Microalgae recovery by ultrafiltration using novel fouling-resistant PVDF membranes with in situ PEGylated polyethyleneimine particles Taewoon Hwang a , Madhusudhana Rao Kotte b , Jong-In Han a , You-Kwan Oh c , Mamadou S. Diallo b,* a Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305701, Republic of Korea b Graduate School of Energy, Environment, Water and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea c Biomass and Waste Energy Laboratory, Climate Change Research Division, Korea Institute of Energy Research (KIER), Daejeon 305-343, Republic of Korea article info Article history: Received 26 June 2014 Received in revised form 28 October 2014 Accepted 3 December 2014 Available online 10 January 2015 Keywords: Water treatment Resource recovery Mixed matrix membranes Fouling resistant membranes Microalgae harvesting abstract In this article, we report the preparation, characterization and microalgae recovery po- tential of a new family of fouling-resistant polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes embedded with hydrophilic and PEGylated polymeric particles. To opti- mize membrane performance for microalgae harvesting, we investigate the effects of three hydrophilic additives (Pluronic F-127, polyvinylpyrrolidone and polyethylene glycol) on the morphology, pore size, bulk composition, surface composition, wettability and surface charge, flux and fouling resistance of the mixed matrix PVDF membranes with in situ PEGylated polyethyleneimine (PEI) particles. Our filtration experiments show that a mixed matrix PVDF membrane with PEGylated PEI particles and Pluronic F-127 additive (PNSM-1) has an algae retention of 100% with a permeate flux of 96 L/m 2 /hr that is larger (by ~50%) than that of a commercial and hydrophilic PVDF UF membrane with a molecular weight cut-off of 30 kDa using a suspension of Chlorella sp. KR-1 microalgae with 1.2e1.4 g/L of dry biomass. The algae and water flux recovery rates of our new PNSM-1 are equal to~ 94% and 100%, respectively, following a simulated membrane wash with deionized water and two subsequent water and microalgae filtration cycles. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction The sustainable supplies of clean water, carbon-neutral en- ergy and food are among the most challenging problems facing society and the global economy in the 21st century (Diallo and Brinker, 2010; Diallo et al., 2013; Fromer and Diallo, 2013). The availability and supplies of water, energy and food are strongly coupled. Oil production and electricity generation by thermal/nuclear power plants require abundant amounts * Corresponding author. E-mail addresses: mdiallo@kaist.ac.kr, diallo@wag.caltech.edu (M.S. Diallo). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/watres water research 73 (2015) 181 e192 http://dx.doi.org/10.1016/j.watres.2014.12.002 0043-1354/© 2015 Elsevier Ltd. All rights reserved.