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In this study, the UV-Fenton process was used to treat a spent electroless nickel plating bath, and to recover high purity ferric phosphate which could be used as a raw material in lithium ferric phosphate batteries. The effects of different parameters such as the H2O2 dosage, the H2O2 and Fe2+ feeding modes and the initial temperature on the treatment efficiency of the process were investigated. The results indicated that the UV-Fenton process could effectively remove the chemical oxidation demand by about 96.1%. Meanwhile, the phosphate produced from the complete oxidation of hypophosphite and phosphite was recovered as a precipitation of ferric phosphate. According to the results, about 99.9% of the phosphorus in the spent electroless nickel plating bath can be recovered. Recovered ferric phosphate particles were high in purity and nanometer-sized. This method utilizes relatively clean and economical reagents in the recovery of phosphorus resources, and does not generate hazardous substances. It will provide a new green method for the spent electroless nickel plating bath treatment. [ABSTRACT FROM AUTHOR]

Hazardous organic wastes from industrial, military, and commercial activities represent one of the greatest challenges to human beings. Advanced oxidation processes (AOPs) are alternatives to the degradation of those organic wastes. However, the knowledge about the exact mechanisms of AOPs is still incomplete. Here we report a phenomenon in the AOPs: induced effects, which is a common property of combustion reaction. Through analysis EDTA oxidation processes by Fenton and UV-Fenton system, the results indicate that, just like combustion, AOPs are typical induction reactions. One most compelling example is that pre-feeding easily oxidizable organic matter can promote the oxidation of refractory organic compound when it was treated by AOPs. Connecting AOPs to combustion, it is possible to achieve some helpful enlightenment from combustion to analyze, predict and understand AOPs. In addition, we assume that maybe other oxidation reactions also have induced effects, such as corrosion, aging and passivation. Muchmore research is necessary to reveal the possibilities of induced effects in those fields. [ABSTRACT FROM AUTHOR]

The destruction of low concentration of toluene (0-30 ppm) has been studied under the UV/photogenerated O3/MnO2-impregnated granular activated carbon (MnO2-impregnated GAC) process by the combination of self-made high frequency discharge electrodeless lamp (HFDEL) with MnO2-impregnated GAC catalyst. Experimental results showed that the initial toluene concentration can strongly affect the concentration of photogenerated O3 from HFDEL and the efficiency and mass rate of destruction of toluene via HFDEL/MnO2-impregnated GAC system. Active oxygen and hydroxyl radicals generated from HFDEL/MnO2-impregnated GAC system played a key role in the decomposition of toluene process and the intermediates formed by photolysis are more prone to be mineralized by the subsequent MnO2-impregnated GAC catalyst compared to the original toluene, resulting in synergistic mineralization of toluene by HFDEL/MnO2-impregnated GAC system. The role of MnO2-impregnated GAC catalyst is not only to eliminate the residual O3 completely but also to enhance the decomposition and mineralization of toluene. [ABSTRACT FROM AUTHOR]

This study examined the photocatalytic degradation efficiency under high UV photon flux (intensity normalized by photon energy) irradiation; the incident UV photon flux was 1.71 x 10-6-3.13 X 10-6 einstein cm-2 s-1 made by a super high-intensity UV apparatus. A comparative study between high photon flux photocatalytic process and routine low photon flux photocatalytic process for methylene blue degradation has been made in aqueous solution. The experimental results showed that under the best conditions of high UV photocatalytic reaction 99% decolorization and 95% TOC removal of 20mg L-1 methylene blue could be achieved in 30 s and 120 s of UV irradiation time, respectively. To the best of our knowledge, photocatalytic decolorization and photocatalytic degradation of dyes in such a short time has not been reported. Aiming at the low photonic efficiency in high photon flux photocatalytic process, we found that reducing the density of excited electron-hole appropriately could improve initial apparent photonic efficiency effectively. The TOC experiments under high UV photon flux showed a faster mineralization rate and a different mineralization process compared to that under low UV photon flux. [ABSTRACT FROM AUTHOR]