多功能吸附材料——钛锰复合氧化物的制备及砷、铅吸附行为研究

	多功能吸附材料——钛锰复合氧化物的制备及砷、铅吸附行为研究
	张伟 1,2
学位类型	硕士
导师	张高生
	2015-04
学位授予单位	中国科学院大学
学位授予地点	北京
学位专业	环境工程
关键词	钛锰复合氧化物吸附 As(v) As(Iii) Pb 去除机理
摘要	近几十年，重金属在工业生产中应用越来越广泛。伴随着重金属矿物开采、加工及应用，部分重金属进入水环境中，造成水体污染，严重影响了生态系统及人体健康安全。因此，水体重金属污染去除得到越来越多的关注。砷是一种自然环境中广泛存在的类重金属元素，毒性很大且具致癌性。砷在水溶液中通常以As(V)和As(III)两种形态存在，As(III)比As(V)有更高的毒性，且前者比后者更难以去除。铅是另一种在工业生产中广泛应用的重金属，对人体健康有严重危害，可导致多种疾病发生，特别是影响儿童智力发育。铅在水溶液中主要以二价阳离子形态存在。这两种重金属具有典型的代表性，它们的去除得到更多关注。与其他传统除砷、铅方法相比，吸附法是最有应用前景的一种方法。因为它操作简单、经济高效、无污泥产生且吸附材料可多次循环再生。但现有的吸附材料通常很难同时去除含砷和铅的污水，即很难同时去除含有阴离子型和阳离子型重金属污染物的污水。因此，开发新型、廉价、高效的除重金属吸附材料以降低水处理成本具有非常重要的意义。以研制能同时高效去除砷和铅的吸附材料为目的，本研究将钛氧化物对As(V)的高吸附性能与二氧化锰对Pb的高吸附性能及其对As(III)的氧化性能结合在一起，研制了一种多功能吸附材料——钛锰复合氧化物，并在材料制备、表征、砷和铅吸附性能及其去除机理方面开展了系统研究。通过上述研究，获得了以下主要成果： 1. 采用氧化还原/共沉淀一步合成法制备了钛锰复合氧化物，该吸附材料具有较大的比表面积（349.5 m²/g），发达的孔结构，含有丰富的表面金属羟基，主要以无定型形式存在。 2. 钛锰复合氧化物对As(V)和As(III)的吸附容量均很高，对As(III)和As(V)的最大吸附容量分别为107.0 mg/g和87.2 mg/g，表明该吸附材料对As(III)的去除效果更好。钛锰复合氧化物能快速同时去除溶液中As(V)和As(III)，且能有效的将As(III)迅速氧化成As(V)，可应用的pH范围比较宽，再生性能良好，可在实际生产应用中循环使用。 3. As(V)与钛锰复合氧化物形成了内表面配合络合物，而As(III)的去除机理为氧化还原/吸附机制。As(III)被二氧化锰氧化成As(V)的同时，二氧化锰被还原溶解，导致在材料表面生成新的活性吸附位点，这可能是As(III)去除效果显著优于As(V)的主要原因。 4. 钛锰复合氧化物能快速去除溶液中的Pb，且对Pb有很好的吸附效果，特别是在低浓度条件下，对Pb的最大吸附容量为186.3 mg/g，可应用的pH范围比较宽，对Pb有很强的特异性选择，再生性能较好，具有良好的实用性。 5. Pb与钛锰复合氧化物发生了化学吸附，在材料表面上形成了单齿单核或双齿单核的内配位络合物。
其他摘要	Heavy metals are extensively used in industrial production in the last few decades. With their mining, processing and application, heavy metals were released to aquatic environment, causing serious pollution of received water bodies and consequently, posing threat to the ecosystem and human health. Therefore, the removal of heavy metals from water is attracting more and more attention. Arsenic, a well-known highly toxic and carcinogenic element, is ubiquitous in the environment. In natural environments, arsenic exists in two predominant species, arsenate [As(V)] and arsenite [As(III)]. As(III) is much more toxic, more soluble, more mobile and therefore more difficult to be removed than As(V). Lead, another highly toxic and extensively used element, has seviously adverse effect on human health. Ingestion of lead may result in many diseases and particlully influence children's mental development. Lead mainly exists in bivalent cation form in natural water. These two kinds of heavy metals are typically representative and their removal gets increasing attentions. Compared with other traditional treatment technologies for arsenic and lead removal, adsorption technique is considered one of the most popular and practical methods for arsenic and lead removal due to its high efficiency, low cost and reusable characteristics. However, now existing adsorption material is often difficult to remove arsenic and lead wastewater at the same time, namely, it is hard to purify sewage containing anionic and cationic heavy metal pollutants simultaneously. Therefore, it is necessary to develop new, cost-effective, efficient heavy metal removing materials to reduce the cost of water treatment. A multifunctional absorbent material —— Ti-Mn binary oxide which combined the high adsorption features to As(V) of titanium oxides, the high adsorption features to Pb(II) of manganese dioxide and its oxidation property to As(III), were developed aiming at simultaneously effectively removing both As and Pb from drinking water. A systematic investigation including optimization of preparation, characterization of adsorbent, evaluation of adsorption performance, and arsenic, lead removal mechanisms was conducted in present paper. The following results were obtained. 1. A novel Ti-Mn binary oxide adsorbent has been synthesized by a one-step simultaneous oxidation and coprecipitation method. The synthetic Ti-Mn binary oxide with a high BET surface area (349.5 m²/g), a huge pore volume and an abundant surface hydroxyl groups was amorphous structure. 2. Ti-Mn binary oxide has high adsorption capacities of As(V) and As(III), especially As (III). At pH 7.0, the maximum adsorption capacities of As(III) and As(V) on Ti-Mn binary oxide adsorbent are 107.0 mg/g and 87.2 mg/g, respectively. This adsorbent could effectively oxidize As(III) to As(V), and also could be effective in removing As in a wide pH range. Moreover, the adsorbent could be readily regenerated and repeatedly used. 3. As(V) was removed by forming an inner-sphere complex on surface of the adsorbent. The removal mechanism of As(III) is an oxidation coupled with sorption approach. During As(III) oxidation, fresh adsorption sites for arsenic adsorption were created at the solid surface, due to the reductive dissolution of manganese dioxide. This was responsible for the higher As(III) uptake. 4. Ti-Mn binary oxide has a high Pb adsorption capacity, especially at low concentrations. At pH 5.0, the maximum Pb adsorption capacity is 186.3 mg/g. This adsorbent could be effective in removing Pb in a wide pH range, and also could be readily regenerated and repeatedly used. 5. The adsorption process may be chemisorption between Pb and Ti-Mn binary oxide, and Pb form monodentate mononuclear or bidentate mononuclear inner sphere complexes with the Ti-Mn binary oxide surface, respectively.
语种	中文
文献类型	学位论文
条目标识符	http://ir.yic.ac.cn/handle/133337/7942
专题	中国科学院烟台海岸带研究所知识产出_学位论文
作者单位	1.中国科学院烟台海岸带研究所 2.中国科学院大学
第一作者单位	中国科学院烟台海岸带研究所
推荐引用方式 GB/T 7714	张伟. 多功能吸附材料——钛锰复合氧化物的制备及砷、铅吸附行为研究[D]. 北京. 中国科学院大学,2015.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
多功能吸附材料——钛锰复合氧化物的制备及（2983KB）	学位论文		开放获取	CC BY-ND	浏览请求全文