摘要
通过共沉淀法和煅烧法制备不同煅烧温度的水滑石,并对其进行XRD、FT-IR及BET表征.结果表明,煅烧水滑石后使水滑石的特征峰消失,层状结构塌陷,并生成了镁铝复合氧化物,比表面积增加,平均孔径减少.将水滑石进行硝态氮的吸附性能研究,结果表明,煅烧450℃水滑石除硝态氮效果优于其他煅烧温度下的水滑石,对10 mg/L的硝态氮吸附240 min后平衡浓度低于1 mg/L.最后,研究水滑石对硝态氮的吸附动力学与吸附等温线,结果表明准二级动力学模型和Langmuir吸附等温线能较好地描述硝态氮在水滑石上的吸附行为,吸附过程分为快速吸附阶段和慢速吸附阶段,水滑石对硝态氮的吸附过程主要为化学吸附,偏向于单分子层的吸附过程,但也不能排除多分子层吸附的存在.
Layered double hydroxide（ LDH） were synthesized by co-precipitation method and its calcination products（ LDH450） was prepared by heating LDH at 450 ℃. The materials were characterized by X-ray diffraction（ XRD）,Fourier transform infrared spectroscopy（ FT-IR） and Brunauer-Emmett-Teller（ BET）.Results indicate that the characteristic peaks（ 003） and（ 006） of LDH450 disappeared,a mixed oxide Mg（ Al）O was formed,and the BET SSA of LDH450 increased,and the average pore size reduced. The adsorption capacity of hydrotalcite was studied. Results indicate that nitrate adsorption by LDH450 was superior to the others. When initial concentrations of nitrate was 10 mg / L,the adsorption reaction reached a balance in 240 min,and the equilibrium concentration was less than 1 mg / L. Finally,the adsorption kinetics and adsorption isotherm showed that the Pseudo-second-order kinetic model and Langmuir isotherm model could be used to describe nitrate adsorption satisfactorily. Adsorption process divided into two stages,included fast stage and slow stage,and mainly chemical adsorption,the adsorption process in favor of a single molecular layer,but can not exclude the presence of multiple molecular layer adsorption.
出处
《湖北大学学报（自然科学版）》
CAS
2016年第3期201-207,共7页
Journal of Hubei University：Natural Science
基金
国家自然科学基金(51374157)
教育部新世纪优秀人才计划项目(NCET-12-0713)
湖北省自然科学基金(2013CFA106)
武汉工程大学研究生教育创新基金(CX2014111)资助
关键词
水滑石
煅烧
硝态氮
吸附
layered double hydroxide
heating nitrate
adsorption
