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Kinetics and mechanism of nitrobenzene degradation by hydroxyl radicals-based ozonation process enhanced

Weizhou Jiao, Shengjuan Shao, Peizhen Yang, Kechang Gao, Youzhi Liu

《化学科学与工程前沿(英文)》 2021年 第15卷 第5期   页码 1197-1205 doi: 10.1007/s11705-020-1998-6

摘要: This study investigated the indirect oxidation of nitrobenzene (NB) by hydroxyl radicals (·OH) in a rotating packed bed (RPB) using competitive kinetics method with -nitrochlorobenzene as a reference compound. The rate constants of NB with ·OH are calculated to be between (1.465±0.113) × 10 L/(mol·s) and (2.497±0.192) × 10 L/(mol·s). The experimental data are fitted by the modified Arrhenius equation, where the activation energy is 4877.74 J/mol, the order of NB concentration, rotation speed, and initial pH is 0.2425, 0.1400 and 0.0167, respectively. The ozonation process of NB could be enhanced by RPB, which is especially effective for highly concentrated NB-containing wastewater under alkaline conditions. The high gravity technology can accelerate ozone mass transfer and self-decomposition of ozone to produce more ·OH, resulting in an increase in the indirect oxidation rate of NB by ·OH and consequently effective degradation of NB in wastewater.

关键词: high gravity technology     hydroxyl radicals     nitrobenzene     reaction kinetics    

Decontamination of Cr(VI) facilitated formation of persistent free radicals on rice husk derived biochar

Kaikai Zhang, Peng Sun, Yanrong Zhang

《环境科学与工程前沿(英文)》 2019年 第13卷 第2期 doi: 10.1007/s11783-019-1106-7

摘要:

PFRs were produced on biochar during Cr(VI) decontamination.

PFRs formation on biochar was owing to the oxidization of phenolic-OH by Cr(VI).

Appearance of excessive oxidant led to the consumption of PFRs on biochar.

Biochar charred at high temperature possessed great performance to Cr(VI) removal.

关键词: Biochar     Persistent free radicals     Phenolic hydroxyl groups     Cr(VI) reduction    

A combined experimental and theoretical study of micronized coal reburning

Hai ZHANG, Jiaxun LIU, Jun SHEN, Xiumin JIANG

《能源前沿(英文)》 2013年 第7卷 第1期   页码 119-126 doi: 10.1007/s11708-012-0226-6

摘要: Micronized coal reburning (MCR) can not only reduce carbon in fly ash but also reduce NO emissions as compared to the conventional coal reburning. However, it has two major kinetic barriers in minimizing NO emission. The first is the conversion of NO into hydrogen cyanide (HCN) by conjunction with various hydrocarbon fragments. The second is the oxidation of HCN by association with oxygen-containing groups. To elucidate the advantages of MCR, a combination of Diffuse Reflection Fourier Transform Infrared (FTIR) experimental studies with Density Functional Theory (DFT) theoretical calculations is conducted in terms of the second kinetic barrier. FTIR studies based on Chinese Tiefa coal show that there are five hydroxide groups such as OH-π, OH-N, OH-OR , self-associated OH and free OH. The hydroxide groups increase as the mean particle size decreases expect for free OH. DFT calculations at the B3LYP/6-31 G(d) level indicate that HCN can be oxidized by hydroxide groups in three paths, HCN+OH→HOCN+H (path 1), HCN+OH→HNCO+H (path 2), and HCN+OH→CN+H O (path 3). The rate limiting steps for path 1, path 2 and path 3 are IM2→P1+H (170.66 kJ/mol activated energy), IM1→IM3 (231.04 kJ/mol activated energy), and R1+OH→P3+H O (97.14 kJ/mol activated energy), respectively. The present study of MCR will provide insight into its lower NO emission and guidance for further studies.

关键词: hydroxyl radicals     Fourier transform infrared spectroscopy (FTIR)     density functional theory (DFT)     homogeneous reaction mechanism     NOx    

Ozonation of the 5-fluorouracil anticancer drug and its prodrug capecitabine: Reaction kinetics, oxidation mechanisms, and residual toxicity

Siyu Chen, Lee Blaney, Ping Chen, Shanshan Deng, Mamatha Hopanna, Yixiang Bao, Gang Yu

《环境科学与工程前沿(英文)》 2019年 第13卷 第4期 doi: 10.1007/s11783-019-1143-2

摘要:

Specific second-order rate constants were determined for 5-FU and CAP with ozone.

