The present work studied the formation of ultra fine metal particles (UFPs) by feeding a solution of nickel acetate tetrahydrate into RF plasma using a two liquid atomizing spray nozzle. X-ray diffraction and TEM observation revealed that the UFPs produced by this method were isolated spherical metal nickel particles with a narrow particle size distribution. It was shown that the nickel acetate tetrahydrate was a suitable raw material for the production of metal nickel UFPs using liquid spraying method.

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Filtration behaviors of sewage secondary effluent pretreated with flocculant were studied under constant filtration rate condition using ceramic microfiltration membranes. The process consisted of the periodic operations of the filtration (fouling) and backwashing (cleaning) cycles. The system was capable of selecting two modes of membrane backwashing, i. e., physical backwashing or chemically enhanced backwashing. The time dependency of pressure drop across the filter cake in an operating cycle mainly due to the cake build-up was well described by the constant rate filtration equation for the compressible filter cake, and the increase with the cycle number in pressure drop across the membrane mainly due to the pore blocking was adequately correlated by the intermediate blocking law. Our experimental data clearly showed that the combined operation of physical and chemically enhanced backwashing was highly effective for the filtration of sewage secondary effluent when accompanied by the flocculation operation. The increased dosage of flocculant substantially reduced the cake resistance and irreversible pore plugging. Particularly, less frequent physical backwashing by addition of flocculant led to an increase in the average filtration rate.

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Polyvinyl chloride (PVC) powders with various chlorine (Cl) contents (49.5, 56.7, 64.0 and 69.5%) were mixed with NaOH pellets at a different Na/Cl molar ratio, and the mixture was ground in air by a planetary ball mill in order to investigate the mechanochemical (MC) dechlorination. The MC reaction formed NaCl and partially dechlorinated PVC in the product as the grinding progressed. The reaction rate increased at a higher Clcontent in the PVC, because of enhanced contact frequency between Cl and Na in solid phase during the grinding. The extent of dechlorination increased with Na/Cl molar ratio at a low Clcontent (49.5 and 56.7%), while it decreased with Na/Cl molar ratio at a high Clcontent (64.0% and 69.5%). This is because water generated by the grinding changed the powder into a paste, which hindered the dechlorination. The molar ratio of Na/Cl would be one of the most important factors for dechlorination at a high Clcontent.

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