富勒烯(C_(60))与双层氢氧化物的凝聚动力学

Aggregation Kinetics of Fullerene-C_(60) and Layered Double Hydroxides

该文为探究纳米颗粒进入环境后,与环境中无机矿物发生相互作用而导致的凝聚状态变化,通过在20℃和90℃制备2种双层氢氧化物MgAl-LDH20和MgAl-LDH90,采用Zeta电位分别研究了单一和混合纳米颗粒体系富勒烯(C_(60))的凝聚动力学。结果表明,往MgAl-LDHs的悬浮液中加入电解质(NaCl),计算得到其临界凝聚浓度(CCC)分别为CCC_(MgAl-LDH20)=209.12 mmol/L和CCC_(MgAl-LDH90)=166.27 mmol/L。MgAl-LDHs悬浮液与C_(60)悬浮液按不同比例(120∶1、60∶1、30∶1)混合后,Zeta电位(ζ)显著下降,且ζ的下降程度随C_(60)浓度的升高而增大。在单一体系中,MgAl-LDHs的k_(fast)均小于3,而在加入C_(60)后,混合体系的k_(fast)均大于3,表明MgAl-LDHs与C_(60)由于静电作用加速了颗粒的聚集。LDHs的存在能够降低水环境中C_(60)迁移性,且微量的C_(60)进入MgAl-LDHs悬浮液体系时,MgAl-LDHs悬浮液单一体系的稳定性是混合体系稳定性的决定性因素。

To investigate the aggregation state changes that occur when nanoparticles enter the environment and interact with inorganic minerals,a laboratory experiment was conducted with two types of layered double hydroxides,namely MgAl-LDH20 and MgAl-LDH90,were prepared at respectively 20℃and 90℃,meantime the aggregation kinetics of both single and mixed nanoparticle of fullerene-C_(60) were studied using Zeta potential(ζ)analysis techniques.Consequently,the experi⁃ment showed that the critical aggregation concentration(CCC)values of MgAl-LDH20 and MgAl-LDH90 were 209.12 mmol/L and 166.27 mmol/L,respectively;the Zeta potential(ζ)of MgAl-LDHs suspension was significantly de⁃creased after being mixed with C_(60) suspension at different ratios(120∶1,60∶1,30∶1),and the decline degree ofζincreased with the raising of C_(60) concentration;and the kfast of MgAl-LDH was<3 in the single system,while the kfast of the mixed system was>3 after being added with C_(60),which suggested that the aggregation of the particles was accelerated due to the electrostatic interactions between MgAl-LDHs and C_(60),and the presence of MgAl-LDHs could slow down the mobility of C_(60) in the aqueous environment.Moreover,the stability of the mixed suspension system was determined by MgAl-LDHs when only a few amounts of C_(60) entered the LDHs suspension system.