Reaction sites were confirmed by kinetics, Fukui analysis, and products.

The olefin moiety was the main ozone reaction site for 5-FU and CAP.

Carboxylic acids comprised most of the residual TOC for 5-FU.

Ozonation removed the toxicity associated with 5-FU and products but not CAP.

关键词: Ozone     5-fluorouracil     Capecitabine     Hydroxyl radicals     Chemotherapy agents     Toxicity    

A pulsed switching peroxi-coagulation process to control hydroxyl radical production and to enhance 2,4

Yaobin Lu, Songli He, Dantong Wang, Siyuan Luo, Aiping Liu, Haiping Luo, Guangli Liu, Renduo Zhang

《环境科学与工程前沿(英文)》 2018年 第12卷 第5期 doi: 10.1007/s11783-018-1070-7

摘要:

• A new pulsed switching peroxi-coagulation (PSPC) system was developed.

• The ECT for 2,4-D removal in the PSPC was lower than that in the EF.

• The iron consumption for 2,4-D removal in the PSPC was lower than that in the PC.

关键词: Pulsed switching peroxi-coagulation system     Energy consumption     Hydroxyl radical production     2     4- Dichlorophenoxyacetic acid    

Light-induced variation in environmentally persistent free radicals and the generation of reactive radical

Yafang Shi, Yunchao Dai, Ziwen Liu, Xiaofeng Nie, Song Zhao, Chi Zhang, Hanzhong Jia

《环境科学与工程前沿(英文)》 2020年 第14卷 第6期 doi: 10.1007/s11783-020-1285-2

摘要: Abstract • Light irradiation increased the concentration of free radicals on HS. • The increased spin densities on HS readily returned back to the original value. • The “unstable” free radicals induced the formation of reactive radical species. • Reactive radicals’ concentration correlated strongly with EPFRs’ concentration. Environmentally persistent free radicals (EPFRs) in humic substances play an essential role in soil geochemical processes. Light is known to induce EPFRs formation for dissolved organic matter in aquatic environments; however, the impacts of light irradiation on the variation of EPFRs in soil humic substances remain unclear. In this study, humic acid, fulvic acid, and humin were extracted from peat soil and then in situ irradiated using simulated sunlight. Electron paramagnetic resonance spectroscopy results showed that with the increasing irradiation time, the spin densities and g-factors of humic substances rapidly increased during the initial 20 min and then gradually reached a plateau. After irradiation for 2h, the maximum spin density levels were up to 1.63 × 1017, 2.06 × 1017, and 1.77 × 1017 spins/g for the humic acid, fulvic acid, and humin, respectively. And the superoxide radicals increased to 1.05 × 1014–1.46 × 1014 spins/g while the alkyl radicals increased to 0.47 × 1014–1.76 × 1014 spins/g. The light-induced EPFRs were relatively unstable and readily returned back to their original state under dark and oxic conditions. Significant positive correlations were observed between the concentrations of EPFRs and reactive radical species (R2 = 0.65–0.98, p<0.05), which suggested that the newly produced EPFRs contributed to the formation of reactive radical species. Our findings indicate that under the irradiation humic substances are likely to be more toxic and reactive in soil due to the formation of EPFRs.

关键词: Peat     Humic substances     Environmentally persistent free radicals     Light irradiation     Reactive radical species    

水力空化反应器的最新进展——空化机理、反应器设计与应用 Review

Haoxuan Zheng, Ying Zheng, Jesse Zhu

《工程(英文)》 2022年 第19卷 第12期   页码 180-198 doi: 10.1016/j.eng.2022.04.027

摘要:

