| As the continuing development of human society and the frequent human activities, a large amount of degradation-resistance toxicants produced by industrious and agricultural activities have been discharged to the water body, the conventional waste water treatment methods, however, have been hardly to meet the need of pollutant removal. Fenton oxidation technology has been proved as an effective way to address the issue of degradation-resistance toxicants removal, however, this system is haunted with some manifest flaws which can only be operated in a low pH circumstance, moreover, the secondary pollution may occur as the creation of iron mud. The modification of Fenton oxidation technology has become the hottest topic of this filed. Bisphenol A(BPA) is a new emerging degradation-resistance endocrine disrupter which may cause many kinds of diseases. Nowaday, the appearance of BPA in human’s food is rising people’s awareness towards health risks.EDDS is a kind of eco-friendly metal chelating agent, magnetite is a good solid catalyst, in this paper, EDDS and magnetite would be applied to heterogeneous photo-Fenton system, to study the degradation effect of this system on BPA. the main experimental content and results have been outlined below:(1) The adsorption experiment was conducted by adsorbing the BPA onto the magnetite under different conditions, as the results indicate, in a certain range, the adsorption rate is relatively low. The removal rate will increase as the augment of the dosage of magnetite; If the dosage of magnetite remain unchanged, the removal rate will be decreased along with the increase of the initial concentration of BPA; when pH value is neutral, the adsorption effect tend to become better.(2) The results of the experiment of BPA degradation by EDDS+ magnetite +photo-Fenton system indicate, the optimum condition for the degradation of BPA is:the dosage of magnetite is 0.2 g/L, the concentration of H2O2 is 0.5mmol/L and EDDS is 0.1mmol/L respectively, pH is set as 6.3. under this condition, the removal rate of BPA can reach as high as 70.5%; through conducting a kinetic analysis on the BPA sewage degraded by the catalytic oxidation system, a conclusion can be made that the degradation reaction of BPA solution in such system fits the first-order kinetic formula well.(3) Through conducting the degradation experiments of BPA under the circumstance of pH=6.3 in different systems (photo+magnetite+H2O2+ EDDS, magnetite+H2O2+EDDS, photo+magnetite+H2O2, magnetite+ H2O2) a summary can be made:The treatment effect of photo+magnetite+ H2O2+EDDS system to BPA is better than others, namely, The addition of EDDS gives obvious improvement for BPA removal by heterogeneous photo-Fenton system.(4) Based on the experiment of bisphenol A degradation by EDDS+ magnetite +photo-Fenton system, through detecting the contribution rate of hydroxyl radical and the proportion of total iron under different pH conditions(3.5,6.3,9.0), a conclusion can be made:under the same pH environment, the dissolving-out quantity of iron in solution which exposed to the light is much higher than that of non-lighting condition; when pH=3.5, a considerable enhance in the dissolving-out quantity of iron can easily be spotted, after 11 hours, the dissolving-out quantity had reached 30.1umol/L, which is much higher than in the pH circumstance of 6.3,9.0; when pH=6.3,the contribution rate of hydroxyl radical to bisphenol A peaked at 78.2%; however, the contribution rate has also surpassed 70% under the pH condition of 3.5 and 9.0, hence, the oxidation of ·OH play the dominant role in this reaction system. |
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