SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2019
·
IF 2.931
Jing Zou,Yixin Huang,Lirong Zhu,Zheng Cui,Baoling Yuan
A spectrophotometric method using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) as the indicator was proposed for measuring persulfates, i.e., peroxymonosulfate (PMS) and peroxydisulfate (PDS). This method was based on the direct oxidation of the colorless ABTS by PMS/PDS to generate the green-colored ABTS + at neutral pH and room temperature . The generated ABTS + had four different characteristic absorption peaks at 820 nm, 732 nm, 650 nm and 415 nm. The absorption values at these wavelengths increased with the increase of PMS/PDS concentration, and there were well linear relationships (R 2 > 0.998) between the corresponding absorption values and the concentrations of PMS/PDS in the range of 3–500 μM. Monitoring the change of PMS/PDS concentration by the proposed ABTS method was in good agreement with that monitored by the common spectrophotometric method using potassium iodide as the indicator. The green-colored waste solutions produced after PMS/PDS analysis with the ABTS method showed no bactericidal effect towards Escherichia coli . The proposed multi-wavelength spectrophotometric method using ABTS as the indicator could be employed as a candidate method for the accurate and convenient measurement of PMS/PDS in water.
研究领域:
分析化学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Water
·
2022
·Vol. 14
·期 9
·1420
·
IF 3.53
Juan Peng,Yameng Ma,Xiao Huang,Jianghua Yu,Fengjiao Yu,Jingsi Gao
Ni-ethylenediaminetetraacetic acid (Ni-EDTA) poses serious threats to the ecological environment and human health, due to its acute toxicity and low biodegradability. The decomplexation efficiency of Ni-EDTA through the conventional Fenton process has been constrained to pH; thus, other appropriate approaches are required to destroy the stable chelate structure at a neutral pH. In this study, the effect of operating parameters such as the pH, Fe2+concentration, particle electrode dosage, current density, and coexisting ions was studied. The results revealed that the 3D-EF system owned advantages for the removal of Ni-EDTA in the broadening of the pH application window. The Ni-EDTA removal efficiency in the 3D-EF system reached 84.89% after 120 min at a pH of 7. In addition, the presence of coexisting ions slightly affected the decomplexation efficiency of Ni-EDTA.Keywords:Ni-EDTA;three-dimensional electro-Fenton;neutral pH;decomplexation
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
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IF 9.446
Tianyuan Xu,Runliang Zhu,Gangqiang Zhu,Jianxi Zhu,Xiaoliang Liang,Yanping Zhu,Hongping He
Heterogeneous photo-Fenton catalysts generally show very weak photo-Fenton activity at near-neutral pH because of the relatively low rate of Fe 2+ regeneration. The aim of this work is to develop novel heterogeneous photo-Fenton catalysts, which can accelerate the regeneration of Fe 2+ and thus have superior photo-Fenton activity at near-neutral pH. In this study, ferrihydrite (Fh) was modified with BiVO 4 to synthesize BiVO 4 /Fh composites, and we expected that the photogenerated electrons from BiVO 4 would accelerate the regeneration of Fe 2+ on Fh. Mechanistic investigation of H 2 O 2 consumption showed that the introduction of BiVO 4 promoted the decomposition of H 2 O 2 into reactive oxygen species (ROS). In addition, the presence of BiVO 4 deterred O 2 − production and accelerated the formation of OH, according to the results of ROS formation, as shown with EPR spectroscopy and fluorescent probes tools. Furthermore, the Fe 2+ concentration on the surface of BiVO 4 /Fh was higher than that on Fh based on the results of XPS characterization and quantitative measurement with a 1,10-phenanthroline spectrophotometric method. These results demonstrated that the introduction of BiVO 4 can accelerate the reduction of Fe 3+ to Fe 2+ by transferring photogenerated electrons from BiVO 4 to Fe 3+ on the surface of Fh. Meanwhile, a higher decolorization efficiency of acid red 18 by BiVO 4 /Fh than by Fh and pure BiVO 4 verified that the introduction of BiVO 4 can significantly enhance the photo-Fenton catalytic activity of Fh even at near-neutral pH. Overall, our work has important implications for understanding the photo-Fenton mechanisms on semiconductor modified heterogeneous photo-Fenton catalysts and confirms that the introduction of a semiconductor can enhance the photo-Fenton catalytic activity of heterogeneous photo-Fenton catalysts in acidic and neutral pH.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY
