Source composition and seasonal variation of particulate trace element fluxes in Prydz Bay, East Antarctica.

Particulate fluxes of trace elements (Al, Fe, Mn, Cu, Pb, Zn, Cd and Co) in the polynya area of Prydz Bay were measured using time series sediment trap lasting from December 16th 2010 to December 16th 2011. The comparison of annual fluxes from different regions, the seasonality and sources of trace element, and their association with organic matters were investigated. The fluxes of Cu, Zn and Cd in the polynya area of Prydz Bay are dominated by marine biogenic sources. Their similar seasonality with the export of biological materials (biogenic silica, organic carbon, and calcite carbonate) is strongly related to the ice coverage and biological production. Mineral debris derived from Antarctic continent is suggested to account for the particulate fluxes of Al, Fe, Mn, Pb and Co in the polynya. Their seasonal variations are most likely controlled by ice melting and freezing process. Furthermore, their fluxes are also influenced by scavenging onto biogenic material for Pb and uptake by phytoplankton for Co. The excess fluxes of Cu, Zn and Cd have good relationship with organic carbon export. The coupling patterns are mainly regulated by source composition of trace elements and non-lithogenic input from atmospheric deposition or upwelling, and partly influenced by biological uptake process.

Star-shaped poly(L-lactide)-b-poly(lactobionamidoethyl methacrylate) with porphyrin core: synthesis, self-assembly, singlet oxygen research and recognition properties.

Star-shaped porphyrin-cored poly(L-lactide)-b-poly(lactobionamidoethyl methacrylate) block copolymers (SPPLA-b-PLAMA) were synthesized via RAFT of unprotected Lactobionamidoethyl methacrylate (LAMA) in 1-methyl-2-pyrrolidinone (NMP) solution at 70 °C. The structure of this as-synthesized SPPLA-b-PLAMA block copolymer was thoroughly studied by nuclear magnetic resonance spectroscopy, gel permeation chromatography (GPC), and Fourier transforms infrared. Moreover, under the irradiation, such SPPLA-b-PGAMA copolymer exhibits efficient singlet oxygen generation (0.17) and indicates high fluorescence quantum yields (0.20). Notably, with UV-vis investigation, SPPLA-b-PLAMA showed a very specific recognition with RCA120 lectin. This will not only provide potentially prophyrin-cored star-shaped SPPLA-b-PLAMA block copolymers for targeted photodynamic therapy, but also improve the physical, biodegradation, biocompatibility properties of PLA-based biomaterials.

Adsorption of lead(II) by silica/cell composites from aqueous solution: kinetic, equilibrium, and thermodynamics studies.

Silica/cell composites were prepared for the adsorption of lead ions, Pb(II), from aqueous solution in a batch system. The silica/cell composites possessed micropores, high surface area, and abundant functional groups. Adsorption performance was investigated by analyzing the effects of such factors as the initial pH, contact time with different initial concentration, and initial Pb(II) concentration at different temperature. The kinetic data were fitted to pseudo-second-order and intraparticle diffusion kinetic models. The results were better fitted by the pseudo-second-order kinetic model. Intraparticle diffusion increased with an increase of initial concentration and the sorption process was controlled by film diffusion. The Langmuir isotherm model was fitted to the experimental data significantly better than Freundlich and Dubinin-Radushkevich isotherm models. The maximum adsorption capacity was 97.10 mg g(-1), according to the Langmuir isotherm model. Thermodynamics parameters confirmed the spontaneous, endothermic, and entropy-gained nature within the studied temperature range (from 298 to 318 K). The composites could be effectively desorbed by the 2.0 mol L(-1) HNO3 solution and would be a potential adsorbent.

Biosorption of Pb(II) by biomass of KC-2: kinetic, equilibrium and characteristic studies.

Performance and characteristics of biosorption of Pb(II) had been studied in a batch system using the fungal strain biomass, KC-2. The biosorption performance was investigated by analysing the effects of such factors as the initial pH, initial Pb(II) concentration, and contact time at 303 K. The maximum Pb(II) adsorption was obtained at pH 5.0. The experimental data were described by the pseudo first-order, pseudo second-order and intraparticle diffusion kinetic models, and were closely followed the pseudo second-order kinetic model. The equilibrium experimental data were well fitted to Langmuir model and the maximum biosorption capacity was 84.03 mg g(-1). The adsorption mechanism was examined by FTIR, SEM and EDAX analysis. Results indicated that carboxylic, hydroxyl and amine groups were involved in the biosorption and ion exchange mechanism existed.

