Synthesis of [H22·Zr5·WO4·10 P2O7]n·26n H2O by response surface methodology to adsorb Ca(II) in manganiferous wastewater.

The presence of calcium challenges the manganese recovery from manganiferous wastewater. In this paper, a kind of mesoporous material named [H22·Zr5·WO4·10 P2O7]n·6n H2O is investigated as an ion exchanger to remove calcium ion from manganese slag percolate. The synthesis of zirconium tungstopyrophosphate (ZWPP) was optimized by response surface methodology , and its adsorption capacity and equilibrium were tested. The adsorption data have been confirmed by the use of various techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy and Brunauer, Emmett and Teller. An empirical formula of ZWPP was obtained by X-ray diffraction and thermal analysis. The adsorption process conformed to pseudo-second-order kinetics and the Langmuir isotherm, which described the equilibrium powerfully. Furthermore, different thermodynamic parameters were evaluated. And it was found that Gibbs free energy change is negative, indicating the adsorption process was spontaneous, whereas the enthalpy change and entropy change are positive indicating endothermy and increased randomness nature of the adsorption process. As a result, ZWPP could be a possible ion exchanger material in the area of removing Ca2+ from processing water or wastewater.

Construction of adsorptive nanorods from polyoxometalates and ionic liquid and their adsorption properties for silver ion from AMD.

A new structure of hybrid nanorods adsorbent ([n-BBIM]9PW9O34) was synthesized by a simple molecular assembly of polyoxometalates with ionic liquids (ILs). The nanocomposite was characterized by Fourier transform infrared (FT-IR), ultraviolet-visible (UV-Vis), scanning electron microscope, energy dispersive X-ray and X-ray diffractometer. Adsorption of silver from acid mine drainage (AMD) was studied using batch experiments. The impact of several parameters, like ion concentration, pH, adsorbent dosage, and temperature was elucidated and optimization was carried out by single-factor experiment and response surface methodology. Analysis of variance of the quadratic model suggested that experimental data were excellently fitted to the quadratic model. Optimum conditions for removal of Ag(+) from AMD were determined to be an initial concentration 143 mg/L, adsorbent dosage 2.69 g/L, temperature 35 °C to achieve the maximum adsorption of Ag(+) 99.03%, which was very close to the predicted value (100%). The adsorption was confirmed as oxidation-reduction mechanism following a complexation process, and has been verified according to results from FT-IR and UV-vis spectra. The selective experiment suggested that the nanorods adsorbent could adsorb silver ions in AMD well. Based on the adsorption/desorption study result, the adsorbent can be efficiently recovered.

[Etiologic characteristics of adult patients with community-acquired pneumonia in Beijing].

OBJECTIVE: To explore the etiologic characteristics of adult patients with community-acquired pneumonia (CAP) in Beijing. METHODS: A multicenter cohort of 510 adult CAP patients were enrolled from Beijing during the period of November 2010 to May 2012. Multiplex polymerase chain reaction (PCR), real-time fluorescence quantitative PCR and legionella urinary antigen were used to detect common respiratory viruses, Mycoplasma pneumoniae and legionella respectively. Bacteria were detected by sputum culture, blood culture and Streptococcus pneumoniae urinary antigen. Statistical analyses were performed for the etiologic characteristics and seasonal distribution of detected pathogens. RESULTS: Pathogens were detected in 240/500 (47.1%) study patients. The mixed infection of different pathogens was present in 42 cases (8.2%), viruses in 164 (32.2%), Mycoplasma pneumoniae in 91 (17.8%), bacteria in 26 (5.1%) and Legionella in 3 (0.6%). Among 164 patients infected with viruses, 194 viral strains were detected. Influenza virus represented the greatest proportion with 105 (54.1%) in viral infections. Between November 2010 to October 2011, Influenza A infections increased gradually in November 2010, peaked in February 2011 and declined by March 2011 in China. Mycoplasma pneumoniae was predominant in winter and spring. CONCLUSIONS: There is a high detection rate of virus and Mycoplasma pneumoniae in adult CAP patients in Beijing. And more consideration should be given to influenza virus and Mycoplasma pneumoniae infections in winter and early spring.

Magnetic Zn (II) ion-imprinted polymer prepared by the surface imprinting technique and its adsorption properties.

A novel magnetic Zn (II) ion-imprinted polymer was prepared by the surface ion-imprinted technique by using magnetic Fe3O4@SiO2 microspheres as supporter, methacrylic acid and salicylaldoxime as monomers, ethylene glycol dimethacrylate as the crosslinker. The products were characterized by Fourier transform infrared, X-ray photoelectron spectrometer, vibrating sample magnetometer and scanning electron microscope. The adsorption experiments showed that the imprinted polymer was employed successfully in comparison with non-imprinted polymer. When the temperature was in a range of 291-297 K, the maximum adsorption was about 52.69 mg g(-1) with an optimal pH 6.0 for an equilibrium time of 40 min. The imprinted polymer possessed high selectivity and specific recognition towards Zn (II). The Langmuir adsorption model was more favourable than the Freundlich or the Temkin adsorption model. Thermodynamic experiment showed that the adsorption was a spontaneous and endothermic process for Zn (II). The mechanism for Zn (II) adsorption on the imprinted polymer was investigated.