Evaluation of different algogenic organic matters on the fouling of microfiltration membranes

Abstract

This paper systematically investigated the microfiltration membrane fouling behavior of various algogenic organic matters (AOMs) that were extracted from five classical bloom algae (cyanobacteria, green algae and diatoms). The results indicated that membrane fouling by different algae varied significantly by algal species and AOM chemical compositions. Cyanobacteria of the species Aphanizomenon flos-aquae (APF)-AOM caused the strongest flux decline, followed by Anabaena flos-aquae (ANF)- and Microcystis aeruginosa (MA)-AOMs. Analysis of AOM characteristics indicated that the membrane fouling depended on the synergies that arose from specific combinations of fluorescence excitation–emission matrix (EEM), molar sizes and/or membrane material properties. By applying the extended version of Derjaguin Landau Verwey Overbeek (XDLVO) theory, it was found that the cohesion free energies and the adhesion free energies between APF-, ANF-, and MA-AOMs and each of the membranes were more negative than those between membranes and the green algae and the diatoms of Scenedesmus obliquus (SO)- and Cyclotella (Cy)-AOMs; more negative energies indicate that the attraction forces are much stronger and can cause heavier membrane fouling. SO-AOM and Cy-AOM have less negative cohesion free energies and adhesion free energies with the membranes, and there was less membrane fouling with those AOMs. The surface free energy of membranes and foulants is a useful parameter for membrane fouling analysis.