【摘要】 为了研究水化硅酸钙在形成过程中对Cr(Ⅵ)的俘获情况,利用分析纯CaO、H2SiO3和Na2CrO4溶液人工合成n(Ca)/n(Si)为1.6和0.7的2种含Cr(Ⅵ)的C—S—H。合成实验结果表明,当合成溶液中CrO42-的浓度为1 000mg/L时,C—S—H对CrO42-的俘获量约为0.820~1.173 mg/g,其中n(Ca)/n(Si)为1.6的C—S—H对CrO42-的俘获量较大一些。2种C—S—H所俘获的CrO42-大约有66%~68%能被Ca(OH)2溶液中的OH-所替换。这表明,C—S—H对CrO42-的俘获有2种方式,一是通过物理吸附把大部分CrO42-俘获到C—S—H特征扩散层中,二是以化学吸附的形式把少量的CrO42-俘获到C—S—H的扩散双电层内。测定发现,C—S—H在俘获CrO42-后,其XRD图谱发生了一些变化。更多还原

【Abstract】 In order to investigate the entrapment of Cr(Ⅵ)by calcium-silicate-hydrate, C—S—H containing Cr(Ⅵ)at n(Ca)/n(Si)=0.7 and 1.6 were synthesized using analytical reagent grade CaO,H2SiO3 and Na2CrO4.The synthesis experiments show that the entrapment capacity of CrO2-4 by C—S—H is about 0.820 mg/g to 1.173 mg/g and the capacity increases with n(Ca)/n(Si) values.About 66%～68% of the entrapped CrO2-4 on these two kinds of C—S—H can be desorbed by OH-from Ca(OH)2 solution,indicating that the entrapment of CrO2-4 by C—S—H is carried out by two forms.One is physical adsorption in which the majority of adsorbed CrO2-4 is captured into C—S—H diffuse layer.The other is chemical adsorption in which the minority of adsorbed CrO2-4 is entrapped in C—S—H adsorption layer.The X-ray diffraction patterns of C—S—H changed a little after they accommodate CrO24.更多还原