Search

A middle grade siliceous phosphorite from Yunnan province was selected to treat Cd2+ bearing aqueous solutions. The siliceous phosphorite was tested by X-ray fluorescence spectrometer, X-ray diffraction, infrared spectrometer and scanning electron microscopy. The results present that the valuable mineral is nanostructured carbonated fluorapatite and the major gangue mineral is quartz. The amount of Cd2+ sorbed by the siliceous phosphorite tends to increase with the increase of initial pH or the initial Cd2+ concentration of the simulated waste water. The reaction process of Cd2+ removal from aqueous solutions is highly fitted with the pseudo-second order kinetic model. The results indicate that nanostructured carbonated fluorapatite bearing siliceous phosphorite can effectively immobilize aqueous Cd2+.

This paper reports a novel coprecipitation process for the preparation of strontium-barium hydroxyapatite [Sr5-xBax(PO4)3OH]. Strontium nitrate, barium nitrate and phosphoric acid were dissolved in water to form a homogeneous Sr-Ba-P aqueous solution. The samples were characterized by powder X ray diffraction, Fourier transformed infrared spectroscopy and scanning electron microscopy. The results showed that the barium phosphate [Ba3(PO4)2] phase appeared at the samples prepared at the pH value lower than 12. A series of Sr5-xBax(PO4)3OH samples had beenobtained by adding sodium hydroxide aqueous solution into the Sr-Ba-P solution to pH12.5 and following aging at 60 °C for 24h. The so-prepared samples are metallic cation-deficient hydroxyapatite solid solutions. The samples present low degree of crystallinity, irregular short rod-like morphology and nanometer size. The crystal cell parameters of Ca5-xSrx(PO4)3OH samples are nearly linear to their barium content, and their infrared absorption bands of PO43- groups shift to lower wave numbers with the increase of the barium content.

A chelating starch (SMAEN) containing amidocyanogen and acyl functions was prepared through a two-step reaction. The structure of SMAEN was determined by FTIR spectrum. The amination extent was traced by estimating the nitrogen content of SMAEN. The SMAEN was tested as an adsorbent in Cu2+ metal aqueous solution. The parameters influencing the efficiency of preconcentration Cu2+ including sample acidity, adsorption conditions were investigated. The Cu2+ ion was accomplished good adsorption amount at pH＞4. The maximum adsorption capacity was 2.69mmol per gram of dried SMAEN.