MY@SiO_2-PEI磁性复合生物材料对二元Ce^(3+)/Sr^(2+)混合离子的吸附性能研究

Adsorption of mixed Ce_(3+)/Sr^(2+) in binary system onto MY@ SiO_2-PEI magnetic composite biomaterial

采用生物材料酵母作为基质材料,纳米四氧化三铁为磁敏源,3-氯丙基三甲氧基硅烷(CP)作为硅源与偶联剂,聚乙烯亚胺(PEI)为功能单体,利用两步溶液聚合法制备磁性复合生物材料(MY@SiO2-PEI).同时,采用FT-IR、SEM、VSM、等电位点测定及接触角测定等方法对材料的理化性能进行了表征,并考察其对二元体系(Ce3+/Sr2+)混合液的吸附性能及机理.结果表明,MY@SiO2-PEI实现了PEI的成功嫁接,材料的表面变得粗糙,等电位点pHzpc变大,材料的接触角由疏水变成亲水.吸附实验结果表明,MY@SiO2-PEI具有更好的吸附性能,对二元体系中Ce3+和Sr2+的最大吸附量分别为80.24 mg·g-1和63.51 mg·g-1.准二级动力学方程与Freundlich吸附等温模型的线性回归系数(R2)均大于0.99,准二级动力学模拟的理论吸附容量(Qe,cal)更接近于实验值(Qe,exp),Freundlich等温模型中的吸附强度(1/n)均小于1,吸附为多层,有利于化学吸附过程;pH=5.5~6.0为最适吸附pH范围;MY@SiO2-PEI的磁性强度为10.03 emu·g-1,满足分离富集的要求.

Magnetic composite biomaterials（ MY@ SiO2-PEI） were prepared through two-step solution polymerization method,which took biological material,the yeast,as the original material,nano-sized particles Fe3O4as magnetism source,γ-chloropropyl trimethoxysilane（ CP） as silicon source and coupling agent,and poly-ethyleneimine（ PEI） as functional agent. MY @ SiO2-PEI were characterized by FT-IR,SEM,VSM,Equipotential point（ pHzpc） determination and Contact Angle Measurement. The adsorption performance was investigated in binary mixed solution system（ Ce3＋/Sr2＋）. The characterization results indicated that PEI agent were grafted onto MY@ SiO2-PEI successfully in that the surface became rough,the pHzpcincreased sensitively and the contact angle of MY @ SiO2-PEI became hydrophilic. The adsorption experiments illustrated that MY @ SiO2-PEI exhibited better adsorption performance than non-grafted composite and its max adsorption capacity was 80. 24 mg·g-1and 63. 51 mg·g-1for Ce3＋and Sr2＋,respectively.The linear regression coefficient（ R2） of pseudo-second adsorption kinetics was higher than 0.99 as well as Freundlich adsorption isotherm model,the academic adsorption capacity（ Qe,cal） became closer to experimental value（ Qe,exp）,and the adsorption strength（ 1/n） in Freundlich adsorption isotherm model were all less than1,which indicated that the adsorption process was chemical adsorption as well as multilayer and favorable adsorption. The bestsuitable pH range was 5. 5 ~ 6. 0 under experimental conditions. The saturation magnetization（ Ms） was 10. 03 emu·g-1which met the needs of separation and enrichment of adsorbent.