he electrical property,stability and rheological property of mixed metal hydroxide(MMH)-clay aqueous suspensions were studied via determining elec- trophoretic mobilities,heterocoagulation and rheological parameters....he electrical property,stability and rheological property of mixed metal hydroxide(MMH)-clay aqueous suspensions were studied via determining elec- trophoretic mobilities,heterocoagulation and rheological parameters. The suspen- sions of MMH-Na-montmorillonite and MMH-Kaolinite may be transformed from negatively charged systems into positively charged systems through changing the ratio of MMH to clav. The increase of MMH content makes the stability of dilute MMH-clay suspensions decreased in negatively chrged systems and increased in positively chrged systems. The complete coagulations at near neutral systems oc- curs. In the concentrated MMH-clay suspension,the steric network structures may be formed between MMH and clay particles,which cause the apparent viscosity(AV)and Bingham yield point(YP) of the suspentqion to increase. There is a suit- able ratio of MMH to clay at which the AV and YP of the suspension attain a maximum value,which in agreement with “bridging theory”of polymer flocculation.展开更多
One of the central theoretical problems in the colloid field is to determine the rheological relation between the macroscopic properties of colloidal suspensions and the microstructures of the systems. In this work, t...One of the central theoretical problems in the colloid field is to determine the rheological relation between the macroscopic properties of colloidal suspensions and the microstructures of the systems. In this work, the authors develop a method of transformation field by which one call calculate the effective viscosity of an incompressible: viscous fluid containing colloidal particles (either solid particles: or liquid drops) fixed at the points of a periodic lattice. The effective viscosity of a colloidal dispersion of spherical particles is calculated. The predictions of the theory are in good agreement with the Einstein's formula for suspensions and the Taylor's formula for emulsions at low particle concentrations. At higher particle concentrations, the theory reproduces the results of Nunan and Keller. The method is also applicable to the viscosity of colloidal systems with non-spherical particles.展开更多
Colloidal dispersions are common in nature with wide industrial applications. One of the central theoretical problems in the field is to determine the rheological properties of the colloidal dispersion from the micros...Colloidal dispersions are common in nature with wide industrial applications. One of the central theoretical problems in the field is to determine the rheological properties of the colloidal dispersion from the microstructures of the systems. Because of the difficulties associated with the boundary-value problems of the many-particle system, existing theories for colloidal suspensions are limited to low particle concentrations. In this work, a method of transformation field is developed by which one can calculate the effective viscosity of an incompressible viscous fluid containing colloidal particles ( either solid particles or liquid drops). The predictions of the theory are in goad agreement with the Einstein's formula for suspensions and the Taylor's formula for emulsions at low particle concentrations. At higher particle concentrations, the results of Nunan and Keller are produced. The method is also applicable to the viscosity of colloidal systems with non-spherical particles.展开更多
Based on statistical mechanics for classical fluids,general expressions for hydrodynamic stress in inhomogeneous colloidal suspension are derived on a molecular level.The result is exactly an extension of the Iving-Ki...Based on statistical mechanics for classical fluids,general expressions for hydrodynamic stress in inhomogeneous colloidal suspension are derived on a molecular level.The result is exactly an extension of the Iving-Kirkwood stress for atom fluids to colloidal suspensions where dynamic correlation emerges.It is found that besides the inter-particle distance,the obtained hydrodynamic stress depends closely on the velocity of the colloidal particles in the suspension,which is responsible for the appearance of the solvent-mediated hydrodynamic force.Compared to Brady’s stresslets for the bulk stress,our results are applicable to inhomogeneous suspension,where the inhomogeneity and anisotropy of the dynamic correlation should be taken into account.In the near-field regime where the packing fraction of colloidal particles is high,our results can reduce to those of Brady.Therefore,our results are applicable to the suspensions with low,moderate,or even high packing fraction of colloidal particles.展开更多
文摘he electrical property,stability and rheological property of mixed metal hydroxide(MMH)-clay aqueous suspensions were studied via determining elec- trophoretic mobilities,heterocoagulation and rheological parameters. The suspen- sions of MMH-Na-montmorillonite and MMH-Kaolinite may be transformed from negatively charged systems into positively charged systems through changing the ratio of MMH to clav. The increase of MMH content makes the stability of dilute MMH-clay suspensions decreased in negatively chrged systems and increased in positively chrged systems. The complete coagulations at near neutral systems oc- curs. In the concentrated MMH-clay suspension,the steric network structures may be formed between MMH and clay particles,which cause the apparent viscosity(AV)and Bingham yield point(YP) of the suspentqion to increase. There is a suit- able ratio of MMH to clay at which the AV and YP of the suspension attain a maximum value,which in agreement with “bridging theory”of polymer flocculation.
基金the Research Grants Council of the Hong Kong Government under Project Number CUHK 461/95P. G.Q .G.acknowledges the support of t
文摘One of the central theoretical problems in the colloid field is to determine the rheological relation between the macroscopic properties of colloidal suspensions and the microstructures of the systems. In this work, the authors develop a method of transformation field by which one call calculate the effective viscosity of an incompressible: viscous fluid containing colloidal particles (either solid particles: or liquid drops) fixed at the points of a periodic lattice. The effective viscosity of a colloidal dispersion of spherical particles is calculated. The predictions of the theory are in good agreement with the Einstein's formula for suspensions and the Taylor's formula for emulsions at low particle concentrations. At higher particle concentrations, the theory reproduces the results of Nunan and Keller. The method is also applicable to the viscosity of colloidal systems with non-spherical particles.
文摘Colloidal dispersions are common in nature with wide industrial applications. One of the central theoretical problems in the field is to determine the rheological properties of the colloidal dispersion from the microstructures of the systems. Because of the difficulties associated with the boundary-value problems of the many-particle system, existing theories for colloidal suspensions are limited to low particle concentrations. In this work, a method of transformation field is developed by which one can calculate the effective viscosity of an incompressible viscous fluid containing colloidal particles ( either solid particles or liquid drops). The predictions of the theory are in goad agreement with the Einstein's formula for suspensions and the Taylor's formula for emulsions at low particle concentrations. At higher particle concentrations, the results of Nunan and Keller are produced. The method is also applicable to the viscosity of colloidal systems with non-spherical particles.
基金Supported by the National Natural Science Foundation of China under Grant No.21503077the Fundamental Research Fund for the Central Universities of China under Grant No.2016MS156the Research Project from Hebei Education Department under Grant No.QN2018119
文摘Based on statistical mechanics for classical fluids,general expressions for hydrodynamic stress in inhomogeneous colloidal suspension are derived on a molecular level.The result is exactly an extension of the Iving-Kirkwood stress for atom fluids to colloidal suspensions where dynamic correlation emerges.It is found that besides the inter-particle distance,the obtained hydrodynamic stress depends closely on the velocity of the colloidal particles in the suspension,which is responsible for the appearance of the solvent-mediated hydrodynamic force.Compared to Brady’s stresslets for the bulk stress,our results are applicable to inhomogeneous suspension,where the inhomogeneity and anisotropy of the dynamic correlation should be taken into account.In the near-field regime where the packing fraction of colloidal particles is high,our results can reduce to those of Brady.Therefore,our results are applicable to the suspensions with low,moderate,or even high packing fraction of colloidal particles.