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2022
·Vol. 38
·期 5
·1-8
·
IF 4.253
Li Yudi,Chen Guiying,Ge Fanglan,Dang Ting,Ren Yao,Zeng Bei,Li Wei
γ-aminobutyric acid (GABA) has various physiological functions and is widely used in medicine, food, and other fields. Glutamate decarboxylase (GAD) is a key enzyme that catalyzes the decarboxylation of L-glutamate to synthesize GABA. However, the industrial application of microorganism-derived GAD is limited by its rapid loss of enzymatic activity with pH approaching neutrality. In this study, a novel glutamate decarboxylase, GAD MSM, from Mycobacterium smegmatis was overexpressed and purified. On the basis of homologous modeling and substrate molecular docking, several GAD MSM mutants were constructed, and their enzymatic properties were analyzed. The results showed that the optimal pH of wild-type GAD MSM is 5.4; at pH 6.2, 22.8% enzymatic activity was retained. The T211I replacement in GAD and C-terminal deletion mutant GAD MSMΔC showed relatively high catalytic activity in a pH range of 5.0–7.0. The V max and K m values of GAD MSMΔC were 14.69 and 5.70, respectively, at pH 5.5, and 9.87 and 6.17, respectively, at pH 7.0. Compared with the wild-type GAD, GAD MSMΔC maintained higher affinity and enzymatic activity of the substrate, maintaining 78.5% of the highest enzymatic activity even at pH 7.0, which is the highest reported activity retention for GAD under neutral pH condition. Therefore, GAD MSMΔC can be used for the transformation of high-yielding strains and industrial production of GABA.
研究领域:
微生物学
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酶工程
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生物化学
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Chuhan Gu,Lei Song,Maofeng Shi,Yihong Wu,Jiaxian Zhang,Jingyu Lv
In this study, we investigated the efficiency of activation of CaO 2 by oxalic acid (OA) chelated with electrochemically (EF)-released Fe 2+ (EF-CaO 2 /OA) in improving the performance of sludge dewatering under neutral conditions. We also explored the mechanism of OA-reinforcement of EF-CaO 2 in enhancing the performance of wastewater-activated sludge dewatering by investigating the water content (Wc), specific resistance to filtration (SRF), pH, bound water content, extracellular polymers in the sludge, the secondary structure of proteins, the soluble ferric ions, and the morphology of the sludge. The EF-CaO 2 /OA process was better than the EF-CaO 2 process in terms of sludge dewatering. OA introduction significantly inhibited the increase of solution pH, which in turn promoted CaO 2 dissolution and persistent H 2 O 2 generation. The persistent oxidative reaction contributed to the degradation of hydrophilic protein fractions in EPS and the reduction of the proportion of hydrophilic structures in the secondary structure of proteins, which in turn improved the hydrophobicity of the sludge. The changing profile of DNA content in EPS proved that EF-CaO 2 /OA led to the damage of more sludge cells. It suggested that OA enhanced the oxidizing efficacy of EF-CaO 2 , which in turn promoted the release of bound water from more sludge cells. Moreover, OA significantly increased the amount of dissolved iron in solution by chelating the electrochemically released iron, which contributed to the stabilization of the oxidation reaction. Under the optimal conditions, sludge Wc and SRF treated by EF-CaO 2 /OA were reduced by 30.1% and 96.9%, respectively, and the dewatered sludge cake remained neutral. In conclusion, EF-CaO 2 /OA may be an efficient and feasible technique for deep sludge dewatering.
