论文部分内容阅读
The co-oxidation of As(III) and Fe(II) in acidic solutions by pressured oxygen was studied under an oxygen pressure between 0.5 and 2.0 MPa at a temperature of 150℃. It was confirmed that without Fe(II) ions, As(III) ions in the solutions are virtually non-oxidizable by pres-sured oxygen even at a temperature as high as 200℃ and an oxygen pressure up to 2.0 MPa. Fe(II) ions in the solutions did have a catalysis effect on the oxidation of As(III), possibly attributable to the production of such strong oxidants as hydroxyl free radicals (OH·) and Fe(IV) in the oxida-tion process of Fe(II). The effects of such factors as the initial molar ratio of Fe(II)/As(III), initial pH value of the solution, oxygen pressure, and the addition of radical scavengers on the oxidation efficiencies of As(III) and Fe(II) were studied. It was found that the oxidation of As(III) was lim-ited in the co-oxidation process due to the accumulation of the As(III) oxidation product, As(V), in the solutions.