General introduction

Abstract

In order to review the present state of optical studies for the detection of, and quantitative measurement on, adsorbed layers at interfaces, it seems appropriate to consider four main topics: (i) circumstances leading to the acceptance of optical methods for studying interfaces ; (ii) present-day interests in applying optical methods ; (iii) relative merits of the various optical methods ; (iv) interpretation of optical data.

Development and Characterization of Ultrafiltration TiO2 Magnéli Phase Reactive Electrochemical Membranes

“…Cell potentials from 0 to 10 V were tested. The following equation was derived from the extended Nernst–Plank equation and was used to simulate ClO 4 – and NO 3 – concentrations in the permeate stream (see SI for details) where J i is the membrane permeate water flux (m s –1 ) calculated at the inner membrane surface, D j is the diffusion coefficient for species j (m 2 s –1 ) (1.32 × 10 –9 for NO 3 – and 1.7 × 10 –9 for ClO 4 – ), , C p,j and C f,j are the ion concentrations of species j in the permeate and feed solutions, respectively (mol m –3 ), Φ is the applied cell potential (V), u is the average solution velocity in the membrane pore entrance (m s –1 ), and L is the distance between the anode and cathode (1.7 × 10 –3 m).…”

“…These promising results suggest that reaction rates can be increased by simply increasing the permeate flux and that intrinsic reaction rates of the electrode should be obtained at sufficiently high fluxes. However, the Ebonex REM pore structure was not tailored for water treatment, which resulted in a high-pressure drop across the membrane and thus low pressure-normalized permeate fluxes (e.g., 50–70 L m –2 h –1 bar –1 (LMH bar –1 )). , Additionally, Ebonex electrodes often contain a range of Magnéli phases ( n = 4 to 10), which can affect electrode conductivity and presumably EAOP performance. While it is well-known that Ti 4 O 7 is the most conductive Magnéli phase suboxide (e.g., 20 000–100 000 S m –1 ), , studies focused on providing a link between Magnéli phase composition and EAOP performance are lacking.…”

Highly porous Ti4O7 reactive electrochemical water filtration membranes fabricated via electrospinning/electrospraying

“…The main peaks of interest for characterizing the Ti 4 O 7 Magn eli phase occur at 20.78, 29.68, 31.78, and 34.18. 3,40 All of these peaks are present in the XRD pattern shown in Figure 3, confirming the presence of the Ti 4 O 7 Magn eli phase in the reduced powder, and subsequently successful synthesis of Ti 4 O 7 powder for E/E and solution cast membrane fabrication.…”

“…1,2 The REMs are synthesized by the conversion of nonconductive TiO 2 precursors to conductive Magn eli phases, where Ti 4 O 7 is the most electrically conductive phase. Due to their stability under anodic polarization and resistant to oxidation and corrosion, [3][4][5][6] conductive Ti 4 O 7 electrodes have been utilized for the cathodic protection of metal structures 3 and electrodes for a variety of applications, including leadacid batteries, 7,8 rechargeable zinc-air batteries, 5,6 and fuel cells. 4,[9][10][11] While only few studies have reported on the use of Ti 4 O 7 for water purification, 1,2,[12][13][14][15][16][17] Zaky and Chaplin 1,2 have expanded the use of Ti 4 O 7 for water treatment by utilizing it as a REM to study the removal of a series of p-substituted phenolic compounds that were used as model organic contaminants.…”

“…PSU is a commonly used polymer in filtration membranes [32][33][34][35] and Ti 4 O 7 has previously been used for REMs due to its high conductivity and corrosion resistant properties. 3,5,6 Characterization of the E/E REMs was performed using x-ray diffraction (XRD), scanning electron microscopy (SEM), and Hg porosimetry analysis. The electrochemical properties and water filtration performance of these E/E REMs were evaluated using electrical impedance spectroscopy (EIS), cyclic voltammetry (CV), and cross-flow filtration experiments.…”