的磁性分离。吸附-解吸附实验证实在经过5次的循环使用后,复合材料仍具有较好的油水分离性能,因此,此类碳基纳米材料/LDHs复合材料在含油污水的处理方面有着较大的实际应用潜力。
Abstract
sui zhao she hui de jin bu he ren lei huo dong de zeng jia ,ge chong gong ye fei shui he ju min sheng huo wu shui de pai fang liang zhu nian zeng jia 。zai zhe chong qing kuang xia ,shui ti zhong cun zai zhao bu tong lei xing 、bu tong jie gou che du de wu ran wu ,ji zhong chong jin shu 、fen lei yi ji you lei wu ran wu yin ju you nan sheng wu jiang jie 、du xing gao 、qian yi su lv kuai 、chu li nan du da 、chu li cheng ben gao deng te dian ,shou dao le huan jing gong zuo zhe de gao du guan zhu 。da liang de gong cheng shi jian yi ji yan jiu biao ming ,xi fu fa shi chu li shang shu nan jiang jie wu ran wu de you xiao tu jing zhi yi 。yin ci kai fa xing neng you yi 、an quan 、jing ji de xi fu cai liao bing kai zhan ji ying yong xing neng yan jiu zai shui wu ran fang zhi ling yu you zhao chong yao yi yi 。ceng zhuang shuang jin shu qing yang hua wu (Layered Double Hydroxides,jian chen LDHs)shi you liang chong huo liang chong yi shang de jin shu yang li zi zu cheng de ju you lei shui mei dan ceng zhuang jing ti jie gou de qing yang hua wu 。LDHsju you du te de er wei ceng zhuang na mi jie gou 、jiao gao de zheng dian he mi du yi ji jiao jiang de li zi jiao huan neng li ,shi yi chong kai fa qian li ju da de xi fu cai liao 。dan LDHszai gan zao zhi hou ceng pian yi dui die ,ke li zhi jian yi fa sheng tuan ju ,mo fa jiao hao de fen san yu shui rong ye zhong 。tong shi ,cai yong chang gui fang fa zhi bei de LDHsju you jiao jiang de qin shui xing ,shi ji dui shu shui xing you ji wu ran wu de qin he du jiao cha ,chu li xiao lv jiao di 。ci wai ,LDHszai shi ji ying yong shi hai cun zai gu ye fen li kun nan ,xun huan li yong lv di deng wen ti 。zai xi fu ji li de tan jiu fang mian ,xiang guan wen suo jun ji yu dui hong guan shi yan jie guo de ding xing jie shi ,dui LDHsji xi fu ji she ji dao de li zi jiao huan fan ying 、qing jian zuo yong deng xiang hu zuo yong ji li que fa fen zi ceng mian de ji tong li lun fen xi 。ben wen zai zeng ge guo nei wai da liang wen suo de ji chu shang ,zhen dui LDHszai shi ji ying yong shi chu xian de shang shu wen ti ,shi yong bu tong de zhi bei fang fa gou zhu ju you du te na mi jie gou de LDHsza hua cai liao ,di gao LDHsde shui fen san xing ,zeng da ji bi biao mian ,jin er di gao LDHsdui chong jin shu yi ji fen lei de xi fu xing neng ,ci wai hai jiang LDHsyu tan na mi cai liao yi ji ci xing ke li jin hang fu ge ,li yong ge zu fen xing neng zhi jian de xie tong xing he jian rong xing di sheng fu ge cai liao dui ru hua you lei wu shui de you shui fen li xing neng 。ben wen shi yong duo chong biao zheng ji shu shou duan dui suo zhi bei de LDHsji za hua fu ge cai liao de wei guan xing mao jie gou he biao mian xing zhi jin hang fen xi ,bing ji tong de yan jiu le fu ge cai liao dui shui ti zhong liu jia ge li zi (Cr(Ⅵ))、2,4-er lv ben fen (2,4-DCP)yi ji bu tong lei xing de ru hua you de xi fu xing neng ,dui hong guan shi yan yi ji wei guan li lun ji suan jie guo jin hang fen xi tan jiu xi fu ji li 。ben lun wen de yan jiu cheng guo jiang wei LDHsji shui chu li xi fu cai liao de yan zhi kai fa yi ji shi ji ying yong dian ding jian shi de li lun ji chu 。zhu yao yan jiu nei rong yu jie guo ru xia :(1)tong guo li zi jiao huan fa ge cheng le ru suan yin li zi cha ceng de LDHs(LCT-LDHs),bing jiang ji zai shui rong ye zhong bao li xing cheng LDHsde na mi ceng pian (LDHNSs)。