红辉沸石两步水热制备高品质X型分子筛及其高效吸附Cd^(2+)、Ni^(2+)性能研究

Two-step Hydrothermal Synthesis of Stellerite Zeolite to High Quality Zeolite X and Its Efficient Adsorption Performance Study for Cd ^(2+)and Ni ^(2+)

本研究以红辉沸石为原料,经两步水热法制备高品质的X型分子筛,探究了n(H_(2)O/SiO_(2))、n(Na_(2)O/SiO_(2))、n(Al_(2)O_(3)/SiO_(2))、陈化时间、晶化温度、晶化时间等因素对红辉沸石转化为X型分子筛的影响,以及考察了X型分子筛对Cd^(2+)、Ni^(2+)的吸附性能。研究表明,X型分子筛的最优转化条件为:n(H_(2)O/SiO_(2))=55、n(Na_(2)O/SiO_(2))=1.1、n(Al_(2)O_(3)/SiO_(2))=0.33、陈化时间48 h、晶化温度82℃、晶化时间4 h。红辉沸石溶解后解聚为低聚态Si物种且在体系中保留参与分子筛的生长,使得所合成的X型分子筛相对结晶度达100%、n(Si/Al)值为1.14,并缩短了晶化时间和降低了晶化温度,其中所合成的X型分子筛对Cd^(2+)和Ni^(2+)的吸附容量分别达到173.553 mg/g和75.897 mg/g。因此,本研究将为天然矿物快速转化为高品质的X型分子筛设计与制备提供理论基础和技术支持。

In this study,high quality zeolite X was conversed from stellerite zeolite by a two-step hydrothermal method.The influence of n(H_(2)O/SiO_(2)),n(Na_(2)O/SiO_(2)),n(Al_(2)O_(3)/SiO_(2)),aging time,crystallization temperature and crystallization time of the stellerite zeolite conversion into zeolite X were investigated,and the adsorption performance for Cd ^(2+)and Ni ^(2+)of zeolite X was investigated.The results showed that the optimal conversion conditions of zeolite X were as follows:n(H_(2)O/SiO_(2))=55,n(Na_(2)O/SiO_(2))=1.1,n(Al_(2)O_(3)/SiO_(2))=0.33,aging time 48 h,crystallization temperature 82℃and crystallization time 4 h.After dissolution,the stellerite zeolite depolymerized into the oligomeric Si species and remained in the system to participate in the growth of zeolite X,prompting the relative crystallinity and n(Si/Al)value of the synthesized zeolite X were 100%and 1.14,respectively.It was beneficial to shorten the crystallization time and reduce the crystallization temperature.And the adsorption capacity of Cd ^(2+)and Ni ^(2+)for zeolite X were 173.553 mg/g and 75.897 mg/g,respectively.Therefore,this study would provide theoretical basis and technical support for the rapid conversion of natural minerals into high quality zeolite X design and preparation.