Room temperature spontaneous surface condensation of boronic acids observed by scanning tunneling microscopy

Herein, we discovered that the surface-confined condensation of boronic acid can happen spontaneously at room temperature, by comparing the kinetics of condensation of boronic acids with and without the negative sample bias, we found that the negative sample bias indeed accelerates the self-condensation reaction of boronic acid. Combining with in-situ STM images and ultraviolet photoemission spectrum (UPS) analysis, a reversible adsorption mechanism model was proposed and reasonably explains the reversible electric-field-induced phase transformation.     

Flux enhancement during dean vortex tubular membrane nanofiltration. 10. Design,construction, and system characterization

Controlled centrifugal instabilities (called Dean vortices) resulting from flow in helical tubes have been used to reduce concentration polarization and membrane fouling during nanofiltration. These vortices enhance back-migration of solute through convective flow away from the membrane–solution interface and allow for increased membrane permeation rates. Based on the theory of Dean vortex flow, a new prototype vortex generating tubular nanofiltration element was designed. Two sets of nanofiltration modules were constructed; a linear module and a new module containing hollow fibers wrapped around rods of small diameter in helical geometry. Optimization of the design is discussed with respect to the diameter and thickness of the hollow fibers. Axial pressure drop and energy consumption measurements for the helical module agreed very well with available correlations for various experimental conditions. Water permeabilities for the helical modules were similar to those of the conventional linear modules. No significant effect of pH was observed on the water permeability.