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1
Content available The surface features of activated stibnite surface with copper or lead ion
Cao Q., Huang Y., Zou H., Wen S.
Physicochemical Problems of Mineral Processing
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2018
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Vol. 54, iss. 3
763--770
EN
Cu2+ and Pb2+ are widely used as activators for the flotation of stibnite. In this work, by the treatment of Cu2+ or Pb2+, the activation product and the thickness of activation layer on the stibnite surface were both investigated. Based on the flotation results, zeta potential analysis and X-ray photoelectron spectroscopy (XPS) study, it was found that Cu2+ was reduced to Cu+ at the stibnite surface and a layer of Cu2S was formed at the surface. While, a PbS layer presenting at the stibnite surface is responsible for the activation flotation of stibnite with Pb2+. Time of flight secondary ion mass spectrometry (TOF-SIMS) analysis further implies that, when stibnite was activated with 5×10-5 mol/dm3 of CuSO4 or Pb(NO3)2, the thickness of Cu2S layer on the Cu-activated surface was close to 2.7 nm, while the thickness of PbS layer was about 1.8 nm on the Pb-activated surface.
2
Content available remote Isolation of quinolone alkaloids from Tetradium ruticarpum via preparative high-speed counter-current chromatography and evaluation of their binding affinities for bovine serum albumin
Zou H., Guo G., Wang M., Huang G.
Acta Chromatographica
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2018
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Vol. 30, no. 2
73--80
EN
By application of preparative high-speed counter-current chromatography (HSCCC) to the crude quinolone alkaloids (1.1 g) from the fruit of Tetradium ruticarpum, 1-methyl-2((6Z,9Z)-pentadecadienyl)-4(1H)-quinolone (1, 8.4 mg), dihydroevocarpine (2, 27.0 mg), and 1-methyl-2-pentadecyl-4(1H)-quinolone (3, 18.8 mg) were isolated in one step with sufficient purity using the solvent system composed of hexane–ethyl acetate–methanol–water (Hex–EtOAc–MeOH–H2O, 5:2:5:3). Further purification of the subfraction was performed by amending the solvent composition and achieved another three quinolone alkaloids, i.e., 1-methyl-2-undecylquinolin-4(1H)-one (4, 13.7 mg), (Z)-1-methyl-2-(tridec-5-en-1-yl) quinolin-4(1H)-one (5, 14.0 mg) from subfraction FR3-A3-85 using Hex–EtOAc–MeOH–H2O (5:3.5:8.75:8.25), and 1-methyl-2-nonylquinolin-4(1H)-one (6, 15.1 mg) from subfraction FR3-A3-36 using Hex–EtOAc–MeOH–H2O (5:3.8:5:4.8). The relationship between the structure of the six alkaloids and their affinities for bovine serum albumin (BSA) was investigated using fluorescence titration analysis. The length and the presence of double bond of the side chain affected their binding process with BSA. The binding behavior might influence their other biological activities.
3
Content available Denitrifying phosphorus accumulating organisms enrichment and their characteristics in a denitrifying enhanced biological phosphorus removal system
Zou H., Wang Y.
Environment Protection Engineering
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2017
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Vol. 43, nr 3
225--237
EN
Denitrifying phosphorus accumulating organisms (DPAOs) play an important role in simultane-ous removal denitrifying nitrogen (N) and phosphorus (P). Their enrichment and characteristics were investigated. A denitrifying EBPR reactor, performing continuous anaerobic/anoxic conditions, was used to enrich DPAOs in this study. Through 60 days operation, DPAOs was successfully cultivated in the denitrifying EBPR system and P concentration in the effluent was stable and low with less than 0.5 mg/dm3. Energy dispersive spectroscopy (EDS) analysis showed that P content in anoxic end sludge gradually increased with enrichment operation, which accounted for 2.9, 4.7, 6.2, and 7.9 wt. % in sludge samples at day 0 (i.e., seed sludge), and days 20, 40 and 60, respectively. Based on the batch test, a significant positive correlation was found between COD consumption and P release in anaerobic conditions and between nitrogen removal and phosphorus uptake in anoxic conditions. Furthermore, in anaerobic conditions, the P release rate was 4.2 mg P/(g MLSSh) being higher than the P uptake rate (2.8 mg P/(g MLSS h)) in anoxic conditions. Despite this, total anaerobic P release (8.5 mg P/(g MLSS)) was lower than anoxic P uptake total amount (11.2 mg P/(g MLSS)), implying an excess P uptake in anoxic environment. One whole cycle displayed the obviously denitrifying simultaneous nitrogen and phosphorus removal with more than 95% removal efficiencies in the denitrifying EBPR system.
