Abstract
The objective of this study is to optimize the process parameters for preparing polystyrene (PS) PM2.5 particles by supercritical antisolvent (SAS) method. Toluene was selected as the solvent and supercritical carbon dioxide (SC-CO2) was used as the antisolvent. The Box–Behnken design-response surface method was applied to investigate the effect of crystallizer pressure, PS massic concentration, flow ratio of CO2/solution and crystallizer temperature on the size and the distribution of PS particles, systematically. It is found that crystallizer temperature is the most significant variable on the size and the distribution of PS particles, followed by flow ratio of CO2/solution and PS massic concentration, and crystallizer pressure is the slightest significant factor. The particle size increases with the increase of crystallizer temperature. The optimum conditions are obtained as crystallizer pressure 9.8 MPa, PS massic concentration 1.6 wt%, flow ratio of CO2/solution 140 g/g and crystallizer temperature 309 K. Under these conditions, the PS particle with the size of 2.78 μm and a narrow size distribution has been prepared, meeting PM2.5 standard aerosols. The results suggest that it is feasible to produce PM2.5 standard aerosols by SAS.
Highlights
The objective of this study is to optimize the process parameters for preparing polystyrene (PS) PM2.5 particles by supercritical antisolvent (SAS) method
Total 29 experimental results of precipitated PS particles obtained are shown in Table 2, indicating that the particle size ranged from 1.2 to 11.0 μm
The second-order polynomial [Eq [2]] obtained by multi-regression analysis of experimental data represents the mathematical relationship between examined variables and response (PS particle size)
Summary
The objective of this study is to optimize the process parameters for preparing polystyrene (PS) PM2.5 particles by supercritical antisolvent (SAS) method. The optimum conditions are obtained as crystallizer pressure 9.8 MPa, PS massic concentration 1.6 wt%, flow ratio of C O2/solution 140 g/g and crystallizer temperature 309 K Under these conditions, the PS particle with the size of 2.78 μm and a narrow size distribution has been prepared, meeting PM2.5 standard aerosols. Supercritical carbon dioxide (SC-CO2) has been the most popular solvent as its advantages like non-toxic, non-flammable, economical, evaporates residue-free at ambient p ressure.The particle precipitation mechanisms between mass transfer, hydrodynamic and phase equilibrium of the system, as well as kinetics of nucleation and growth were discussed in many p apers17–20 It is well-known that numerous investigations about PS particles prepared by SAS process have been conducted previously. The results demonstrated that it is feasible to acquire PS particles by SAS process, but the PS PM2.5 standard particles have not been prepared
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
