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The 12 th U.S.-Korea Forum on Nanotechnology Potentiostatic Anodization for Resource Recovery and Purification in Water October 5, 2015 Jong-Oh Kim Department of Civil and Environmental Engineering Hanyang University, Republic of Korea Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology 01 Iron Oxide Nanotubes for Phosphate Recovery in Water. 02 Photocatalytic Metal Membrane with Self-organized Reactive TiO 2 Nanotubes. Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Anodization Nanotube Formation ■ Useful method for modifying the surface structure to obtain nanoporous array. ■ The surface of valve metal is instantaneously covered with a native oxide film when these metals are exposed to oxygen containing environment .  High surface area.  Short solid-state diffusion path for catalysis and energy application.  Fabrications are simple and cost effective. Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Iron Oxide Nanotubes for Recovery in Water Phosphate Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Phosphorus Fertilizer Cleaner Dyestuffs Various Demand Detergent Polisher Soap Dees Lijmbach (Chris Thornton) Others: Lithium Ion Battery, Developer, Ceramics, "Phosphate removl and phosphate recovery: Cosmetics, Cement, Artificial teeth etc . towards sustainable development" COPPERAS-November 2000 ■ Phosphorus is an essential component for food production and industrial growth. ■ The global supply of this non-renewable resource is limited. ■ Most researches were focused on the removal not recovery. ■ Recovered phosphate can be reused at various demands. Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Schematic diagram of Iron Oxide Nanotubes Fe 0 Fe 2 O 3 (hematite), Fe 3 O 4 (magnetite) Fe 0 Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology A lab-scale column for An anodization apparatus continuous adsorption Power Supply Device for desorption Reactor Circulator

The 12 th U.S.-Korea Forum on Nanotechnology FE-SEM images of INTs Ethylene glycol + 3.0 wt% NH 4 F 40 V & 60 min 40 V & 90 min 60 V & 60 min 60 V & 90 min 1M Na 2 SO 4 + 0.5 wt% NH 4 F 20 V & 5 min 20 V & 30 min 20 V & 60 min 20 V & 90 min Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology AFM 2D and 3D images 2D 3D (b) INTs (a) Fe foil Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology XRD pattern Magnetite 3.0 wt% NH4F (60 min) Hematite Iron 1.5 wt% NH4F (60 min) Intensity 1.0 wt% NH4F (60 min) Fe Foil 20 30 40 50 60 70 2 Theta (degree) Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Kinetic Model Analyses for Adsorption (a) (b) (a) Pseudo first-order model (b) Pseudo second-order model (c) Elovich model (c) Environmental Materials Laboratory (EML)

Desorption and Reusability (a) (b) (a) Desorption efficiency of phosphate- (b) Repeated adsorption and adsorbed INTs depending on desorption for reusability. various concentrations of NaOH. Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology X-ray Photoelectron Spectroscopy (XPS) of INTs 3.5e+5 Atomic fraction (%) 3.0e+5 Fe O P Before adsorption 23.6 74.8 - 2.5e+5 After adsorption 10.5 78.8 10.7 After desorption 12.9 86.2 0.4 Counts/s 2.0e+5 1.5e+5 1.0e+5 Before adsorption 5.0e+4 After adsorption After desorption 0.0 0 200 400 600 800 1000 1200 Binding energy (eV) Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Photocatalytic Metal Membrane with Self-Organized Reactive TiO 2 Nanotubes. Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology TiO 2 ▪ Water and wastewater treatment systems Organics H 2 O, CO 2 using TiO 2 photocatalytic reaction have been widely developed. - High oxidation-reduction potential for refractory organics decomposition. - Reduction of excess sludge. - Low cost & Non-toxic. ▪ Problem : Separation between TiO 2 particles and purified water. • Requires post-TiO 2 particles recovery process. • Causes engineering difficulties in automatic operation. Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology ▪ Although several immobilization methods were tried to improve the treatment performance, there are not satisfied aspects due to TiO 2 particle exfoliation and activity decrease in long-term operation . Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Characteristics of proposed technology Ti membrane TiO iO 2 na nano notub ube anodization Nanostructured photocatalytic TiO 2 membrane Feed . . . . . . . . . . . . . . . . . . . . . . . . . . . . - No requirement of catalyst separation process . - Enhancement of adsorption - Long retention time for photocatalytic reaction Minimize membrane fouling & Permeate Maximize degradation efficiency of Ti contaminants membrane Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology FE-SEM images Stable TiO 2 Soluble TiO 2 , pH vs. pF curve in various electrolyte Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Before anodization After anodization L 150 mm D 15 mm Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Energy Dispersive X-ray spectroscopy (EDX) TiO 2 membrane embedded with nano tube Pure Ti membrane Oxygen content 41 wt% Oxygen content 9 wt% Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology X-ray diffraction (XRD) TEM analysis patterns (a) cross section (b) a part of nano tube b (c) Crystal fringe distance (a) Anodization and annealing Crystal fringe distance (b) Untreated Ti membrane : 3.51 Å corresponding to spacing of (101) of the anatase phase TiO 2 Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Photocatalytic activities Organics removal 50 50 With anodization/UV on Ln (C 0 /C t , COD cr base) Ln (C 0 /C t , TOC base) 40 40 With anodization/UV off Without anodization/UV on 30 30 20 20 10 10 0 0 0 30 60 90 120 0 30 60 90 120 Time (minute) Time (minute) Rate constants : TiO 2 membrane with UV > TiO 2 membrane without UV > without anodization with UV . Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Permeation flux ratio ( J / J 0 ) of anodized TiO 2 metal membrane 1 0.8 Distilled water 0.6 J/ J 0 Humic acid + UV on Humic acid + UV off 0.4 0.2 0 0 30 60 90 120 Time (minute) Permeation flux ratio with UV-on showed about 8 times higher value than that of UV-off at 2 hrs filtration. Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Conclusion ■ The use of nanomaterials in water and wastewater treatment has attracted a growing amount of attention due to the excellent electrical, magnetic, and catalytic properties of nanomaterials. ■ In phosphate recovery, INTs are useful to recover phosphates in wastewater because additional collection of adsorbents is unnecessary and industrial byproducts can be used as raw materials to prepare INTs. Disinfection Oxidation ■ Anodization enabled the fabricated nano-structured TiO 2 metal filter with dual functions of filtration and oxidation, at the same time. Filtration ■ With this new technology combined with NT and ET, we are hoping for a marked improvement on phosphate recovery and treatment efficiency compared to the conventional methods. Environmental Materials Laboratory (EML)

The 12 th U.S.-Korea Forum on Nanotechnology Acknowledgements This work was supported by Basic Science Research Program through National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2013R1A2A1A09007252). Environmental Materials Laboratory (EML)