The microspheres/nanosheets of the ZnSe were prepared by solvothermal route. The morphological, structural, optical, as well as photocatalytic properties of the ZnSe products were studied. SEM and TEM results showed that morphologies of the products were sensitive to the presence of water or not, and a mechanism was proposed. The products shows a weak blue emission band centered at 476 nm, which is attributed to the near-bandedge emission of the products, and the strong and broad peak at 520 nm is attributed to a defect-related emission. The PL and XRD results indicate that ZnSe microspheres have high crystalline and few defects compared with ZnSe nanosheets, the degradation for Rhodamine 6G shows that the photoactivity of ZnSe nanosheets is nearly twice that of ZnSe microspheres. Therefore, the decrease of defects implies the decrease of photocatalytic activity, and nanosheets is more suitable for the degradation of Rhodamine 6G.

Acid and base treated alumina particles were studied to assess their capacities for the adsorption of fluoride from aqueous solutions. The surface morphology of untreated alumina was analyzed by SEM and its crystal structure was checked by XRD, and was analyzed by FTIR, SEM and EDS mapping after fluoride adsorption. SEM and EDS were also used to understand the surface change of the alumina after acid and base treatment. Fluoride adsorptions at two different initial fluoride concentrations were investigated. The results show that the fluoride adsorption mainly superficially happened on the alumina particle surface. SEM images show base treatment caused the alumina particle recrystallize, while acid treatment made the alumina particle more amorphous. The adsorption capacity of acid treated alumina was about twice compared with that of alumina, while the capacity of base treated alumina was only about half of that of alumina at the solution pH=7. The high adsorption capacity of acid treated alumina makes it suitable for potential application in fluoride removal from water.