水力空化因其能效高、操作成本低、能够诱导化学反应并可规模化等优势,被认为是一种很有前途的工艺强化技术。近十年来,人们对水力空化及其主要变量的基本认识取得了一些进展,为水力空化在自由基诱导化学反应过程中的应用提供了基础。在这里,我们对这些研究工作进行了广泛回顾,包括水力空化的基本原理、空化反应器的设计、空化诱导的反应增强及相关的工业应用。比较了两种类型的水力空化反应器,即固定式和旋转式水力空化反应器。讨论了水力空化反应器的设计参数及其在实验室和中试尺度上的反应器性能,并就其最佳操作和几何条件提出了建议。本文首次回顾了目前市场上的商业空化反应器。水力空化的独特特点已广泛应用于各种化学反应,如氧化反应和废水处理,以及如乳化液生成和组分提取等物理过程。文中也详细讨论了自由基和气泡内爆的作用。

关键词: 水动力空化作用     空化核     羟基自由基     固定/旋转水动力空化反应器     反应增强     空化应用    

Regulation of radicals by hydrogen-donor solvent in direct coal liquefaction

《化学科学与工程前沿(英文)》 2022年 第16卷 第12期   页码 1689-1699 doi: 10.1007/s11705-022-2186-7

摘要: Radicals are important intermediates in direct coal liquefaction. Certain radicals can cause the cleavage of chemical bonds. At high temperatures, radical fragments can be produced by the splitting of large organic molecules, which can break strong chemical bonds through the induction pyrolysis of radicals. The reaction between the formation and annihilation of coal radical fragments and the effect of hydrogen-donor solvents on the radical fragments are discussed in lignite hydrogenolysis. Using the hydroxyl and ether bonds as indicators, the effects of different radicals on the cleavage of chemical bond were investigated employing density functional theory calculations and lignite hydrogenolysis experiments. Results showed that the adjustment of the coal radical fragments could be made by the addition of hydrogen-donor solvents. Results showed that the transition from coal radical fragment to H radical leads to the variation of product distribution. The synergistic mechanism of hydrogen supply and hydrogenolysis of hydrogen-donor solvent was proposed.

关键词: direct coal liquefaction     hydrogen-donor solvent     induced pyrolysis     radical mechanism     density functional theory calculations    

Persistent free radicals in humin under redox conditions and their impact in transforming polycyclic

Hanzhong Jia, Yafang Shi, Xiaofeng Nie, Song Zhao, Tiecheng Wang, Virender K. Sharma

《环境科学与工程前沿(英文)》 2020年 第14卷 第4期 doi: 10.1007/s11783-020-1252-y

摘要: Abstract • Regulation of redox conditions promotes the generation of free radicals on HM. • HM-PFRs can be fractionated into active and inactive types depending on stability. • The newly produced PFRs readily release electrons to oxygen and generate ROS. • PFR-induced ROS mediate the transformation of organic contaminants adsorbed on HM. The role of humic substance-associated persistent free radicals (PFRs) in the fate of organic contaminants under various redox conditions remains unknown. This study examined the characterization of original metal-free peat humin (HM), and HM treated with varying concentrations of H2O2 and L-ascorbic acid (VC) (assigned as H2O2-HM and VC-HM). The concentration of PFRs in HM increased with the addition of VC/H2O2 at concentrations less than 0.08 M. The evolution of PFRs in HM under different environmental conditions (e.g., oxic/anoxic and humidity) was investigated. Two types of PFRs were detected in HM: a relatively stable radical existed in the original sample, and the other type, which was generated by redox treatments, was relatively unstable. The spin densities of VC/H2O2-HM readily returned to the original value under relatively high humidity and oxic conditions. During this process, the HM-associated “unstable” free radicals released an electron to O2, inducing the formation of reactive oxygen species (ROS, i.e., •OH and •O2−). The generated ROS promoted the degradation of polycyclic aromatic hydrocarbons based on the radical quenching measurements. The transformation rates followed the order naphthalene>phenanthrene>anthracene>benzo[a]pyrene. Our results provide valuable insight into the HM-induced transformation of organic contaminants under natural conditions.

