废水
化学
阳极
Boosting(机器学习)
铵
阳极氧化
制浆造纸工业
废物管理
环境化学
环境科学
电极
环境工程
计算机科学
工程类
有机化学
物理化学
机器学习
作者
Yan Zhang,Wenjian Kuang,Yu Lei,Weiye Zheng,Hengyi Fu,Han Li,Zhenchao Lei,Xin Yang,Shishu Zhu,Chunhua Feng
标识
DOI:10.1021/acs.est.3c06326
摘要
Mixed metal oxide (MMO) anodes are commonly used for electrochlorination of ammonium (NH4+) in wastewater treatment, but they suffer from low efficiency due to inadequate chlorine generation at low Cl- concentrations and sluggish reaction kinetics between free chlorine and NH4+ under acidic pH conditions. To address this challenge, we develop a straightforward wet chemistry approach to synthesize BiOCl-functionalized MMO electrodes using the MMO as an efficient Ohmic contact for electron transfer. Our study demonstrates that the BiOCl@MMO anode outperforms the pristine MMO anode, exhibiting higher free chlorine generation (24.6-60.0 mg Cl2 L-1), increased Faradaic efficiency (75.5 vs 31.0%), and improved rate constant of NH4+ oxidation (2.41 vs 0.76 mg L-1 min-1) at 50 mM Cl- concentration. Characterization techniques including electron paramagnetic resonance and in situ transient absorption spectra confirm the production of chlorine radicals (Cl• and Cl2•-) by the BiOCl/MMO anode. Laser flash photolysis reveals significantly higher apparent second-order rate constants ((4.3-4.9) × 106 M-1 s-1 at pH 2.0-4.0) for the reaction between NH4+ and Cl•, compared to the undetectable reaction between NH4+ and Cl2•-, as well as the slower reaction between NH4+ and free chlorine (102 M-1 s-1 at pH < 4.0) within the same pH range, emphasizing the significance of Cl• in enhancing NH4+ oxidation. Mechanistic studies provide compelling evidence of the capacity of BiOCl for Cl- adsorption, facilitating chlorine evolution and Cl• generation. Importantly, the BiOCl@MMO anode exhibits excellent long-term stability and high catalytic activity for NH4+-N removal in a real landfill leachate. These findings offer valuable insights into the rational design of electrodes to improve electrocatalytic NH4+ abatement, which holds great promise for wastewater treatment applications.
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