Flue Gas Desulfurization (FGD) Wastewater Treatment Using Polybenzimidazole (PBI) Hollow Fiber (HF) Membranes.

Polybenzimidazole (PBI) hollow fiber membranes were used to treat flue gas desulfurization (FGD) wastewater (WW) from a coal fired power plant. Membranes were tested using both single salt solutions and real FGD WW. The PBI membranes showed >99% rejection for single salt solutions of NaCl, MgCl, CaSO, and CaCl at approximately 2000 PPM (parts per million).

p-Type PbSe and PbS quantum dot solids prepared with short-chain acids and diacids.

We show that ligand exchange with short-chain carboxylic acids (formic, acetic, and oxalic acid) can quantitatively remove oleic acid from the surface of PbSe and PbS quantum dot (QD) films to yield p-type, carboxylate-capped QD solids with field-effect hole mobilities in the range of 10(-4)-10(-1) cm(2) V(-1) s(-1). For a given chemical treatment, PbSe devices have 10-fold higher mobilities than PbS devices because of stronger electronic coupling among the PbSe QDs and possibly a lower density of surface traps. Long-term optical and electrical measurements (i) show that carboxylate-capped PbSe QD films oxidize much more gradually in air than do thiol-capped PbSe films and (ii) quantify the slower and less extensive oxidation of PbS relative to PbSe QDs.