Studies have shown that phosphorus (P) recovered from wastewater as the mineral struvite [MgNH<sub>4</sub>PO<sub>4</sub>·6(H<sub>2</sub>O)] may be a viable alternative fertiliz...Studies have shown that phosphorus (P) recovered from wastewater as the mineral struvite [MgNH<sub>4</sub>PO<sub>4</sub>·6(H<sub>2</sub>O)] may be a viable alternative fertilizer-P source. This study aimed to compare the effectiveness of electrochemically precipitated struvite (ECST), reclaimed from synthetic wastewater, to other commercial fertilizer-P sources in cultivated soils from Arkansas [AR;silt loam (SiL) and loam (L)], Missouri (MO;SiL), and Nebraska [NE;SiL and sandy loam (SL)]. A plant-less, moist-soil incubation experiment, including ECST, chemically precipitated struvite (CPST), monoammonium phosphate (MAP), triple superphosphate (TSP), and an unamended control (UC), was conducted to quantify soil pH, nitrate (NO<sub>3</sub>-N), ammonium (NH<sub>4</sub>-N), and Mehlich-3 (M3)-P, -Ca, -Mg, and -Fe concentrations at 0.5, 1, 2, 4, and 6 months. All measured soil properties differed (P ·kg<sup>-1</sup> for AR-L-TSP after 1 month and NE-SiL-MAP after 6 months, respectively. Soil M3-P ranged from -29.6 mg·kg<sup>-1</sup> in the AR-L-UC after 1 month to 429 mg·kg<sup>-1</sup> AR-SiL-TSP after 0.5 months. Results showed that, over time, ECST had comparable pH and soil NO<sub>3</sub>-N, NH<sub>4</sub>-N, and M3-P, -Ca, -Mg, and -Fe behavior compared to CPST, MAP, and TSP across various soil textures.展开更多
Indium tin oxide(ITO)nanopowders were prepared by a modified chemical co-precipitation process.The influence of different SnO2 contents on the decomposition behavior of ITO precursors,and on the phase and morphology o...Indium tin oxide(ITO)nanopowders were prepared by a modified chemical co-precipitation process.The influence of different SnO2 contents on the decomposition behavior of ITO precursors,and on the phase and morphology of ITO precursors and ITO nanopowders were studied by X-ray diffractometry,transmission electron microscopy and differential thermal and thermogravimetry analysis methods.The TG-DSC curves show that the decomposition process of precursor precipitation is completed when the temperature is close to 600 ℃and the end temperature of decompositionis somewhat lower when the doping amount of SnO2 is increased.The XRD patterns indicate that the solubility limit of Sn4+ relates directly to the calcining temperature. When being calcined at 700℃,a single phase ITO powder with 15%SnO2(mass fraction)can be obtained.But,when the calcining temperature is higher than 800℃,the phase of SnO2 will appear in ITO nanopowders which contain more than 10%SnO2.The particle size of the ITO nanopowders is 15-25 nm.The ITO nanoparticles without Sn have a spherical shape,but their morphology moves towards an irregular shape when being doped with Sn4+.展开更多
文摘Studies have shown that phosphorus (P) recovered from wastewater as the mineral struvite [MgNH<sub>4</sub>PO<sub>4</sub>·6(H<sub>2</sub>O)] may be a viable alternative fertilizer-P source. This study aimed to compare the effectiveness of electrochemically precipitated struvite (ECST), reclaimed from synthetic wastewater, to other commercial fertilizer-P sources in cultivated soils from Arkansas [AR;silt loam (SiL) and loam (L)], Missouri (MO;SiL), and Nebraska [NE;SiL and sandy loam (SL)]. A plant-less, moist-soil incubation experiment, including ECST, chemically precipitated struvite (CPST), monoammonium phosphate (MAP), triple superphosphate (TSP), and an unamended control (UC), was conducted to quantify soil pH, nitrate (NO<sub>3</sub>-N), ammonium (NH<sub>4</sub>-N), and Mehlich-3 (M3)-P, -Ca, -Mg, and -Fe concentrations at 0.5, 1, 2, 4, and 6 months. All measured soil properties differed (P ·kg<sup>-1</sup> for AR-L-TSP after 1 month and NE-SiL-MAP after 6 months, respectively. Soil M3-P ranged from -29.6 mg·kg<sup>-1</sup> in the AR-L-UC after 1 month to 429 mg·kg<sup>-1</sup> AR-SiL-TSP after 0.5 months. Results showed that, over time, ECST had comparable pH and soil NO<sub>3</sub>-N, NH<sub>4</sub>-N, and M3-P, -Ca, -Mg, and -Fe behavior compared to CPST, MAP, and TSP across various soil textures.
基金Project(U0837604)supported by the Natural Science Foundation of Yunnan Province,ChinaProject(07C40291)supported by Research Fund of Yunnan Education Department,ChinaProject(2007003)supported by Research Fund of Kunming University of Science and Technology,China
文摘Indium tin oxide(ITO)nanopowders were prepared by a modified chemical co-precipitation process.The influence of different SnO2 contents on the decomposition behavior of ITO precursors,and on the phase and morphology of ITO precursors and ITO nanopowders were studied by X-ray diffractometry,transmission electron microscopy and differential thermal and thermogravimetry analysis methods.The TG-DSC curves show that the decomposition process of precursor precipitation is completed when the temperature is close to 600 ℃and the end temperature of decompositionis somewhat lower when the doping amount of SnO2 is increased.The XRD patterns indicate that the solubility limit of Sn4+ relates directly to the calcining temperature. When being calcined at 700℃,a single phase ITO powder with 15%SnO2(mass fraction)can be obtained.But,when the calcining temperature is higher than 800℃,the phase of SnO2 will appear in ITO nanopowders which contain more than 10%SnO2.The particle size of the ITO nanopowders is 15-25 nm.The ITO nanoparticles without Sn have a spherical shape,but their morphology moves towards an irregular shape when being doped with Sn4+.
