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1.
研究了基于硫酸根的高级氧化技术UV/过二硫酸盐(UV/PDS)对水体中组胺H2受体拮抗剂(HRAs)的降解,并选取HRAs中的典型物质西咪替丁(CMTD)为目标污染物.采用竞争动力学方法得到了HRAs和·OH及SO4-·反应的二级速率常数,k·OH/HRAs为(2.8—14.6)×109 L·mol-1·s-1,kSO4-·/HRAs为(0.81—8.10)×109 L·mol-1·s-1.研究在实验基础上建立了UV/PDS的自由基拟稳态模型,模拟结果表明,UV/PDS对污染物的降解,其间接光解起主要作用,体系中·OH和SO4-·是间接光解的主导自由基.在(0.1—0.5) mmol·L-1 PDS投加量下,·OH和SO4-  相似文献   

2.
以离子液体为氮源、磷源和氟源,采用一步水热法将N、P、F的3种元素掺杂到FeCo2O4中合成了NPF-FeCo2O4催化剂,用于活化过一硫酸氢钾(PMS)降解水中2,4-二氯苯氧乙酸(2,4-D).分别采用透射电子显微镜(TEM)、X射线光电子能谱(XPS)、傅立叶红外光谱(FTIR)、X射线衍射(XRD)对催化剂进行表征.实验结果表明,当催化剂投加量为0.1 g·L-1、PMS浓度为1 mmol·L-1时,反应30 min后2,4-D的去除率可达100%;初始pH值在3到9的范围内,体系对2,4-D的去除效果不受影响,水中低浓度的Cl-、HCO3-和腐殖酸对反应有轻微的抑制.通过电子自旋共振波谱(EPR)测试结果显示,相较于FeCo2O4和NP-FeCo2O4催化剂,NPF-FeCo2  相似文献   

3.
为了有效去除废水中的有机污染物和实现赤泥(RM)的再利用,利用废弃活性炭(WAC)作为碳源,通过还原焙烧-磁选二步法制备了赤泥基零价铁(ZVI/RM)材料作为类芬顿催化剂催化氧化废水中常见的有机污染物罗丹明B (RhB)和磺胺嘧啶(SD).材料表征结果表明,零价铁均匀分布在材料上,且材料具有明显的介孔结构.当初始pH为3.00,H2O2的浓度为1mmol·L-1,ZVI/RM投加量为200 mg·L-1,RhB初始浓度为50 mg·L-1时,10 min内RhB的降解率达到99.9%.当初始pH为3.00,H2O2的浓度为1 mmol·L-1,ZVI/RM投加量为100 mg L-1,SD初始浓度为20 mg·L-1时,10 min内SD的降解率达到99.9%,根据已知中间产物提出了SD的降解路线.研究结果表明,复合材料ZVI/RM能有效催化降解RhB和SD,有望运用于...  相似文献   

4.
采用钴铜双金属氧化物(Co-Cu)为催化剂,活化过一硫酸盐(PMS)降解水中的磺胺甲噁唑(SMX).使用场发射扫描电镜(FESEM)、透射电镜(TEM)、X射线光电子能谱(XPS)、X射线衍射(XRD)对催化剂的形貌和元素组成进行表征.考察了催化剂和PMS浓度、无机阴离子和富里酸(FA)对Co-Cu/PMS体系降解SMX的影响.结果表明,当pH为7.0时,在催化剂用量为50 mg·L-1,PMS浓度为0.5 mmol·L-1条件下,50 mg·L-1的SMX在30 min内去除率为95.6%,增加PMS浓度或提高催化剂用量均可加快SMX的降解速率.水中FA与HCO3-对SMX的去除率有一定的抑制作用,而Cl-和SO42-对反应无影响.淬灭实验与电子顺磁共振(EPR)结果显示,硫酸根自由基(SO4·-)和单线态氧(1O2)为Co...  相似文献   

