摘要
在研究聚羧酸减水剂在水泥颗粒表面的吸附量、吸附速率的基础上,运用不同吸附动力学模型对试验结果进行拟合。吸附量测试结果表明:掺0.5%、1.0%Na2SO4会显著降低聚羧酸减水剂在水泥颗粒表面的吸附量,但掺0.1%、0.2%的Na2SO4有利于聚羧酸减水剂的吸附;CaSO4·2H2O对聚羧酸减水剂的吸附量影响不显著。吸附速率测试及拟合结果表明:硫酸盐对聚羧酸减水剂在水泥颗粒表面吸附动力学的影响规律符合Langmuir准二级吸附动力学模型,Na2SO4通过改变聚羧酸减水剂在水泥颗粒表面的准二级吸附速率常数影响聚羧酸减水剂吸附达到平衡的时间,0.2%、1.0%掺量的Na2SO4均延迟了聚羧酸减水剂达到吸附平衡的时间。掺0.2%Na2SO4使准二级吸附速率常数较不掺硫酸盐时有所提高;掺1.0%Na2SO4的准二级吸附速率常数较不掺硫酸盐时大大降低;CaSO4·2H2O对准二级吸附速率常数的影响较Na2SO4要小。
The experimental results on the effect of adsorption quantity and rate of polycarboxylate-type superplasticizer on cement particles were presented. The experimental results followed different adsorption kinetics models. It was indicated that the Na2SO4 addition of 0.5% or 1.0% had negative influence on the adsorption quantity of polycarboxylate-type superplasticizer on cement parti- cles. However, the Na2SO4 addition of 0.1% or 0.2% could favor the adsorption. CaSO4.2H2O had little effect on the adsorption quan- tity of polycarboxylate-type superplasticizer. The results on the effect of sulfate on the adsorption of polycarboxylate-type superplas- ticizer on cement particles followed the Langmuir pseudo-second-order adsorption kinetics model. Na2SO4 affected the time of equi- librium adsorption via the reduction of pseudo-second-order adsorption rate constant and delayed the time of equilibrium adsorption. The Na2SO4 addition of 0.2% increased the pseudo-second-order adsorptive rate constant, while the Na2SO4 addition of 1.0% de- creased the pseudo-second-order adsorptive rate constant. CaSO4-2H2O could result in a slight effect on the pseudo-second-order adsorption rate constant rather than Na2SO4.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2012年第11期1586-1591,共6页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金(50972170)资助项目
关键词
硫酸盐
聚羧酸减水剂
吸附量
吸附速率
准二级吸附速率常数
sulfate
polycarboxylate-type superplasticizer
adsorption quantity
adsorption rote
pseudo-second-order adsorption rate constant
