Qing Xuan Zeng

Preparation and Characterization of Copper Oxide and Copper Nanoparticles

Copper oxide was prepared via the calcination of copper oxalate precursor. By using high-temperature solvent method, the precursor decomposed under nitrogen atmosphere and copper nanoparticles were obtained. The microstructure and properties of the products were characterized by scanning electron microscopy, X-ray diffraction, UV-Vis spectroscopy, Fourier transform infrared spectroscopy and other analysis methods. The results show that the obtained copper oxide is constructed by nanoparticles. The sample is porous and has a good catalytic activity. Three copper samples were obtained by controlling the reaction time. The particle size of the samples was calculated to be about 44.3 nm, 17.1 nm and 9.9 nm respectively.

Synthesis of Copper Nanoparticles by Chemical Reduction Method and its Influential Factors

Synthesis of copper nanoparticles was achieved by reduction of copper sulfate solution using sodium hypophosphite (NaH2PO2). The nanoparticles are characterized by using SEM and XRD techniques. The XRD analysis and theoretic calculation indicate that the products have a fcc structure, and the size of crystallite is about 20 nm. Different solvents have been used to produce copper particles with different shapes, and the size of the particles can be controlled by varying reaction condition.

Removal of Copper-Cyanide Complexes from Electroplating Industry Effluents by Ion-Exchange Fiber

Removal of copper-cyanide complexes from electroplating industry effluent were studied by using an ion-exchange process. A kind of polypropylene strong alkaline anion exchange fiber was used to perform packed beds continuous experiments. The conditions of adsorption were wastewater pH value 9.0 and flow rate 90-120 BV•h-1 at room temperature. The packed beds were exhausted at 1300 bed volumes for copper-cyanide complexes The elution of copper-cyanide complexes from ion-exchange fiber was studied. The results showed that copper-cyanide complexes were easily eluted from ion exchange fiber using either 2.0 mol•L-1 NaNO3 or NaCl. With 1.0 mol•L-1 NaNO3 solution at 30 BV•h-1, the regenerating rate of copper-cyanide complexes was more than 95%.

Thermodynamics of Cr(VI) Adsorption on Thiourea Chelating Ion Exchange Fiber

A chelating ion exchange fiber containing thioureido groups for the removal of Cr (VI) has been prepared from chloramethylated styrene grafted polypropylene fiber (2.96 mmol/g Cl) reacted with thiourea, batch adsorption experiments are adopted to investigate its adsorption equilibrium properties, Adsorption isotherms at various temperatures were obtained. Langmuir linear equation model can well describe the adsorption equilibrium data suggesting that the adsorption process involves both chemisorption and physisorption. The values of thermodynamic parameters, including ΔH, ΔG and ΔS, indicate that the adsorption of Cr (VI) is a spontaneous, entropy-driven and endothermic process.

Key Fabrication Technology Research of Exploding Foil Initiator

In order to realize consistency and low cost in the production process of the exploding foil initiator, the manufacturing method of exploding foil initiator was studied using micro processing technology. Microcrystalline glass was used as substrate, and magnetron sputtering,photolithography and wet etching technology were utilized to product the metal bridge foil on the surface of the substrate. SU-8 photoresist was used as the barrel material and scanning electron microscope was exploited to characterize structure of the initiator. Through the electrical tests, the flyer was successfully generated and after the barrel had a good integrity.

Tandem Extraction of Gold (I) from Cyanide Leaching Solution by Weak-Strong Alkaline Anion Exchange Fiber

The objective of the study is separating the gold (I) and its coexistence base metals from cyanide leaching solution by homemade weak and strong alkaline anion exchange fiber inseries, by using their selectivity and the adsorption capacity, respectively. The optimal conditions of the adsorption/elution are as follows: for WAAEF, the suitable flow rate of the adsorption is 61.4 BV/h, and the loading density is 0.262 g/cm3; for SAAEF, the suitable flow rate of the adsorption is 872.2 BV/h, and the loading density is 0.202 g/cm3. A mixture of 2.5 mol/L NH4SCN with 0.1 mol/L NaOH is chosen as the gold (I) eluent, and the eluention flow rate is 96.9 BV/h. The conclusion is that the homemade fibers could be used inseries to extract the gold (I) from cyanide leaching solution.

Study on Continuous Separation of High Concentration Cr (III) and Cr (VI) from Strong Acidic Aqueous Solution Using Strong Alkaline Anion Exchange Fiber Column

The continuous separation of high concentration Cr (III) and Cr (VI) from strong acidic aqueous solution was achieved in column packed with strong alkaline anion exchange fiber (SAAEF). The optimal operation conditions are as follows: flow rate 5.0 BV· h-1 and room temperature. The absorbed Cr (VI) on column could be recycled as Na2Cr2O7 or K2Cr2O7 solution after separation from Cr (III), using saturated NaCl+2.0% NaOH or saturated KCl+2.0% KOH.

The Study of Solubility of Barium Nitrate Prepared from Barium Chromate and Nitric Acid

In this paper, the solubility of barium nitrate prepared from barium chromate and nitric acid was investigated. The effects of reaction time, reaction temperature, stirring rate, the concentration of nitric acid and the amount of the initial content of barium chromate have been studied. The results showed that the solubility of barium nitrate decreased with increasing reaction time, stirring rate and concentration of nitric acid, increased with reaction temperature but had nothing to do with the amount of the initial content of barium chromate. Finally, the reaction optimum conditions were determined that the reaction time was kept at 30 min, reaction temperature was 40-50 °C, stirring rate was 100-200 rpm, and the concentration of nitric acid was 15 mol/L.

Comparison of Different Ion-Exchangers’ Performances for Removal of Cadmium(ll) from Aqueous Solution

In this paper, comparison of the ion-exchange characteristics of removal cadmium (Ⅱ) ions from aqueous solution was investigated. In the experiments, three strong cation-exchangers, 732 resin, K-1 fiber and ZB-1 fiber with sulfonate groups, weak cationic exchanger 724 resin with carboxylate groups and X-1 chelating fiber with diethylamino functional groups as well as the AK-22 amphoteric fiber with amino and carboxylate groups were used. In the pH value range from 2.0 to 7.0, all the candidate materials had the maximal removal Cd (Ⅱ) up to 98% except AK-22 (only 65%). The loading and eluting kinetics results showed that the exchange rate of ion-exchange fibers (especially ZB-1) were higher than ion-exchange resins. Therefore, it was found that ZB-1 ion-exchange fiber was the most effective for removal and elution of Cd (Ⅱ) and had the potential application for the purification of waters polluted by Cd (Ⅱ).

Sorption Behavior of Strong Acid Cationic Exchange Fiber for Indium

In (III) was quantitative adsorption by strong acid cationic exchange fiber (SACEF) in the medium of pH=2.50 sulphuric aicd. The statically saturated sorption capacity of SACEF was 153.8 mgg-1. 0.5 molL-1 H2SO4 could be used as an eluant. The elution efficiency was 99%. The SACEF could be regenerated and reused without apparent decrease of sorption capacity. The sorption rate constant was k287K=0.09379 gmg-1min-1, k300 K=0.1159 gmg-1min-1, k321 K=0.4046 gmg-1min-1 and k350 K=0.6678 gmg-1min-1, respectively. The apparent sorption activation energy of SACEF for In (III) was 28.28 kJmol-1.The sorption behavior of SACEF for In (III) obeyed the Freundlich isotherm. The enthalpy change was H=5.67 kJmol-1.