Day 1 :
University of Duisburg-Essen, Germany
Time : 10:00-10:30
Hans-Curt Flemming Study of chemistry in Stuttgart and Freiburg, Scholarship of Fritz ter Meer-Stiftung, Heinrich-Hörlein-Award of the German Biological Society. He was Chair for Aquatic Microbiology, University of Duisburg; Member of the board of scientific directors of the IWW Centre for Water, Mülheim/Ruh. He was Managing Director of the Biofilm Centre and also a Member of Specialist Group Steering Group of IWA.
Biofouling is caused by biofilms, but not all biofilms cause biofouling. Only if biofilm growth and effects exceed a given threshold of interference in a membrane process, the quest for reasons begins and if everything else is excluded, biofouling remains as a kind of “joker”. The first intuitive response of the operator is to “disinfect” the system. However, this does not necessarily work and if so, not for a long time. Here we address the most common mistakes of operation and maintenance of membrane plants in terms of biofouling, which we call “deadly sins”: 1. ignoring that nutrients are potential biomass and removal of biologically degradable organic carbon or phosphate from the water by pre-treatment would restrict biofilm accumulation; 2. Unintentional dosing of nutrients after pre-treatment, undoing the effect of pre-treatment. Organic acids, antiscalants and even biocides can be biodegradable, supporting biofilm growth; 3. Killing instead of cleaning: Biofouling is essentially caused by extracellular polymeric substances (EPS) produced by the bacteria. Inactivation only, will leave biomass and thus, the problem in place. Cleaning is more important than killing; 4. No early warning systems. All water systems bear biofilms but only the excess of biofilm effects above threshold of interference causes problems. Early warning of (sudden) biofilm accumulation enables earlier and more effective corrective actions. Monitors are available but usually considered as too expensive, although their use may considerably reduce costs; 5. Rely only on conventional feed spacer design in membrane elements. With a modified spacer design, biofilm effects can be reduced; 6. Ignorance about advanced technologies e.g., feed flow reversal in pressure vessels, pressure vessel loop operation, hybrid membrane systems and others; 7. Sticking to high flux membrane systems. A high flux sounds attractive, but compacts the EPS in biofilms, leading to increasing hydraulic resistance. If the scientific laws for biofilm formation and development are acknowledged and followed, it is possible to live with biofilms and successfully manage biofouling.
Angers University, France
Keynote: Water treatment using membranes : Desalination of brackish / sea or surface waters ? Big size unit and isolated pilot
Time : 10:30-11:00
Maxime Pontie, born on March 14, 1968, in Montauban, France, is professor and works at the University of Angers since 2004. He received a DSc degree under professors D. Lemordant and M. Rumeau in 1996 from the University Francois Rabelais in Tours, France. After a postdoctoral research study with professor R.W. Bowen, Swansea University of Wales, UK, with a research topic dedicated to mass transfer mechanism in nanofiltration. His current research interests is water desalination membrane processes with a way to intensified the processes in a sustainable development approach. He has over 100 publications that have been cited over 100 times, and his publication H-index is 35 and has been serving as an editorial board member of reputed Journals. He was a board member of the European Desalination Society for 2012
The keynote will start by a general overview of membrane science as a pluridisciplinary science, usable everywhere in the world and by everyone. After this short introduction, a conference will develop the potentialities of membrane processes for water treatment dedicated to drinking water production, taking into account the resource quality and the regulation (world health organization, WHO). Our experience acquired in Senegal (Thiadiaye, the first world nanofiltration unit for brackish water defluoridation (), in Morocco (Tan-Tan), in Mauritania (Nouakchott), in Cameroon (Dschang) and very recently in Colombia for isolated sites (i.e. Barrancabermeja).
