• Analytical Science and Technology
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• v.14 no.1
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• pp.72-79
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• 2001

Oxidative decomposition of 2, 4, 6-trichlorophenol(TCP) was studied in aqueous solution. Iron and manganese protoporphyrin [or tetrakis(p-carboxyphenylporphyrin)] and their polymer supported derivatives were used as catalysts, and $KHSO_5$ and tert-butyldroperoxide(TBHP) as oxidants. Metalloporphyrin itself shows very poor catalytic activity in oxidative decomposition of TCP with oxidant. However, very high catalytic activity was observed when metalloporphyrin was chemically bound to newly synthesized polymers or XAD2 resin. Additionally, it revealed much higher catalytic activity in the presence of water-soluble polymers having a electron-donating axial ligand such as pyridine and immidazole. Maleic acid and chloromaleic acid were found in the resulting solution by ESI-MS. Especially, XAD2-supported metalloporphyrins can be reused as catalysts due to insolubility to solvent, and stability against oxidant.

• Tribology and Lubricants
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• v.33 no.5
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• pp.228-233
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• 2017

Chemical Mechanical Polishing of chemically stable sapphire substrates is dominantly affected by the mechanical processing of abrasives, in terms of the material removal rate. In this study, we investigated the effect of electrostatic force between the abrasives and substrate, on the polishing. If potassium chloride (KCl) is added to slurry, water molecules are decomposed into $H^+$ and $OH^-$ ions, and the amount of ions in the slurry changes. The zeta potential of the abrasives decreases with an increase in the amount of $H^+$ ions in the stern layer; consequently, the electrostatic force between the abrasives and substrate decreases. The change in zeta potential of abrasives in the slurry is affected by the slurry pH. In acidic zones, the amount of ions bound to the abrasives increases if the amount of $H^+$ ions is increased by adding KCl. However, in basic zones, there is no change in the corresponding amount. In acidic zones, zeta potential decreases as molar concentration of potassium increases; however, it does not change significantly in basic zones. The removal rate tends to decrease with increase in molar amount of potassium in acidic zones, where zeta potential changes significantly. However, in basic zones, the removal rate does not change with zeta potential. The tendencies of zeta potential and that of the frictional force generated during polishing show strong correlation. Through experiments, it is confirmed that the contact probability of abrasives changes according to the electrostatic force generated between the abrasives and substrate, and variation in removal rate.