4
Content available Optimization of induced crystallization reaction in a novel process of nutrients removal coupled with phosphorus recovery from domestic wastewater
Zou H., Wang Y.
Archives of Environmental Protection
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2017
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Vol. 43, no. 4
33--38
EN
Phosphorus removal and recovery from domestic wastewater is urgent nowadays. A novel process of nutrients removal coupled with phosphorus recovery from domestic sewage was proposed and optimization of induced crystallization reaction was performed in this study. The results showed that 92.3% of phosphorus recovery via induced Hydroxyapatite crystallization was achieved at the optimum process parameters: reaction time of 80 min, seed crystal loads of 60 g/L, pH of 8.5, Ca/P mole ratio of 2.0 and 4.0 L/min aeration rate when the PO43-P concentration was 10 mg/L in the influent, displaying an excellent phosphorus recovery performance. Importantly, it was found that the effect of reaction temperature on induced Hydroxyapatite crystallization was slight, thus favoring practical application of phosphorus recovery method described in this study. From these results, the proposed method of induced HAP crystallization to recover phosphorus combined with nutrients removal can be an economical and effective technology, probably favoring the water pollution control and phosphate rock recycle.
5
Content available remote Thermal effect on the dynamic error of a high-precision worktable
Zou H., Wang B.
Archives of Civil and Mechanical Engineering
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2017
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Vol. 17, no. 2
336--343
EN
This paper investigates the thermal effect on the dynamic error of a high-precision machine worktable during operation. The thermo-mechanical model was established to obtain the motion errors of the worktable by considering the combined effects of varying internal heat sources and external thermal drifts. The temperature tests were performed to obtain the initial conditions of the model and provide a verification for the analytical convection coefficients and heat flux, which were obtained by inverse analysis. The predicted yawing errors of the worktable were confirmed by interferometer tests. Numerical and experimental results suggest that the environmental temperature fluctuation is the largest contributor to the motion errors of the worktable, and they increase with the increasing of environmental temperature. This study allows deeper insights into the underlying mechanisms that result in the motion accuracy variations of the worktable due to the thermal effects, which can provide a strategy for manufacture to further compensate the thermal error and realize ultra precision.
6
Content available Distribution and sources of n-alkanes in surface sediments of Taihu Lake, China
Yu Y., Li Y., Guo Z., Zou H.
Archives of Environmental Protection
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2016
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Vol. 42, no. 1
49--55
EN
The last study on n-alkanes in surface sediments of Taihu Lake was in 2000, only 13 surface sediment samples were analysed, in order to have a comprehensive and up-to-date understanding of n-alkanes in the surface sediments of Taihu Lake, 41 surface sediment samples were analyzed by GC-MS. C10 to C37 were detected, the total concentrations of n-alkanes ranged from 2109 ng g−1 to 9096 ng gg−1 (dry weight). There was strong odd carbon predominance in long chain n-alkanes and even carbon predominance in short chain n-alkanes. When this finding was combined with the analysis results of wax n-alkanes (WaxCn), carbon preference index (CPI), unresolved complex mixture (UCM), hopanes and steranes, it was considered that the long chain n-alkanes were mainly from terrigenous higher plants, and that the short chain n-alkanes mainly originated from bacteria and algae in the lake, compared with previous studies, there were no obvious anthropogenic petrogenic inputs. Terrestrial and aquatic hydrocarbons ratio (TAR) and C21−/C25+ indicated that terrigenous input was higher than aquatic sources and the nearshore n-alkanes were mainly from land-derived sources. Moreover, the distribution of short chain n-alkanes presented a relatively uniform pattern, while the long chain n-alkanes presented a trend that concentrations dropped from nearshore places to the middle of lake.
7
Content available A novel process of dye wastewater treatment by linking advanced chemical oxidation with biological oxidation
Zou H., Ma W., Wang Y.
Archives of Environmental Protection
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2015
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Vol. 41, no. 4
33--39
EN
Dye wastewater is one of typically non-biodegradable industrial effluents. A new process linking Fenton’s oxidation with biological oxidation proposed in this study was investigated to degrade the organic substances from real dye wastewater. During the combination process, the Fenton’s oxidation process can reduce the organic load and enhance biodegradability of dye wastewater, which is followed by biological aerated filter (BAF) system to further remove organic substances in terms of discharge requirement. The results showed that 97.6% of chemical oxygen demand (COD) removal by the combination process was achieved at the optimum process parameters: pH of 3.5, H22
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