Coating Ultrafiltration Membranes with Iron Nanoparticles to Enhance Operation During Periods of Severe Algal Blooms

摘要

The release of high concentrations of Transparent Exopolymer Particles (TEPs) by phytoplanktons during algal blooms (e.g. red tides) can cause severe impairment of ultrafiltration (UF) operation in seawater reverse osmosis (SWRO) pretreatment (Villacorte et al, 2010). TEP are negatively charged acidic polysaccharides and glycoproteins reaching a few hundred microns in length, and are transparent but can be visualized by staining with Alcian Blue. TEP can be measured in the particulate range >0.4um (Passow et al, 1995) and in the colloidal range >0.1um (Villacorte et al, 2009), but measurements of biopolymer concentrations using the liquid chromatography - organic carbon detection (LC-OCD) method can provide an indication of the concentration of TEP in source waters. TEPs are reportedly 2-4 orders of magnitude stickier than normal particles in seawater (Passow, 2002) and may cause operational problems by attaching to UF membrane surface or pores, resulting in both a higher rate of pressure increase and reduced permeability recovery.