Advanced Materials Research Vol. 549

Abstract: The catalytic oxidation of cyclohexane to cyclohexanone and cyclohexanol using hydrogen peroxide over phosphomolybdic acid were studied. Factors such as the amount of catalyst, amount of the oxidant (H₂O₂), reaction temperature and reaction time were investigated. The conversion of cyclohexane was 35.35%, the total selectivity to cyclohexanone and cyclohexanol was 97.68% at a reaction temperature of 70 °C, reaction time of 8 h, 10 mL of acetone, 0.01 g of phosphomolybdic acid and 0.5 mL of hydrogen peroxide.

Abstract: Degradation of the wastewater of washing oil tanks after degreasing and minimal treatment by photocatalysis is studied by using a rotating photoreactor and TiO₂ photocatalyst of Degussa P25. Effects of irradiation time and pH value on removing efficiency are investigated. The results show that the COD down to about 80mg/L can be achieved at the irradiation time of about 4-5 hours at mild pH valus. At the pH value from 1.5 to 3.2, the COD down to about 80mg/L can be achieved at the irradiation time less than 1 hour, and the COD down to about 20mg/L could be achieved at the irradiation time of about 4 hours at a pH value of about 3.2.

Abstract: Using Palygorskite as matrix, chitosan(CTS) as functional monomer, and introducing the ion-imprinting technique to the synthesis process, a new Cd²⁺-IIP was prepared for selective separation of Cd²⁺ from aqueous solution was prepared. The static method was adopted to study the adsorption capacity of Cd²⁺-IIP for Cd²⁺, and the effects of contact time, pH value, adsorbent dosage and temperature of the initial solution on the adsorption characters of Cd²⁺ were investigated. Experiment results indicated that the adsorption was rapid during the first 20 minuts and equilibrium were attained within 70 minutes. The Cd²⁺-IIP had higher adsorption capacity to Cd²⁺ than other different ions. There were less difference in the adsorption capacity between different dosages of Cd²⁺-IIP, but the adsorption capacity of Cd²⁺ adsorbed onto Cd²⁺-IIP decreased with increasing the dosages.Under the optimum conditions, the ions-imprinted polymer offered a fast adsorption of Cd²⁺ and the maximum capacity was 18.20 mg/g.

Abstract: In this paper, a crosslinked porous lignin beads (PLB) as adsorbent was adopted to adsorb toxic Pb²⁺ and Cd²⁺ ions from aqueous solutions. The pore structure and surface morphology of PLB were characterized by by a variety of techniques. The influences of pH, contact time, initial metal ions concentration, temperatures were investigated. The results showed that the adsorption of both heavy metal ions increases with pH. The adsorption equilibrium data under different temperature can be successfully described by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. The Langmuir adsorption model showed the best fit to the adsorption data of Cd²⁺ and D-R model fits best to the adsorption data of Pb²⁺. The results obtained also indicated that the adsorption of Cd²⁺ and Pb²⁺ increased with increasing temperature indicating endothermic nature of the adsorption process. The kinetic study showed that Cd²⁺ adsorption followed pseudo-second order rate kinetics and Pb²⁺ adsorption followed pseudo-first order rate kinetics. Cd²⁺ adsorption on PLB was mainly through the chemisorption mechanism (E_D-R between 12.62 kJ•mol^-1 and 16.20 kJ•mol^-1) while physical and chemical absorption coexistence was observed to Pb²⁺ adsorption. Desorption studies revealed that the desorption rate increased with increasing hydrochloric acid concentration and could finally reach 94 % and 85.1 % for Cd²⁺ and Pb²⁺, respectively, by adding 3 mol/L of HCl.

Abstract: This paper studied the purification of metallurgy grade silicon by acid leaching with different type acid and concentration. Before experiment, silicon metal had already handled by slagging process, so most boron was removed. In this paper, we grinded materials into 80-400 mesh powder, and compared the purification effect of using aqua regia, hydrochloric acid and hydrofluoric acid, respectively. With regard to the silicon metal, single acid cannot remove the impurities perfectly, but the effect of using hydrochloric acid first and following with hydrofluoric acid can be better. The removal rates of Mg, Al, Ca, Fe, and Ti were 96.8%, 96.8%, 98.2%, 99.7%, and 98.0%, respectively. Then adjust the concentration of both acid to be 14% and 7% by weight, it turned out that 14% was much better. The removal rates of Mg, Al, Ca, Fe, and Ti were 87.1%, 97.4%, 99.0%, 99.7%, and 99.1%, respectively. The results indicate that purification by multiple acids and 14% concentration could be an effective condition to remove impurities in silicon for acid leaching.

Abstract: This paper provides the results of an experimental research on the performance of catalytic combustion of gasoline vapor. A packed bed reactor was built to test the effect of inlet temperature and concentration on catalytic combustion of gasoline vapor over P_d/Al₂O₃. The study shows that catalytic combustion is a cost-effective and environmental friendly method to control this kind of emission. The light-off temperature is quite low and full conversion rate is easy to achieve. Meanwhile, the method of controlling the bed temperature is proposed to avoid sintering if the technology is utilized in larger-scale equipment.

Abstract: Solubilities of the reciprocal quaternary system (Li⁺, Mg²⁺//Cl^-, SO₄^2-–H₂O) at 273.15K were calculated using Pitzer and its extended HW model. The values of the Pitzer single-salt parameters β⁽⁰⁾, β⁽¹⁾, β⁽²⁾ and C^φ for LiCl, MgCl₂, Li₂SO₄, and MgSO₄, the mixed ion-interaction parameters θ_Li,Mg, θ_Cl,SO4, ψ_Li,Mg,Cl, ψ_Li,Mg,SO4, ψ_Li,Cl,SO4 and ψ_Mg,Cl,SO4, and the Debye–Hückel parameter A^φ in the system at 273.15K were derived either temperature-dependent equation or through fitting solubility data of the ternary system by multiple linear regression method. Based on the Jänecke indexes, the phase diagram was plotted. This study affords the necessary parameters for solubility predictions of complicated systems and establishes a theoretical basis for the separation of these valuable minerals from salt lake brine.

Abstract: ITO (Indium Tin Oxides) nano-powder was prepared by the method of ammonia complexation. The chemical composition, morphology and crystal structure were characterized by X-ray diffraction (XRD) ,transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy analysis(XPS). Base on the nucleation and growth mechanism of the powder, the temperature of heat treatment impacting on size and morphology was discussed briefly. The results showed that the nano-ITO powder of particle size 20nm-40nm with well-pleasing particle shape and dispersion can be prepared at 800°C.

Abstract: A novel catalyst for the copolymerization of CO2 and cyclohexene oxide(CHO) was prepared by using BTE and ZnCl2. The zinc complex showed catalytic activity for the copolymerization. The obtained copolymer was characterized by IR and NMR. Effect of reaction time on copolymerization was investigated.

Abstract: The effect of propanediyl-α, ω-bis-(N-dodecyl benzimidazole ammonium bromide), (abbreviated as BIMGCS12-3)， as the inhibitor for the corrosion of mild steel in 1M vitriolic acid was tested. It was found by Tafel polarization curves that BIMGCS12-3 as mixed type inhibitor adsorbed on the mild steel surface forming a protecting film. EIS measurements were carried out in a frequency range of 100kHz to 10mHz with amplitude of 5mV using ac signals at open circuit potential. Changes in impedance parameters (charge transfer resistance, Rct, and double layer capacitance, Cdl) were indicative of the feasibility of BIMGCS12-3 as excellent mild steel corrosion inhibitor in 1M sulfuric acid. Surface morphology of the specimens was examined by SEM.