Zhou Kang-gen

Study on the Removal of MIBK from Aqueous Solution by Vacuum Membrane Distillation

Methyl isobutyl ketone(MIBK) is widely used as extraction agent in hydrometallurgy. As it has a definite solubility in water, so when using MIBK as extraction agent, there will be MIBK in stripping solutions inevitably, which not only pollutes working conditions, but also affects the quality of ultimate product. In order to remove MIBK from aqueous solutions, the means of flat vacuum membrane distillation(VMD) is studied in the paper. The area of the membrane used in the study is 0.02 m2, the initial volume of feed is 2 L, each experiment was conducted over a time period of 60–120 min. The influences of the factors such as temperature(34.8–55.0 °C); pressure in the permeate side(10.67–14.67 kPa) and feed flow rate(27.8–69.4 mL/s) were experimentally studied. Increasing the temperature or reducing the pressure in the permeate side results in a faster removal of MIBK; however there is a decrease in removal factor β, increasing the feed flow rate results in a faster removal of MIBK and an increase of removal factor β, especially in the range of lower flow rate. The study indicates that the aim of MIBK removal and recycle from dilute aqueous solutions can be achieved by VMD.

Electrodeposition of copper by IMPC method

In order to develop an energy-saving electrodeposition process of copper, the electrodeposition of copper in copper sulfate solution by the ion-exchange membrane primary cell (IMPC) method has been studied. The experiments were carried out in an ion-exchange membrane primary cell with dimensions of 200 mm in length, 52 mm in width and 90 mm in height. The influences of temperature (294–323 K), interval between the anode and cathode (1.5–3.5 cm), mass concentrations of Cu2+ (6–40 g/L), H2SO4 (0–120 g/L) and Fe3+ (3–9 g/L) in catholyte and solution flow rate (0–8 cm/s) on current density and current efficiency were investigated experimentally. The current density increases with the increase of temperature and concentrations of Cu2+ and H2SO4 in catholyte. Cathode current efficiency decreases with the increase of concentration of Fe3+ in catholyte and anode current efficiency decreases with the increase of temperature. The high-quality cathodic copper can be obtained and the current density of membrane can be higher than 150 A/m2 and the current density of cathode can be higher than 300 A/m2. The experiment results show that IMPC method is effective for electrodeposition of copper.

Solvent extraction of niobium from alkali solution by methyltrioctylammonium chloride

For the purpose of developing an alkali leaching-solvent extraction directly from alkali solution process, the extraction of niobium from alkali solution by long-chain alkyl quternary ammonium salt (methyltrioctylammonium chloride R4NCl) in toluene was investigated. The experiments were carried out under conditions of 25 °C, Nb(V) concentration 0.01 mol/L, pH 10.7–13.8, R4NCI concentration 0.02–0.14 mol/L. It has been found that the distribution ratio of niobium increases with increasing R4NCl concentration and with decreasing KCl concentration, but it shows maximum value at pH value of about 12 and decreases below or above this pH value. Distribution ratio of niobium goes up to over 1 000 in appropriate conditions, and so it has been proved that R4NCl is an effective extractant for extraction of niobium from alkali solution.

Treatment of industrial wastewater from an alumina plant by membrane (I)

In order to design the technological process of desalination by electrodialysis for the industrial wastewater of an alumina plant, the limit current density of the industrial wastewater is measured, and the equations of limit current density, voltage drop of the unit membrane pair at the limiting current and desalination ratio at the limiting current were obtained.

Removal of organic matter from H2TaF7 solution by adsorption

The removal of organic matter from H2TaF7 solution by adsorption was investigated in order to reduce the carbon content in the K2TaF7 crystal. Three kinds of adsorbent, LSA-5 resin, LSA-20 resin and active carbon were applied in the fixed bed respectively. Experimental results indicate that LAS-5 resin, LAS-20 resin, the mixture of LAS-5 resin and LAS-20 resin (with volume ratio of 1:1), and the active carbon can all reduce chemical oxygen demand (COD) value of the H2TaF7 solution, and reduce consequently carbon content of K2TaF7 crystal to 0.0010%–0.0015% from 0.0025%–0.0030%. Comparing with the others, the active carbon is an approved adsorbent whose bed volumes of effluent reaches 70. In addition, there is a linear relationship between the COD value of H2TaF7 solution and the carbon content in K2TaF7 crystal, and the carbon content in K2TaF7 crystal decreases with the decreasing of COD value of H2TaF7 solution. When the COD value of H2TaF7 solution is lower than 7 mg/L, the carbon content in K2TaF7 crystal would decrease to less than 0.0015%.

Asymmetric synthesis of 3β-acetoxy-17, 17-ethylendioxy-15β, 16β-methylene-5-androsten-7β-ol

Abstract3β-acetoxy-17, 17-ethylendioxy-15β, 16β-methylene-5-androsten-7β-ol(I) was prepared by 3 steps from 3β-acetoxy-15β, 16β-methylene-5-androsten-17-one (II) with overall yield of 52.7%. Thus, interaction of ethylene glycol and material (II) gave 3β-acetoxy- 17, 17-ethylendioxy-15β, 16β-methylene-5-androsten (III) which was subsequently oxidated and stereoselectively reduced to produce compound(I). The normal influencing factors, such as the types of oxidants and reductives, the mole ratio of reactants, the reaction temperature, and the addition ways of reactants, in oxidation and reduction were discussed. The results show that the oxidation rate order is CrO3-C5H5N (1:1, mole fraction)>CrO3-C5H5N(1:2)>(C5H5NH)2Cr2O7 in terms of the oxidant, the yield of the oxidation becomes higher with increasing the oxidant stoichiometry and raising the reaction temperature. And the optimum condition is that the reaction temperature is at 30 °C, and n(III)/n(CrO3-C5H5N(1:2))=1:20. The yield of the −7β alcohol order with Li[Al(OC(CH3)3)3H] (e. g. 78.6%) is more than that with NaBH4 (e. g. 14.5%) in terms of the reductive agent and the reduction rate decreases in the course of reaction. The compound (I) is characterized by IR and MS.