[Analysis of properties of cadmium adsorption onto whisker surface ion-imprinted polymer by inductively coupled plasma atomic emission spectrometry].

A new type of surface ion-imprinted polymer was synthesized in aqueous media with sodium trititanate whisker in the presence of Cd(II), chitosan and gamma-glycidoxypropyl trimethoxysilane (KH-560). A batch of adsorption experiments were performed to evaluate its adsorption of Cd(II) using inductively coupled plasma atomic emission spectrometry (ICP-AES). The factors affecting adsorption capacity, including pH and sorbent amount, were discussed. The adsorption kinetics and adsorption isothermals were also obtained. The Langmuir isotherm can fit in the experimental equilibrium data. Under the optimum conditions, the value of the adsorption was above 99%, and the maximum adsorption capacity was 52.34 mg x g(-1). In accordance with the parameters distribution coefficient (K(d)) and selectivity coefficient (K), the selectivity for Cd(II) of the prepared imprinted polymer was estimated. Finally, the adsorption mechanism was discussed and the detection limit of 0.024 microg x mL(-1) with the relative standard deviation (RSD) of 1.74% (c = 1.0 microg x mL(-1), n = 13) for Cd(II) was obtained. Results showed that the surface Cd(II)-imprinted polymer was a solid sorbent with high efficiency, low-cost, convenient separation/enrichment for environmental trace Cd(II).

Citricoccus zhacaiensis sp. nov., isolated from a bioreactor for saline wastewater treatment.

A Gram-positive, neutrophilic, non-motile and non-spore-forming actinobacterium, strain FS24(T), was isolated from a bioreactor treating salt-containing wastewater. This isolate grew in the presence of 0-15 % (w/v) NaCl and at 10-37 degrees C. The optimum NaCl concentration for growth of FS24(T) was 5 % (w/v) at 37 degrees C or 1 % (w/v) at 25 degrees C. Chemotaxonomic analysis revealed MK-9(H(2)) as the predominant menaquinone and the major cellular polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, four unknown glycolipids, two unknown phospholipids and an unknown lipid. The major fatty acids were anteiso-C(15 : 0 ), iso-C(15 : 0), iso-C(16 : 0 ) and anteiso-C(17 : 0). The genomic DNA G+C content was 66.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain FS24(T) clustered with members of the genus Citricoccus, exhibiting high sequence similarity to the 16S rRNA gene sequences of the type strains of Citricoccus alkalitolerans (98.9 %) and Citricoccus muralis (98.8 %), respectively. The DNA-DNA relatedness values of strain FS24(T) to C. alkalitolerans DSM 15665(T) and C. muralis DSM 14442(T) were 54 and 39 %, respectively. On the basis of phenotypic and genotypic data, strain FS24(T) represents a novel species of the genus Citricoccus, for which the name Citricoccus zhacaiensis sp. nov. is proposed. The type strain is FS24( T) (=CGMCC 1.7064(T) =JCM 15136(T)).

Extraction and mechanism investigation of trace roxithromycin in real water samples by use of ionic liquid-salt aqueous two-phase system.

The ionic liquid, as a green solvent, has several advantages over the organic solvents in traditional liquid-liquid extraction. Aqueous two-phase system (ATPS) consisting of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoraborate, [Bmim]BF(4)) and Na(2)CO(3), which is a novel, simple, non-toxic and effective sample pretreatment technique coupled with molecular fluorescence spectrophotometry, was developed for the simultaneous separation, enrichment and rapid analysis of roxithromycin. The extraction yield of roxithromycin in [Bmim]BF(4)-Na(2)CO(3) aqueous two-phase system is influenced by the types of salts, concentrations of Na(2)CO(3) and [Bmim]BF(4), as well as the extracting temperature. Under the optimum conditions, the average extraction efficiency is up to 90.7%. The mechanism of ionic liquid-salt ATPS formation was discussed by hydration theory, and the extraction mechanism of the [Bmim]BF(4)-salt ATPS was investigated by FT-IR spectroscopy and UV-vis spectroscopy. The results demonstrate that no chemical (bonding) interactions are observed between ionic liquid and roxithromycin, while the nature properties of the roxithromycin are not altered. This method was practical when applied to the analysis of roxithromycin in real water samples with the detection limit of 0.03 microg mL(-1), relative standard deviation (RSD) of 1.9% (n=13), and linear ranges of 1.00-20.00 microg mL(-1). The proposed extraction technique will be promising in the separation of other small biomolecules.