Oak Ridge National Laboratory, USA
Keynote: Nanostructured polymer-graphene hybrid coatings for membrane separations and energy applications
Time : 11:20-11:50
Michael Z Hu is a Chemical and Biochemical Engineer by education, serving as a Senior Research Staff Member at the Oak Ridge National Laboratory. Meanwhile, he is appointed by the University of Tennessee as a Joint Faculty Professor at the UT Bredesen Center and an Adjunct Professor at the Chemical & Biomolecular Engineering Department. He is the Founder Editor-in-Chief for the Journal of Nanomaterials. He has over 24 years of research experience in Advanced Nanomaterials and Chemical Processing Technologies for separations and catalysis. He is a Team Leader for the Department of Energy (DOE) program that won a 2014 R&D100 Award based on Advanced Nano-Membranes Research. His membrane technology development work became a success story in July 2017. He has been the Principal Investigator and also served as the Thermochemical Pathway Team Lead for a multi-lab separations consortium program addressing separation challenges related to processing of biofuels and bioproducts from biomass.
Research work on new nanostructured polymer-graphene hybrid coatings/membranes are presented with two major illustrated examples in energy and water-related applications (e.g., membrane separations of molecules/ions and high-performance supercapacitor electrodes). This work intends to develop the understanding to control the fundamental nanostructure of buildingblock graphene unit (i.e., stacked parallel graphene sheets of defined 2D dimension with precisely controlled interspacing by molecular spacers) as well as the architecture of the 3D graphene-polymer materials (i.e., the vertical orientation and connectivity of graphene units inside the polymer-bond hybrids). Several orders-of-magnitude performance enhancements (e.g., in molecular water permeability and ion transport) could be realized due to the well control of nanostructure and architecture of the synthesized hybrid interfacial materials. One key thrust for the functionalized porous inorganic membranes is to enable the use of larger nonzeolitic pores (>1 nm) for the greater permeation flux with enhanced surface selectivity for molecular separations. Specifically, the polybenzimidazole polymer and graphene oxide hybrid coating layers on porous metallic/ceramic tube supports have been developed and evaluated for biofuel thermochemical processing related separations such as dewatering of hydrothermal liquefaction (HTL) aqueous fractions for carbon (carboxylic acids) recovery and vapor-phase chemistry tailoring of the catalytic fast pyrolysis process. For supercapacitor electrode development, both nanosized dimension and vertical orientation of ligand functionalized graphene oxide sheet particles have demonstrated their significant effects on performance. The size control enhancement was more effectively achieved by ~4.2 times higher capacitance, 4.0 times lower IR drops and order of magnitude enhanced mass transport. Compared to the non-aligned counterparts, the coating containing vertically aligned graphene sheet particles have shown ~1.6 times higher values in capacitance (430 F/g at 0.5 A/g) and ~67% reduction in equivalent series resistance. Such hybrid materials are also being developed for other potential applications such as in batteries, desalination, and bioseparations processing.
Universite Savoie Mont Blanc, France
Time : 11:50-12:20
BAS Corine is Professor of Polymer Science at the University Savoie Mont Blanc. She worked on the characterization of polymer membrane to determine microstructural probe for gas separation, in particular based on positron annihilation spectroscopy. Now, her research mainly focuses on the degradation characterization of proton exchange membranes for fuel cell applications to improve their durability.
The proton exchange membranes such as perfluorosulfonic acid ionomer (PFSA) are used as electrolytes in low temperature fuel cell. When cationic impurities are present in the polymer electrolyte membrane, the performance of fuel cell can be significantly reduced due to the conductivity decrease. At the same time, the presence of cations within the ionomer impacts the mechanical behaviour of the membrane. No impact on the energy necessary to initiate cracks in the membrane was measured, but cationic contaminants strongly emphasize their propagation. A sharp change in the thermal behaviour was evidenced at a given threshold and also is controlled by the Lewis acid strength (LAS) of the cations. These results were correlated to vibrational changes, especially to the polar groups as revealed by infrared spectroscopy. For example, a stepwise behaviour of the symmetrical stretching band at 970 cm-1 appears correlated to the evolution of drop modulus temperature determined by dynamic mechanical analysis. In addition, an estimation of the amount of contaminants and their identification was made possible through the relative intensity of the bending vibration of the hydronium, while the identification of cations may be confirmed with the wavenumbers of lateral group vibrations. These calibration curves were applied to analyze long side chain (LSC) and short side chain (SSC) PFSA membranes after fuel cell operation. Cations within the membrane after fuel cell operation originate from the degradation of the radical scavenger.