Jewel A. Gomes

Electrochemical treatment of Orange II dye solution--use of aluminum sacrificial electrodes and floc characterization.

Electrocoagulation (EC) of Orange II dye in a flow through cell with aluminum as sacrificial electrodes was carried out under varying conditions of dye concentration, current density, flow rate, conductivity, and the initial pH of the solution in order to optimize the operating parameters for maximum benefits. Maximum removal efficiency of 94.5% was obtained at the following conditions: dye concentration=10 ppm, current density=160 A/m(2), initial pH 6.5, conductance=7.1 mS/cm, flow rate=350 mL/min, and concentration of added NaCl=4.0 g/L of dye solution. The EC-floc was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy, and powder X-ray diffraction techniques. The removal mechanism has been proposed that is in compliance with the Pourbaix diagram, solubility curve of aluminum oxides/hydroxides, and physico-chemical properties of the EC-floc.

Water-related matrix isolation phenomena during NO2 photolysis in argon matrix.

Photolysis (350–450 nm) of NO2 molecules trapped in argon matrices at 10 K has been studied using Fourier transform infrared (FT-IR) spectroscopy to examine the mobility of the photolysis products, O(3P) and NO, and their subsequent reactions. The formation of N2O5 and N2O3 from reactions of these mobile species with immobilized NO2 and N2O4 is confirmed. Water molecules from the background gases in the vacuum have been found to be isolated in the argon matrix during deposition of diluted NO2 in Ar. The entrapped water molecules along with some of their NO2 adducts have been characterized. Exposure of the matrix to photons to photolyze NO2 resulted in not only internal matrix reactions, but also an enhanced deposition of ice over the surface of the argon matrix. This is caused by photodesorption of water molecules from the walls of the matrix isolation chamber and their subsequent condensation on the matrix surface. This ice overlayer has been found to give a very significant dangling OH band and a substantial librational band in the FT-IR spectra, indicating substantial surface area and internal porosity, respectively. The potential of using photodesorbed water to establish high surface area ice interfaces with dangling OH groups for heterogeneous photoreaction studies is discussed.

Fourier Transform Infrared-Probed O(3P) Microreactor: Demonstration with Ethylene Reactions in Argon Matrix

To demonstrate the development of an oxygen atom microreactor in the form of liquid-helium-cooled solid argon matrix deposited on an infrared (IR) window, the oxidation of ethylene by mobile O atoms has been investigated. O atom diffusion through the argon matrix is confirmed and used to examine ethylene–oxygen atom reactions. In a bench-scale matrix isolation system probed with a Fourier transform infrared (FT-IR) spectrometer, matrices of solid Ar at 8–10 K doped with NO2 and ethylene have been prepared on a ZnSe window within an evacuated cryostat. The matrices have been photolyzed using 350–450 nm photons, and the reaction products resulting from the reaction of O(3P), one of the photolysis products of NO2, with ethylene have been identified using FT-IR and a Gaussian 98W simulation program. These products include oxirane, acetaldehyde, ethyl nitrite radical, and ketene. The temperature effect in the range of 10–30 K on the products formed has also been investigated. The reaction mechanisms are discussed and the viability of the solid Ar matrix being a low temperature microreactor to examine reaction mechanisms of mobile oxygen atoms is elaborated.

Viscosity of Liquid – Inorganic Compounds

Publisher Summary This chapter presents the values of viscosity of liquid (inorganic compounds) in tabular form. For the tabulation, an equation is selected for liquid viscosity as a function of temperature. The tabulation is arranged by alphabetical order such as Ag, Al, Ar, and Zr to provide ease of use in quickly locating the data by using the chemical formula. The compound name and chemical abstracts registry number (CAS No) are also provided in tabular form. Values for regression coefficients are given in the adjacent columns. The temperature range for use is also given in the columns (TMIN and TMAX). The equation should not be used for temperatures outside this range. The next column provides the code for the tabulation. The last three columns provide values for liquid viscosity at representative temperatures. For liquid viscosities, the experimental data for inorganics is very limited or scarce when compared to that available for organics. The estimation methods for inorganics are also very limited or scarce in comparison to organics. Thus, in the absence of experimental data and the scarcity of estimation methods, the estimates for inorganics should be considered as very rough approximations. A comparison of calculated and data values is also given for a representative compound. The graph shows favorable agreement of equation and data.