suo de chan wu LDHNSsyu chang gui LDHsxiang bi ju you geng hao de fen san xing ,geng duo de xi fu dian wei yi ji geng da de jie chu mian ji ,bing you xiao jiang di le LDHsyin jie gou xiao ying suo zao cheng de dui ke ti yin li zi de kuo san zu li ,da da jia kuai le li zi jiao huan su lv ,shi yan jie guo xian shi ,LDHNSsdui liu jia ge li zi (Cr(Ⅵ))ju you you yi de xi fu xing neng 。dang shui zhong de Cr(Ⅵ)li zi nong du wei 20-200 mg/Lshi ,xi fu guo cheng jun ke zai 8 minnei da dao ping heng zhuang tai 。ci wai ,LDHNSszai jian xing tiao jian xia dui Cr(Ⅵ)ju you jiao hao de qu chu xiao lv ,LDHNSsde zui jia tou jia liang wei 2.0 g/L,Langmuirdeng wen mo xing ke geng hao de miao shu ji xi fu guo cheng ,zai 288 K,298 Kyi ji 308 Ktiao jian xia bao he xi fu liang fen bie wei 108.91 mg/g,116.47 mg/gyi ji 125.97 mg/g。re li xue can shu fen xi biao ming LDHNSsdui Cr(Ⅵ)de xi fu guo cheng shi zi fa de ,xi re fan ying 。jie ge hong guan shi yan jie guo yi ji mi du fan han li lun fen xi ke zhi ,LDHNSsdui Cr(Ⅵ)de xi fu ji li zhu yao shi zai jing dian yin li qu dong xia suo fa sheng de li zi jiao huan fan ying ,ji ci ,zai xi fu guo cheng zhong Cr(Ⅵ)li zi yu LDHsceng ban zhi jian hai cun zai qing jian xiang hu zuo yong 。(2)cai yong xi sheng mo ban fa zhi bei le zhong kong na mi ke jie gou hun ge jin shu yang hua wu (HNLDOs)。HNLDOsju you jiao di de mi du ,jiao hao de shui fen san xing ,feng fu de kong xi du ,jiao da de bi biao mian ji yi ji jiao hao de biao mian shen tou xing ,yin ci ,HNLDOsdui 2,4-er lv ben fen (2.4-DCP)ju you you yue de xi fu neng li 。shi yan jie guo zheng shi zai 293 K,303 K,he 313 Kwen du tiao jian xia HNLDOsdui 2.4-DCPde zui da xi fu liang fen bie shi 566.08 mg/g,490.44 mg/g,he 451.44 mg/g。yu bu tong lei xing de xi fu ji bi jiao ,HNLDOszai xi fu rong liang shang zhan ju you shi 。ci wai dang rong ye chu shi pHzhi wei 7.0shi ,HNLDOsdui 2.4-DCPju you jiao gao de xi fu rong liang 。dang 2,4-DCPde chu shi nong du fan wei zai 5-300 mg/Lzhi jian shi ,xi fu jun ke zai 480 minnei da dao ping heng 。jing guo ni ge fa xian xi fu deng wen xian shu ju geng jia fu ge Langmuirxi fu deng wen mo xing 。ji suan suo de re li xue can shu xian shi xi fu fan ying shi zi fa de ,fang re guo cheng 。zui hou tong guo fen zi dong li xue mo ni que ding le xi fu chan wu 2,4-DCP/LDHsceng jian de zui you shui hua zhuang tai ,zai ci jie guo de ji chu shang ,tong guo mi du fan han li lun ji suan chu xi fu neng ,bing ming que le fan ying guo cheng zhong cun zai zhao hua xue xi fu ,tong shi zheng shi le 2.4-DCPyu LDHsceng ban zhi jian hai cun zai zhao qing jian xiang hu zuo yong 。zeng ge fen xi hong guan shi yan yi ji li lun ji suan de jie guo ke zhi ,HNLDOsdui 2,4-DCPxi fu fan ying de zhu yao ji li wei zai jing dian yin li de qu dong xia suo fa sheng de “jie gou ji yi xiao ying ”yi ji qing jian xiang hu zuo yong 。zui hou tong guo xi fu -jie xi fu shi yan fa xian ,HNLDOszai dui 2.4-DCPde xi fu fan ying zhong ju you jiao hao de zai sheng neng li ,yin ci ,ci lei xing xi fu ji ju you chu li shi ji lv fen lei fei shui de ying yong qian li 。(3)yi yang hua dan mo (GO)zuo wei ji de ,tong guo liang bu fan ying zhi de bu tong LDHs:MGOzhi liang bi de MGO/LDHsfu ge cai liao 。you yu fu ge cai liao ge zu fen zhi jian xing neng de xie tong zuo yong ,shi ji zhan xian chu le you yi de you shui fen li xing neng 。