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ABSTRACT: The objectives of this work were to prepare and characterize an anti-algal sustained-release granule, then study its mode of action on Microcystis aeruginosa. The anti-algal sustained-release granule was prepared with artemisinin using alginate-chitosan microcapsule technology and characterized by a high performance liquid chromatography with an evaporative light-scattering detector, Fourier transform infrared spectral analysis, and a scanning electron microscope. The optimum preparation (in %, w/v) using the orthogonal method was: 2.5 sodium alginate; 0.25 chloride; 0.6 artemisinin; 2 calcium chloride; and 1.5mL of the cross-linking agent, glutaraldehyde. These artemisinin sustained-release granules had a high encapsulation efficiency (up to 68%) and good release properties (release time of more than 40d). Artemisinin sustained-release granules released cumulatively in a solution containing M. aeruginosa, and the stress on algae increased gradually within 30d. Artemisinin sustained-release granules decreased the content of the soluble protein, Chlorophyll a in 30d, increased the superoxide dismutase activity of M. aeruginosa, but exerted no effect on the soluble sugar content. Compared to direct dosing of artemisinin, algae can be inhibited longer and more effectively by the artemisinin sustained-release granules. The results of our research can aid in the development of new anti-algal sustained-release granules and lead to further study of their application in the field.
Chemosphere 01/2013; · 3.21 Impact Factor
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ABSTRACT: Effects of artemisinin (derived from Artemisia annua) on the photosynthetic activity of Microcystis aeruginosa was investigated by using chlorophyll a (Chl a) fluorescence transient O-J-I-P and JIP-test after exposure to elevated artemisinin concentration. High artemisinin concentration resulted in a significant suppression in photosynthesis and respiration. Results showed that the OJIP curves flattened and the maximal fluorescence yield reached at the J step under artemisinin stress. The decreased values of the energy needed for the RCs' closure (Sm) and the number of oxidation and reduction (N) suggested that the reduction times of primary bound plastoquinone (Q(A)) was also decreased. The absorption flux (ABS/RC) per photosystem II (PSII) reaction center and the electron transport flux (ET(0)/RC) decreased with increasing artemisinin concentration. Excess artemisinin had little effect on the trapping flux (TR(0)/RC). The results showed that the decrease of photosynthesis in exposure to excess artemisinin may be a result of the inactivation of PSII reaction centers and the inhibition of electron transport in the acceptor side.
Bulletin of Environmental Contamination and Toxicology 10/2012; · 1.02 Impact Factor
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ABSTRACT: The goals of this work were to isolate and identify an anti-algal compound from extracts of Artemisia annua and study its mode of action on Microcystis aeruginosa. The anti-algal compound was isolated from the extracts using column chromatography and activity-guided fractionation methods. Artemisinin with strong anti-algal activity was identified by gas chromatography-mass spectrometry and (1)H Nuclear Magnetic Resonance. The EC(50) of artemisinin on M. aeruginosa was 3.2mg L(-1). Artemisinin decreased the soluble protein content and increased the superoxide dismutase activity and ascorbic acid content of M. aeruginosa, but exerted no effect on soluble sugar content. The results suggested the mode of action of artemisinin on algae may primarily be the increasing level of reactive oxygen species in algae cells. The results of our research could aid in the development of new anti-algal substances and lead to further study of mechanisms of inhibitory effect on algae.
Chemosphere 06/2012; 88(9):1051-7. · 3.21 Impact Factor
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ABSTRACT: Study was carried out for the removal of hazardous organic compound from aqueous solution by using water/perfluorodecalin loaded ozone two-phase system. p-Chloronitrobenzene was used as hazardous organics to examine the efficiency of the two-phase ozonation system. Effects of initial pH in water, stirring speed, initial molar ratio of O(3)/p-chloronitrobenzene (M), and free radical scavenger on the removal rate of p-chloronitrobenzene were investigated respectively. It was revealed that ozone had low decomposed rate coefficient k = 0.0035 min(-1) and solubility of 61.94 mg/L at 25°C in perfluorocarbon. In contrast to pH 2.0, higher level of pH (8.0) in water increased the removal rate of p-chloronitrobenzene in water/perfluorocarbon two-phase ozonation system. Removal rate of p-chloronitrobenzene was increased with the elevation of initial M value in water/perfluorocarbon two-phase ozonation system. Stirring speed was needed to control with proper level of speed in water/perfluorocarbon two-phase system. Compared to the conventional gas/water ozonation system, NaHCO(3) (20 mmol/L) had no obvious negative effect on the p-chloronitrobenzene degradation in water/perfluorocarbon ozonation system. Oxidation efficiency of ozonation in water/perfluorocarbon system was superior to that of in conventional gas/water system.
