Papers by Keyword: Ammonium Thiocyanate

Abstract: The paper presents a novel method for the separation/enrichment of trace Zn²⁺ using NH₄SCN –dodecyl dimethyl benzyl ammonium bromide (DDBAB)-water system.The effects of different parameters on the enrichment yield of Zn²⁺ have been investigated. The possible enrichment mechanism of Zn²⁺ was discussed.The results show that under the optimum conditions, Zn (SCN)₄^2- produced by Zn²⁺ and SCN^- reacts with DDBAB cation (DDBAB ⁺) to form the water-insoluble ternary association complex of [Zn (SCN)₄](DDBAB)₂, so Zn²⁺ was enriched quantitatively.While Al³⁺,Mn²⁺,Ni²⁺ and Pb²⁺ could not be enriched. Thereby, the quantitative separation of Zn²⁺ from the above metal ions could be achieved.A new method for the separation/enrichment of trace zinc was established. The proposed method has been successfully applied to the separation/enrichment of trace Zn²⁺ in the samles of synthetic water, and the enrichment yield is 96.4%-99.5%.

Abstract: The flotation separation and determination behaviours of mercury (Ⅱ) by sodium bromide -ammonium thiocyanide-octadecyl trimethyl ammonium bromide system were studied. The effects of different parameters,such as the dosages of NH₄SCN and octadecyl trimethyl ammonium bromide (OTMAB),various salts and acidity etc. on the flotation yield of Hg²⁺ have been investigated to select the experimental conditions.The results showed that in the presence of 1.0g NaBr and when the dosage of 0.1 mol/L NH₄SCN was 0.50 mL and 0.01 mol/L OTMAB solution was 1.00 mL respectively, the formed water-insoluble ternary association complex of (OTMAB)₂[Hg(SCN)₄] floated above water phase and liquid-solid phases were formed with clear interface. In this condition, Cd²⁺,Mn²⁺,Ni²⁺,Co²⁺,Fe²⁺ and Pb²⁺ could not be floated and Hg²⁺ could be floated quantitatively at pH2.0.Therefore, the quantitative separation of Hg²⁺ from the above metal ions could be achieved. A new method of determination of trace mercury by flotation separation was established.The proposed method has been successfully applied to the determination of Hg²⁺ in the sample of synthetic water and the flotation yield was 94.2%~97.9%.