Abstract:
With Ce-La-TiO
2 hollow microspheres and hexadecanol (H)-palmitic acid (PA)-lauric acid (LA) as carrier material and phase change material respectively, H-PA-LA@(Ce-La-TiO
2) photocatalytic-heat-mositure composites were made by sol-gel method and the vacuum adsorption method. By combining the uniform design and radial basis function(RBF) neural network, the effect of preparation factors (i.e. speed of the magnetic stirring, temperature of constant temperature reflow, rate of increase in calcining and vacuum degree of vacuum thermostatic oven) on particle size distribution of the H-PA-LA@(Ce-La-TiO
2) photocatalytic-heat-mositure composites was investigated experimentally. In addition, the H-PA-LA@(Ce-La-TiO
2) photocatalytic-heat-mositure composites with optimal uniform particle size distribution was tested and characterized. The results show that RBF neural network has the best approximation effect when spreading coefficient is 0.45~0.55. To obtain H-PA-LA@(Ce-La-TiO
2) photocatalytic-heat-mositure composites with optimal uniform particle size distribution, the preparation parameters were identified as follows:magnetic stirring speed of 1 762 r/min, temperature of constant temperature reflow of 66.9℃, increase rate in calcining of 2.43℃/min and vacuum of vacuum thermostatic oven of 0.58 MPa. On the base of the above preparation parameters, median diameter
d50 is 190.02 nm, the measured value of particle size distribution range is 180.50 nm. The measured value agrees well with the predictive value (relative error is 3.58%). In the case of relative humidity between 35% and 85%, the equilibrium moisture content is obtained to be between 0.0369 g/g and 0.1702 g/g, phase transition temperature between 24.21℃ and 29.48℃, phase change enthalpy between 31.24 J/g and 33.07 J/g, and formaldehyde degradation rate reaches 56.92% after 5 h.