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Zhao L.L.,Kunming University of Science and Technology | Yang Y.Z.,Kunming University of Science and Technology | Zhang M.,Kunming Institute of Environmental Science | Li Y.W.,Kunming University of Science and Technology | Jiang Y.X.,Kunming University of Science and Technology
Advanced Materials Research | Year: 2014

Lanthanum-copper Composite Oxide Compounds were prepared from lanthanum chloride (LaCl3) and copper chloride (CuCl2), and used sodium hydroxide (NaOH) as precipitating agent. The research results showed that: the best preparation condition, which is the copper content3%;water bath temperature,70°C; agitation time,2 hours; calcination temperature,400°C; calcination time,1hour.The adsorption capacity of adsorbent was 63.88mg/g in this state. Analysis results indicate that Copper-doped crystal form dense granule in favour of phosphate adsorption. And La2O3 is very important on removing the phosphate. © (2014) Trans Tech Publications, Switzerland.

Bai Y.,CAS Research Center for Eco Environmental Sciences | Bai Y.,Peking University | Shi Q.,China University of Geosciences | Wen D.,Peking University | And 5 more authors.
PLoS ONE | Year: 2012

Bacteria play an important role in the decomposition and cycling of a variety of compounds in freshwater aquatic environments, particularly nutrient-rich eutrophic lakes. A unique Chinese eutrophic lake - Dianchi - was selected for study because it has two separate and distinct basins, Caohai with higher organic carbon levels and Waihai with lower organic carbon levels. Sediment bacterial communities were studied in the two basins using samples collected in each season from June 2010 to March 2011. Barcoded pyrosequencing based on the 16 S rRNA gene found that certain common phyla, Proteobacteria, Bacteroidetes, Firmicutes and Chloroflexi, were dominant in the sediments from both basins. However, from the class to genus level, the dominant bacterial groups found in the sediments were distinct between the two basins. Correlation analysis revealed that, among the environmental parameters examined, total organic carbon (TOC) accounted for the greatest proportion of variability in bacterial community. Interestingly, study results suggest that increasing allochthonous organic carbon could enhance bacterial diversity and biomass in the sediment. In addition, analysis of function genes (amoA and nosZ) demonstrated that ammonia-oxidizing bacteria (AOB) were dominant in sediments, with 99% belonging to Nitrosomonas. Denitrifying bacteria were comparatively diverse and were associated with some cultivatable bacteria. © 2012 Bai et al.

Zhang C.-N.,Kunming University of Science and Technology | Zhang C.-N.,Kunming Institute of Environmental Science | Ning P.,Kunming University of Science and Technology | Ma C.-X.,Kunming University of Science and Technology
Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology | Year: 2010

The mathematical physics models were founded to reflect the physical phenomenon in the air turbulent flow and dispersion with dense gases in the plateau mountainous city, according to the principles of CFD. The condition to determine the solution was given. They were solved by means of a method based on the SIMPLE algorithm. The influence of dense gas density, air pressure and air temperature on the process of dense gas dispersion was analyzed by this model, the simulation result of flow field and concentration field was verified by the wind tunnel experiment. It shows that the the larger the density of dense gas is, the more obvious the effect of dense gas is. With the same mass flow rate and other condition, the larger the air pressure is, the lower the air temperature is, and the higher the air turbulent dispersion coefficient is, the bigger the dense gas concentration at the same site is. The concentration of dense gas at the normal air pressure is less 6.2%~24.7%, average 19.8%, than plateau with 810 hPa, and the concentration of dense gas at 0°C is 6.9%~8.9% or average 8.2%, less than plateau with 23.5°C.

He J.,Beijing Normal University | He J.,Kunming Institute of Environmental Science | Deng W.,Kunming Institute of Environmental Science | Chen C.,Kunming Institute of Environmental Science | And 4 more authors.
Environmental Earth Sciences | Year: 2015

To determine the ammonia nitrogen adsorption and release characteristics of surface sediments in Dianchi Lake, 36 surface sediment (0–10 cm) samples were collected in 2013. Results showed that compared with other lakes in China (e.g. Erhai Lake and Taihu Lake), Dianchi Lake had high levels of ammonia nitrogen (NH4 +–N) adsorption capacity, release rate and release capacity. The ammonia nitrogen release risk of Dianchi sediments was relatively high. Comparison of the equilibrium ammonium concentration (ENC0) in surface sediments and the ammonium contents in the overlying water of Dianchi Lake indicated that ENC0 was high for most lake sections. Therefore, the sediments of Dianchi Lake would be a pollution source, and ammonia nitrogen release risk was high because the surface sediments of Dianchi Lake were heavily contaminated with nitrogen. The total nitrogen (TN) and NH4 +–N contents of the sediments of Dianchi Lake greatly influenced the ammonia nitrogen adsorption–release process. Aside from TN, nitrogen fractions should also be studied when assessing pollutant release risk from lake sediments. NH4 +–N was the main fraction of nitrogen released from sediments, which was highly significant when evaluating sedimentary release capacity. The sedimentary release capacity and release potential of nitrogen provided important information to assess release risks. © 2015, Springer-Verlag Berlin Heidelberg.

Chen C.,Kunming Institute of Environmental Science | Deng W.,Kunming Institute of Environmental Science | Xu X.,Kunming Institute of Environmental Science | He J.,Kunming Institute of Environmental Science | And 4 more authors.
Environmental Earth Sciences | Year: 2015

Phosphorus adsorption and release characteristics of surface sediments from Dianchi Lake were investigated through indoor simulation experiments. Kinetics and thermodynamics of adsorption and release of phosphorus in sediments were studied, and the influence of different phosphorus fractions on adsorption and release was analysed. Results show that the total phosphorus content in the sediments ranged from 843.96 to 8144.44 mg kg−1, which was 2–8 times as much as those in other lakes in China (e.g. Erhai Lake and Taihu Lake). The average values of different phosphorus forms in the sediment samples were ranked in the order of organic P (OP), calcium-bound P (Ca-P), metal oxide-bound P (Al-P), residual P (Res-P), Fe-bound P (Fe-P) and weakly absorbed P(NH4Cl-P). Compared with the case of other lakes in China, the sedimentary phosphorus adsorption capacity of Dianchi Lake was at a higher level, but its maximal release rate and release capacity were low, indicating a relatively low release risk. By comparing the equilibrium phosphate concentration in the sediments and the soluble reactive phosphorus in the overlying water, the risks of phosphorus release from sediments in Caohai, Lake Central and Southern Waihai were found to be relatively low in the short term, but were high in Northern Waihai. The release behaviour of sedimentary phosphorus in Dianchi Lake was mainly determined by NH4Cl-P, Fe-P and Al-P, among which NH4Cl-P and Fe-P served a greater function. Therefore, the contents of different fractions of phosphorus and their distribution characterization should be considered when characterizing the adsorption and release status of lake sedimentary phosphorus. © 2015, Springer-Verlag Berlin Heidelberg.

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