shi yan jie guo biao ming dang LDHs:MGOzhi liang bi wei 1:1shi ,fu ge cai liao dui yuan you shui bao you ru ye ju you zui gao de you shui fen li xiao lv ,dang LDHs:MGOzhi liang bi wei 1:3shi ,fu ge cai liao dui bai you he gui wan de shui bao you ru ye ju you zui gao de you shui fen li xiao lv 。zai zui jia tou jia liang yi ji LDHs:MGOzhi liang bi de qing kuang xia ,fu ge cai liao dui ru hua you di de qu chu lv jun ke da 99%yi shang 。shi yan shu ju xian shi ,fu ge cai liao dui ru ye zhong ru hua you di de xi fu guo cheng fu ge wei er ji dong li xue fang cheng 。sui zhao wen du de sheng gao ,fu ge cai liao dui san chong ru ye de you shui fen li xiao lv jun jiang di ,sui zhao li zi jiang du de sheng gao ,fu ge cai liao de you shui fen li xiao lv jun sheng gao 。jie ge dui dong tai jie mian zhang li de fen xi yi ji guang xue xian wei jing de guan cha fa xian MGO/LDHsfu ge cai liao dui ru hua you di de xi fu bao gua liang ge guo cheng :(1)fu ge cai liao tong guo zi shen de liang qin xing yi ji yu you di zhi jian de jing dian yin li xi fu yu you shui jie mian ,ji jian yu biao mian huo xing ji SDBSfa sheng xiang hu zuo yong ,you di fa sheng ju bing ;(2)zai wai jia ci chang de zuo yong xia bao guo zhao you di de fu ge cai liao de yi fu ji ,wan cheng you shui fen li de guo cheng 。zui hou xi fu -jie xi fu shi yan zheng shi MGO/LDHsfu ge cai liao zai jing guo 4ci xun huan shi yong hou reng ju you jiao gao de you shui fen li xiao lv 。(4)yi suo ji hua tan na mi guan (CNTs)zuo wei qian qu ti ,tong guo liang bu fan ying zhi bei 5chong bu tong LDHs:MCNTszhi liang bi de MCNTs/LDHsfu ge cai liao 。you yu suo ji hua CNTsde cun zai shi de fu ge cai liao ju you le yi ding de jie mian huo xing ,LDHsde cun zai shi de fu ge cai liao ju you jiao gao de zheng dian he mi du ,di xiao le fu ge cai liao yu ru hua you di zhi jian de jing dian chi li 。yin ci ,MCNTs/LDHsfu ge cai liao ju you you yi de you shui fen li xing neng ,shi yan jie guo xian shi ,dang LDHs:MCNTszhi liang bi wei 1:1shi ,fu ge cai liao dui yuan you de shui bao you ru ye ju you zui gao de you shui fen li xiao lv ,dang LDHs:MCNTszhi liang bi wei 1:5shi ,fu ge cai liao dui dan la you he shi liu wan de shui bao you ru ye ju you zui gao de you shui fen li xiao lv 。zai zui jia tou jia liang yi ji LDHs:MCNTszhi liang bi de qing kuang xia ,fu ge cai liao dui ru hua you di de qu chu lv jun ke da 99%yi shang 。fu ge cai liao dui ru ye de you shui fen li guo cheng wei xi re fan ying ,ru ye de pHzhi dui you shui fen li guo cheng mei you tai da de ying xiang ,sui zhao ru ye zhong li zi jiang du de zeng gao ,fu ge cai liao dui ru ye de you shui fen li xiao lv di gao 。dong tai jie mian zhang li yi ji guang xue xian wei jing de biao zheng zheng shi ,MCNTs/LDHsfu ge cai liao de you shui fen li guo cheng ke fen wei ke li xiang you shui jie mian de qian yi 、ke li zai you shui jie mian shang de xi fu yi ji zui hou de ci xing fen li 。xi fu -jie xi fu shi yan zheng shi zai jing guo 5ci de xun huan shi yong hou ,fu ge cai liao reng ju you jiao hao de you shui fen li xing neng ,yin ci ,ci lei tan ji na mi cai liao /LDHsfu ge cai liao zai han you wu shui de chu li fang mian you zhao jiao da de shi ji ying yong qian li 。
论文参考文献
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论文作者分别是来自山东大学的张波，发表于刊物山东大学2019-07-16论文，是一篇关于层状双金属氢氧化物论文,吸附论文,剥离论文,中空纳米结构论文,碳基纳米材料论文,山东大学2019-07-16论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自山东大学2019-07-16论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。
标签：层状双金属氢氧化物论文; 吸附论文; 剥离论文; 中空纳米结构论文; 碳基纳米材料论文; 山东大学2019-07-16论文;