Bulletin of Environmental Contamination and Toxicology 06/2011; 87(3):297-302. · 1.02 Impact Factor
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ABSTRACT: A method for the determination of polycyclic aromatic hydrocarbons (PAHs) in soil samples using ultrasonic-assisted extraction with internal surrogates combined with solid-phase microextraction and GC-MS has been developed. Five kinds of commercial solid-phase microextraction fibers, 100 microm PDMS, 30 microm PDMS, 65 microm PDMS/DVB, 50 microm DVB/CAR/PDMS and 85 microm PA, were compared to choose the optimal SPME fiber for extraction of PAHs. One hundred micrometers of PDMS fiber was found to be more suitable for the determination of PAHs due to its wider linear range, better repeatability, lower detection and more satisfactory efficacy than the other fibers. Under the recommended conditions, 100 microm PDMS fiber could provide low nanogram level detection limits with correlation coefficient greater than 0.98. The method was also applied to determine PAHs in a spiked soil sample, obtaining recoveries higher than 79.3%. A field study with naturally contaminated samples from local contaminated sites was carried out. The proposed method was found to be a reliable, inexpensive and simple preparation method for quantitative determination of 16 PAHs in soil samples.
Journal of Separation Science 10/2009; 32(22):3951-7. · 2.73 Impact Factor
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ABSTRACT: The morphology and elemental composition of the corrosion products of copper teapot's inner-surface were characterized by the scanning electron microscopy and energy dispersive X-ray surface analysis (SEM/EDS), X-ray powder diffraction (XRD) and X-ray photon spectroscopy (XPS) analysis. It was revealed that Cu, Fe, Ca, P, Si and Al were the main elements of corrosion by-products, and the alpha-SiO(2), Cu(2)O and CaCO(3) as the main mineral components on the inner-surface of copper teapot. The effects of organic matters coming from Chinese tea on soluble copper release from copper teapots in tap water were also investigated. The results showed that the doses of organic matter (as TOC), temperate and stagnation time have significant effects on the concentration of soluble copper released from copper teapots in tap water.
Science of The Total Environment 02/2008; 389(1):202-7. · 3.29 Impact Factor
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ABSTRACT: The selective adsorption of p-chloronitrobenzene (p-CNB) using zeolite as the adsorbent from an aqueous mixture containing p-CNB and o-chloronitrobenzene (o-CNB) was investigated. The maximum adsorption amounts of p-CNB in HZSM-5 zeolite were found to be approximately 4 molecules per unit cell (mol/uc) at all adsorption temperatures investigated. The maximum adsorption amounts of o-CNB in HZSM-5 zeolite were, however, markedly lower than those of p-CNB at different adsorption temperatures. Diffusion results revealed that the diffusivity of p-CNB at 300K was about 100 times higher than that of o-CNB in HZSM-5 zeolite. The remarkable difference in the adsorption amounts and diffusivities between p-CNB and o-CNB resulted in separation factors of 463.6, 96.8 and 21.9 for p-CNB at 278, 300 and 323 K, respectively, indicating a selective adsorption of p-CNB in HZSM-5 zeolite from the aqueous mixture of p- and o-CNB.
Water Research 04/2005; 39(6):1174-82. · 4.86 Impact Factor
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ABSTRACT: The adverse effects of organic matter on orthophosphate corrosion inhibition for copper pipe in simulated soft water were investigated. Sodium alginate and fulvic acid were selected to simulate extracellular polymeric substance produced by bacteria and natural organic matter in potable water. The results showed that the doses of organic matters, pH values and stagnation times had significantly affected on the function of orthophosphate corrosion inhibition for copper pipe in soft water. More soluble copper release was observed in low levels for sodium alginate (1 mg/l as TOC) and in high concentration for fulvic acid (16 mg/l as TOC). When the concentration of fulvic acid was high, the 2-week aged copper pipe released more soluble copper than the 6 and 12-month aged copper pipe. The soluble copper release increased with the reduction of initial pH value. Effect of stagnation time on soluble copper release from different aged copper pipe in soft water was highly variable. Compared to the system of no organic matters, organic matters markedly decreased the efficiency of orthophosphate corrosion inhibition for copper pipe in soft water.
Corrosion Science. 46(1):137-145.
