草酸根对α-FeOOH多相UV-Fenton催化能力的增效实验  

Experiment to Enhance Catalytic Activity of α-FeOOH in Heterogeneous UVFenton System by Addition of Oxalate

作　　者：苗笑增 戴慧旺 陈建新[1,2] 蒋柏泉 龚娴 

机构地区：[1]南昌大学鄱阳湖环境与资源利用教育部重点实验室,南昌330031 [2]南昌大学资源环境与化工学院,南昌330031 [3]南昌市环境监测站,南昌330038

出　　处：《环境科学》2018年第3期1202-1211,共10页Environmental Science

基　　金：国家自然科学基金项目(21367021);江西省教育厅自然科学基金项目(GJJ13072);广东省矿物物理与材料研究开发重点实验室合作研究基金项目(GLMPM-001)

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15min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.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 UVFenton system could increase significantly with oxalate as an enhancing reagent,with the peak values of enhanced efficiency reaching116. 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.

关 键 词：Α-FEOOH 多相UV-Fenton 草酸根 增效 金橙Ⅱ 

分 类 号：X703.1[环境科学与工程—环境工程]