Comparative study on treatment of methylene blue dye wastewater by different internal electrolysis systems and COD removal kinetics, thermodynamics and mechanism.

In this study, Fe/Cu, Fe/Al/Cu, Fe/Cu/C and Fe/Al/Cu/C internal electrolysis systems (IESs) were constructed and used to treat methylene blue dye (MB) wastewater. The effects of filler mass ratio, filler dosage, solution pH, reaction time and reaction temperature on COD removal were discussed, while the kinetics, thermodynamics and mechanism of COD removal were also investigated. The results showed that when the COD removal rates were basically the same, the reaction times of Fe/Al/Cu, Fe/Cu/C and Fe/Al/Cu/C IESs were shorter, and the filler dosages were lower. For the four systems, the appropriate pH was around 5, while the suitable reaction temperature was in the range of 20-25 °C. The COD removals of these four IESs were generally greater than 90%. The COD removal processes of the four systems could be better described by the improved pseudo-second-kinetic model, and the liquid film diffusion was the rate-controlling step. Moreover, the COD removal was a spontaneous and endothermic process. MB was degraded into inorganic substances in four steps. In addition, the FTIR characterization of the fillers before and after reaction suggests the four IESs have good stability.

Electrochemical oxidation of Acid Orange 7 azo dye using a PbO2 electrode: Parameter optimization, reaction mechanism and toxicity evaluation.

In this study, electrochemical oxidation of Acid Orange 7 (AO 7) azo dye has been investigated using a Fe-doped PbO2 electrode. The degradation of AO 7 followed pseudo-first-order reaction kinetics. The removals of AO 7, chemical oxygen demand (COD) and total organic carbon (TOC) were 87.15%, 49.88% and 44.94% after 60 min of electrolysis at the optimal conditions (Na2SO4 concentration 0.1 M, initial pH 5, initial AO 7 concentration 100 mg L-1 and applied current density 20 mA cm-2), respectively. And the corresponding degradation rate constant was 0.035 min-1. The intermediates formed during electrochemical process were identified, and a possible degradation pathway was proposed, which was initiated by the oxidation of azo bond (-NN-), hydroxylation and substitution reaction of -NH2 and -SO3H under the attack of OH, and ended with the formation of mineralization products such as NH4+, NO3-, SO42-, CO2 and H2O. The toxicity of treated AO 7 solution towards Vibrio fischeri increased slightly at first and then rapidly reduced to non-toxicity with prolonging time. The results indicate that electrochemical oxidation of AO 7 using Fe-doped PbO2 electrode is a promising way.

[Working conditions and occupational pathology in electrolytic nickel refinery workers].

The working conditions during electrolytic nickel refinery correspond to Class 3, Grade 3-4, which may give rise to health problems in workers of all occupations employed in this production. Their risk and prevalence are significantly higher in the most exposed occupational group, such as electrolysis workers (40.1% of all cases). The structure of occupational diseases is dominated by respiratory diseases (68.8%), mainly due to exposure to aerosols of nickel compounds. It is concluded that working conditions and medical prevention interventions should be improved for this group of workers.

Improved performance of the microbial electrolysis desalination and chemical-production cell using the stack structure.

The microbial electrolysis desalination and chemical-production cell (MEDCC) is a device to desalinate seawater, and produce acid and alkali. The objective of this study was to enhance the desalination and chemical-production performance of the MEDCC using two types of stack structure. Experiments were conducted with different membrane spacings, numbers of desalination chambers and applied voltages. Results showed that the stack construction in the MEDCC enhanced the desalination and chemical-production rates. The maximal desalination rate of 0.58 ± 0.02 mmol/h, which was 43% higher than that in the MEDCC, was achieved in the four-desalination-chamber MEDCC with the AEM-CEM stack structure and the membrane spacing of 1.5mm. The maximal acid- and alkali-production rates of 0.079 ± 0.006 and 0.13 ± 0.02 mmol/h, which were 46% and 8% higher than that in the MEDCC, respectively, were achieved in the two-desalination-chamber MEDCC with the BPM-AEM-CEM stack structure and the membrane spacing of 3mm.

[Issues of occupational health in the aluminium plant with superpower equipment].

