Anion

Iron-based layered double hydroxides (LDHs) have the general formula [MII(1-x)MIIIx(OH)2]x+·[(x/n) An−, m H2O]x− and contain a molar fraction of iron, i.e. FeII or FeIII situated in the cationic layers, higher than 50%. LDHs containing FeII species are interesting materials for several applications such as the reduction of anionic pollutants or the degradation of organic pollutants. They are mostly prepared either by coprecipitation of dissolved species or by oxidation of hydroxylated FeII species. The synthesis routes were visualised in binary and ternary mass-balance diagrams. The LDH[FeII–FeIII] particles were well crystallised hexagonal plates, the size of which diminishes rapidly when divalent or trivalent cations substitute ions. The LDH[FeII–FeIII–CO3] transformed into a mixture of magnetite Fe3O4 and siderite FeCO3 in alkaline conditions, but the adsorption of silicate or phosphate anions on the lateral faces of the crystal prevented this decomposition. In oxic conditions, t...

The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 m, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L-1 FL-2949 (coagulant) and 12 mg L-1 A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

http://www.ncbi.nlm.nih.gov/pubmed/20450117 
http://www.tandfonline.com/doi/abs/10.1080/09593330903513245#.Ut31zvsRWM8

Reported herein is a straightforward and enantiodivergent synthesis of both enantiomers of trifluoromethylated analogues of calcimimetic NPS R-569 in a highly estereoselective manner. The synthesis features a diastereoselective synthesis of the N-(isopropylsulfinyl)imine unit by the “DAG methodology” and a diastereoselective addition of Ruppert–Prakash's reagent to the imine as the key steps. No protecting groups were necessary, permitting an atom economic synthesis in only six steps. Further addition reactions of the CF3 anion to different N-(isopropylsulfinyl)imines were performed to demonstrate the suitability of the sulfinyl substituent to balance perfectly reactivity and diastereoselectivity.

We present the electro-optical characteristics of LECs based on two copolymers derived from poly(p-phenylene vinylene), DB-alt-BTEM-PPV and BDMOS-co-BTEM-PPV, having ion-transporting side groups. We find typical LEC behaviour upon addition of lithium triflate. Addition of poly(ethylene oxide), PEO, improves the EL efficiency, but the response time increases. We discuss these observations on the basis of PEO-induced phase separation.

An optimized capacitively coupled contactless conductivity detector for microchip electophoresis is presented. The detector consists of a pair of top–bottom excitation electrodes and a pair of pickup electrodes disposed onto a very thin plastic microfluidic chip. The detection cell formed by the electrodes is completely encased and shielded in a metal housing. These approaches allow for the enhancement of signal coupling and extraction from the detection cell that result in an improved signal-to-noise-ratio and detection sensitivity. The improved detector performance is illustrated by the electrophoretic separation of six cations (NH, K+, Ca2+, Na+, Mg2+, Li+) with a detection limit of approximately 0.3 μM and the analysis of the anions (Br−, Cl−, NO, NO, SO, F−) with a detection limit of about 0.15 μM. These LODs are significantly improved compared with previous reports using the conventional top–top electrode geometry. The developed system was applied to the analysis of ions in bottled drinking water samples.