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研究了纳米铜在三聚氰胺吸附过程中的稳定性。通过比较两种不同粒径的纳米铜溶胶与三聚氰胺混合溶液的吸收光谱,发现更小粒径的铜纳米团簇的吸收峰值快速下降并至峰位消失,而粒径稍大的铜纳米粒子的吸收峰值下降较慢;在三聚氰胺吸附过程中,两种粒径的纳米铜溶胶的吸收峰位均未发生红移现象,表明纳米铜没有产生团聚。分析认为三聚氰胺在纳米铜表面的吸附部分取代了纳米铜表面原有的还原剂,使铜单质转化为铜离子,溶液中的纳米铜数量减少,发生纳米铜消溶现象,荧光发射减弱。更小粒径的铜纳米团簇具有更大的有效吸附面积,消溶现象显著,稳定性较低。
The stability of nano-copper in the process of melamine adsorption was studied. By comparing the absorption spectra of the nanocrystalline copper sol and the melamine mixed solution of two different particle sizes, it was found that the absorption peaks of the smaller size copper nanoclusters rapidly decreased and disappeared to the peak position, whereas the larger size copper nanoparticles The absorption peak decreased slowly; in the process of melamine adsorption, the absorption peaks of the nano-sized copper sols of the two particle sizes did not red shift, indicating that the nano-copper did not agglomerate. It is concluded that the adsorption of melamine on the surface of nanocopper partially replaces the original reductant on the surface of nanocopper and the elemental copper is converted to copper ion. The amount of nanocopper in the solution decreases, and the nanometer copper dissolves and the fluorescence emission declines. Smaller particle size copper nanoclusters have larger effective adsorption area, significant dissolution and low stability.