Drying Kinetics Of Basic Magnesium Chloride Nanorods And Molecular Dynamics Simulation

Basic magnesium chloride is a new type of high functional inorganic chemical product, which is often used as flame retardants, hardening filler, filling agent and so on. Basic magnesium chloride nanorods possess the characteristics of nano-materials,which make the nanoscale basic magnesium chloride materials shows the particular property, thus receives more and more attention.Basic magnesium chloride nanorods were prepared by liquid phase method with magnesium chloride hexahydrate and light magnesium oxide.The analysis kinetics method was used to treat the experiental data in order to study the drying mechanism of basic magnesium chloride nanorods.Than,the drying equation MR=exp[-(kt)n]and the drying rate equation-DMR/dt=knMR (-lnMR)(?) were obtained.Thereinto,the drying index n=1.808, the drying rate constant k=Aexp(-CT/T)exp(-CLL)=Aexp[-(Ev+RTCLL)/RT]=Aexp[-(Ev+Ed)/RT]=Aexp(-E/RT),the diffusion activation energy Ed=RTCLL,the apparent activation energy E=Ev+RTCLL. Then, by using the equal moisture ratio method to determine the drying kinetics parameters, the frequency factor A=8.997min-1, the length constant CL=161.380m-1, the activation energy of interface evaporation Ev=15.399kJ·mol-1, and the temperature constant C7=1852.177K were obtained.The drying process of basic magnesium chloride nanorods can be divided into three parts, which got the drying equation and the drying rate equation at different segment.The drying equation in the increasing rate drying period, the constant rate drying period and the decelerating rate drying period are MR=exp[-(kt)n1], MR=a-mkt, MR=exp[-(kt)n2], respectively, and the drying rate equation are-dMR/dt=kn1MR(-lnMR)(?),-dMR/dt=mk,-dMR/dt=kn2MR(-lnMR)(?), respectively.The vapor-liquid interface characteristics of isopropanol were investigated by molecular dynamics simulation(MD),and with the each effect point of isopropanol for object in statistical average method. The distribution regularities of interface characteristics were given, and the influence of cut-off radius, temperature, the number of moleculus and thin slice layer on interface characteristics were studied. The study shows that:The temperature has the opposite influence on the interface characteristics, one of is that with the increase of temperature, the density of gas phase and the interfacial thickness increase gradually, but the density of liquid decreases. The cut-off radius has little effect on the interface characteristics of isopropanol, the simulation value of liquid density is close to experimental value when the rc*=4.0, sorc*=4.0is the optimal cut-off radius for MD of isopropanol,and the interfacial thickness is decreasing with the increase of cut-off radius. The density of gas phase is decreasing with the increase of molecules, whereas, the density of liquid is closer to the experimental value. When the number of thin slice layer was200, the simulation value of liquid density is close to experimental value, but the vapor-liquid interface density and the interfacial thickness had little changed and had no obvious regularity.