Purpose of the research is to provide a hygienic assessment of working conditions at aluminum plants equipped with Central working prebaked (CWPB) cells operating at currents of 330 kA. The studies have indicated that the leading occupational exposures, the levels of which exceed the national standards, are: fluorine compound in the air of work area; unfavorable microclimate, constant magnetic field, the severity of the labour. According to the general hygienic assessment, with account of combined influence harmful occupational factors, the working conditions are attributed to 1-2 degrees of the 3 class of harmful working conditions, that conform to the small (moderate) and significant occupational risk.

Simultaneous treatment of washing, disinfection and sterilization using ultrasonic levitation, silver electrolysis and ozone oxidation.

A new type of ultrasonic washer-disinfector-sterilizer, able to clean, disinfect and sterilize most kinds of reusable medical devices, has been developed by using the ultrasonic levitation function with umbrella-shape oscillators and ozone bubbling together with sterilization carried out by silver electrolysis. We have examined the biomedical and physicochemical performance of this instrument. Prokariotic and gram-negative Escherichia coli and eukariotic Saccharomyces cerevisiae were killed by silver electrolysis in 18 min and 1 min, respectively. Prokariotic and gram-positive Geobacillus stearothermophilus and Bacillus atrophaeus, which are most resistant to autoclave and gas sterilization, respectively, were killed by silver electrolysis within 20 min. Prokariotic and gram-negative Pseudomonas aeruginosa was also killed by silver electrolysis in 10 min. The intensity distribution of the ultrasonic levitation waves was homogeneous throughout the tank. The concentration of ozone gas was 2.57 mg/ kg. The concentration of dissolved silver ions was around 0.17 mg/L. The disulfide bond in proteins was confirmed to be destroyed by silver electrolysis.

Differential electrolytic potentiometric determination of some thiol compounds in their dosage forms.

The application of direct current differential electrolytic potentiometry to an aqueous titration of L-cysteine hydrochloride, captopril and D-penicillamine has been investigated. The basic character of thiol compounds in nitric acid is enhanced to permit their direct titrations with silver nitrate. A pair of silver amalgam electrodes was used as an indicating system. Titration curve shapes obtained are almost symmetrical with sharp peaks. The optimum current density for those titrations was found to be 0.2-2 microA/cm2. The procedure was applied successfully to the determination of certain thiol compounds in drug formulations and the results were favorably compared statistically with those obtained from official methods.

Precise and sensitive determination of nitrite by coulometric backtitration under flow conditions.

A novel method performing for coulometric backtitrations in flow channels was developed, which was applied for the precise and sensitive determination of low concentrations of nitrite. Under acid conditions nitrite is reacting stoichiometrically with hydrazine, the remained excess of which is backtitrated with electrogenerated bromine. The titration course is recorded either amperometrically or chemiluminometrically. Hydrazine can be determined precisely and accurately in the range between 0.1 microM and 1 mM without calibration. Nitrite is reduced by hydrazine according to the reaction 2 NO2- + 2 H+ + NH2-NH2 --> N2O + N2 + 3 H2O. Applying the amperometric and the chemiluminometric end-point location nitrite was determined accurately and precisely in the ranges 0.25-65 microM and 0.10-50 microM, respectively. The method was applied to the determination of nitrite in tap and river water.

[Secretory immunity in workers in electrolysis shops of the nickel- and copper-processing plants]. / Sostoianie sekretornogo immuniteta u rabochikh élektroliznykh tsekhov po proizvodstvu nikelia i medi.

Wide-range screening of workers in shops of electrolytic purification of copper and nickel revealed marked disorders in the local immunity of the mouth which manifested themselves most vividly in the workers exposed to the purification-related copper aerosols. The article narrates on the possible mechanisms of industrial hazards' influence on immunity and non-specific resistance.

Electrolysis and thermolysis for permanent hair removal.

The historical, legal, and theoretical aspects and clinical technics of both electrolysis and thermolysis are critically reviewed. The pitfalls of electronic tweezers and the dangers of self-electrolysis are discussed. Complications of electrolysis and thermolysis and the pathophysiology of hair regrowth are presented. In the United States, the lack of uniform training requirements and standards for electrologists may pose an unrecognized risk to public health. It is suggested that more responsible state legislation be enacted in order to decrease the present potential threat to the public health and safety.