Journal of Chemistry
·
2017
·
IF 1.3
Zhitao Han,Bojun Liu,Shaolong Yang,Xinxiang Pan,Zhijun Yan
The experiments were performed in a lab-scale countercurrent spraying reactor to study the NOx removal from simulated gas stream by cyclic scrubbing using NaClO solution. The effects of NaClO concentration, initial solution pH, coexisting gases (5% CO2 and 13% O2), NOx concentration, SO2 concentration, and absorbent temperature on NOx removal efficiency were investigated in regard to marine exhaust gas. When NaClO concentration was higher than 0.05 M and initial solution pH was below 8, NOx removal efficiency was relatively stable and it was higher than 60%. The coexisting CO2 (5%) had little effect on NOx removal efficiency, but the outlet CO2 concentration decreased slowly with the initial pH increasing from 6 to 8. A complete removal of SO2 and NO could be achieved simultaneously at 293 K, initial pH of 6, and NaClO concentration of 0.05 M, while the outlet NO2 concentration increased slightly with the increase of inlet SO2 concentration. NOx removal efficiency increased slightly with the increase of absorbent temperature. The relevant reaction mechanisms for the oxidation and absorption of NO with NaClO were also discussed. The results indicated that it was of great potential for NOx removal from marine exhaust gas by wet scrubbing using NaClO solution.
研究领域:
环境科学
·
化学工程
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DOI
高影响因子
WATER RESEARCH
·
2020
·
IF 9.13
Simiao Li,Xiuwei Ao,Chen Li,Zedong Lu,Wenfeng Cao,Fangfang Wu,Shuming Liu,Wenjun Sun
The UV/NH 2 Cl process is an emerging advanced oxidation process (AOP) that is greatly effective in degrading pharmaceuticals and personal care products (PPCPs). However, detailed information regarding the process is lacking. The degradation of ibuprofen (IBP, an electron-withdrawing PPCP) and naproxen (NPX, an electron-donating PPCP) in UV/NH 2 Cl and UV/NaClO processes was performed to investigate the applicability and security of the UV/NH 2 Cl process and compare with those of UV/NaClO. UV/NH 2 Cl was effective in degrading both IBP and NPX and the degradation followed pseudo-first order kinetics (k IBP = 0.0037 cm 2 /mJ and k NPX = 0.0044 cm 2 /mJ). This indicated the broad applicability of UV/NH 2 Cl to different kinds of PPCPs. Ranges of values of UV intensity (0.3–1.0 mW/cm 2 ) and pH (6.0–8.0) showed little effect on the degradation of PPCPs by UV/NH 2 Cl based on UV Dose but HCO 3 − (2–8 mM), natural organic matter (NOM, 2–8 mg/L), and the natural water matrixes were inhibitory. Increasing the dosage of NH 2 Cl from 0.15 mM to 0.75 mM, resulted in an even increase of k IBP ; however, k NPX increased slowly after 0.3 mM NH 2 Cl. Mechanism experiments involving nitrobenzene showed that •OH was the major radical involved in degrading IBP and NPX via UV/NH 2 Cl. The electron spin resonance spectroscopy and kinetic modeling results also indicated the larger amount of •OH and weaker reactive chlorine species (mainly ClO• and ClO 2 •) in UV/NH 2 Cl compared with UV/NaClO. Compared to UV/NaClO in synthetic and natural water, UV/NH 2 Cl was a more stable degrader with little pH- and substrate-dependence, while UV/NaClO preferred degrading the electron-donating PPCP and at low pH. The UV/NH 2 Cl produced less halogenated disinfection byproducts (DBPs) (even nitrogenous DBPs) and was less cytotoxic theoretically than UV/NaClO based on the DBPs included in this study. Thus UV/NH 2 Cl process may be an effective AOP for water treatment .
研究领域:
环境科学
·
水处理工程
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DOI
PubMed
高影响因子
CARBOHYDRATE RESEARCH
·
2022
·
IF 2.975
Fangxia Wu,Na Yan,Yan Guo,Xiaoxiao Yu,Lin Yi,Yilan Ouyang,Xin Wang,Zhenqing Zhang
The TEMPO/NaBr/NaClO system was used to modify konjac glucomannan and prepare β-1,4-linked D-mannuronic/glucuronic acid oligosaccharides . The impact of oxidant amount on the degree of oxidation , molecular weight , terminal structure and the ratio of sugar units were systematically investigated. Mannoses were transformed to mannuronic acids quantitatively, while some glucose were transformed to glucuronic acids, some degraded. The unspecific oxidation causes strong degradation of konjac glucomannan sugar chains. Multiple terminal structures were observed in the oxidized KGM products. According to those observations, the oxidation pattern of konjac glucomannan with the TEMPO/NaBr/NaClO system was speculated. It is suggested that the axial hydroxyl group at position 2 in mannose might form a hydrogen bond with the oxygen on the sugar ring. It would against the unspecific oxidation. While, both specific and unspecific oxidations were observed at glucose units with an equatorial hydroxyl group at position 2, and the degradation occurs mostly on glucose during the oxidation.