关键词: Humic substance     Polycyclic aromatic hydrocarbons (PAHs)     Persistent free radicals (PFRs)     Redox     Reactive oxygen species (ROS)    

Hydroxyl radical-involved cancer therapy via Fenton reactions

《化学科学与工程前沿(英文)》 2022年 第16卷 第3期   页码 345-363 doi: 10.1007/s11705-021-2077-3

摘要: The tumor microenvironment features over-expressed hydrogen peroxide (H2O2). Thus, versatile therapeutic strategies based on H2O2 as a reaction substrate to generate hydroxyl radical (•OH) have been used as a prospective therapeutic method to boost anticancer efficiency. However, the limited Fenton catalysts and insufficient endogenous H2O2 content in tumor sites greatly hinder •OH production, failing to achieve the desired therapeutic effect. Therefore, supplying Fenton catalysts and elevating H2O2 levels into cancer cells are effective strategies to improve •OH generation. These therapeutic strategies are systematically discussed in this review. Furthermore, the challenges and future developments of hydroxyl radical-involved cancer therapy are discussed to improve therapeutic efficacy.

关键词: hydroxyl radical     Fenton catalyst     hydrogen peroxide     cancer therapy    

Lignin-based polymer with high phenolic hydroxyl group content prepared by the alkyl chain bridging method

《化学科学与工程前沿(英文)》 2023年 第17卷 第8期   页码 1075-1084 doi: 10.1007/s11705-022-2272-x

摘要: Inspired by the importance of the phenolic group to the electron transporting property of hole transport materials, phenolic hydroxyl groups were introduced in lignosulfonate (LS) via the alkyl chain bridging method to prepare phenolated-lignosulfonate (PLS). The results showed that the phenolic group was boosted from 0.81 mmol∙g–1 of LS to 1.19 mmol∙g–1 of PLS. The electrochemical property results showed two oxidation peaks in the cyclic voltammogram (CV) curve of PLS, and the oxidation potential of the PLS-modified electrode decreased by 0.5 eV compared with that of LS. This result indicates that PLS is more easily oxidized than LS. Based on the excellent electron transporting property of PLS, PLS was applied as a dopant in poly(3,4-ethylenedioxythiophene) (PEDOT, called PEDOT:PLSs). PLS showed excellent dispersion properties for PEDOT. Moreover, the transmittance measurement results showed that the transmittance of PEDOT:PLSs exceeded 85% in the range of 300–800 nm. The CV results showed that the energy levels of PEDOT:PLSs could be flexibly adjusted by PLS amounts. The results indicate that the phenolic hydroxyl group of lignin can be easily boosted by the alkyl chain bridging method, and phenolated lignin-based polymers may have promising potential as dopants of PEDOT to produce hole transporting materials for different organic photovoltaic devices.

关键词: lignosulfonate     phenolic group     PEDOT:PLS     hole extract layer     energy level    

Bacteria inactivation by sulfate radical: progress and non-negligible disinfection by-products

《环境科学与工程前沿(英文)》 2023年 第17卷 第3期 doi: 10.1007/s11783-023-1629-9

摘要:

● Status of inactivation of pathogenic microorganisms by SO4•− is reviewed.

关键词: Sulfate radicals     Disinfection by-products     Inactivation mechanisms     Bacterial inactivation     Water disinfection    

NADPH oxidase and reactive oxygen species as signaling molecules in carcinogenesis

Gang WANG

《医学前沿(英文)》 2009年 第3卷 第1期   页码 1-7 doi: 10.1007/s11684-009-0018-5

摘要: Reactive oxygen species (ROS) are small molecule metabolites of oxygen that are prone to participate in redox reactions their high reactivity. Intracellular ROS could be generated in reduced nicotinamide-adenine dinucleotidephosphate (NADPH) oxidase-dependent and/or NADPH oxidase-independent manners. Physiologically, ROS are involved in many signaling cascades that contribute to normal processes. One classical example is that ROS derived from the NADPH oxidase and released in neurotrophils are able to digest invading bacteria. Excessive ROS, however, contribute to pathogenesis of various human diseases including cancer, aging, dimentia and hypertension. As signaling messengers, ROS are able to oxidize many targets such as DNA, proteins and lipids, which may be linked with tumor growth, invasion or metastasis. The present review summarizes recent advances in our comprehensive understanding of ROS-linked signaling pathways in regulation of tumor growth, invasion and metastasis, and focuses on the role of the NADPH oxidase-derived ROS in cancer pathogenesis.

