低成本模板法可控制备中孔炭材料及其吸附性能研究
发布时间:2018-03-28 12:45
本文选题:中孔炭 切入点:水玻璃 出处:《华东理工大学》2015年硕士论文
【摘要】:中孔炭具有发达的孔结构、良好的导电性、优良的热稳定性和化学性质,广泛应用于吸附、分离、催化、电化学等领域。依据用途对中孔炭的孔结构和形貌进行调节,可使中孔炭具有更好的应用性能。然而,现有的中孔炭制备技术生产成本昂贵、孔结构难以精确调控且制备出的中孔炭多为粉末状或具有不规则外形,大大制约了其应用。因此,中孔炭的结构和形貌控制以及低成本制备研究具有重要的意义。本文以廉价的水玻璃为原料,通过控制水解条件,合成出具有不同尺寸的SiO2纳米溶胶,并与间苯二酚-甲醛(RF)有机溶胶混合,经溶胶-凝胶过程得到有机-无机杂化复合凝胶,再经常压干燥、炭化、酸洗,得到结构可控的中孔炭材料。考察了水解温度、水解时间和反应物组成对孔结构的影响。结果表明:中孔炭的孔隙反相复制于Si02凝胶网络,其平均孔径随水解时间的延长或水解温度的升高而增加,并在6-12 nm范围内精细调控,而其总孔体积(1.1-2.3 cm3/g)可以通过改变炭和Si02前驱体的比例调节。进一步采用喷雾干燥技术,对液相复合溶胶进行雾化干燥,可规模化制备出中孔炭微球。通过控制水解条件(温度、时间)、水玻璃的浓度和反应物组成,实现了材料的孔结构的精确调控。结果表明:二氧化硅作为模板,具有骨架支撑作用,能够有效抑制聚合物微球在干燥和炭化过程中的体积收缩,有利于得到高孔隙率的中孔炭微球。中孔炭微球孔结构可通过调节水玻璃的水解时间、水解温度和浓度,以及前驱体的组成进行调控。本工作所制备的中孔炭微球具有较高的比表面积(1000m2/g)、孔容(1-2.1 cm3/g)和比较窄的孔径分布。最后研究了中孔炭微球对VB12的液相吸附行为。实验结果表明:中孔炭微球具有极高的VB12平衡吸附容量(606mg/g),远超一般的吸附材料。中孔炭微球的孔径和孔容对VB12的吸附具有重要影响,随着孔径的减小或孔容的增大,平衡吸附量增大;随着吸附温度升高,平衡吸附量呈现先增加后减小趋势。中孔炭微球对VB12分子的吸附平衡等温线属于⒈类型,满足Langmuir吸附模型;中孔炭微球对VB12具有优异的吸附动力学,其吸附历程符合准二级动力学模型。
[Abstract]:Mesoporous carbon has developed pore structure, good electrical conductivity, excellent thermal stability and chemical properties. It is widely used in adsorption, separation, catalysis, electrochemistry and other fields. It can make mesoporous carbon have better application performance. However, the production cost of existing mesoporous carbon preparation technology is expensive, the pore structure is difficult to be accurately regulated, and the prepared mesoporous carbon is mostly of powder shape or irregular shape. Therefore, it is of great significance to study the structure and morphology of mesoporous carbon and its low cost preparation. In this paper, cheap sodium silicate was used as raw material, and hydrolysis conditions were controlled. SiO2 nanosol with different sizes was synthesized and mixed with resorcinol-formaldehyde (RF) organic sol. The organic-inorganic hybrid gel was obtained by sol-gel process, and then dried under atmospheric pressure, carbonized and pickled. The effects of hydrolysis temperature, hydrolysis time and reactant composition on the pore structure of mesoporous carbon were investigated. The results showed that the pore phase of mesoporous carbon was reproduced in Si02 gel network. The average pore size increases with the increase of hydrolysis time or hydrolysis temperature, and is controlled in the range of 6-12 nm, and the total pore volume can be adjusted by changing the ratio of carbon to Si02 precursor. The mesoporous carbon microspheres can be prepared on a large scale by atomizing and drying the liquid-phase composite sol. By controlling the hydrolysis conditions (temperature, time, water glass concentration and reactant composition), The results show that silica, as a template, can effectively inhibit the volume shrinkage of polymer microspheres during drying and carbonization. Mesoporous carbon microspheres with high porosity can be obtained by adjusting hydrolysis time, hydrolysis temperature and concentration of sodium silicate. The mesoporous carbon microspheres have high specific surface area of 1000m2 / g, pore volume of 1-2.1 cm ~ 3 / g) and narrow pore size distribution. Finally, the liquid phase adsorption behavior of mesoporous carbon microspheres for VB12 was studied. The results show that the mesoporous carbon microspheres have a very high VB12 equilibrium adsorption capacity of 606 mg / g / g, which far exceeds the normal adsorption materials. The pore size and pore volume of the mesoporous carbon microspheres have an important effect on the adsorption of VB12. With the decrease of pore size or the increase of pore volume, the equilibrium adsorption capacity increases, and with the increase of adsorption temperature, the equilibrium adsorption capacity increases first and then decreases. The adsorption equilibrium isotherms of VB12 molecules on mesoporous carbon microspheres belong to 1 type. The adsorption kinetics of mesoporous carbon microspheres on VB12 was excellent, and the adsorption process was in accordance with the quasi-second-order kinetic model.
【学位授予单位】:华东理工大学
【学位级别】:硕士
【学位授予年份】:2015
【分类号】:TQ127.11
【参考文献】
相关期刊论文 前6条
1 韩伟杰;代斌;朱明远;王绪根;;球形活性炭的孔道结构改性及其对乙炔氢氯化反应的影响[J];功能材料;2013年S2期
2 刘振宇,郑经堂,王茂章,张碧江;多孔炭的纳米结构及其解析[J];化学进展;2001年01期
3 王自新,赵冰;硅溶胶制备与应用[J];化学推进剂与高分子材料;2003年05期
4 王廷吉,陈庆春,周萍华,刘玉兰;表面活性剂在硅灰石制二氧化硅中的应用研究[J];精细化工;2000年08期
5 刘植昌,吕春祥,凌立成,刘朗;金属催化气化法制备中孔活性炭[J];炭素技术;1999年S1期
6 谭作亮;李涛;张桂芳;;单质硅水解与水玻璃滴加法制备硅溶胶的研究[J];中国科技信息;2009年02期
相关硕士学位论文 前1条
1 柳召永;溶胶凝胶法中孔炭材料的制备及其吸附性能研究[D];中国石油大学;2007年
,本文编号:1676384
本文链接:https://www.wllwen.com/kejilunwen/huaxuehuagong/1676384.html