纳米银在地下水环境中的转化过程研究

为探究可作为化妆品添加剂的纳米银(Ag NPs)在进入地下水环境中的转化行为,采用仪器分析手段,从测定粒径、zeta电位、吸光度、SEM图和EDX能谱等几方面对聚乙烯吡咯烷酮-纳米银(PVP-Ag NPs)在沈阳附近地区地下水体系中的转化过程进行了考察。实验结果表明:PVP-Ag NPs加入到地下水样中后粒径变化明显,zeta电位值位于-12~-4 m V之间,说明PVP-Ag NPs处于快速聚凝状态,吸光度不变但吸收峰峰值不断降低证明PVP-Ag NPs浓度逐渐降低,SEM图与EDX能谱结果显示PVP-Ag NPs加入到地下水样中后会发生聚凝沉降,并在此过程中可以与其他离子结合形成共沉淀。此外,在溶解氧高,p H7的情况下,PVP-Ag NPs先溶解释放出银离子从而导致PVP-Ag NPs沉降的速度降低。

Transformation process of silver nanoparticles in underground-water environment

In order to explore the transformation behavior of entering of silver nanoparticles (AgNPs), which can be used as a cosmetic additive, into underground-water environment, instrumental analysis including determination of particle size, zeta potential and light absorbance as well as SEM image and EDX spectrum was adopted for investigation of polyvinylpyrrolidone coated AgNPs (PVP-AgNPs) transformation process entering into the underground-water system in an area nearby Shenyang city. The experimental results showed that after the addition of PVP-AgNPs into the underground-water samples, its particle size changes obviously, and zeta potential value locates between -12 and -4 mV; it indicates that the PVP-AgNPs is in a rapid coagulation state. The light absorbance remains unchanged, but the absorption peak decreases continuously, such phenomenon indicates that the concentration of PVP-AgNPs decreases gradually. The SEM images and EDX spectra indicate that addition of PVP-AgNPs into the underground-water will cause coagulation sedimentation and this process can be combined with other ions to form co-precipitation. In addition, in the case of highly dissolved oxygen state and pH<7, PVP-AgNPs will dissolve and release silver ions first, and result in the decrease of PVP-AgNPs settling speed.