The 1,3,4-oxadiazole ring is known as a group which has high electron affinity and hole blocking effect. The compounds containing such a group are a kind of electro-luminescent material which has good electron transporting capability. The blue-light-emitting organic electro-luminescent material with 1,3,4-oxadiazole ring is recently a research focus in materials science. The research status of molecular structures, properties and related device performance of small molecular and macromolecular blue-light-emitting organic electro-luminescent materials with 1,3,4-oxadiazole ring is reviewed, and the prospect of molecular design to improve the properties of these materials is also presented.

The complex of PVA solution and sodium alginate solution crosslinked by Ca(NO3)2 as entrapment medium was prepared. The mixture of Acidithiobacillus ferrooxidans suspension and the entrapment complex were extruded into a solution of Ca(NO3)2 to form beads, and then the beads were frozen at -20°C for 1~2d and thawed at room temperature. A maximum oxidation rate of 2.90g Fe2+ / (L•h) was achieved in a packed-bed bioreactor with immobilized cells at the dilution rate of 0.5/h. In addition, the operation of this method was very simple, and the gelation solution (calcium nitrate) used was of low toxicity and very cheap. Moreover, the oxidation activity of the beads obtained by this technique was excellent even under non-sterile conditions. So its application on a commercial scale would be practicable.