Lin Sudan,Xu Yongzhi,Fu Chen,Zhang Haifeng,Kong Qiaoping,He Haoran,Liu Siyuan,Shi Xueqing,Zhao Dandan
Recently, selective phosphorus removal from aqueous solution has been a highly desirable strategy to combat eutrophication due to the increasingly stringent phosphorous emission standards. However, conventional adsorbents pose the limitations in phosphate removal suffering from lack of selectivity and stability under complicated condition and poor separation. In this study, novel Y 2 O 3 based calcium-alginate (Y 2 O 3 /SA) beads of feasible stability and highly selectivity towards phosphate by encapsulating Y 2 O 3 nanoparticles inside calcium-alginate beads via Ca 2+ controlled gelation process was synthesized and characterized. The phosphate adsorption performance and mechanism were investigated. In general, a high selectivity among co-existing anions was found with co-existing anion concentration up to 62.5 times of the phosphate concentration. Additionally, phosphate adsorption by Y 2 O 3 /SA beads exhibited stable performance over a wide pH range between 2 and 10, while reaching the maximum adsorption capacity at pH 3 (48.54 mg-P/g). The value of point of zero charge (pH pzc ) of Y 2 O 3 /SA beads was approximately 3.45. Pseudo-second-order and Freundlich isotherm models can well accord with kinetics and isotherms data. The FTIR and XPS characterizations analyzed that inner-sphere complexes were proposed to be the major contributor of Y 2 O 3 /SA beads for phosphate removal. In conclusion, Y 2 O 3 /SA beads as the mesoporous material exhibited excellent stability and selectivity towards phosphate removal.
Lanthanide doped upconversion (UC) materials have attracted much attention owing to their unique near-infrared to visible upconverted emission characteristics. However, it still remains a challenge for a fine tuning of emission colors in UC materials and especially in microcrystals. In this work, we report a novel method to realize emission color tuning in microrods through the plasmonic heating effect generated by the nano-islands (Au NIs) under 980 nm laser illumination. It is found that Au NIs was a good optical heater system and its temperature can be controlled by changing the excitation power. The structure of single NaYF 4 microrod can transform into YOF and Y 2 O 3 by simply altering the local temperature via plasmonic heating effect, which contributes to an excellent crystallinity of YOF and Y 2 O 3 microrods by comparison to conventional heating methods. Importantly, these YOF:Er 3+ /Yb 3+ and Y 2 O 3 :Yb 3+ /Er 3+ microrods show much bright and tunable color output from red to yellow and green in contrast to those obtained by conventional heating methods. Furthermore, the local temperature in the plasmonic heater can be obtained by analyzing the integrated intensity ratio of Er 3+ emissions from the thermally coupled 2 H 11/2 and 4 S 3/2 states, and high local temperature up to 843 K was achieved. Our results provide a new strategy to manipulate the luminescence property of single microcrystal materials and extends the application of surface plasmon to broader fields.
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