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本文研究了pH、Fe(Ⅲ)和柠檬酸初始浓度、陪伴阳离子等溶液因素对Fe(Ⅲ)-柠檬酸络合物光还原Cr(Ⅵ)的影响,并测定了不同pH条件下,Fe(Ⅲ)-柠檬酸络合物光解过程中,Fe(Ⅱ)的生成数量。此外,还比较了不同Fe(Ⅲ)-有机酸络合物光还原Cr(Ⅵ)反应速率大小。结果表明,低pH条件有利于柠檬酸-Fe(Ⅲ)络合物光还原Cr(Ⅵ)。同时,增加柠檬酸或Fe(Ⅲ)的初始浓度将提高Cr(Ⅵ)的光还原比例。Al(Ⅲ)或Cu(Ⅱ)的存在将抑制柠檬酸-Fe(Ⅲ)络合物光还原Cr(Ⅵ),且其浓度越高,抑制作用越明显。三种Fe(Ⅲ)-有机酸络合物光还原Cr(Ⅵ)反应速率有如下大小顺序:酒石酸>柠檬酸>苹果酸。此外,三种Fe(Ⅲ)-有机酸络合物光降解过程中,Fe(Ⅱ)的生成数量也表现类似大小顺序。
In this paper, the effects of pH, Fe (Ⅲ) and initial concentration of citric acid on the photocatalytic reduction of Cr (Ⅵ) with Fe (Ⅲ) -citrate complex were studied. The effects of pH, Fe Ⅲ) - The amount of Fe (Ⅱ) formed during the photolysis of citric acid complex. In addition, the reaction rate of Cr (Ⅵ) with different Fe (Ⅲ) - organic acid complexes was also compared. The results show that low pH conditions favor the photoreduction of Cr (Ⅵ) by citric acid-Fe (Ⅲ) complex. At the same time, increasing the initial concentration of citric acid or Fe (III) will increase the photoreduction ratio of Cr (Ⅵ). The presence of Al (Ⅲ) or Cu (Ⅱ) will inhibit the photoreduction of Cr (Ⅵ) by the citric acid-Fe (Ⅲ) complex, and the higher the concentration, the more obvious the inhibition will be. The reaction rates of three kinds of Fe (Ⅲ) - organic acid complexes for photoreduction of Cr (Ⅵ) are as follows: tartaric acid> citric acid> malic acid. In addition, during the photodegradation of Fe (Ⅲ) -organic acid complexes, Fe (Ⅱ) generation also showed similar order of magnitude.