研究领域:
生物化学
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食品科学
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DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Haiyu Zhang,Qinbo Cao,Yan Yan,Heng Zou,Xingguo Huang,Dianwen Liu
The flotation separation of galena (PbS) and chalcopyrite (CuFeS 2 ) is not yet fully resolved due to the lack of efficient depressants. This study proposed a new depressant, i.e. an Fe 2+ /NaClO system, as an efficient PbS depressant. The inhibition effect of the Fe 2+ /NaClO system is attributed to the oxidation effect of •OH radicals from the reaction between HClO and Fe 2+ . The recovery of PbS is only 9.48 % and that of CuFeS 2 is 82.33 % under the following conditions: pH 3.5, 4 min reaction time, 10:1 Fe 2+ :NaClO molar ratio and 1 × 10 −2 mol/L NaClO concentration. Contact angle test results suggested that the hydrophobicity of PbS was decreased by conditioning with the Fe 2+ /NaClO system. X-ray photoelectron spectroscopy results showed that the S 2− species on the PbS surface was oxidised into SO 4 2− , and thus, PbSO 4 occurred on the PbS surface. Furthermore, SO 4 2− concentration reached 61.67 % of the total S species. Oxidative production coated the PbS surface well, depressing PbS flotation. However, the Fe 2+ /NaClO system barely changed the components of the CuFeS 2 surface. The CuFeS 2 surface still exhibits a high hydrophobic level. Therefore, PbS can be efficiently separated from CuFeS 2 by using the Fe 2+ /NaClO system.
研究领域:
矿物加工工程
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化学工程
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DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2022
·
IF 4.326
Junqi Cheng,Zhitao Han,Jiawei Li,Xinxiang Pan
Previous work proposed a one-stage wet scrubbing in situ combined with O3 oxidation for simultaneous removal of NO and SO2 from flue gas, and the results showed that wet scrubbing combined in situ with O3 injection could effectively improve O3 oxidant utilization efficiency. In this work, a follow-up research work was carried out to further explore the synergistic effect of dual oxidants of NaClO in the liquid phase and O3 in gas phase. The synergistic effects of O3/NO molar ratio and NaClO concentration in the circulating scrubbing solution on NOx removal performance was investigated systematically. The results showed that when molar ratio of O3/NO was 0.5 and NaClO concentration was 25 mM, NO could be oxidized completely and averaged NOx removal efficiency exceeded 70%. NOx concentrations in outlet gas and anion compositions in the scrubbed solution were analyzed, and the possible reaction paths of wet scrubbing NaClO solution in situ with O3 injection in denitration process were also discussed. When the solution pH was around 6, a relative balance between NOx oxidation and absorption might be achieved, resulting in a high NOx removal efficiency. The temperature of inlet flue gas imposed little impact on NOx removal efficiency due to the quick and efficient cooling effect by wet scrubbing. The increase of initial SO2 concentration led to a slight increase of NOx removal efficiency from 70 to 73.5%. A complete removal of SO2 could be achieved, but coexisting SO2 in flue gas would consume NaClO oxidant and shorten the reaction duration.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2020
·
IF 5.162
Jie Hao,Fangxia Wu,Rong Tang,Yuanyuan Sun,Dehua Liu,Zhenqing Zhang
Oxidized starch (oxStarch) is a major derivative of starch. In present study, 4-acetamide-TEMPO system was firstly applied to prepare specifically oxidized starch, homogeneous 1,4-linked α-D-glucuronan. The impact of oxidant amount, 4-acetamide-TEMPO amount and reaction temperature on the properties of products were investigated. The product structures were characterized with 1 H NMR for degree of oxidation (DO), SEC-MALS for MW, MS for analysis of oxidized oligosaccharides , and in-source fragmented MS for analysis of oxidized polysaccharides . The results showed that the DO of oxStarches increased, but their MWs decreased with the raise of oxidant amount; higher 4-acetamide-TEMPO amount provided higher efficiency of specific oxidation of starch, in which the product has higher DO and MW; no significant difference have been observed between the oxStarches oxidized at 4 and 25 °C, but significant degradation was observed at 50 °C. In each product, having a MW distribution, the portion with smaller size has higher DO. While some unspecific oxidation was still observed observed on the second hydroxyl groups of sugar ring in the following order of priority, position 3 > 2 > 1 > 0.
