A porous carbon-based electro-Fenton hollow fiber membrane with good antifouling property for microalgae harvesting

Abstract

Electro-Fenton enhanced porous carbon (PC) - carbon nanotubes (CNT) hollow fiber membranes loaded with Fe2+ were firstly used to alleviate the membrane fouling caused by microalgal cells and extracellular organic matter (EOM) in microalgae harvesting. Electrical repulsion effect could reduce the deposition of oppositely charged algal cells and EOM on the membrane surface. The generation of •OH in-situ in electro-Fenton process could degrade EOM on the membrane surface and even inside the pores. Continuous mode results illustrated that the electro-Fenton enhanced microalgae harvesting process could significantly retard transmembrane pressure increasing and strengthen microalgae concentration capacity by 2.5 times at the optimally applied voltage (−1.0 V). The pure water permeance after operation was 16 times higher compared to the control (without electro-Fenton), and recovered to 98% of the initial value after the hydraulic cleaning, while the control group only recovered to 88%. In intermittent mode, the membrane permeance could recover to 100% after operation by electro-Fenton regeneration for 30 min with microalgae concentrating from 1.05 g/L to 7.45 g/L. The electro-Fenton-enhanced membrane could not only mitigate the reversible fouling, but also effectively inhibit the irreversible fouling, and presented prominent separation abilities without obvious damage to membranes and microalgae cells.