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为比较研究不同纳微米尺寸的一水草酸钙(COM)和二水草酸钙(COD)晶体对阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)的吸附差异,探讨抑制剂对结石形成的抑制机理,本研究测定了各浓度CTAB下不同尺寸COM或COD对CTAB的吸附量；采用XRD和FT-IR表征吸附前后晶体是否发生晶相改变；采用Zeta电位仪测定吸附后晶体表面的Zeta电位随CTAB浓度的变化。结果发现,随着c(CTAB)浓度升高,3μm和10μm的COM、COD晶体的吸附曲线由上升段和平台段组成,而小尺寸的50 nm、100 nm、1μm的COM、COD晶体的吸附曲线为直线型。随着晶体尺寸的增大, COM和COD晶体的吸附量依次降低。当尺寸相同时, COM对CTAB的吸附量要大于COD,归因于CTAB更容易选择吸附在COM表面负电荷的区域。上述结果表明,草酸钙晶体对阳离子表面活性剂的吸附量与比表面积和晶体的晶面结构有关。晶体尺寸越小,比表面积越大,晶面暴露的草酸根密度越大, CTAB的吸附量越大,导致晶体表面Zeta电位绝对值增大,静电排斥力增强,从而抑制尿微晶的聚集,有利于抑制草酸钙结石的形成。

The aim of this study was to compare the adsorption difference of cetyltrimethylammonium bromide (CTAB) on nano/micron calcium oxalate monohydrate (COM) and dihydrate (COD) crystals, so as to explore the stone formation mechanism. The crystal phase transformation before and after adsorption was analyzed by XRD and FT-IR. Adsorbed amount of nano/micron COM and COD to CTAB was detected by colorimetry. Zeta potentials of crystals were measured by Zeta potential analyzer. The adsorption curves of large-sized COM and COD (3μm and 10μm) formed a platform with increase of c (CTAB), while the small-sized COM and COD (50 nm, 100 nm and 1 μm) showed linear-type. The adsorbed amounts of COM and COD crystals were reduced with increase of crystal size. Ad-sorbed amounts of CTAB on COM were more than COD with the same size, because CTAB is more likely to adsorb to the negative charges on the COM surface. In conclusion, adsorption of crystals is related to the specific surface area and crystal structure. The adsorption quantity, absolute values of zeta potential of crystals and electrostatic repul-sive-force are increased with the decrease of crystal size because of the increased specific surface area and exposed oxalate ions. The adsorption could inhibit the aggregation of urine crystals thus reduce the risk of calcium oxalate stone formation.