【作者】 李志强；

【导师】 刘凡；

【作者基本信息】 华中农业大学 ， 环境工程， 2008， 硕士

【摘要】 氧化锰作为环境中重要的吸附载体、氧化还原载体、化学反应催化剂及信息载体,其资源属性和环境属性日益受到人们的关注,因此,促进氧化锰矿物资源的开发与利用具有重要的理论和实践意义。尤其是3×3隧道结构的钙锰矿,由于特殊的结构有利于金属离子的嵌入和脱出,使得其除了在氧化-还原、吸附-解吸方面的应用外,更可以作为离子交换材料、二次锂离子电池电极材料等应用于诸多领域。本文通过改变前驱物的制备,在常压回流和热液高压条件下合成出了不同氧化度系列的钙锰矿—水锰矿混合物,探讨了改进后热液产物对重金属Cr（Ⅲ）的氧化特性和对Pb的吸附性能,以及作为锂离子电池正极材料的充放电性能。取得的主要结果有:1、通过控制水钠锰矿合成过程中Mn（Ⅱ）和Mn（Ⅶ）的比例,获得了不同氧化度系列的前驱物,并通过对传统方法的改进,直接合成了不同氧化度系列结构稳定的布塞尔矿。2、经常压回流和热液转化,获得了以钙锰矿为主的锰氧化物。传统方法获得的前驱物在转化的同时还存在部分水钠锰矿,改进方法合成的前驱物在向钙锰矿转化后,水钠锰矿完全消失,但同时出现了部分水锰矿杂质,结果显示,产物具有不同的锰平均氧化度。3、上述获得的不同氧化度系列的钙锰矿—水锰矿产物对Cr（Ⅲ）表现出了不同的氧化特性,样品的氧化度越大,Cr（Ⅵ）的氧化量越高。4、钙锰矿—水锰矿产物对Pb的吸附表现出了不同的性能:样品氧化度越高,对Pb吸附量越大,在吸附过程中释放的Mn（Ⅱ）也越少;而释放的H⁺则随氧化度的升高有所上升,释放的Mg²⁺与样品氧化度无明显关系。5、不同氧化度系列产物作为锂离子电池正极材料,表现出了不同的充放电性能:氧化度3.46～3.73之间的样品显示出了较高的首次放电比容量,氧化度为3.83的样品在首次放电比容量较小的情况下,表现出了较高的循环稳定性,经40次充放电后,其容量保持率最高,仍然达到79%。更多还原

【Abstract】 Mn oxide minerals are known as important adsorbents,redox agents,catalysts and environmental information carriers in soils,and their resource and environmental properties have been attracting more and more researchers’ concern. Therefore,it is of great significance to promote exploration and utilization of Mn oxide minerals.Yodorokite is one important mineral of them for its 3×3 tunnel structural which is propitious to let the metal ion insert and emerge,and this outstanding property makes it is largely applied not only as oxide-redox and adsorbent,but also as the material for ion-change and electrode of lithium batteries.Based on the todorokite successfully obtained at atmospheric pressure and high pressure,we used general techniques to analyze the similarities and differences of the products synthesized in these two diverse methods.Meanwhile,the characteristics of oxidation of Cr and adsorption of Pb by amendable products were observed under experimental condition,as well as its chargeable and dischargeable capability as electrode of lithium batteries had been understood.The results are as follows:1、To obtain a series of products with different Mn AOS,we controlled the proportion of Mn(Ⅱ) and Mn(Ⅳ) in the precursor-birnessite,and via improve the traditional method,we got buserites with steady frame and different Mn AOS.2、By the method of synthesized at atmospheric pressure and high pressure,we got the Mn oxides which were mainly composed with todorokite.It was testified that birnessite was still remain in the products by traditional method,while it disappeared through the improved way,but some manganite was observed.Testing results identified that the products presented big Mn AOS differences.3、The products of todorokite-manganite with different Mn AOS presented variable oxidation property that was the sample with higher AOS had greater rate of oxidation of Cr(Ⅲ).4、The adsorption to Pb by the todorokite-manganite samples revealed different capability.The higher Mn AOS sample has a greater sorbed capability but lower Mn(Ⅱ) release ability during the adsorption process,and the release amount of H~+ rose when AOS went up,but the release amount of Mg had no remarkable relationship with AOS.5、The samples with different AOS as lithium electrode also revealed different chargeable and dischargeable capability It was noticeable that the samples with AOS between 3.46 to 3.73 demonstrated high capability in the first discharge,while the mineral with AOS 3.83 displayed lesser capability in the first discharge,but its cycles were excellent,the capability still remained about 79%after 40 times of charge and discharge cycles.更多还原