Study on Gold (Ⅰ) Solvent Extraction from Alkaline Cyanide Solution by TBP with Addition of Surfactant

The new solvent extraction system for gold() from alkaline cyanide solution by TBP with addition of surfactant in aqueous phase was studied. The effect of various factors, such as equilibrium pH, constitution of organic phase, molar ratio of CPBAu(CN)2-, extraction time, aqueous/organic phase ratio, different initial gold concentration, equilibrium temperature, different diluent, different types of extractants and surfactants etc., was inspected. The results show that gold() can be extracted quantitatively by controlling the quantity of surfactant (CPB); both the equilibrium pH and diluent hardly influence percent extraction. Gold() percent extraction reaches more than 98% under the optimal experimental conditions. 30% vol TBP diluted by sulphonating kerosene can load gold() to rather high levels. Loading capacity is in excess of 38 g/L. The extraction mechanism is discussed and the overall extraction reaction is deduced.

Solid-phase extraction gold from alkaline cyanide solution with quaternary ammonium surfactant

The solid-phase extraction（SPE） technique applied to the extraction of organic compound was creatively used as the extraction of inorganic gold in the paper.Two types of techniques were proposed and explored,namely the SPE and the liquid–liquid extraction（LLE） of the quaternary ammonium surfactant [cetytrimethyl ammonium bromide（CTMAB）,cetyl pyridine bromide（CPB）,benzyl dimethyl dodecyl ammonium chloride（BDMDAC）,and dodecyl trimethyl ammonium chloride（DTMAC）].The surfactant could react with Au（CN）2^- to form the ionic complex,and the compound could be extracted by SPE column of reversed-phase bonded silica gel.Hence,a new method of SPE was proposed to extract gold with these features of the high selectivity,the reliability,and the simplicity.The experimental result shows that the recovery rate of gold is more than 98 %,and the solid-phase extraction column is not easily damaged and it can be repeatedly used.The new method can be used as the extraction process of gold from alkaline cyanide solution as well.Besides,the paper also puts forward a new process of gold extraction.

Turn-on fluorescence sensing of cyanide ions in aqueous solution

A sensitive fluorescent probe, 2,2＇-bisbenzimidazole （L）, for CN has been developed. This structurally simple receptor displays great selectivity for the cyanide anion over other common inorganic anions in an aqueous environment. In addition, further study demonstrates the lower detection of the fluorescence response of the sensor to CN is in 10 9 mol/L range. Thus, the present probe should be applicable as a practical system for the monitoring of cyanide concentrations in aqueous samples.