VTT approach for membrane materials. Developing future water technologies - Membranes. Espoo 8 th June 2011 J.Sarlin VTT

Transcription

1 VTT approach for membrane materials Developing future water technologies - Membranes Espoo 8 th June 2011 J.Sarlin VTT

2 2 VTT and water technology VTT is a large multidisciplinary R&D organisation: Resources for polytechnic (holistic) solutions. Existing supporting (parallel) activities; biotechnology and biorefinery, materials technology incl. nanomaterials, chemical engineering, etc. Accumulated knowledge and experience on relevant topics; clean surfaces, fouling in pulp and paper industry, etc. Active networking target. Long experience in membrane applications and testing incl. MBR. Membranes common needs: Decreasing energy consumption Low-fouling (high capacity) Separation performance VTT: Strong strategic focus on selected topics, such as: Green Solutions for Water and Waste

3 3 VTT: Green Solutions for Water and Waste January 2011 VTT launched a new spearhead programme: Green Solutions for Water and Waste for years Towards a clean globe by green solutions for water and waste Modules in water technology: Advanced membranes and filters Management of microbes and micropolluntants Sludge and brine Sensors and monitoring Supported by modelling and data management. More information: Mona Arnold, Programme manager.

4 4 System modelling - a tool to optimize separation processes Systemic view: Optimal operation of the whole process brings in the money Why modelling? Modelling enables to get a comprehensive view of the process Modelling alone is not enough! Use with optimizations System model-based optimization: Process dimensioning (e.q. membrane area) Operation (e.g. washing cycles): To minimize energy consumption To maximize throughput To minimize investment costs

5 5 Fouling prevention water pretreatment Particle size increase for prevention of pore blocking Coagulation/flocculation by chemicals Electrocoagulation Scaling prevention in desalination Biofouling detection and prevention Micro- or ultrafiltration as a pre-treatment for nanofiltration or reverse osmosis Real-time fouling/scaling detection for improved process optimisation Silt Density Index monitoring

6 6 MBR - an emerging market MBR is one of the fastest growing wastewater treatment processes, annual growth rate is 10%. Average daily flow treated in MBR plants is about 10 Mm³/d (Global 2010), of which the share of industry is about 25%. MBR treatment plants are relative small, 80% wastewater is treated in plants where average daily flow is less than 10000m 3 /d. But they are increasing in size and bigger plants are under design. Biological process is typically operated in aerobic or anoxic conditions, the use of anaerobic processes will widen in near future. MBR trends in Europe Global MBR trends Source: Lesjean and Huisjes, 2007

7 7 MBR processes at Jyväskylä (2011) and Kuopio (2001) run by VTT MBR: Separate aeration and membrane filtration tanks MBR: Denitrification tank and combined aeration and membrane filtration tank Flat sheet membranes Hollow fibre membranes

8 8 Membrane application some research topics Fouling/scaling prevention Concentration/fractionation of woodbased materials Closing water circuits at P&P sector Treatment of oily wastewaters Membrane bioreactor studies (MBR) Desalination Development of sampling technology based by ultrasound aided filter Recovery of sodium and sulphur from glauber salt using electrodialysis (ED) Flux (l/m 2 h) Membrane: CFCC 0.1 µm Feed: Oil mg/l v = 1.3 m/s T = 25 C Pure water flux E = 5.3 kv/m E = 0 kv/m 0 0,5 1 1,5 2 2,5 Pressure (bar) CR 250, Metso ED, Electrocell

9 9 Facilities for application research Movable equipment for MF- RO and ED studies Replaceable membrane module Pressure, feed flow (crossflow velocity) and temperature adjustment Continuous measuring, monitoring and data collection Pilot facilities Membrane/fouling characterisation e.g. by SEM, AFM, X-ray tomography Water analysing e.g by SDI monitoring RO test equipment SEPA module

10 10 Membrane modifications co-operation with Prof. Tang (NTU Nanyang Technological University, Singapore) To focus on the desalination and water reuse processes To focus RO/NF membrane surface treatments and modifications To understand the membrane fouling and how to deal with it Investigation of surface treatments to be used for membranes to prevent fouling, scaling and especially biofilm formation Decrease the use of e.g. chlorine as water pre-treatment by introducing the novel surface treatments -> low-fouling membranes EXPECTED IMPACTS: -> Less chlorine (less environmental load, not cause membrane degradation) -> Green chemistry and process exploitation (less chlorine) -> Lower energy consumption -> Improved rejection -> longer processing time (less maintenance stops) -> longer life-time of membrane (less economical loss) -> to minimize the impact of fouling

