Dynamic pore modulation of contracted carbon fiber filter for wastewater treatment: Filtration performance and in-situ regeneration mechanism

Abstract

Antifouling and selectivity are the major challenges in membrane separation technologies. Inspired by membranes with tunable pore sizes in filtration systems, we propose a contracted carbon fibrous filter (CCF) with an inversed-triangle structure (ITS) using commercial carbon fibers that can control the filter pore size by adjusting the external force loading. By increasing the force loading on fibers, CCF pores shrunk from 2.02 to 0.98 µm, while maintaining a high rejection efficiency of kaolin particles (>99%) at a water flux ranging from 679.7 to 354.9 L m-2 h−1. The role of the ITS and the filtration mechanism of the carbon fibers was revealed via computational simulations and experimental results. Various cleaning strategies were explored to regenerate CCF performance after fouling. A mean flux recovery of 99.6% could be achieved during the nine-cycle filtration by adjusting the pore size combined with electrocleaning. Additionally, a removal mechanism for internal fouling was proposed. This study demonstrates that the novel CCF provides a simple and reliable strategy for wastewater filtration.