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°C. It was confirmed that without Fe(II) ions, As(III) ions in the solutions are virtually non-oxidizable by pressured oxygen even at a temperature as high as 200°C 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 oxidation 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 limited in the co-oxidation process due to the accumulation of the As(III) oxidation product, As(V), in the solutions.

中文翻译：

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酸性溶液中加压氧对砷（III）和铁（II）离子的共氧化

在150℃的温度下，在0.5至2.0 MPa的氧气压力下，研究了加压氧气在酸性溶液中As（III）和Fe（II）的共氧化。已经证实，即使没有Fe（II）离子，溶液中的As（III）离子甚至在高达200℃的温度和高达2.0MPa的氧气压力下也几乎不能被加压的氧气氧化。溶液中的Fe（II）离子确实对As（III）的氧化具有催化作用，这可能归因于Fe的氧化过程中产生了强氧化剂，例如羟基自由基（OH·）和Fe（IV） （II）。Fe（II）/ As（III）的初始摩尔比，溶液的初始pH值，氧气压力以及自由基清除剂的添加等因素对As（III）和Fe（II）的氧化效率的影响）进行了研究。