# Detection of Filtration Characteristics of Nontraditional Asymmetric Microporous Membranes Using Size-Controllable Micro-Hydrogel

## TL;DR

This paper studies how a special type of asymmetric membrane filters particles, showing it performs better than traditional membranes for certain fluids.

## Contribution

The study introduces a novel asymmetric membrane topology and evaluates its filtration performance using size-controlled micro-hydrogels.

## Key findings

- Asymmetric membranes show higher retention efficiency for micro-hydrogels compared to symmetric ones.
- Internal pore structures significantly influence the retention of particles of the same size.
- Blocking and adsorption models help explain filtration mechanisms in asymmetric membranes.

## Abstract

Microporous membranes are frequently used to remove or concentrate suspended solids. To maximize filtration efficiency for certain high-value liquids, a microporous membrane with a nontraditional asymmetric topology was recently developed to treat bio-based liquids, such as the isolation of proteins/enzymes from concentrates or the concentration of active cells from cultivation media. In this study, compared with both asymmetric and symmetric membranes, we reveal the unique filtration properties of “upper-stream open” asymmetric membrane using four types of fluids comprising monodispersed micro-hydrogels with sizes ranging from 294 to 517 nm. The results indicate that the internal pore structures of the membranes significantly affect the retention of microhydrogels of identical sizes. Asymmetric membranes offer considerable advantages in terms of retention efficiency and particle localization. By applying four classical blocking models along with adsorption models, the primary blockage mechanisms in asymmetric membranes for microgels of different sizes were explored. These results offer a better understanding of the interaction between the membrane and filtrate, assist in membrane selection, and elucidate the experimental results of membrane filtration.