TY - JOUR
TI - Highly selective penetration of red ink in a saline water
AU - Zhou Chan-Juan
AU - Tian Dan
AU - He Ji-Huan
JN - Thermal Science
PY - 2019
VL - 23
IS - 4
SP - 2265
EP - 2270
PT - Article
AB - Water pollution has become a major global problem and requires an immediate  action. It was generally considered that pollutants were diffused gradually  from surface to underwater region, where plants and animals should have less  affected. However, diffusion of contamination is very slow in comparison  with penetration. Here we show saline water has a highly selective  penetration, and the penetration rate is much higher than that of  diffusion. An experiment was carried out using a drop of red ink as a point  pollution source to check both diffusion and penetration processes in  various salt solutions with different concentrations, the salt concentration  greatly affects the penetration process and there is a threshold value  beyond which no penetration occurs. An imaged capillary is adopted in this  paper to explain the selective penetration on a molecular scale, revealing  that the salt concentration and temperature will greatly affect the  capillary pressure and the penetration depth. Our results demonstrate that  the penetration is the main pollution dispersion, and we anticipate our  theory would shed light upon the major pollution problem from theoretical  analysis to pollution control.