研究领域:
化学
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材料科学
·
分析化学
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产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
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IF 9
Hongru Qu,Yimin Zhang,Hong Liu,Nannan Xue,Yiping Wang
In traditional methods for preparing vanadium electrolytes, challenges include lengthy processes, high costs, and difficulties in deeply separating vanadium and impurities. This study introduces an innovative approach utilizing an H 2 O 2 -NaClO efficient selective oxidative stripping system within the D2EHPA extraction process. This method was optimized at a pH of 12, with a phase ratio (O/A) of 6:1, a reaction temperature of 45 °C, and a reaction time of 8 min. The concentration of H 2 O 2 was set at 1.5 %, with a volume ratio between H 2 O 2 and NaClO of 95 % to 5 %. Under these conditions, the vanadium stripping rate in a single stage reached 95.13 %. The low concentration (1.5 %) of H 2 O 2 increased the single-stage stripping rate of vanadium by nearly 50 %, reducing H 2 O 2 usage by at least 25 %, while NaClO enhanced the stability of H 2 O 2 . The prepared electrolyte contained impurity ion concentrations of less than 10 ppm, meeting Chinese national first-class standard of Electrolyte for vanadium flow battery. The electrolyte demonstrated excellent electrochemical and charge–discharge performance, with Coulombic efficiency, voltage efficiency, and energy efficiency reaching 85.45 %, 89.58 %, and 76.55 %, respectively, achieving 95 % of the standard electrolyte’s performance. This method significantly shortens the process and reduces costs by 25.29 % compared to the traditional V 2 O 5 dissolution method. This study offers a novel approach to producing high-purity electrolytes through a shorter, cost-effective process.
研究领域:
化学工程
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材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jin Xu,Xiuhong Liu,Yimai Zhou,Shiyong Zhang,Jiaxin Li,Qing Yang
NaClO, as a common membrane cleaning agent were introduced from the permeate side across membrane, which could diffuse into MBR membrane pool. Microplastics would also accumulate in MBR membrane pool during wastewater treatment, thus, NaClO and MPs are co-exposed to activated sludge. This study investigated the effects of PET-MPs (0, 50, 100 and 300 μg/g-ss) on activated sludge with or without NaClO stress. The presence of PET-MPs had no significant impact on nitrification and denitrification rates, but when exposed to NaClO, the increasing level of PET-MPs (i.e., from 0 to 300 μg/g-ss) inhibited the nitrification (94.85 % to 65.90 %) and denitrification (88.68 % to 60.09 %) rates. For microbial metabolism (key enzymes) evaluated, the key enzymes related to organic matter biodegradation, nitrification as well as denitrification were both inhibited with PET-MPs level rise under NaClO stress. The generation of reactive oxygen species (ROS) and the release of lactate dehydrogenase (LDH) increased significantly indicating NaClO caused the toxicity of MPs to activated sludge by enhancing the oxidative stress level. Correspondingly, a variation in abundance related to membrane pollution, nitrification, and denitrification after exposure to PET-MPs with NaClO stress accompanied these adverse effects.
研究领域:
环境工程
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废水处理
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微生物学
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毒理学
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DOI
高影响因子
JOM
·
2022
·Vol. 74
·期 5
·1934-1944
·
IF 2.597
Liu Peiwen,Fei Zitong,Zhang Yingjie,Dong Peng,Meng Qi,Yang Xi
Developing a green and efficient approach for recovering Li from cathode materials is important in recycling spent LiFePO 4 batteries. A facile and efficient oxidation process was developed to selectively recover Li from spent LiFePO 4 batteries. The common oxidant NaClO was used to avoid using acid or alkali in the leaching process. The leaching rate of Li reached 99.8% under the selective optimal leaching conditions of 0.54 mol/l NaClO, leaching time 60 min, leaching temperature 60°C and solid–liquid ratio 1 g/l. The high leaching efficiency can be ascribed to the combination of oxidability and high pH value of the NaClO solution. Meanwhile, leaching and precipitation were carried out simultaneously in this process, which promoted the leaching reaction. High performance LiFePO 4 /C was resynthesized using the recovered products. The specific capacity of the first discharge at 1 C was 147.1 mAh/g and the capacity retention rate at 1 C was 97.55% after 200 cycles. The oxidation approach is acid free and has low energy consumption for green recovery of spent LiFePO 4 batteries.
