Brownian dynamics simulations on sedimentation behaviour of a dispersion composed of spherical and rod-like particles (For development of a new technology to improve the visibility of small lakes and ponds)

Abstract

In the previous study, we investigated the adsorption phenomenon where the adsorption agent or spherical particles adsorb turbidity-causing (TC) particles in the sedimentation process in the gravitational field by means of Brownian dynamics simulations. These results may certainly contribute to the development of a technology for improving the visibility in small lakes and ponds. We here extend the previous study to an adsorption agent of non-spherical particles where the particle rotational Brownian motion is significantly expected to contribute to the adsorption performance in addition to the translational Brownian motion. Hence, we have employed the modelling of adsorption particles as large spherocylinder particles and TC particles as small spherical particles with a sub-micron size in order to perform Brownian dynamics simulations. For the case of a large aspect ratio rp =15, in the situation that the particle volumetric fraction is constant, the adsorption rate is much better than spherical particles by 75% improvement, and therefore it is seen that the rotational Brownian motion of the rod-like particles gives rise to a much more significant adsorption performance. From these results, we understand that the use of rod-like particles with a large aspect ratio as adsorption agents can adsorb TC substances much more efficiently in comparison with spherical particles.

Keywords

• adsoption rate
• adsorption particle
• suspended substance
• rotational brownian motion
• brownian dynamics simulations