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Homogeneous photocatalytic degradation of azo dye Reactive Black 5 using Fe(III) ions under visible light
Environmental Technology ( IF 2.8 ) Pub Date : 2020-06-20 , DOI: 10.1080/09593330.2020.1782995
Shailaja P Sadhu 1 , J P Ruparelia 2 , Upendra D Patel 1
Affiliation  

ABSTRACT

Efficient and cost-effective method to destroy complex dyes is warranted to combat increasing water pollution. In the present study, homogeneous photocatalytic oxidation (PCO) of Reactive Black 5 (RB5) dye was studied using ferric ions (Fe(III)) under visible light (VL) irradiation and sunlight (SL). In the presence of 5 mM ferric ions and at pH 2.6, more than 80% of initial 20 mg/L RB5 was decolourized in 60 min under artificial VL. Decolourization followed pseudo first-order kinetics with the reaction rate constant 0.0356 min−1. 79% of initial COD was removed at the end of 60 min, suggesting mineralization of RB5 as the main cause of decolourization. Using similar experimental conditions under SL, more than 90% RB5 was decolourized in 15 min with an almost 10-fold increase in the reaction rate constant (0.34 min−1). Rate and extent of RB5 destruction significantly decreased in the presence of •OH scavenger indicating photoreduction of Fe-hydroxo species and generation of •OH as the main mechanism of RB5 degradation. RB5 removal increased from ca. 30% to 84% with the increase in Fe(III) concentration from 0.5 to 5 mM. The corresponding 1st-order rate constants increased linearly from 0.006 to 0.036 min−1. RB5 degradation decreased linearly (R2 = 0.98) from 91.7% to 63.3% with the increase in initial RB5 concentration from 10 to 40 mg/L. Fe(III) induced homogenous PCO appears to be a reliable and low-cost method of advanced oxidation without the need for costly reagent such as H2O2.



中文翻译:

可见光下使用 Fe(III) 离子均匀光催化降解偶氮染料 Reactive Black 5

摘要

有必要采用有效且具有成本效益的方法来破坏复杂的染料,以对抗日益严重的水污染。在本研究中,使用铁离子 (Fe(III)) 在可见光 (VL) 照射和阳光 (SL) 下研究活性黑 5 (RB5) 染料的均相光催化氧化 (PCO)。在存在 5 mM 铁离子和 pH 2.6 的情况下,超过 80% 的初始 20 mg/L RB5 在人工 VL 下在 60 分钟内脱色。脱色遵循准一级动力学,反应速率常数为 0.0356 min -1. 在 60 分钟结束时去除了 79% 的初始 COD,表明 RB5 的矿化是脱色的主要原因。在 SL 下使用类似的实验条件,超过 90% 的 RB5 在 15 分钟内脱色,反应速率常数增加了近 10 倍(0.34 分钟-1)。在•OH 清除剂存在下RB5 破坏的速率和程度显着降低,表明Fe-羟基物质的光还原和•OH 的产生是RB5 降解的主要机制。RB5 去除率从 ca 增加。随着 Fe(III) 浓度从 0.5 到 5 mM 增加,30% 到 84%。相应的一阶速率常数从 0.006 线性增加到 0.036 min -1。RB5 降解线性下降 (R 2 = 0.98) 从 91.7% 到 63.3%,初始 RB5 浓度从 10 增加到 40 mg/L。Fe(III) 诱导的均相 PCO 似乎是一种可靠且低成本的高级氧化方法,无需昂贵的试剂如 H 2 O 2

更新日期:2020-06-20
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