Jiawei Liu

Phosphorylated cross-linked cellulose microspheres (U-PCMs) were prepared via urea-mediated phosphate esterification (UMPE), simultaneously exhibiting enhanced mechanical properties and high-resolution weak cation exchange ability.

The aeration performance of inverted umbrella aerator is optimized through response surface methodology. The Box-Behnken design (BBD) method is used to design the experimental scheme, and three variables (blade number, plate tilt angle and plate gap opening) are selected to optimize the structure of the inverted umbrella aerator impeller and improve the aeration performance. The corresponding response value is obtained by experiments through the established scheme. The regression model is fitted through the response value, and the variance analysis is performed on the regression model to test the significance of the model. The results show that the P-value is less than 0.05. Therefore, the model is significant and fits well in the regression area. The effect of the blade number and the plate tilt angle on the target is significant, while plate gap opening is not significant. The inverted umbrella aerator has the best aeration performance when the number of the blades is 6, the plate tilt angle is 65° and the plate gap opening is 16.07%. The aeration performance and flow field before and after optimization are compared. It shows that the standard oxygen mass transfer coefficient after optimization increases by 1.59%, and the standard aeration efficiency increases by 4.78%. The flow becomes more intense after optimization. The oxygen mass transfer process is further strengthened, and the aeration performance of inverted umbrella aerator is optimized.