JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2016
·Vol. 92
·期 4
·827-833
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IF 2.738
Jinxi Feng,Shenyu Lan,Chunyang Yao,Ya Xiong,Shuanghong Tian
BACKGROUND Electro-generation of NaOH and H 2 SO 4 with organic compound-free Na 2 SO 4 wastewater has been known for many years, but actually, lots of Na 2 SO 4 wastewater contains organic pollutants, such as black liquor, dyeing and sulphonating wastewater etc., therefore, there is a strong demand for investigations on performance and effect of the organic pollutants in electrochemically splitting Na 2 SO 4 into H 2 SO 4 and NaOH from these wastewaters. RESULTS Co-electrolysis of Na 2 SO4 (1.13 mol L −1 ) and AO7 (50 ∼ 500 mg L −1 ) was investigated in a diaphragm cell with IrO 2 -coated Ti electrodes. It was found that the concentrations of the resulting NaOH and H 2 SO 4 could remain at about 0.73 mol L −1 and 0.36 mol L −1 , respectively, although the COD removal was increased from 50.3 mg L −1 to 166.3 mg L −1 with the increase of AO7 concentration, for 120 min. CONCLUSION In a diaphragm cell with IrO 2 -coated Ti electrodes, NaOH and H 2 SO 4 could be effectively generated, and simultaneously, AO7 could also be degraded for the wastewater containing Na 2 SO 4 and AO7. Interestingly, the electro-generation of NaOH and H 2 SO 4 was not significantly affected by the occurrence and degradation of AO7 in the range 0–500 mg L −1 . The phenomenon of constant acid–base yield contributed to the independence of the main acid-generating reactions on the electro-oxidation of AO7. © 2016 Society of Chemical Industry
研究领域:
环境科学
·
电化学工程
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Zhihua Sun,Shiyao Li,Haojie Ding,Yunhua Zhu,Xuxu Wang,Huanfang Liu,Qin Zhang,Chun Zhao
Acid Orange 7 (AO7), as a most common and widely used synthetic dyes in the printing and dyeing industry, was hardly degradable by traditional wastewater treatment methods. Here, activated carbon fiber (ACF) as an in-situ regenerated cathodic adsorbent in the electrochemical/Fe 3+ /peroxymonosulfate process (EC/ACF/Fe 3+ /PMS) was firstly investigated for AO7 removal and compared with several different processes. The results indicated that the effective adsorption of AO7 on ACF can be enhanced under electrolytic conditions, while the adsorbed AO7 on ACF can be completely degraded and mineralized in EC/ACF/Fe 3+ /PMS process resulting in the in-situ regeneration of ACF. Besides, the electrical energy per order values were investigated, which showed an apparent reduction of electrical energy consumption from 0.42831 to 0.09779 kWh m −3 when ACF-cathode replaced Pt-cathode. Further study revealed that higher conversion rate of Fe 2+ from Fe 3+ was observed with ACF-cathode. It deserved to be mentioned that the removal efficiency of AO7 was satisfactory and stable even after reusing ACF cathode for 10 times. Furthermore, structure and elements of ACF surface were investigated, which indicated the structure of ACF was intact in EC/ACF/Fe 3+ /PMS due to inhibition of ACF corrosion by electron migration at cathode. In addition, the total iron content of the effluent in EC/ACF/Fe 3+ /PMS was lower than that of EC/Fe 3+ /PMS due to the deposition of iron on ACF-cathode surface. Therefore, advantages of EC/ACF/Fe 3+ /PMS for AO7 degradation were not only a much higher oxidation efficiency and in-situ regenerated cathodic adsorbent, but also a lower electrical energy consumption and lesser iron ions contents in the effluent.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2017
·
IF 4.208
Yang Li,Lei Li,Zi-Xi Chen,Jie Zhang,Li Gong,Yi-Xuan Wang,Han-Qing Zhao,Yang Mu
Advanced oxidation processes offer effective solutions in treating wastewater from various industries. This study is the first time to investigate the potential of carbonate-activated hydrogen peroxide (CAP) oxidation process for the removal of organic pollutant from highly alkaline wastewaters. Azo dye acid orange 7 (AO7) was selected as a model pollutant. The influences of various parameters on AO7 decolorization by the CAP oxidation were evaluated. Furthermore, the active species involved in AO7 degradation were explored using scavenger experiments and electron spin resonance analysis. Additionally, AO7 degradation products by the CAP oxidation were identified to elucidate possible transformation pathways. Results showed that the CAP oxidation had better AO7 decolorization performance compared to bicarbonate-activated hydrogen peroxide method. The AO7 decolorization efficiency augmented from 3.70 ± 0.76% to 54.27 ± 2.65% when carbonate concentration was increased from 0 to 50 mM at pH 13.0, and then changed slightly with further increasing carbonate concentration to 70 mM. It increased almost linearly from 5.95 ± 0.32% to 94.03 ± 0.39% as H 2 O 2 concentration was increased from 5 to 50 mM. Moreover, trace amount of Co(II) could facilitate AO7 decolorization by the CAP reaction. Superoxide and carbonate radicals might be the main reactive oxygen species involved in the CAP process. Finally, a possible degradation pathway of AO7 by the CAP oxidation was proposed based on the identified products.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Yuhan Long,Songrong Li,Peizhen Yang,Xi Chen,Wenhao Liu,Xuesong Zhan,Cheng Xue,Dongfang Liu,Wenli Huang
MOF-derived metal-carbon composite catalyst was an alternative high-efficient catalyst for activating peroxymonosulfate (PMS). In this study, a novel cobalt-carbon-nitrogen doped composite catalyst with honeycomb porous structure (Co-HPNC) was obtained through a simple strategy consisting of three steps: self-growth of ZIF-67 on the SiO 2 core, pyrolysis, and NaOH etching away SiO 2 core. The Co-HPNC exhibited an outstanding catalytic performance (98.1% in 10 min) to activate PMS for acid orange 7 (AO7) degradation. The observed reaction kinetic constant (0.4319 min −1 ) was 2.64 times superior to that of the unmodified Co/NC catalysis system (0.1636 min −1 ). In the meantime, the catalyst demonstrated a high PMS activation capacity over a wide pH range of 3–11 and strong adaptability to the high concentration of inorganic anions (Cl - , SO 4 2- , and CO 3 2– ). After being recycled three times, the removal efficiency could still reach 92.7% in 25 min. The quenching tests and EPR spectrum illustrated the existence of radical and non-radical pathways, in which singlet oxygen was dominant during the degradation process. It was hypothesized that Co(0)/Co(Ⅱ)/Co(Ⅲ), pyridinic-N and pyrrolic-N contributed to the generation of hydroxyl and sulfate radicals, while C=O functional group and graphitic-N were catalytic sites for singlet oxygen. Finally, the radical electrophilic attacking sites of AO7 were calculated by the density functional theory (DFT), and the degradation routes of AO7 were speculated by GC–MS. The toxicity test illustrated that the Co-HPNC/PMS system was an environmental-friendly technology for AO7 degradation. The prepared Co-HPNC with a unique honeycomb porous structure presents a novel synthesis route for MOF-derived catalyst applied in the PMS activation system for wastewater treatment.
研究领域:
环境科学
·
催化
·
材料科学
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水处理
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）