高价小分子型分散剂在Al_2O_3表面的吸附研究

Investigation on the Adsorption of Polyvalent Low-molecular-weight Dispersants on Alumina

采用 5-硝基水杨酸合铁 ( )分光光度法测定了 2 -膦酸丁烷 -1 ,2 ,4 -三羧酸 ( PBTCA)及柠檬酸在 Al2 O3表面的等温吸附线 ,发现二者的饱和吸附量均随 p H值的升高而减小 ,且 PBTCA比柠檬酸的饱和吸附量高 .ζ电位及沉降实验亦表明 ,与柠檬酸相比 ,PBTCA的吸附使 Al2 O3 表面的有效负电荷量更高 ,且其分散作用也更佳 .采用 FTIR及 AES研究了 PBTCA在 Al2 O3 表面的吸附机理 .膦酸基的存在提高了 PBTCA在碱性条件下的吸附能力 .

The adsorption of 2 phosphonobutane 1,2,4 tricarboxylic acid (PBTCA) and citric acid on alumina was determined by using the ferric 5 nitrosalicylate spectroscopic method. The saturation adsorption of PBTCA was found to be much higher than that of citric acid. FTIR and AES results revealed that the phosphonyl group participated in the chemisorption of PBTCA onto alumina. The higher dispersing efficiency of PBTCA than citric acid was attributed to its high number of charges and high chelating ability at high pH.