11 11 Our novel thin film and coating technologies for membrane modification Coatings which thickness is below 10 µm ALD (Atomic layer deposition) Controlled method for preparation one or multilayer structures Currently a vacuum (batch) process Coating thickness < 50 nm Hydrophilication, hydrophobication, barrier-properties (e.g. WVTR, O 2, ) Plasmadeposition Precursor deposition via carrier gas which are activated to attach and polymerised to the surface Coating thickness nm Coating structure and functionality can be tuned with precursor and gas selection Surface modification, grafting, hydrophilication, hydrophobication, barrier From vacuum batch to continuous roll-to-roll processes, but currently a slow process Sol-gel based coatings Inorganic or hybrid coating materials (inorganic-organic) Inorganic polymerisation through sol-gel route and organic polymerisation by heat or radiation Coating thicknesses 100 nm -10 µm Coating structure and functionality can be tuned with precursor selection Surface modification, grafting, hydrophilication, hydrophobication, barrier, wear resistance Solvent-borne systems, coating deposition by wet chemical methods (e.g. spraying) Batch or continuous process, potentiality for high speed processing (e.g. paper converting)

12 12 VTT Biotechnology in Membrane Research Water intensive processes Food and non-food applications Water purification, filtration Recycling, reuse Biofilms, biofouling Desalination Membrane bioreactors (MBR) VTT Research approaches Prevention of biofouling Antimicrobial agents Active surfaces Monitoring and management of microbial diversity Process control Improvement of (bio)process performance Enzymatic applications Microbial inoculants Environmental safety Activated sludge Firmicutes mix and EUB I

13 13 Biotechnology activities in water treatment from process scale to lab scale Tools and devices Molecular biology tools for monitoring microbial diversity & biofilm formation and function Bioreactors, MBR modules Aerobic and anaerobic facilities Flow through models (Modified Robbins device) Bioprocess optimization Detection methods for microbial activity and metabolites Enzyme discovery and utilization Biosafety monitoring Microbiology in: Nutrient removal Pollutant degradation Pathogen removal Biofouling Process performance

14 14 Nanoparticles and catalytic functionality New advances in nanotechnology give methods to add synenergist effects on water treatment photocatalytic tackling against biofouling? Nanoparticles can be assembled onto porous membrane surface or particles can be mixed into membrane matrix (composite or mixed matrix membranes). Examples: Semiconductive nanoparticles (such as TiO 2 ) decrease fouling by built-in oxidative functionality and increase permeate quality. Carbon nanostructures inactivate bacteria and viruses. Catalytic nanoparticles how to immobilise particles onto organic surface? A.Kronlöf: A stable inorganic cage for nanoparticles. Micrograph: U.Tapper.

15 15 Biobased Materials in Membrane Technology Applications and possibilities: Hydrophilicity makes cellulose-based materials suitable for aqueous membrane processes such as kidney dialysis, microfiltration and ultrafiltration. Use as coagulants and flocculants in waste and run-off water treatment; Chemical treatment of waste waters Use of nanocellulose: Isolated fibrils, crystallites and whiskers from wood. Nanosized also: bacterial cellulose and electrospun cellulosic nanofibres. Modification of cellulose for controlled adsorption and release properties of chemical substances selective removal of e.g. heavy metals or biological agents in specific applications. Inclusion of functional properties, for example, stimuli-responsive properties. In addition to absorption, the products may have thermal properties (exothermic reaction) and can be used as odor control.

16 16 Biobased Materials in Membrane Technology at VTT: Some examples of material development Thermo-responsive cellulose (MFC) based membrane with stimuli-responsive properties (FuBio program of TEKES and Forest Cluster, => continuing in ) Flux, kg/(m 2 hbar) T 750 FILTER PAPER Behaviour of the filter with stimuli-responsive polymer Temperature, o C without stimuliresponsive Pnipa278.xls properties An industrial cellulose based filter modified with a stimuliresponsive polymer (10 % wt-%). Smart Filter project More information: Pirkonen et al. Thermal Stimuli Controlled Functional Filter Cloth For Liquid Filtration, Filtration , REVIEW: Stimuli-responsive membranes, Wandera et al. J. Membrane Sci. (2010): Stimuli-responsive membranes have strong potential for future applications in tissue engineering, bioseparations, antifouling surfaces, and drug delivery among others. Reversible changes to surface composition, surface energy, adhesion and wettability of stimuli-responsive membranes will provide ways of fabricating membranes with new functions, such as self-cleaning and selfrefreshing abilities. Switchable membrane surface properties will improve the efficiency of many technological processes.

17 17 Thanks my colleagues! Mona Arnold GWW Program Manager Hanna-Leena Alakomi biotechnology Antti Grönroos membrane applications and performance Pirjo Heikkilä bio based materials Anu Kapanen - biotechnology Hanna Kyllönen water pretreatment, membrane applications and performance Riitta Mahlberg photocatalytic materials Juha Nikkola membrane modification Pentti Pirkonen - MBR Jouni Savolainen system level modelling Harri Setälä stimuli responsive materials Tekla Tammelin bio based materials

18 18 VTT creates business from technology