Removal of Microalgae in Ballast Water by Coal-based Porous Carbon Membrane: Removal of Microalgae in Ballast Water by Coal-based Porous Carbon Membrane

Introduction of invasive species via ballast water has been identified as one of the greatest threats to oceans. The coal-based porous carbon membrane with low cost for removal of microalgae in ballast water was prepared by carbonization of tubular carbonaceous precursor obtained by extrusion method. Scanning electron microscopy and bubble-pressure method were employed to investigate the morphology and pore structure characteristics of carbon membrane. Effects of microalgae size, transmembrane pressure and crossflow velocity on the steady-state flux were also studied. The results indicate that the as-prepared carbon membrane has smooth surface, rich and uniform porous structure, which are beneficial for removing microalgae in ballast water. A decrease in steady-state flux is observed as the microalgae size increases. High transmembrane pressure is more prone to block the membrane pore and results in the decrease of the steady-state flux. High crossflow velocity is favorable to increase the steady-state flux owing to the inhibition of fouling layer development through the high shear stress on membrane surface. After being treated by coal-based carbon membrane, no microalgae are detected. It indicates that coal-based carbon membrane is of great potential to ballast water treatment.