电解质对Mg-Al HTlc溶胶聚集动力学行为的影响

Effect of Electrolytes on Kinetic Behavior of Colloidal Dispersions of Mg-Al Hydrotalcite-Like Compounds

采用动态光散射法研究了电解质对Mg Al类水滑石 (HTlc)溶胶聚集动力学行为的影响 ,发现随惰性电解质 (NaCl ,NaNO3 )浓度的增大 ,Mg AlHTlc溶胶经历稳定、慢速聚集和快速聚集三个区域 ,而特性吸附电解质 (NaOH )在所研究的浓度范围 ( 0～ 4mmol/L)内未观察到快速聚集 .NaCl和NaNO3 的临界聚沉浓度分别为 12 7和 180mmol/L ,慢速聚集区稳定比与NaCl,NaNO3 和NaOH浓度间的关系式分别为 :logW =10 18-4 44logC ,logW =11 98-4 79logC ,logW =1 92 -0 74logC .

Colloidal stability and aggregation kinetics of the Mg-Al HTlc dispersion were investigated at various electrolyte concentrations by dynamic light scattering (DL-S). It was found that the Mg-Al HTlc dispersions go through mostly stable, slow aggregating and fast aggregating stages in turn with the increase of the inertia electrolyte concentration ( NaCl, NaNO3), while those phenomena do not occur in the dispersions with various NaOH concentrations (0 similar to 4 mmol/L) in our studies. The critical electrolyte concentrations of NaCl and NaNO3 for this MgAl HT1c dispersion are found to be 127 and 180 mmol/L respectively. The relations between the stability ratio and the concentration of NaCl, NaNO3 and NaOH in the slow aggregating stage have been measured to be log W = 10.18 - 4.44logC, logW = 11.98 - 4.79logC and logW = 1.92 - 0.74logC, respectively. The aggregation of this dispersion has been induced much more easily by NaOH than by NaCl or NaNO3.