Solution plasma processing, a reaction field available for chemical engineering, has high chemical activity because of its high electron temperature in the liquid, but low gas temperature. Consequently, it supplies activated species from plasma to liquid phases. Therefore, solution plasma has been anticipated for application to chemical processes such as synthesis of metal nanoparticles, and as a water treatment for sterilization and waste. We sought to synthesize silica by solution plasma, and to examine the effects of pH in the solution on the morphology and the chemical bonding state. Aqueous solutions containing tetraethoxysilane (TEOS) and ethanol were used as starting solutions. Then HCl or DEA (2.2'-iminodiethanol) was added to the solution to adjust the pH. The obtained materials were evaluated using scanning electron spectroscopy (SEM) and nuclear magnetic resonance (NMR). The morphology changes were observed as a two-dimensional tabular structure in an acid state, three-dimensional spherical structure in a base state, and two-dimensional and three-dimensional mixed structures in a neutral state. These structures originate mainly from the chemical bonding state of Si(OR)3(OSi), Si(OR)2(OSi)2 in an acid state, Si(OR)1(OSi)3, Si(OSi)4 in a base state, and Si(OR)2(OSi)2 and Si(OR)(OSi)3 in a neutral state.
Wastewater containing 1,4-dioxane and detergent from metal washing processes was treated using UV ozone oxidation and ion exchange resin. The chemically stable 1,4-dioxane was decomposed easily and quickly by UV ozone oxidation. The oxidized water was deionized using ion exchange resin by applying a mixed bed resin system. The electric conductivity of the effluent from the ion exchange resin column was less than 1.2 μS cm－1. COD（Chemical Oxygen Demand）and TOC（Total Organic Carbon）, which indicate organic matter contents, were 1.0 mg dm－3 and 0.15 mg dm－3, respectively. This purified water is reusable as rinsing water during surface finishing. Based on these experiments, we devised a practical recycling system by which contaminated wastewater can be decontaminated and reused as purified water on an industrial scale at a surface finishing factory. A salient benefit of this combined process （UV ozone oxidation and ion exchange resin method）is that it uses no chemicals and that it entails no production of salts that must be removed before using the treated water. These results suggest that this process causes no secondary pollution, and that it has a high probability of practical application as recycling water during surface finishing.
We investigated oxidation and reduction responses of hydrogen peroxide using a carbon electrode with platinum particles deposited by cathodic reduction of cis-diamminedichloroplatinum（II）（cisplatin）. Platinum deposition led to a marked increase of oxidation and reduction currents for hydrogen peroxide compared to currents observed using the carbon electrode without platinum. The reduction response is particularly useful for determination of cisplatin because the electrochemical reaction forms no bubbles.