摘要
研究了H_2PdCl_4和金属离子在Al_2O_3上的吸附行为及它们的相互影响,发现H_2PdCl_4,H_2PtCl_6,HAuCl_4和Cu(NO_3)_2,Ni(NO_3)_2,Co(NO_3)_2在Al_2O_3上均呈Langmuir型等温吸附。预浸金属离子对H_2PdCl_4在Al_2O_3上的吸附有影响,但两者在Al_2O_3上吸附量之和与H_2PdCl_4单独浸渍时的吸附量相近,并由此讨论了它们在Al_2O_3上的吸附机理。预浸乙酸、柠檬酸和马来酸等竞争吸附剂对金属离子在Al_2O_3上的吸附亦有影响。分别测试了H_2PdCl_4、金属离子和竞争吸附剂溶液以及由它们组成的混合溶液的吸收光谱,讨论了这些组分在混合溶液中可能发生的作用。
The adsorption of H2PdCl4 and metallic ions on A12O3 and their dependence have been studied. The adsorption isotherms of H2PdCl4, H2PtCl6, HAuCl4 and Cu(NO3)2, Co(NO3)2, Ni(NO3)2 on Al2O3 were all of Langmuir type. The amount of H2PdCl4 adsorbed on A12O3 was decreased by pre-impregnation with metallic ions. Because the total adsorption amount of H2PdCl4 and metallic ion was approximately similar to that of H2PdCl4 adsorbed alone, it was suggested that PdCl42- and metallic ion might be adsoibed on the same sites of A12O3. UV diffuse reflection spectra of solid samples impregnated with H2PdCl4 solution of different acidities suggest that there are two adsorption mechanisms:when pH value of impregnation solution is lower, PdCl42- may be adsoibed on positive charge sites of Al2O3, when pH is higher, PdCl42- may interact with the surface hydroxy of A12O3 and precipitate on the surface. The amount of metallic ion adsorbed on A12O3 was also affected by pre-impregnation with competitive adsorbates, such as acetic, citric and maleic acid. The absorption spectra of H2PdCl4, metallic ion, competitive adsorbate solutions and the mixed solutions of two of them were studied by spectrophotometer. The interaction between the two components in the solutions was discussed.
基金
国家自然科学基金