研究领域:
环境科学
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污水处理
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
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2020
·
IF 6.146
Mei-Rong Liu,Yang-Peng Lin,Kai Wang,Shumei Chen,Fei Wang,Tianhua Zhou
Cobalt-based phosphate/phosphonates are a class of promising water oxidation catalysts at neutral pH. Herein, we reported a facile hydrothermal synthesis of various nanostructured cobalt phenylphosphonates. It is found that the number of hydroxyl group of structure-directing reagent is crucial for the construction of 3D hierarchical structures including hierarchical nanosheet flower-like assemblies and nanothorn microsphere. These samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, infrared, and X-ray photoelectron spectroscopy techniques. They can act as highly efficient electrocatalysts for the oxygen evolution reaction at neutral pH. Among these, hierarchical cobalt phenylphosphonate nanothorn flowers present excellent performance, affording a current density of 1 mA cm −2 required a small overpotential of 393 mV. This work offers a new clue to develop high-performance metal phosphonate/phosphate catalysts toward electrochemical water oxidation.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
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IF 6.551
Hejun Ren,Xiong Jin,Chenguang Li,Tingting Li,Yang Liu,Rui Zhou
In this study, we reported that the presence of rosemary acid (RA) could strongly enhance the Fe(III)-mediated Fenton oxidation of 2,4-DCP as the model contaminant at near neutral pH. This enhancement was verified by the strong chelating and reducing ability of RA, which could prevent ion precipitation and accelerate the Fe 3+ /Fe 2+ cycle. Radical quenching experiments and electron paramagnetic resonance confirmed the existence and roles of hydroxyl radicals in the Fe 3+ /RA/H 2 O 2 system. Lot size optimized experiments were executed to achieve efficient 2,4-DCP degradation (99.93%) under the optimum conditions of 100 μmol/L Fe 3+ , 100 μmol l/L RA and 8 mmol/L H 2 O 2 within 60 min. In addition, co-existing metal ions , inorganic anions and natural organic matters were proved that they could inhibit removal efficiency and rate at varying degrees. Total organic carbon and chloride ion measurements were employed to probe the mineralization of organic matters (including RA and 2,4-DCP). This study provides a new modified Fenton system to enhance the oxidation removal of refractory organics in water and will enrich the understanding on effective H 2 O 2 activation at neutral pH.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Yusi Tian,Minghua Zhou,Yuwei Pan,Jingju Cai,Gengbo Ren
Pre-magnetized Fe 0 (Pre-Fe 0 ) was for the first time applied as heterogeneous catalyst to enhance the oxidation efficiency of electro-Fenton (EF) for the degradation of p -nitrophenol (PNP). The parameters including current, initial pH and pre-Fe 0 dosage of Pre-Fe 0 /EF process were optimized and compared with other two processes (conventional Fe 0 /EF and electro-oxidation) to confirm its advantage. The rate constants of PNP removal were 1.40–3.82 folds of those by Fe 0 /EF process under various experimental conditions. The application of pre-Fe 0 as catalyst could extend the working pH range from 3.0 to neutral conditions for PNP removal and reduce the Fe 0 dosage from 2 to 0.5 mM corresponding to Fe 0 /EF, avoiding the second pollution of iron sludge . The superiority of Pre-Fe 0 /EF process was also verified to improve the degradation and mineralization of other phenols and antibiotics. Furthermore, a possible pathway of PNP degradation was revealed by the identification of intermediates and organic acids, and the possible mechanism of pre-Fe 0 efficiently enhanced the EF efficiency was proposed. This work demonstrated that such a novel heterogeneous EF process using pre-Fe 0 catalyst was clean and promising for the degradation of refractory organic pollutants .
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2021
·
IF 7.086
Zejun Liu,Jinquan Wan,Yongwen Ma,Yan Wang
The traditional Electro-Fenton (EF) is an efficient technology for wastewater treatment but suffers from the acidic condition requirement and external catalyst addition. To overcome these challenges, a GF@MoS 2 @FeOCl cathode was fabricated using a facile method. The as-prepared GF@MoS 2 @FeOCl cathode showed excellent performance for ciprofloxacin (CIP) degradation in EF process with RuO 2 /Ti electrode as the anode. H 2 O 2 was electro-generated and activated on-site at the cathode at mild pH without adding Fe 2+ . CIP was 100% removed with 74.4% of mineralization in 90 min at pH 6. The GF@MoS 2 @FeOCl cathode exhibited good reusability after consecutive runs of degradation. The degradation intermediates were investigated, and the possible mechanism was proposed. This work demonstrated that the prepared GF@MoS 2 @FeOCl cathode is a promising candidate for contaminants treatment in an EF system.
