摘要
主要考察了MFI和BEA结构纳米沸石的胶体化学性质 ,对与纳米组装过程直接相关的纳米沸石的电动性质 (主要体现为 ζ电势 )和自聚集性质进行了研究 .考察了pH值、离子强度和硅铝比对沸石 ζ电势的影响 .发现纳米沸石表面电性的变化取决于其骨架结构和组成 ,而电解质浓度的增大可使沸石胶粒的 ζ电势减小 ;pH增大可使 ζ电势向负电性增大的方向变化 .较高的 ζ电势是维持沸石胶液稳定的基本条件 ;而过小的 ζ电势则将导致纳米沸石的聚集或沉降 .在毛细管力作用下纳米沸石可以自组装成沸石纤维 ,沸石的粒径是影响该组装的关键因素 ,沸石粒径越小 。
In this paper, the colloidal properties of nanosized zeolites with MFI and BEA topology structure were investigated. It is found that zeta potential of nanosized zeolites varied with the change of zeolite structures and composition. The influences of salt concentration and pH value on the zeta potential of the nanosized zeolites have been studied. With the increase of the salt concentration, the zeta potential gradually decreased and even possessed opposite charges. The effects of zeta potential on the colloidal aggregation and stability are also detected. A cretain zeta potential is necessary to stabilize the zeolite colloid, while too low zeta potential may bring on aggregation of the colloid. At stuitabie temperature, nanozeolite can be self-assembled by capillary force to form transparent self-standing fibers. The crystal size significantly influences the character of the products. The. zeolites with smaller crystal size are rather apt to form long, dense and transparent zeolite fibers.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2003年第3期354-358,共5页
Acta Chimica Sinica
基金
国家重点基础研究发展规划 (No.2 0 0 0 0 7750 7)
国家自然科学基金 (No .2 0 2 730 1 6
2 0 2 330 30 )
教育部博士学科点专向科研基金
上海市科技发展项目 (纳米专项 ) (No.0 2 4 9nm0 2 8)资助
