Selective recovery of lead from zinc oxide dust with alkaline Na_2EDTA solution

The selective recovery of lead from the zinc oxide dust using an alkaline Na2EDTA solution was investigated. The effects of temperature, leaching time, Na2EDTA concentration and initial NaOH concentration on the leaching rates of lead and zinc were studied. The following optimized leaching conditions were obtained： liquid-to-solid ratio 5：1 mL/g, stirring speed 650 r/min, Na2EDTA concentration 0.12 mol/L, initial NaOH concentration 0.5 mol/L, leaching temperature 70 ℃, leaching time 120 min. Under the optimized conditions, the average leaching rates of lead, zinc, fluoride and chloride are 89.92%, 0.94%, 62.84% and 90.02%, respectively. The filtrate was used to electrowin lead powders. The average current efficiency of electrowinning is about 93% and lead content is higher than 98% under the conditions of temperature of 60 ℃, current density of 200 A/m2, H3PO4 concentration of 1.5 g/L, and lead ion concentration of above 5 g/L. The consumption of Na2EDTA and the direct current are about respectively 0.218 kg and 0.958 kW·h for per kilogram of lead powder.

Stable pillar[5]arene-based pseudo[1]rotaxanes formed in polar solution

Mono-alkyl-functionalized pillar[5]arenes PI, P2, and P3 were synthesized by click reaction, which exhibited different self-assembly behavior in polar solvent DMSO. Stable pseudo[ 1 ]rotaxane was formed by the self-complexation from P1 or P2, whereas, concentration-dependent pseudorotaxane structures were generated by P3 which bearing more flexible side chain. Interestingly, the obtained pseudo[1]rotaxanes exhibited a dynamic fast assembly process upon adding NaBF4, resulting in the formation of Na＋-induced pseudorotaxanes.

A Rapid and Effective HPLC Method for Identification of Bovis Calculus in Chinese Patent Medicines

Objective Due to the limited resource and the large demand,many kinds of Bovis Calculus(BC) including artificial Bovis Calculus(ABC),in vivo cultured Bovis Calculus(in vivo CBC),and in vitro cultured Bovis Calculus(in vitro CBC)were used in Chinese patent medicines(CPMs).Previous studies have shown that the chemical constituents of ABC and their properties were different from other BC.The two types of CBC with much higher price than ABC were approximately equivalent with natural Bovis Calculus in quality and clinical effect.The aim of the study is to establish a rapid and effective method for the identification of BC in CPMs.Methods An HPLC method with the higher specificity for analyzing bilirubin was established to distinguish ABC from other three kinds of BC by comparing the change of bilirubin content with the addition of EDTA-2Na as the extraction solvent and stabilizer.Results The bilirubin content in CPMs containing ABC was basically unchanged,while that in CPMs containing other kinds of BC showed significant difference.The proposed method was employed to analyze a variety of CPMs containing Bovis Calculus(CPMBCs) and proven to be universal.Conclusion An effective analytical method is established for the quality control of CPMBCs and further ensures the safety and efficacy of these drugs in clinical practice.