Study on Treating Stench Wastewater Containing Dodecyl Mercaptan by Electrolyzing Sodium Sulfate Solution
This paper suggests a technological process to oxidize stench sulfide wastewater containing dodecyl mercaptan with electrolyzing Na2SO4 in the presence of active carbon. Preliminary experiments were conducted and good results were obtained. Under the condition that electrolyzing 1%(m/V)Na2SO4 with 1A current and the reaction temperature remains 30 and the reaction time lasts 10 ~ 30 s, the stench dodecyl mercaptan was eliminated.
Electrochemical Destruction of Aniline and 4‐Chloroaniline for Wastewater Treatment Using a Carbon‐PTFE O 2 ‐ Fed Cathode
The electrochemical degradation of 100 ppm aniline and 4-chloroaniline in basic aqueous solutions of pH ranging between 10.1 and 12.7 has been studied at constant current intensity using a Pb/PbO{sub 2} anode and a carbon-polytetrafluoroethylene O{sub 2}-fed cathode. Under these conditions, hydrogen peroxide was electrogenerated in the cell via a two-electron reduction of oxygen gas fed to the cathode. The current efficiency for H{sub 2}O{sub 2} generation depended on the applied current intensity and the background electrolyte used. The concentration decay for each contaminant with electrolysis time was followed by high pressure liquid chromatography (HPLC). Kinetic analysis of these data showed a pseudo first-order decomposition reaction for both substrates at anodic current densities of 30 mA cm{sup {minus}2} or higher, as well as a decrease, of their half-lifetimes when current intensity increased. A gradual decrease in total organic carbon (TOC) for 0.05 mol/dm{sup 3} NAOH solutions with electrolysis time was always found. Product analysis of these electrolyzed solutions by gas chromatography-mass spectroscopy (GC-MS) and HPLC allowed the detection of nitrobenzene and 1-chloro-4-nitrobenzene proceeding from the anodic decomposition of aniline and 4-chloroaniline, respectively. Maleic acid was also detected as intermediate and ammonia was found as final product. Destruction of initial pollutantsmore » and intermediates is explained by their oxidative reactions with OH and HO{sub 2} radicals at the anode reaction layer. The effect of HO{sub 2} upon decomposition pathways of anilines is discussed.« less
Numerical tools applied to power reactor noise analysis
In order to be able to calculate the space- and frequency-dependent neutron noise in real inhomogeneous systems in two-group theory, a code was developed for the calculation of the Green's function (dynamic transfer function) of such systems. This paper reports on the development as well as the test and application of the numerical tools employed. The code that was developed yields the space-dependence of the fluctuations of the neutron flux induced by fluctuating properties of the medium in the two-group diffusion approximation and in a two-dimensional representation of heterogeneous systems, for both critical systems and non-critical systems with an external source. Some applications of these tools to power reactor noise analysis are then described, including the unfolding of the parameters of the noise source from the induced neutron noise, measured at a few discrete locations throughout the core. Other concrete applications concern the study of the space-dependence of the Decay Ratio in Boiling Water Reactors, the noise-based estimation of the Moderator Temperature Coefficient of reactivity in Pressurized Water Reactors, the modeling of the beam- and shell-mode core-barrel vibrations in Pressurized Water Reactors, and the investigation of the validity of the point-kinetic approximation in subcritical systems driven by an external source. In most of these applications, calculations performed using the code are compared with at-power plant measurements. Power reactor noise analysis applications of the above type, i.e. core monitoring without disturbing plant operation, is of particular interest in the framework of the extensive program of power uprates worldwide.