title: Mechanism of oxidation of 3-hydroxy-2,7-naphthalenedisulfonic acid disodium salt with oxygen in subcritical water.
abstract: The article presents the results of studies on the oxidation mechanism of 3-hydroxy-2,7-naphthalenedisulfonic acid disodium salt (R-salt) with oxygen in subcritical water. To this aim, a series of experiments were carried out which showed that at a temperature of 413 K and pH > 9 the oxidation reaction of a substrate with oxygen was relatively quick and after approximately 40 min the R-salt oxidation yield exceeded 95%. In an acidic medium (pH < 7), the rate of R-salt oxidation is small. In order to identify the mechanism of R-salt oxidation, experiments were carried out at 413-569 K in solutions with pH = 10.0 and at partial oxygen pressure pO2= 1.73 MPa. As a result of these experiments, a stable oxidation product was isolated from the reaction mixture and subjected to spectroscopic analysis. The analysis ofHNMR of this product proved that a stable intermediate product of R-salt oxidation was 4-sulfophthalic acid sodium salt. The results of the experiments have shown that destructive oxidation of R-salt can easily be obtained at a temperature of 413 K, but satisfactory reduction of TOC in wastewater containing this substrate requires the use of very high temperature: at 569 K only 60% reduction of TOC was achieved.
authors.affiliation: Faculty of Process and Environmental Engineering, Lodz University of Technology, Poland. Electronic address: imbier@wipos.p.lodz.pl.
authors.forename: Mirosław
authors.initials: M
authors.lastname: Imbierowicz
mesh_terms: D052918:Environmental Restoration and Remediation / Q000379:methods*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D009282:Naphthalenesulfonates / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D012492:Salts; D062065:Wastewater / Q000737:chemistry; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D009282:Naphthalenesulfonates; D010100:Oxygen; D012492:Salts; D062065:Wastewater; D014867:Water; D014874:Water Pollutants, Chemical; C026496:2-naphthol-3,6-disulfonic acid
keywords: 3-hydroxy-2,7-naphthalenedisulfonic acid disodium salt; R-salt; Reaction mechanism; Wet oxidation