Effects of reaction conditions on nuclear laundry water treatment in Fenton process

This study presents the efficiency of Fenton process in the degradation of organic compounds of nuclear laundry water. The influence of Fe(2+) and hydrogen peroxide ratio, hydrogen peroxide dose, pH and treatment time were investigated. The degradation of non-ionic surfactant and other organic compounds was analysed as COD, TOC and molecular weight distribution (MWD). The most cost-effective degradation conditions were at H(2)O(2)/Fe(2+) stoichiometric molar ratio of 2 with 5 min mixing and H(2)O(2) dose of 1000 mg l(-1). With the initial pH of 6, the reductions of COD and TOC were 85% and 69%, respectively. However, the removal of the organic compounds was mainly carried out by Fenton-based Fe(3+) coagulation rather than Fenton oxidation. Fenton process proved to be much more efficient than previously performed ozone-based oxidation processes.     

Template-free synthesis of beta-In2S3 superstructures and their photocatalytic activity

In this article, we have successfully fabricated various morphological beta-Indium sulfide (In2S3) superstructures by using indium thiocyanate complex at acidic pH. All the synthesis has been performed by a template-free, hydrothermal method at 195 degrees C for 3 h. The photocatalytic activity of synthesized In2S3 have been investigated by using UV-B (lamda = 365 nm) light with Methyl Orange dye as a model pollutant. The synthesized photocatalyst was characterized by using XRD, FE-SEM, HR-TEM, DRS spectra and nitrogen adsorption analysis. The influence of indium precursors and solvents on the morphology as well as the surface properties has also been discussed. The XRD result shows that cubic phase beta-In2S3 formed under all experimental conditions. A plausible mechanism of the In2S3 microsphere formation has been discussed based on experimental observations.     

Stamp transferred suspended graphene mechanical resonators for radio frequency electrical readout

We present a simple micromanipulation technique to transfer suspended graphene flakes onto any substrate and to assemble them with small localized gates into mechanical resonators. The mechanical motion of the graphene is detected using an electrical, radio frequency (RF) reflection readout scheme where the time-varying graphene capacitor reflects a RF carrier at f = 5-6 GHz producing modulation sidebands at f ± f(m). A mechanical resonance frequency up to f(m) = 178 MHz is demonstrated. We find both hardening/softening Duffing effects on different samples and obtain a critical amplitude of ~40 pm for the onset of nonlinearity in graphene mechanical resonators. Measurements of the quality factor of the mechanical resonance as a function of dc bias voltage V(dc) indicates that dissipation due to motion-induced displacement currents in graphene electrode is important at high frequencies and large V(dc).     

Landau–Zener Interferometry in a Cooper-Pair Box

In a driven system, a sequence of Landau–Zener transitions occur, and they may interfere with each other. We present experimental evidence of quantum interference effects in a superconducting charge qubit, a Cooper-pair box, where the LZ tunneling occurs at the charge degeneracy. By employing weak capacitive monitoring, we observe interference between consecutive LZ tunneling events.     

Ozonation for the Degradation of Organic Compounds from Nuclear Laundry Water

In this study, the efficiency of ozone to degrade organic compounds of nuclear laundry water was studied at different pH and temperatures and at elevated temperature with hydrogen peroxide. The degradation of non-ionic surfactant and other organic compounds was analyzed by COD, TOC, BOD and molecular weight distribution measurements. Zeta potential measurements were also performed in order to interpret the obtained results. The most favorable degradation conditions were at pH 7 with 43%, 34% and 61% reductions of COD, TOC and BOD, respectively.     

Deactivation of a Pt/Silica–Alumina Catalyst and Effect on Selectivity in the Hydrocracking of n-Hexadecane

The deactivation behavior of a bifunctional catalyst consisting of platinum on amorphous silica–alumina was studied in the hydrocracking of n-hexadecane. The initial decline in activity and the change in selectivity were monitored at the following reaction conditions: pressure = 30 bar; temperature = 310 °C; hydrogen-to-hexadecane feed molar ratio = 10. Initially, hexadecane conversion and selectivity to cracking products decreased rapidly with time-on-stream, and stabilized after 40 h on stream. This could be related to an initial loss of metal surface area, which decreased the activity of monofunctional hydrogenolysis generating cracking products. The acidic function seemed to be unaffected under these reaction conditions. The stable catalyst was exposed to a lower hydrogen-to-hexadecane ratio to accelerate deactivation by coking. A decline in the activity of both functions was observed. The activity of the acidic function could be almost completely recovered by oxidative regeneration, while the metal activity was only partially recovered.     

Field evaluation of a new particle concentrator- electrostatic precipitator system for measuring chemical and toxicological properties of particulate matter

Background  

A newly designed electrostatic precipitator (ESP) in tandem with Versatile Aerosol Concentration Enrichment System (VACES) was developed by the University of Southern California to collect ambient aerosols on substrates appropriate for chemical and toxicological analysis. The laboratory evaluation of this sampler is described in a previous paper. The main objective of this study was to evaluate the performance of the new VACES-ESP system in the field by comparing the chemical characteristics of the PM collected in the ESP to those of reference samplers operating in parallel.     

Optimizing Graphene Oxide Encapsulated TiO2 and Hydroxyapatite; Structure and Biological Response

Nanocomposites based on hydroxyapatite (HAP) are fabricated with/without combining titanium oxide (TiO₂) and graphene oxide. Structure investigation was done for all compositions using X-ray diffraction (XRD), Fourier-transform infrared in addition to X-ray photoelectron to study the chemical compositions of the obtained nanocomposites. The surface morphology investigation was done with the scanning electron microscope and transmission electron microscope. In this regard, TiO₂ nanoparticles were exhibited in spherical shapes, while HAP was detected as nanorods. The dimensions of HAP have been decreased from 53 and 18 to 27 and 10 nm for length and diameter, respectively. The crystallite sizes obtained from XRD data are around 15 and 33 nm for HAP and TiO₂ respectively. Moreover, the diameter of TiO₂ reached 80 nm. Further, the average roughness parameter (R_a) improved from 9.2 to 11.1 nm from HAP to TNC. Besides, the root mean square (R_q), maximum height of the roughness (R_t), and maximum roughness valley depth (R_v) increased to 14.7, 104, and 55.9 nm, respectively. Furthermore, cell viability enhanced from 96.3?±?3 to 102.4?±?3%. Besides, the antibacterial behavior improved to be 15.3?±?1.3 and 14.2?±?0.9 mm for TNC against E. coli and S. aureus respectively.