研究领域:
材料科学
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环境科学
·
能源技术
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DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 29
·43984-44002
·
IF 5.19
Liu Anchen,Lin Wenting,Ping Senwen,Guan Wenqi,Hu Ningyi,Zheng Sichun,Ren Yuan
Antihistamines (ANTs) are medicines to treat allergic diseases. They have been frequently detected in the natural water environment, posing potential threats to the ecological environment and human health. In this study, the degradation of three common antihistamines, loratadine, fexofenadine, and cetirizine, was estimated under different oxidation methods (NaClO, UV, and UV-NaClO). The results showed that UV-NaClO had the highest degree of degradation on the drugs under most conditions: 100% degradation for fexofenadine within 20 s at pH 7 and 10. Under UV irradiation, the degradation efficiencies of the three drugs during 150 s were all above 77% at a pH of 7. The drugs’ removal by NaClO was much lower than that of the previous two methods. In addition, this study explored the contribution rates of active oxygen species in the photolysis process. Among them, the contribution of 1 O 2 to the fexofenadine and cetirizine removal rate reached 70%. Different aqueous matrices (HCO 3 − , NO 3 − , and humic acid) had varying degrees of influence on the degradation. Acute toxicity tests and ultraviolet scans of the degradation products showed that the drugs were not completely mineralized, and the toxicities of the intermediates were even higher than those of the parent drugs. There were 9, 8, and 10 chloride oxidation products of loratadine, fexofenadine, and cetirizine, respectively, and 8 photolysis products of cetirizine were identified. For cetirizine, it was found that there were three identical intermediates produced by photodegradation and NaClO oxidation. Graphical abstract
研究领域:
环境科学
·
药理学
·
毒理学
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DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2024
·
IF 2
Hongxiang Xu,Wentao Li,Junfeng Wang,Jiushuai Deng,Shangqing Chen
After the NaClO solution was used to purify acetylene gas, the solution contained significant amounts of NaCl, Na2SO4, and Na2HPO4. The phase equilibrium data is the most important basic information for recovering sodium salts. In this study, the solubilities and dry-salt phase diagram for the system (Na+//Cl–-SO42–-HPO42–-H2O) were systemically studied. The dry-salt phase diagram contained one invariable point, three univariate solubility curves, and three single salt crystallization regions corresponding to NaCl, Na2SO4, and Na2HPO4·12H2O at 298.15 K and 0.1 MPa. Based on the ELEC-NRTL and Pitzer model embedded in the Aspen Plus, the phase equilibrium data for the ternary subsystem (Na+//Cl–-SO42–-H2O, Na+//Cl–-HPO42–-H2O, and Na+//SO42–-HPO42–-H2O) at 298.15 K and 0.1 MPa taken from the literature were first predicted to verify the applicability of parameters from the default database and literature. Subsequently, the models were optimized by literature solubility data, and then, the obtained parameters can well predict the phase equilibrium data for the ternary subsystem at 298.15 K and 0.1 MPa. All of these will provide basis data for the separation of sodium salt from the Na+//Cl–-SO42–-HPO42–-H2O system.
研究领域:
化学工程
·
环境科学
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产品关联
DOI
高影响因子
Water
·
2023
·Vol. 15
·期 13
·2498
·
IF 3.4
Jiaqi Ding,Ying Wan,Yujia Zou,Songlin Wang,Xiaolong Huang,Pengchao Xie
Sodium hypochlorite (NaClO) solution is wildly used to remove membrane fouling-derived organic materials and restore membrane flux, which can result in the formation of halogenated by-products. To reduce the halogenated by-products, a combined cleaning process with NaClO and peroxides including hydrogen peroxide (H2O2), peroxydisulfate (PDS), and peroxymonosulfate (PMS) were applied in offline mode to remove the organic fouling. It was found that all the combined cleaning processes could effectively restore the membrane flux. Compared with the process of NaClO cleaning followed by peroxide cleaning (NaClO–peroxide), fewer halogenated by-products were generated in the NaClO post-combined cleaning process (peroxide–NaClO), and the PDS–NaClO cleaning process exhibited the best performance in controlling by-products. Overall, most by-product generation showed a positive correlation with reaction time and temperature.Keywords:membrane fouling;chemical cleaning;halogenated by-products;sodium hypochlorite (NaClO);peroxide
研究领域:
环境科学
·
水处理工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）