3at. % Eu3+ doped (Y, Gd)2O3 precursor powders with various compositions were synthesized via a sol-gel process, and the precursors were sintered at different temperatures. XRD, FT-IR, Raman and photoluminescence spectroscopy were used to study the phase, microstructure and luminescent properties of the precursors and the sintered powders. The results show that pure (Y, Gd)2O3 polycrystalline phase can be obtained from sintering the precursors at 700°C. The influences of the host compositions on the microstructures and fluorescence properties were analyzed, and the optimized composition was obtained for 3at. % Eu3+ doped (Y, Gd)2O3 powders.

Heavy metal pollution in the soil have caused many environmental events and pose a great threat to human and animals. There are many methods to remediation of contaminated soil while the broad range application is phytoremediation. And the plant growth regulator can enhance the efficiency of phytoremediation. Cytokinins, one kind of phytohormones play an important role in the plant growth. This review summarizes the present knowledge about phytoremediation and the cytokinins assisted phytoextraction.

3at% Eu:YGO polycrystalline powders with different Y3+/Gd3+ ratios were synthesized by a co-precipitation method using NH4HCO3 as the precipitant. The Eu:YGO precursors were transformed into pure cubic phase YGO at 600°C. The luminescence properties and optimal Y3+/Gd3+ ratio of the 3at% Eu:YGO phosphors were studied using photoluminescence spectroscopy. The emission spectra (λex=274nm, λex=394nm) and excitation spectra (λem=610nm) of Eu:YGO powder shows the polycrystalline powders have good luminescence; energy transfer between Gd3+ and Eu3+ occurs and (Y0.6Gd0.37Eu0.03)2O3 shows the optimal luminescence properties among the synthesized samples.

The present paper summarizes the main arsenic forms and its toxicity in the environment. For various speciation of arsenic in the environmental and biological systems, the pretreatment of samples and selective separation and detection analysis is the most important problems to be considered. The technology of atomic fluorescence spectrometry has the advantages of high sensitivity, easy operation and low cost that attractive of the forming elements analysis. The more research of separation and detection, and meet the ultra-trace analysis requirement of arsenic separation should be paid.

A field survey on the contents of heavy metals in soil and plants in Yangzonghai phosphogypsum stacking area was carried out, and the absorption, translation and accumulation characteristics of heavy metals between plants and soil were compared. The results showed that the average concentrations of Arsenic (As) and Cadmium (Cd) in soil at the study site exceeded Grade square criteria of the national environmental quality standard for soils (GB15618-1995). Among 18 species of plants, Artemisia argyi Levl had better tolerance of As, Cu and Pb, with TF value of 3.716, 2.535, 1.140, respectively. Solanum pseudocapsicum L, Perilla frutescens (L.) Britt and Herba Taraxaci L had maximum absorption of Cd and Zn, with their transfer and bioaccumulation factor were higher than 1. Crofton Weed had lowest enrichment ability (BF<1), but had a good tolerance of other four heavy metals (As, Cd, Pb, Zn, TF>1). All plants did not showed accumulative effects on As, Pb and Cu. The above plants had a better potential and practical use in phytoremediation as their favorable resistibility to heavy metals, and the plants had not reach the critical level of hyperaccumulator.