PAA与PBTCA对CaCO_3显微结构的影响

Effects of PAA and PBTCA on CaCO_3 Micro-Structure

利用扫描电镜(ＳＥＭ)和原子力显微镜(ＡＦＭ)研究了分散剂ＰＡＡ与ＰＢＴＣＡ对ＣａＣＯ３显微结构的影响．结果表明,与ＰＡＡ相比,ＰＢＴＣＡ对ＣａＣＯ３的沉积形貌具有更大的影响．ＳＥＭ表明,在两种分散剂的存在下,沉积物的形貌皆发生了变化,随着阻滞影响增大,沉积物晶型畸变程度随之严重,沉积物形貌的分维值也随之增大．ＸＲＤ分析表明,随着阻滞影响增大,ＣａＣＯ３晶相中球霰石的含量增大．在分散剂存在下,热力学上属亚稳态的文石和球霰石从动力学上被稳定住了．ＡＦＭ研究表明,随着阻滞影响增大,ＣａＣＯ３晶体表面上台阶间距变大．同时,发现了ＣａＣＯ３晶体表面台阶的聚并现象并进行了讨论．

The effects of two dispersant, polyacrylic acid (PAA) and 2-phosphonobutane-l,2, 4-tricarboxylic acid (PBTCA), on the calcium carbonate microstructure were studied by using SEM and AFM. XRD analysis demonstrates that the content of vaterite increases with the increase in inhibition effects. The metastable crystal forms of vaterite and aragonite are stabilized kinetically in the presence of dispersants. The fractal analysis result shows that the fractal dimension is higher in the presence of dispersants. The better the inhibition effect, the higher the fractal dimension. The step morphology observed by AFM images shows that the step space on the CaCO3 surface increases in the presence of dispersants. Moreover, with the increase of inhibition effect, both the step space and fractal dimension increase. Step bunching was found on the CaCO3 crystal surfaces by AFM and discussed.