Water Decontamination from Cr(III)-Organic Complexes Based on Pyrite/H2O2: Performance, Mechanism, and Validation
Water Decontamination from Cr(III)-Organic Complexes Based on Pyrite/H2O2: Performance, Mechanism, and Validation
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基于黄铁矿/H2O2 的 Cr(III)-有机配合物的水净化：性能、机理和验证
DOI：
10.1021/acs.est.8b01693
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发表时间：
2018
影响因子：
11.4
通讯作者：
Pan Bingcai
中科院分区：
文献类型：
--
作者：
Ye Yuxuan;Shan Chao;Zhang Xiaolin;Liu Hui;Wang D;an;Lv Lu;Pan Bingcai
芬顿反应是一种广泛应用的降解有毒金属有机络合物的预处理技术。然而，其效率是大大损害的Cr（III）-有机络合物，由于积累更有毒的Cr（VI）和pH值的依赖性。在此，我们提出了一种结合黄铁矿/过氧化氢沉淀过程，以有效地去除铬（III）（最初在10.4毫克铬/L）络合的各种配体（柠檬酸盐，EDTA，草酸盐，酒石酸盐）。黄铁矿/H_2O_2-沉淀法在pH 3 ~ 9的范围内，Cr（VI）含量可忽略不计，Cr <0.3mg/L。而在pH> 5时，ZVI/H2 O2沉淀法处理后，Cr（VI）> 0.5mg/L，Cr（VI）>5 mg/L。在机理上，黄铁矿/H2 O2体系产生大量Fe（II）水溶液引发芬顿反应，同时释放大量H+，使反应pH保持在3.0左右，而与初始pH无关。生成的·OH自由基将Cr（III）氧化成Cr（VI），从而释放出有机配体以进一步矿化。生成的Cr（VI）被Fe（II）和FeS 2水溶液原位还原回Cr（III）。随后，通过沉淀除去所有游离金属离子，包括Cr（III）、Fe（III）和Fe（II）。动力学模型的黄铁矿/H2 O2过程涉及17个反应进行验证所提出的机制。此外，该组合工艺的有效性进一步验证了其令人满意的性能处理真实的制革废水。
Fenton reaction is a widely used pretreatment technology to degrade toxic metal–organic complexes. However, its efficiency is greatly compromised for Cr(III)–organic complexes due to accumulation of more toxic Cr(VI) and pH dependence. Herein, we proposed a combined pyrite/H2O2-precipitation process to efficiently remove Cr(III) (initially at 10.4 mg Cr/L) complexed by various ligands (citrate, EDTA, oxalate, and tartrate). Negligible Cr(VI) and <0.3 mg/L Cr were detected in the effluent treated by pyrite/H2O2-precipitation over a wide pH range of 3–9. In contrast, > 0.5 mg/L Cr(VI) and >5 mg/L Cr remained after treatment by the ZVI/H2O2-precipitaion process at pH0> 5. As for the mechanisms, pyrite/H2O2produced a considerable amount of aqueous Fe(II) to initiate Fenton reaction, concurrently releasing massive H+to keep the reaction pH at ∼3.0 irrespective of the initial pHs. The generated •OH radicals oxidized Cr(III) into Cr(VI) and thereby releasing the organic ligands for further mineralization. The generated Cr(VI) was in situ reduced back to Cr(III) by aqueous Fe(II) and FeS2. Subsequently, all the free metal ions including Cr(III), Fe(III), and Fe(II) were removed via precipitation. Kinetic modeling of the pyrite/H2O2process involving 17 reactions was performed to verify the proposed mechanism. Additionally, the effectiveness of the combined process was further validated by its satisfactory performance in treating authentic tannery wastewater.