摘要
以二乙烯三胺基丙基三甲氧基硅烷为偶联剂,采用后期修饰方法,制备出氨基修饰SBA-15(SBA代表University of California,Santa Barbara,USA)。利用扫描电镜、傅立叶红外光谱仪、N2吸附-脱附对其结构进行表征。以修饰后的SBA-15为吸附剂,对水中Cu2+的吸附过程进行了动力学与热力学探讨。结果表明:修饰后的SBA-15是一种理想的铜吸附剂,pH值适应范围较宽(3~6),吸附平衡时间较短(120 min),最大吸附量可达37.94 mg/g。修饰后SBA-15对Cu2+吸附动力学符合拟二阶动力学方程,吸附过程可分为三个阶段且不只受内扩散控制。Langmuir吸附模型和Dubinin-Radushkevich(D-R)吸附模型能更好地描述了Cu2+在修饰后SBA-15上的吸附行为,其吸附平均活化能E值分别为-16.44,-17.05,-17.20 kJ/mol,表明该吸附过程为表面络合。热力学参数表明吸附过程是自发、吸热、混乱度增加的过程,升温有利于吸附。
Mesoporous silica SBA-15 functionalized by amine were prepared by a post-synthesis method using N1-[3-( Trimethoxysiyl) propyl]diethylenetriamine as the coupling agent. The materials were characterized by X-ray powder diffraction( XRD), Fourier-transform infrared spectroscopy( FT-IR) and N2adsorption-desorption isotherms. The functionalized SBA-15 was used as adsorbent for Cu2 +ions in aqueous solution. And then the copper adsorption process has been thoroughly studied on both kinetics and thermodynamics. The results showed amine-functionalized SBA-15 was an ideal absorbent for aquatic copper removal characterized by a wide adaption range of pH( from 3 to 6),short adsorption equilibrium time( 120 min),and high adsorption capacity( 37. 94 mg /g). The study indicated that the pseudo-second-order kinetic model could stimulate the entire adsorption process. The adsorption was controlled by three different phases and the intraparticle diffusion was not the sole rate controlling step. Adsorption equilibrium data could be also described well by Langmuir and Dubinin-Radushkevich( D-R) isotherm models. Based on the D-R model,the adsorption energy E was calculated as- 16. 40,- 17. 05,- 17. 20 kJ /mol respectively, which defined the adsorption course as a surface complexation.Thermodynamic calculations suggested that the adsorption of Cu2 +ions on amine-functionalized SBA-15 was spontaneous and endothermic causing,increase of the degree of randomness at the solid /solution interface,favorable at a higher temperature.
出处
《环境工程》
CAS
CSCD
北大核心
2014年第11期69-76,共8页
Environmental Engineering
基金
国家自然科学基金(41161075)
广西科技攻关项目(桂科攻1355003-7)
广西教育厅项目(2013YB111)
