| 草酸根对α-FeOOH多相UV-Fenton催化能力的增效实验 |
| 摘要点击 2291 全文点击 743 投稿时间：2017-06-09 修订日期：2017-09-06 |
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| 中文关键词 α-FeOOH 多相UV-Fenton 草酸根 增效 金橙Ⅱ |
| 英文关键词 α-FeOOH heterogeneous UV-Fenton oxalate enhancement Orange Ⅱ |
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| 中文摘要 |
| 采用均匀沉淀法合成α-FeOOH，并利用XRD、FT-IR、SEM、BET、EDS等仪器进行分析表征.以金橙Ⅱ为目标污染物，研究254 nm紫外光照射下，草酸根对α-FeOOH多相UV-Fenton催化能力的增效实验.结果表明，合成的催化剂为针棒状，无其他杂元素.草酸根对α-FeOOH多相UV-Fenton降解金橙Ⅱ具有显著的增效能力，并在0.4 mmol ·L-1时取得最佳增效效果.在紫外光照射下，初始pH值为3、催化剂用量1 g ·L-1、H2O2浓度10 mmol ·L-1、草酸根浓度0.4 mmol ·L-1时，反应15 min即可对初始浓度为0.2 mmol ·L-1的金橙Ⅱ达到99%以上的脱色效果.对比α-FeOOH多相UV-Fenton体系，其增效率高达116.9%.相同条件下，丙二酸根、乙酸根、EDTA、柠檬酸根对原体系分别有5.2%、8.1%、23.2%、25.7%的抑制率.相同条件下，草酸根增效体系对有机物的矿化速率常数比基础体系提高69.9%，能大大缩短矿化处理所需时间.草酸根增效机制主要是为亚铁离子的生成提供新的光致还原途径，并在反应初期提高铁离子的浓度、增加体系均相反应比重，进而提高体系HO ·的浓度.草酸根增效α-FeOOH多相UV-Fenton体系是一种稳定可靠的方法.增效体系在3次循环之后对金橙Ⅱ的降解仍有101.5%的增效率；反应结束后，草酸根增溶的铁离子能被催化剂重新吸附回表面，避免了催化剂活性组分的流失与铁离子的二次污染. |
| 英文摘要 |
| α-FeOOH was prepared by a symmetrical precipitation method and characterized by XRD, FT-IR, SEM, BET, and EDS techniques. The oxalate enhanced experiment for the catalytic activity of α-FeOOH during the degradation of Orange Ⅱ by the heterogeneous UV-Fenton process was evaluated. The results showed that the rate of Orange Ⅱ degradation in this heterogeneous UV-Fenton system could increase significantly with oxalate as an enhancing reagent, with the peak values of enhanced efficiency reaching 116.9% when the concentration of additional oxalate was 0.4 mmol·L-1. Under this condition, more than 99% of Orange Ⅱ (0.2 mmol·L-1) was degraded in 15 min. However, under the same condition, the inhibition ratios of malonate, acetate, EDTA and citrate were 5.2%, 8.1%, 23.2%, and 25.7%, respectively. Compared with the basic system, the enhanced efficiency of the mineralization rate constant can reach 69.9% when the concentration of additional oxalate was 0.4 mmol·L-1. As a result, the time required for mineralization could be reduced greatly. In the heterogeneous UV-Fenton system, the additional oxalate could provide a new photo-reduction pathway for Fe3+ to Fe2+, enhancing the ratio of the homogeneous UV-Fenton process by increasing the Fe leaching of α-FeOOH and the concentration of hydroxyl radicals, leading to higher degradation efficiency of Orange Ⅱ. As a result, an enhancement effect of 101.5% could be obtained even after three cycles. The iron ions leached from catalysts could be re-adsorbed after treatment, avoiding the loss of active species from catalysts and additional pollution caused by iron ions. The results indicated that additional oxalate was a stable and reliable enhancing reagent on the catalytic activity of α-FeOOH in the heterogeneous UV-Fenton system. |
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