Materials development for inorganic membrane layers at ECN B.C. Bonekamp Presented at XXV EMS Summerschool, Leuven, Belgium, September ECN-M--09-062 May
Materials Development for Inorganic Membrane Layers at ECN. Ben C. Bonekamp www.ecn.nl
2 EMS Summerschool Leuven What about?
Molecular Separations Pervaporation, Gas separation & Nanofiltration Feed Permeate 3 EMS Summerschool Leuven
1m 2 pervaporation unit Membrane Systems 4 EMS Summerschool Leuven
Porous Membranes virus bacteria protein coloïdal particles µm Pore size 10 1 1 10-1 10-2 Microfiltration Ultrafiltration salt/metal ions gases 10-3 10-4 Nanofiltration Pervaporation Gas separation Activities ECN-MST 5 EMS Summerschool Leuven
ECN Energy Efficiency in Industry Molecular Separation Technology Materials development Separation processes Systems development 6 EMS Summerschool Leuven
Ceramic membrane preparation Inorganic sol-gel thin films Supported Microporous Stable 7 EMS Summerschool Leuven
Tubular microporous membranes 1000 nm Pores < 1nm ZrO2 /TiO 2 4 nm pores 120 nm pores 8 EMS Summerschool Leuven
Sol-Gel Thin Film on Porous Support Support ~100 nm thin film 2 mm f(d p ) d p (nm) 0 1 2 3 defect less support Pores < 1 nm 9 EMS Summerschool Leuven
10 EMS Summerschool Leuven Why?
Trias Energetica: Pathway to sustainable energy system 1. Reduce demand (energy saving) 2. Maximise the use of renewable energy sources 3. Use fossil fuels in the cleanest possible way Energy demand 11 EMS Summerschool Leuven
Energy savings Efficient separation processes Molecular separation with membranes 12 EMS Summerschool Leuven
13 EMS Summerschool Leuven How?
Sol-Gel Thin Films Sol synthesis Sol-Gel Technology Substrate preparation Thin film coating Reducing defect density Hydrothermal stability 14 EMS Summerschool Leuven
Sol-Gel Thin Films Microporous films Hydrothermally stable Polymeric sols Nanoparticle sols OrganoSilica ZrO 2 TiO 2 15 EMS Summerschool Leuven
Hydrothermal stability at 150 0 C Time 2y <1d 2w Si CH 3 -Si -Si-CH 2 CH 2 -Si 16 EMS Summerschool Leuven
Performance hybrid membranes, 150 o C 8000 Fluxes and water conc. in permeate vs. time 100 Fluxes [g/m 2 *h] 7000 6000 5000 4000 3000 2000 1000 0 125 o C 95 o C 150 o C Water flux Butanol flux Water in permeate 0 50 100 150 200 250 300 350 400 450 500 550 600 Time [days] 80 60 40 20 0 Water in permeate [wt.%] Feed = 5 wt.% water in nbuoh Lifetime > 650 days Life time state of the art methylated silica J. Mater. Chem., 18, 2150-2158 17 EMS Summerschool Leuven
Support Microporous + molecular ZrO 2 on multilayer separation porous layer support Pores < 1nm ZrO2 1000 nm 4 nm pores 160 nm pores 18 EMS Summerschool Leuven
Mesoporous TiO 2 on Multilayer porous support TiO 2 1000 nm α-al 2 O 3 19 EMS Summerschool Leuven
ECN-proprietary coat speed Film coating dry wet evaporation Dynamic wetting coat vessel septum 20 EMS Summerschool Leuven Colloidal dispersion suspension
21 EMS Summerschool Leuven Sol-Gel Thin Film Stability
What can happen with a sol-gel coating during and after liquid film coating? From Kheshgi (1997) Chapter 6 in Liquid Film Coating, Eds Kistler & Schweizer. 22 EMS Summerschool Leuven
Sources of Defects Wet Sol-Gel Film 1 Substrate 3 4 2 6 5 Dust particle Substrate cleaning Clean room 23 EMS Summerschool Leuven
Methylated Silica coating Dewetting instability 24 EMS Summerschool Leuven
Membrane surface after testing (Me-SiO 2 ) Severely damaged Dense white particles Many pinholes Illustrative example (Me-SiO 2, 135 C, 7 days) 25 EMS Summerschool Leuven
26 EMS Summerschool Leuven Sols
New membrane materials: Hybrid membranes BTESE Water, HNO 3, EtOH Reflux at 60ºC, 3 hrs Mix Coating and calcination Mix in EtOH MTES 27 EMS Summerschool Leuven
Zirconia sol preparation Premixing of H 2 O, hexanol, cyclohexane Slow addition of to zirconium n-propoxide in cyclohexane Addition of HAc as dispersant DLS measurements Intensity (%) 10 8 6 4 2 after 1 day after 1 day duplo after 2 days after 7 days Stable nano-particle sols (4-5 nm) Highly reproducible 0 10 0 10 1 10 2 10 3 10 4 diameter (nm) 28 EMS Summerschool Leuven
Particle size measurement Sol viscosity Dynamic Light Scattering Rheometry 29 EMS Summerschool Leuven
Modification of zirconia sol Increasing amount of HAc - [HAc]/[Zr] > 2 needed - Improved coating Intensity (%) 10 8 6 4 Cyclohexane/hexanol Isopropyl alcohol Change of solvent by dialysis - In IPA larger particles - Improved coating (slightly) 2 0 10 0 10 1 10 2 10 3 10 4 diameter (nm) 30 EMS Summerschool Leuven