关键词: free radicals     tumor     phox     cell proliferation     cancer therapy    

Plasma-assisted oxidation of benzoic acid

Anna Khlyustova, Nikolay Sirotkin

《化学科学与工程前沿(英文)》 2020年 第14卷 第4期   页码 513-521 doi: 10.1007/s11705-019-1825-0

摘要: Plasma-assisted oxidation of organic compounds is one of the developing technologies for wastewater treatment. Plasmas effectively accelerate degradation processes due to plasma generated reactive species and ultra-violet radiation. Oxidation of benzoic acid in aqueous solutions by the atmospheric pressure glow discharge and underwater diaphragm discharge was studied and monitored by fluorescence and spectrophotometric methods. Discharge type and solution pH affect the formation rates of mono- and dihydroxybenzoic acids. Dihydroxyl derivatives were formed only by glow discharge action. The yields of hydroxyl radical were estimated on the kinetics data for the hydroxylation of benzoic acid. The steps of the hydroxylation processes and further oxidation were described.

关键词: atmospheric pressure glow discharge     underwater diaphragm discharge     oxidation     benzoic acid     hydroxyl radical    

One-pot hydrothermal fabrication of BiVO/FeO/rGO composite photocatalyst for the simulated solar light-driven degradation of Rhodamine B

《环境科学与工程前沿(英文)》 2022年 第16卷 第3期 doi: 10.1007/s11783-021-1470-y

摘要:

• BiVO4/Fe3O4/rGO has excellent photocatalytic activity under solar light radiation.

关键词: Photocatalysis     Ternary magnetic photocatalyst     Visible-light-driven     Free radicals trapping     Reusability     Recycling    

标题 作者 时间 类型 操作

Kinetics and mechanism of nitrobenzene degradation by hydroxyl radicals-based ozonation process enhanced

Weizhou Jiao, Shengjuan Shao, Peizhen Yang, Kechang Gao, Youzhi Liu

期刊论文

Decontamination of Cr(VI) facilitated formation of persistent free radicals on rice husk derived biochar

Kaikai Zhang, Peng Sun, Yanrong Zhang

期刊论文

A combined experimental and theoretical study of micronized coal reburning

Hai ZHANG, Jiaxun LIU, Jun SHEN, Xiumin JIANG

期刊论文

Ozonation of the 5-fluorouracil anticancer drug and its prodrug capecitabine: Reaction kinetics, oxidation mechanisms, and residual toxicity

Siyu Chen, Lee Blaney, Ping Chen, Shanshan Deng, Mamatha Hopanna, Yixiang Bao, Gang Yu

期刊论文

A pulsed switching peroxi-coagulation process to control hydroxyl radical production and to enhance 2,4

Yaobin Lu, Songli He, Dantong Wang, Siyuan Luo, Aiping Liu, Haiping Luo, Guangli Liu, Renduo Zhang

期刊论文

Light-induced variation in environmentally persistent free radicals and the generation of reactive radical

Yafang Shi, Yunchao Dai, Ziwen Liu, Xiaofeng Nie, Song Zhao, Chi Zhang, Hanzhong Jia

期刊论文

水力空化反应器的最新进展——空化机理、反应器设计与应用

Haoxuan Zheng, Ying Zheng, Jesse Zhu

期刊论文

Regulation of radicals by hydrogen-donor solvent in direct coal liquefaction

期刊论文

Persistent free radicals in humin under redox conditions and their impact in transforming polycyclic

Hanzhong Jia, Yafang Shi, Xiaofeng Nie, Song Zhao, Tiecheng Wang, Virender K. Sharma

期刊论文

Hydroxyl radical-involved cancer therapy via Fenton reactions

期刊论文

Lignin-based polymer with high phenolic hydroxyl group content prepared by the alkyl chain bridging method

期刊论文

Bacteria inactivation by sulfate radical: progress and non-negligible disinfection by-products

期刊论文

NADPH oxidase and reactive oxygen species as signaling molecules in carcinogenesis

Gang WANG

期刊论文

Plasma-assisted oxidation of benzoic acid

Anna Khlyustova, Nikolay Sirotkin

期刊论文

One-pot hydrothermal fabrication of BiVO/FeO/rGO composite photocatalyst for the simulated solar light-driven degradation of Rhodamine B

期刊论文