新型无机抗菌材料:载铜蒙脱石及其抗菌机理讨论

以内蒙赤峰蒙脱石为原料合成了载铜蒙脱石,它对革兰氏阴性菌E.coli和革兰氏阳性菌S.faecalis均有很强的抑止和杀灭作用,其抗菌能力大大优于载铜沸石,蒙脱石在载铜反应后矿物表面带有剩余正电荷,它的抗菌能力来自两方面因素,一方面是矿物对带相反电荷的细菌的吸附作用,另一方面是矿物释放出的铜离子对细茵的杀灭作用,这是载铜蒙脱石抗菌能力优于载铜沸石的本质原因。

A New Type of Inorganic Antibacterial Material: Cu-bearing Montmorillonite and Discussion on Its Mechanism

With the raw material coming from Chifeng, the Inner Mongolia Autonomous Region, Cu bearing montmorillonite (Cu-MMT) was synthesized through cation exchange reaction. XRD analysis shows that, (001) basal spacing of montmorillonite expends from 1.544 nm to 1.588 nm after cation exchange. This indicates that Cu2+ enters interlayer position of montmorillonite as hydrated cation or composite cation. Through antibacterial experiment, it is found that Cu-MMT has strong antibacterial ability on E. coli and S. faecalis. Minimal inhibitory concentration (MIC) and killing concentration are 10 and 50 ppm respectively. The antibacterial ability of Cu-MMT is much better than that of Cu-carrying zeolite. Taking the up-to-date characterization on Cu-MMT and Cu-zeolite into account, it is clear that Cu-zeolite retains electric neutrality after cation exchange. Its antibacterial capacity relies on the amount of Cu2+ released into medium. On the other hand, Cu-MMT has residual positive charge after cation exchange. Its antibacterial ability results from two aspects, one is electrostatic attraction which makes large amount of bacterium being adhered on montmorillonite surface, the other is the same as Cu-zeolite, i.e., Cu2+ slowly released into medium which can kill bacterium. The former aspect is the main reason that Cu-MMT has better antibacterial ability than Cu-zeolite.