纳米银在地下水环境中的转化过程研究

Transformation process of silver nanoparticles in underground- water environment

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 H<7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。

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 result in the decrease of PVP - state and pH 〈 7, PVP - AgNPs will dissolve and release silver ions first, and AgNPs settling speed.