The present work investigates dependence of heterogeneous nucleation of solids on the gas bubble-solution interface in a process termed as "Precipitation by Gas-Bubbling" (PGB), through experiments and modeling. This process involves bubbling of CO₂ gas at ambient condition through a solution of cholesterol in acetone, which is simultaneously cooled by an external coolant. The process parameters selected are coolant temperature, initial solution concentration, and CO₂ flow rate. The flowing CO₂ gas bubbles facilitate reduction in metastable zone width and induction time for cholesterol precipitation, rendering more efficient surface-mediated crystallization, thereby enabling process intensification of cooling crystallization. Faster precipitation of cholesterol at higher CO₂ flow rate, i.e., higher CO₂ bubble-solution interfacial area, demonstrates gas bubble-solution interface acting as a substrate for heterogeneous nucleation. Accordingly a mechanism for heterogeneous nucleation of cholesterol is proposed and validated by developing a model for prediction of final average particle size. The kinetic model parameters, namely, the pre-exponential factor as per the classical nucleation theory, and the crystal growth coefficient are regressed by comparing the predicted values of average particle size with the corresponding experimental data, and are found to be proportional to the surface area of gas bubbles and in turn on CO₂ flow rate.

目前的工作通过实验和建模研究了在称为“气泡沉淀”（PGB）的过程中固体异相成核对气泡-溶液界面的依赖性。该过程涉及在环境条件下通过胆固醇在丙酮中的溶液使CO ₂气体起泡，同时由外部冷却剂冷却该溶液。选择的工艺参数是冷却剂温度、初始溶液浓度和 CO ₂流速。流动的 CO ₂气泡有助于减少亚稳态区的宽度和胆固醇沉淀的诱导时间，使表面介导的结晶更有效，从而使冷却结晶的过程强化。_{在更高的 CO 2}流速下更快地沉淀胆固醇，即更高的 CO ₂气泡-溶液界面区域，展示了气泡-溶液界面作为异质成核的基质。因此，通过开发用于预测最终平均粒径的模型，提出并验证了胆固醇异质成核的机制。通过将平均粒径的预测值与相应的实验数据进行比较，对动力学模型参数，即经典成核理论的指前因子和晶体生长系数进行回归，发现与表面成正比气泡的面积，进而开启CO ₂流速。