The Key Lab of Advanced Functional Materials, Ministry of Education China, School of Materials Science and Engineering, Beijing University of Technology, Beijing 100022, China.
The Key Lab of Advanced Functional Materials, Ministry of Education China, School of Materials Science and Engineering, Beijing University of Technology, Beijing 100022, China.
J Environ Sci (China). 2020 May;91:92-104. doi: 10.1016/j.jes.2020.01.006. Epub 2020 Jan 25.
Highly efficient and sustainable conversion technologies to generate uniform sodalite (Na(AlSiO)(OH)) zeolite microspheres with low-grade waste natural diatomite as raw materials via a solution-mediated crystallization route were developed in the present study. The synthesis process can be considered as an in-situ zeolitization of diatomite precursor without involving any mesoscale template and any post-synthetic modification. The mass ratios of diatomite and AlCl·6HO have remarkable effect on the morphology, crystal structure and porosity of sodalite zeolite product. The preferred sodalite microspheres with uniform mesoporous of size 3.5-5.5 nm and large surface area of 162.5 m/g exhibit well removal performance for heavy metal ions (Pb(II), Cd(II), Zn(II), and Cu(II)), with the highest adsorption abilities for Pb(II) ions of 365 mg/g. In addition, the effect of contact time, initial ion concentration, competitive adsorption and solution pH were evaluated. The removal performance results from synergistic effects of dominating cation-exchange and additional surface chemisorption. The study may broadly help unveil chemical control reactions of the zeolitization processes of diatomite, and thus facilitates the development of promising zeolite materials for the use in natural and engineered aquatic environments by recycling waste diatomite resources.
本研究开发了一种高效、可持续的转化技术，可利用低品位天然硅藻土为原料，通过溶液介导的结晶途径生成均匀的方钠石（Na(AlSiO)(OH))沸石微球。该合成过程可视为硅藻土前体的原位沸石化，不涉及任何介观模板和任何后合成修饰。硅藻土和 AlCl·6HO 的质量比对方钠石沸石产物的形貌、晶体结构和孔隙率有显著影响。优选的方钠石微球具有均匀的介孔尺寸（3.5-5.5nm）和大的比表面积（162.5m/g），对重金属离子（Pb(II)、Cd(II)、Zn(II)和 Cu(II)）具有良好的去除性能，对 Pb(II)离子的吸附能力最高可达 365mg/g。此外，还评估了接触时间、初始离子浓度、竞争吸附和溶液 pH 的影响。去除性能源自主导的阳离子交换和额外的表面化学吸附的协同效应。该研究可能广泛有助于揭示硅藻土沸石化过程的化学控制反应，从而通过回收废硅藻土资源，为天然和工程水生环境中使用的有前途的沸石材料的开发提供帮助。
