In-situ construction of antifouling separation layer via a reaction enhanced surface segregation method

ABSTRACTWe have studied the deposition of GexSi1−x layers on (100) Si substrates by gas source molecular beam epitaxy (GSMBE) using disilane and germane.The investigation of RHEED intensity oscillations during growth reveals the well known rate enhancement obtained when adding a small amount of germane to the disilane flux. However, when exposing a previously deposited Ge layer to a pure disilane flux the growth rate during the first few monolayers remains at an enhanced value but returns to its homoepitaxial value after about 10 to 15 monolayers. This behaviour was observed under a variety of growth conditions. It is in marked contrast to the experience obtained in conventional Si/Ge MBE and suggests a catalytic effect of the particular surface present during GSMBE growth. We propose that this effect is caused by the surface segregation of Ge species and leads to a smear-out of the Ge profile in the layer.

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Study Of Al Surface Segregation In Icosahedral A162Cu25.5Fe12.5

MRS Proceedings ◽

10.1557/proc-553-75 ◽

1998 ◽

Vol 553 ◽

Cited By ~ 8

Author(s):

M. GIL-GAVATZ ◽

D. Rouxel ◽

P. Pigeat ◽

B. Weber ◽

J.-M. Dubois

Keyword(s):

Surface Segregation ◽

Vacuum Chamber ◽

High Vacuum ◽

Ultra High Vacuum ◽

Electron Spectrometer ◽

Temperature Dependent ◽

Self Diffusion ◽

Different Temperatures ◽

High Vacuum Chamber

AbstractSurface segregation of aluminium was observed during oxidation experiments of icosahedral A162Cu25.5 Fel12.5, performed in-situ and at different temperatures in the ultra-high vacuum chamber of a scanning Auger electron spectrometer. Two regimes, below and above 770K, were observed in relation with severe segregation of Al atoms at the surface for T > 770K. We postulate that this temperature dependent segregation rate is representative of the aluminium transport towards the surface of the quasicrystal. By analogy with classical diffusion experiments, we can thus determine reasonable estimates of the activation energy for Al self-diffusion in this quasicrystal. The results are consistent with the existence of phason flips below 770K and thermal vacancies above this temperature.

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Enhanced surface properties of CeO2 by MnO doping and their role in mechanism of methane dry reforming deduced by means of in-situ DRIFTS

Applied Catalysis A General ◽

10.1016/j.apcata.2020.117603 ◽

2020 ◽

Vol 599 ◽

pp. 117603 ◽

Cited By ~ 4

Author(s):

Vikram Tatiparthi Sagar ◽

Albin Pintar

Keyword(s):

Surface Properties ◽

Dry Reforming ◽

In Situ Drifts ◽

Methane Dry Reforming ◽

Enhanced Surface

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In Situ Modification of Reverse Osmosis Membrane Elements for Enhanced Removal of Multiple Micropollutants

Membranes ◽

10.3390/membranes9020028 ◽

2019 ◽

Vol 9 (2) ◽

pp. 28 ◽

Cited By ~ 7

Author(s):

Katie Baransi-Karkaby ◽

Maria Bass ◽

Viatcheslav Freger

Keyword(s):

Boric Acid ◽

Reverse Osmosis ◽

Composite Membranes ◽

Low Pressure ◽

Pharmaceutically Active Compounds ◽

Surface Polymerization ◽

In Situ Modification ◽

Endocrine Disrupting ◽

Enhanced Surface

Reverse osmosis (RO) membranes are widely used for desalination and water treatment. However, they insufficiently reject some small uncharged micropollutants, such as certain endocrine-disrupting, pharmaceutically active compounds and boric acid, increasingly present in water sources and wastewater. This study examines the feasibility of improving rejection of multiple micropollutants in commercial low-pressure RO membrane elements using concentration polarization- and surfactant-enhanced surface polymerization. Low-pressure membrane elements modified by grafting poly(glycidyl methacrylate) showed enhanced rejection of all tested solutes (model organic micropollutants, boric acid, and NaCl), with permeability somewhat reduced, but comparable with commercial brackish water RO membranes. The study demonstrates the potential and up-scalability of grafting as an in situ method for improving removal of various classes of organic and inorganic micropollutants and tuning performance in RO and other dense composite membranes for water purification.

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