Filtration-based separation of Chlorella vulgaris, a species with excellent potential for CO2 capture and lipid production, was investigated using a surface-modified hydrophilic polytetrafluoroethylene (PTFE) membrane. Coagulation using polyaluminum chloride (PACI) attained maximum turbidity removal at 200 mg L-1 as Al2O3. The membrane filtration flux at 1 bar increased as the PACI dose increased, regardless of overdosing in the coagulation stage. The filtered cake at the end of filtration tests peaked in solid content at 10 mg L-1 as Al2O3, reaching 34% w/w, roughly two times that of the original suspension. Differential scanning calorimetry (DSC) tests demonstrate that the cake with minimum water-solid binding strength produced the driest filter cake. Coagulation using 10 mg L-1 PAC as Al2O3, followed by PTFE membrane filtration at 1 bar, is an effective process for harvesting C. vulgaris from algal froth. (C) 2011 Elsevier Ltd. All rights reserved.