UV-Fenton体系处理准好氧矿化垃圾床渗滤液尾水中难降解有机物

采用紫外(UV)耦合Fenton反应产生活性氧物种降解准好氧矿化垃圾床渗滤液尾水中的难降解污染物.考察了初始pH值、双氧水和二价铁(Fe~(2+))投加量对污染物去除效能的影响,并采用醇类猝灭实验和三维荧光技术解析了体系产生的主要活性氧物种及其腐殖质的降解机制.结果表明,UV-Fenton体系可协同、有效地处理准好氧矿化垃圾床渗滤液尾水中的污染物.增大双氧水和二价铁投加量可提高体系降解有机物的能力与反应速率,初始pH值为3.0时有机物降解效果最佳,中性与碱性环境均会显著抑制体系对有机物的降解.在H_2O_2投加量为0.084 mol·L~(-1),Fe~(2+)投加量为0.056 mol·L~(-1),初始pH值为3.0的条件下,渗滤液尾水COD去除率与反应速率常数最终分别为77.22%和0.04679.经UV-Fenton体系处理后,得益于体系主要的活性氧物种·OH与O■对渗滤液尾水中芳香类有机物质的有效降解,同时,可见区荧光峰值降低了51.00%,紫外区荧光峰值先增大后减小.因此,渗滤液中大分子物质大幅减少,小分子物质相对增多.

Treatment of recalcitrant organics of semi-aerobic aged refuse bioreactor leachate tail water by UV-Fenton process

In this study, ultraviolet (UV)-coupled Fenton process was used to produce reactive oxygen species (ROS) to degrade refractory organic pollutants in leachate tail water from semi-aerobic aged refuse bioreactor (SAARB). The effects of initial pH value, H₂O₂ dosage, and Fe²⁺ dosage on removal efficacy of organic matter were investigated. In addition, alcohol quenching experiments were carried out to identify predominant ROS in the UV-Fenton process. Three-dimensional excitation and emission (3D-EEM) spectra were used to reveal the degradation mechanism of humic substances by UV-Fenton process. Results showed that UV-Fenton process was able to co-efficiently and effectively degrade organic pollutants in leachate tail water from SAARB. Removal efficacies of organic matter can be greatly enhanced by increasing H₂O₂ and Fe²⁺ dosages. Acidic ambient (especially pH=3.0) favored treatment efficacy, but neutral and base ambient depressed the treatment efficacy. Under conditions of initial pH=3.0, H₂O₂ dosage 0.084 mmol·L^-1, and Fe²⁺ dosage 0.056 mmol·L^-1, the removal efficiency and removal rate of COD were 77.22% and 0.04679, respectively. Owing to the contribution of ·OH and O₂^·-, aromatic substances in leachate tail water were greatly degraded. Meanwhile, the fluorescent peak value of fulvic substances in visible light region decreased by 51.00%, and the fluorescent peak value of fulvic substances in ultraviolet light region increased at first and then decreased, leading to a significant content decrease of macromolecular organic matters and an increase of small organic matters.