研究领域:
环境科学
·
材料科学
·
污水处理
✓ 已验证
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Tianyao Li,Fei He,Bin Liu,Tao Jia,Boyang Shao,Ruoxi Zhao,Hui Zhu,Dan Yang,Shili Gai,Piaoping Yang
Chemodynamic therapy (CDT) based on the Fenton reaction is a promising strategy for nonlight cancer treatment. However, the traditional Fenton reaction is only efficient in strongly acidic conditions (pH = 2–4), resulting in the limited curative effect in a weakly acidic tumor microenvironment (TME). Herein, we first developed a simple in situ growth method to confine FeOCl nanosheets into hollow dendritic mesoporous organosilicon (H-DMOS) nanoparticles to obtain FeOCl@H-DMOS nanospheres. Ascorbic acid (AA) was then absorbed on the nanosystem as a H2O2 prodrug and, meanwhile, was used for the regeneration of Fentons reagent for Fe2+. Finally, poly(ethylene glycol) (PEG) was coated on FeOCl@H-DMOS-AA to enhance the permeability and retention (EPR) effect in tumor tissue. The as-fabricated FeOCl@H-DMOS-AA/PEG can generate a large amount of highly toxic hydroxyl radicals (•OH) by catalyzing H2O2 even in neutral pH conditions with the help of AA. As a result, the effect of CDT has been markedly enhanced by the increased amount of H2O2 and the efficient Fenton reaction in mild acidic TME, which can remove almost all of the tumors in mice. In addition, FeOCl also endows the nanosystem with T2-weighted MR imaging capability (r2 = 34.08 mM–1 s–1), thus realizing the imaging-guided cancer therapy. All in all, our study may contribute a new direction and may have a bright future for enhanced CDT with a neutral pH range.
研究领域:
生物医学工程
·
肿瘤学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2021
·
IF 11.236
Jia Deng,Enlai Gao,Feng Wu,Zhixiong You,Xiaozhong Li,Shuxian Gao,Li-Zhi Huang
Atomic hydrogen (H•) is highly reactive for the hydrodechlorination of trichloroethylene (TCE). In this work, we found that the coprecipitation of Ni 2+ and Fe 2+ at neutral pH led to an unprecedented catalytic generation of H•. The generated H• effectively dechlorinate TCE to nontoxic ethylene and ethane, and Fe 2+ is the only electron donor. The abundant adsorbed H• produced with a Ni/Fe ratio of 0.4 enhances hydrogen evolution reaction causing a low efficiency for hydrodechlorination. In contrast, the active absorbed H• is generated in the crystal lattice of Ni-Fe hydroxides with a Ni/Fe ratio of 3.0 causing highly efficient hydrodechlorination of TCE. This work not only reveals the mechanism of catalytic hydrodechlorination by Ni-Fe hydroxides at neutral pH, but also provides a novel approach to detoxify TCE in contaminated water using facile precipitated Ni-Fe hydroxides.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Xiaodong Ma,Tiantong Rao,Mingchen Zhao,Zhiwei Jia,Gengbo Ren,Jingyang Liu,Haiwei Guo,Zhineng Wu,Haijiao Xie
In-situ generation of iron catalysts in electro-Fenton (EF) process deserves more attention like in-situ generation of H 2 O 2 . In this work, a novel induced zero-valent iron (ZVI) electrode, which was composed of a graphite plate with good conductivity, ZVI powders and a small magnet, was for the first time designed through magnetic assembly. Fe 2+ could be slowly generated in-situ from induced ZVI electrode and effectively trigger EF oxidation of chlorobenzenes (CB) under neutral pH. Compared to the in-situ rapid release of Fe 2+ from sacrificial anodes and traditional one-time external dosing of Fe 2+ in EF, in-situ slow release of Fe 2+ from induced ZVI electrode was the most effective way to activate electrogenerated H 2 O 2 under neutral pH. Induced ZVI electrode had obvious advantages in terms of effective active areas, corrosion potentials and current responses. The optimum conditions including pH of 7.0, current of 29.9 mA, ZVI of 0.10 g and electrolysis time of 35.25 min were obtained by the response surface methodology (RSM) model with the maximum removal efficiency of 99.12%. The uniformed weak positive charge on the ZVI powders induced by the electric field was the dominant contribution to the in-situ slow release of Fe 2+ from the induced electrode. And, the impact of magnetic field on the CB removal and the release of iron ions was negligible. The degradation mechanism was revealed through the Fukui function based on the density functional theory (DFT) and by-products analysis. The evolution of acute toxicity to zebrafish in EF was further clarified. Besides, this induced ZVI electrode could be easily reused and has satisfactory stability. In briefly, this work provided a novel idea for the in-situ slow release of Fe 2+ in EF process.
研究领域:
环境科学
·
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）