An effective-charge model for the trapping of impurities of fluids in channels with nanostructured walls

TL;DR

This paper introduces a model for impurity trapping in nanostructured channels, highlighting how effective charge influences trapping regimes and suggesting experimental validation to understand enhanced filtration.

Contribution

The paper develops a phenomenological model incorporating effective charge density to describe impurity trapping regimes in nanostructured channels, providing a framework for experimental testing.

Findings

Identification of three trapping regimes: linear, logarithmic, and saturation.

Prediction of how effective charge density decreases with impurity accumulation.

Proposal for experimental validation of the trapping regimes.

Abstract

We present model equations for the trapping and accumulation of particles in a short cylindrical channel with nanostructured inner walls when a fluid passes through, carrying a moderate load of impurities. The basic ingredient of the model is the introduction of a phenomenological "effective-charge density" of the walls, related to the electrical charges exposed in the nanotexture, and which is gradually reduced as the flow runs through the channel and the trapped impurities cover the internal walls. By solving the proposed equations, three regimes are predicted for the channel: a linear or clean-filter regime, a logarithmic or half-saturation regime, and the saturation limit. It is proposed that experimentally testing these regimes may help to understand the enhanced trapping capability observed in many diverse nanotextured channel structures.