ABSTRACT
A porous, sintered, and reaction-bonded Si3N4 (SRBSN) planar membrane was prepared by phase-inversion tape-casting, nitridation (at 1350 °C), and sintering (at 1650 °C) of silicon slurry. The membrane was comprised of uniform rod-like β-Si3N4 crystals with a large length/diameter ratio and had high porosity and bending strength. The prepared membrane features a typical asymmetric structure with a skin layer, a sponge layer, and finger-like voids and an average pore size of 0.61 μm. A high permeation flux of 367 L m−2 h−1 and an oil rejection of 88.6% were recorded in oil-in-water emulsion separation experiments. These results suggest that SRBSN membranes have excellent potential for the treatment of oily wastewater.
ABSTRACT
Single-phase white light-emitting Ca x Ba(9-x)Lu2Si6O24:Eu2+/Mn2+ codoped phosphors were successfully synthesized, and their photoluminescence properties were experimentally determined. The analysis of the experimental results suggests that the partial substitution of Ba2+ ions by smaller Ca2+ ions alters the distribution of the Eu2+ luminescence center among the three available Ba2+ sites in the host lattice, which enables the emission to be efficiently tuned from blue to blue-green-yellow region. The incorporation of Mn2+ ions resulted in a red light emission at around 618 nm, through energy transfer from Eu2+ to Mn2+ ions via dipole-dipole interactions. The incorporation of Ca2+ and Mn2+ ions also resulted in improved thermal stability. The results qualify the produced Ca x Ba(9-x)Lu2Si6O24:Eu2+/Mn2+ composition as a potential ultraviolet-convertible white light-emitting phosphor.
