Abstract The effects of pH on the structures, compositions, morphologies, Zeta potential, and gel properties of montmorillonite, palygorskite and their composite clays were investigated in the study. With the increase in pH, the above properties of montmorillonite, palygorskite and their composite clays showed different changing trends. The compositions of montmorillonite and palygorskite basically remained unchanged in the pH range of 1–13. The dissociation and dispersion degrees of montmorillonite sheets, the separation and dispersion degrees of palygorskite fiber cluster and the absolute value of Zeta potential increased. The viscosity of palygorskite sample firstly increased and then decreased. The viscosity of montmorillonite and composite clay samples increased and the increase was rapid especially at pH above 12. The viscosity of montmorillonite and composite clay samples reached 9151 mPa·s at pH 13, but the viscosity of composite clay sample was lower than that of montmorillonite at the same pH value. The influencing factors of viscosity mainly included the dissociation degree of montmorillonite sheets, the separation degree of palygorskite fibers and the Zeta potential. The higher degrees of dissociation and dispersion corresponded to the higher viscosity. With the increase in the absolute value of Zeta potential, the viscosity of montmorillonite and composite samples increased, but the viscosity of palygorskite increased firstly and then decreased. The potential mismatch between palygorskite and montmorillonite was responsible for the lower actual viscosity of the composite sample compared to the calculated viscosity.

中文翻译：

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pH值对蒙脱石、坡缕石和蒙脱石-坡缕石复合粘土凝胶性能的影响

摘要 研究了pH对蒙脱石、坡缕石及其复合粘土的结构、组成、形貌、Zeta电位和凝胶性质的影响。随着pH值的升高，蒙脱石、坡缕石及其复合粘土的上述性质呈现不同的变化趋势。蒙脱石和坡缕石的成分在1-13的pH范围内基本保持不变。蒙脱石片的解离度和分散度、坡缕石纤维簇的离解度和分散度以及Zeta电位的绝对值增大。坡缕石样品的粘度先升高后降低。蒙脱石和复合粘土样品的粘度增加，并且增加很快，尤其是在 pH 值高于 12 时。蒙脱石和复合粘土样品在pH 13时的粘度达到9151 mPa·s，但在相同pH值下，复合粘土样品的粘度低于蒙脱石。粘度的影响因素主要包括蒙脱石片的解离度、坡缕石纤维的分离度和Zeta电位。较高的离解度和分散度对应于较高的粘度。随着Zeta电位绝对值的增加，蒙脱石和复合样品的粘度增加，但坡缕石的粘度先增加后降低。坡缕石和蒙脱石之间潜在的不匹配是导致复合样品的实际粘度低于计算粘度的原因。