硝酸反萃体系中表面活性剂对传质的影响

在改进的传质池中研究了 3种表面活性剂对硝酸反萃体系传质的影响。实验表明 ,在不加界面激励时 ,表面活性剂的存在大大降低硝酸反萃的传质系数 ;加界面激励时 ,阴、阳离子表面活性剂会增加硝酸反萃的传质系数 ,非离子表面活性剂则减小传质系数。

Hydrogen Adsorption on Pt, Rh and Pt-Rh Electrodes

The hydrogen adsorption on Pt-Rh alloys in sulfuric acid aqueous solutions was studied by the method of cathode pulses. Hydrogen adsorption on the electrode with all ratio of alloy components (ωRh = 0-100%) is well described by the Temkin logarithmic isotherm. The surface coverage by adsorbed hydrogen at the same potential is decreased with increasing content of rhodium in the system. A linear dependence of adsorption peak potential on the alloy compositions in the case of weakly bonded adsorbed hydrogen is established. Hydrogen adsorption heat as a function of surface coverage for Pt-Rh-electrodes was obtained. The shape of the current-potential curve and position of the weakly bonded hydrogen adsorption on the potential scale are all related to alloy compositions, thus can serve as the basis for the determination surface composition of alloys.

Efficient Removal of La(III) and Nd(III) from Aqueous Solutions Using Carbon Nanoparticles

Environmental pollution caused by release of toxic metals (rare earth elements, etc.) into aquatic environment as a result of industrial activity is one of the serious global issues, thus development of different efficient methods for removal of these metals from wastewaters seems to be important subject today. Carbon nanoparticles (CNPs) are well-known to have the superior adsorption efficiency toward heavy metals in aqueous solution. However, little research has been dedicated to exploit their use for the removal of rare earth elements (REEs) from contaminated water. Therefore, the environmental application of CNPs to remove Lanthanum (La III) and Neodymium (Nd III) from wastewater was performed. In this work, Adsorption experiments were carried out by batch mode adsorption to investigate the influence of different conditions that enhanced the adsorption of La(III) and Nd(III) by CNPs such as pH of solution, adsorbent dose, contact time, and initial concentration of investigated rare earth elements. The obtained results showed that the optimum adsorption for the removal both studied metals from contaminated water were 0.02 g/25 ml of CNPs at pH 7.0 after 40 min of adsorption. This work demonstrates that CNPs can be considered as potential adsorbents to target metal ions from wastewater.

, Optimization Studies on Synthesis of TKX-50

A systematic study of TKX-50 and ABTOX synthesis using both Klap6tke and Tselinskii modified procedures is described. The influence of temperature, moisture, acid amount and nature on the most critical synthesis step - diazidoglyoxime cyclization is shown. Experimental results show that presence of moisture in reaction mixture leads to product yield decreasing. The reaction temperature is another key parameter affecting product yield. High reaction temperature shows negative influence on the product yield in Klap6tke method. In Tselinskii procedure the yield of product grows with the reaction temperature increasing. For Klap6tke one-pot method, combination of N-methyl-2-pyrrolidone with 1,4-dioxane is the best solvent, whereas Tselinskii one-pot procedure gives high yield of product when combination of toluene with 0.5 equiv, of 1,8-diazabicyclo[5.4.0]undec-7-ene （DBU） is used. Us- ing optimized conditions one-pot five-step synthesis of TKX-50 starting from glyoxime is successfully performed and scaled up to 50 g.

Preparation and photocatalytic kinetics of nano-ZnO powders by precipitation stripping process

Ultra-fine zinc oxalate powders were prepared through a precipitation stripping method with bis(2-ethylhexyl)phosphate(HDEHP)diluted by tetrachloride carbon as the extractant,and oxalic acid ethanol aqueous solution as the re-extractant and precipitator.Zinc oxide powders were obtained by decomposing zinc oxalate powders at 450℃.The prepared zinc oxide powders were characterized by transmission electron microscope(TEM),Scanning electron microscope(SEM),Thermogravimetric analysis(TG),X-ray diffraction(XRD)and Fourier transmission infrared(FT-IR)spectrum.The photocatalytic performance of methylene blue by zinc oxide was studied based on the Langmuir model and Photo-Layer model.The results show that some zinc oxide powders were micro-multipore materials with hexagonal crystal.The particle size was around 32 nm.The photocatalytic process was the control step in the chemical reaction.The photo catalytic process followed pseudo-first order kinetics and NOH concentration inside the photo-layer in different reaction condition were calculated according to the Photo-Layer model.