31 EMS Summerschool Leuven Supports
Porous α-alumina Sol-Gel substrates Pores~180 nm Pores~80 nm 1000 nm 1000 nm Scanning Electron Microscopy 32 EMS Summerschool Leuven
Suspension structure stable Φ = 0.4 (from Wyss, JACerS 88 p2337( 2003)) 33 EMS Summerschool Leuven
Dispersion coating 34 EMS Summerschool Leuven
Film Coating 100 cm Coat Vessel coat speed meniscus 35 EMS Summerschool Leuven
Optimizing the support system Design of Experiments Support tube Stacking of layers Minimum defect density L T = L 1 + L 2 +? Defect flux L T High Troughput experiments 36 EMS Summerschool Leuven
Bubble porometry EtOH P Ceramic porous tube N 2 #Bubbles/dm 2 P ΔP = 4γ d 37 EMS Summerschool Leuven
Bubble porometry 38 EMS Summerschool Leuven
Porometry double A6 support coating 70 60 50 40 30 20 10 0 bubbles/dm 2 1 x A6 A6 2 x A6 Hg Intrusionvolume [cm 3 /g] J[μm -1 ] 0.16 0.14 0.12 0.1 0.08 0.06 0.04 J [ m -1 ] 0.02 0 0 10 20 30 40 50 60 200 170 100 d[nm] 39 EMS Summerschool Leuven
A6 γ A* 120 100 80 60 40 20 Porometry A6 and A* coatings bubbles/dm 2 bulk A6 γ A* bulk d=86 nm Hg Intrusionvolume [cm 3 /g] J[μm -1 ] J [ m -1 ] 0 15 35 55 75 266 170 114 73 d[nm] 53 J. Membrane Science 278, p349-356, July 2006 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 40 EMS Summerschool Leuven
Sol-Gel Thin Film Forming 41 EMS Summerschool Leuven
Colloidal wet compaction Dense support Sol-Gel by drying Porous support Sol-Gel by filtration & drying t 1 t 2 t 3 time 42 EMS Summerschool Leuven
Optical microscopy Calcined mesoporous alumina film Calcined microporous hybrid organosilica film 43 EMS Summerschool Leuven
SEM Calcined microporous hybrid silica film; fracture surface Calcined microporous hybrid silica film; surface 44 EMS Summerschool Leuven
Optical microscopy Dried mesoporous titania film Dried microporous titania film 45 EMS Summerschool Leuven
Permporometry Manometer FIC 1 FI 3 FI 4 FI 5 H E L I U M Droger H2O FIC 2a H2O FIC 2b CEM 1 CEM 2 PERMEAAT ΔP 1 ΔP 2 Koudeval FEED RETENTAAT PIC 3 FI 6 Koudeval Membrane He flux He+H 2 O P 1 P 2 46 EMS Summerschool Leuven
Thin Film Permporometry Overview He permeance (mol/m 2.s.Pa) 1,6E-05 1,4E-05 1,2E-05 1,0E-05 8,0E-06 6,0E-06 4,0E-06 2,0E-06 0,0E+00 0 2 4 6 8 10 Kelvin diameter (nm) Gamma alumina Titania membrane Titania pervap Zirconia membrane MeSi 47 EMS Summerschool Leuven
Permporometry microporous membranes Permporometry with H 2 O Suitable for thin toplayers All membranes similar N 2 and mercury adsorption methods are for bulk material, not for thin layers! Normalised permeance 1.0 0.8 0.6 0.4 0.2 0.0 0 1 2 Kelvin diameter (nm) Methylated Silica Bridged Silica Zirconia Titania 3 4 48 EMS Summerschool Leuven
49 EMS Summerschool Leuven Concluding remarks
Conclusions Highly reproducible organosilica sols and nanoparticle ZrO 2 and TiO 2 sols. Successful large surface area thin film preparation Control over defect density and size Long term hydrothermal stability High performance microporous organosilica, ZrO 2 and TiO 2 sol-gel thin films on large tubes 50 EMS Summerschool Leuven
Acknowledgements The MST group at ECN 51 EMS Summerschool Leuven
Questions? Contact: bonekamp@ecn.nl 52 EMS Summerschool Leuven
53 EMS Summerschool Leuven Additional
Introduction BUT Pervaporation membrane stability is limited with respect to: - (Hydro) thermal conditions - Solvent resistance - Acids 54 EMS Summerschool Leuven
Pervaporation membrane materials: goals set Test conditions dehydration of organics by pervaporation: 1. Temperature: 150 C. 2. Mixture 5 wt.% water in n-butanol. 3. Acidity: ph 2-10. 4. Pressures and pressure differences up to 30 bar and the membrane process should meet the following industrial demands: 1. Water flux of 5 kg/m 2 h. 2. Selectivity of at least 360 (feed 5 wt.% water permeate 95 wt.% water). 3. Run time of 3 years = average maintenance time of a process. 4. Change of flux and selectivity of less than 10% per year. 55 EMS Summerschool Leuven
Introduction - 474 PJ/year Energy use in NL (petro)chemical (NL 2400 clean air PJ/year) Waste heat Waste heat - Separation processes 190 Separation PJ/year - Low exergetic efficiency, so large energy saving potential raw materials contaminants Separation and.. REACTOR and.. recycle by products products By 2015 potential energy savings in dehydration pervaporation: and.. - NL: 7 PJ/yr (2% Separation of industrial energy consumption) - World: 240 PJ/yr clean water Scheiding Separation 56 EMS Summerschool Leuven