摘要
以煅烧硅藻土和熟石灰为原料,通过水热反应制备了硅钙多孔矿物材料,研究了石灰水热条件下硅藻土微结构的演化;以亚甲基蓝为吸附对象考察了硅藻土微结构改变对其吸附性能的影响,并对吸附机理进行了分析。结果表明:在含石灰水热条件下,煅烧的硅藻土中SiO2与Ca(OH)2反应生成单斜脱贝莫来石晶体;硅藻土中硅藻圆盘结构消失,生成的片状单斜脱贝莫来石相互堆积形成硅钙多孔矿物材料;多孔材料孔体积较煅烧硅藻土增加了10倍,且材料表面活性羟基数量增多。硅钙多孔矿物材料对亚甲基蓝有良好的吸附效果和循环使用性能,相同条件下吸附量是煅烧硅藻土的6.5倍,饱和吸附量可达384.51 mg/g;吸附动力学模型可由准二级动力学方程描述,吸附过程符合Langmuir等温吸附方程,是吸热的自发反应。在pH>4时,硅钙多孔矿物材料表面带负电,材料表面活性羟基与溶液中的季铵盐阳离子MB+通过静电吸引形成氢键,从而完成吸附,同时硅钙多孔矿物材料较大的比表面积也为亚甲基蓝提供了更多的吸附位点,利于吸附进行。
Si-Ca porous mineral material was prepared with calcine diatomite and slaked lime via a hydrothermal reaction method.The microstructure of diatomite under lime-containing hydrothermal conditions was characterized.The effect of microstructure change of diatomite on its adsorption performance was investigated with methylene blue as an adsorbent,and the mechanism of Si-Ca porous mineral material was analyzed.The results show that SiO2 in calcined diatomite reacts with Ca(OH)2 to generate clinotobermorite under the lime-containing hydrothermal conditions.The diatoms disk structure disappears and the flaky clinotobermorite stacks up into Si-Ca porous mineral.The volume of porous material is 10 times greater than that of calcined diatomite,and the amount of hydroxyl on the surface of the material increases.Si-Ca porous mineral material exhibits good methylene blue adsorption and recycling performance.The adsorption capacity of Si-Ca porous mineral is 6.5 times greater than that of calcined diatomite,and its saturated adsorption capacity can reach 384.51 mg/g.The adsorption process of diatomite board towards methylene blue can be described by the pseudo-second-order kinetic model.Its adsorption isotherms can be fitted by the Langmuir model,and the adsorption is a spontaneous endothermic process.When p H value>4,the surface of Si-Ca porous mineral is negatively charged,the adsorption is completed by the active hydroxyl group of the mineral surface and the quaternary ammonium salt cationic in the solution form the hydrogen bond through electrostatic attraction,Also,the large specific surface area of Si-Ca porous mineral can provide the more adsorption sites for methylene blue,which is conducive to the adsorption.
作者
李铭哲
郑水林
孙志明
刘碧璇
李春全
LI Mingzhe;ZHENG Shuilin;SUN Zhiming;LIU Bixuan;LI Chunquan(School of Chemical and Environment Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2020年第4期567-576,共10页
Journal of The Chinese Ceramic Society
基金
吉林省科技发展计划资助项目(20180201078GX).
关键词
煅烧硅藻土
硅钙多孔矿物材料
亚甲基蓝
吸附
calcine diatomite
silicon-calcium porous mineral material
methylene blue
adsorption