5.
张中欣  罗腾  陈正山  陈刚  杨晨  肖吉 《环境化学》2022,41(2):643-652
贵州息烽温泉被誉为“亚洲第一氡泉”,富含多种有益元素.选取息烽地热水和与其有关的地表径流水及岩溶泉水为研究对象,利用水文地球化学、δ34S(SO42-)、δ13C(HCO3-))同位素等方法对区内富氡地热水中硫、碳元素来源及水-岩作用过程进行研究.结果显示,地热水水化学类型为HCO3·SO4-Ca·Mg型,pH呈弱碱性,其阴离子主要为HCO3-和SO42-,阳离子主要Ca2+和Mg2+,阴离子浓度变化范围为86—191.01 mg·L-1,阳离子浓度变化范围为20.7—57.4 mg·L-1.地热水中δ13C(HCO3-))值为-4.85‰—-9.1...  相似文献   

6.
为探索水体环境中有机污染物在硫酸根自由基(·SO4-)作用下的迁移转化规律,构建了UVC/过硫酸盐(PDS)/非质子极性溶剂反应体系,模拟了茜素类染料在·SO4-作用下的降解动力学与反应机制.媒染橙1在不同溶剂体系中的降解动力学常数大小为:(90%乙腈(ACN)+10%水(H2O))>100%H2O>100%二甲基亚砜(DMSO)>100%二甲基甲酰胺(DMF).并且媒染橙1比茜素黄GG具有更高的降解反应速率. UVC/PDS/(90%ACN+10%H2O)体系中PDS用量、底物浓度、反应温度和光照强度等因素对茜素类染料降解动力学均有明显的影响.高温和强的光强有利于茜素类染料的降解,而过高PDS用量和底物浓度降低了茜素类染料的反应速率.·SO4-对茜素类染料的降解占据主导作用.而茜素类染料的初始降解途径主要包括单电子转移反应导致的脱磺酸基和偶氮键断裂以及吸氢反应和取代反应等...  相似文献   

7.
以MoS2为载体,通过水热法合成Fe3O4/MoS2催化剂,采用X射线衍射、透射电子显微镜和X射线光电子能谱分析对材料进行表征,研究了Fe3O4/MoS2/PMS体系中2,4-二氯苯氧基乙酸(2,4-D)的降解效率并探究了其反应机理.结果表明,以Fe3O4、MoS2和Fe3O4/MoS2为催化剂,30 min内2,4-D的去除率分别为31%、 20%和89%.表征结果发现,在MoS2的存在下,Fe3O4表面的Fe(Ⅲ)还原为Fe(Ⅱ),Mo(Ⅳ)被氧化为Mo(Ⅵ),Fe3O4和MoS2间的协同作用加强了PMS分解,提高了2,4-D去除效率.自由基淬灭实验表明,·OH、 SO<...  相似文献   

8.
采用CTAB辅助水热法合成钼酸铋(Bi2MoO6,BMO)微球,并将其用于活化过一硫酸盐(PMS),在可见光下降解废水中的偶氮染料金橙Ⅱ(AO7).利用X射线衍射(XRD),傅里叶红外光谱仪(FT-IR),扫描电子显微镜(SEM),X射线能谱(XPS),透射电子显微镜(TEM)和紫外-可见漫反射光谱(UV-vis)对催化剂进行了表征,并通过降解实验测试其催化性能.结果表明,合成的催化剂具有良好的吸附、催化降解AO7的性能.在中性条件下,催化剂投加量0.3 g·L-1,AO7浓度0.1 mmol·L-1,PMS浓度1 mmol·L-1,可以在30 min内完全降解AO7.研究了催化剂含量、pH、共存阴离子等对AO7降解效果的影响.通过自由基消除实验,探索了0.10CTAB-BMO/光/PMS体系中存在的活性物种(h+、·O2-1O2、·OH和SO4...  相似文献   

9.
本研究构建了以BDD电极为阳极,自然空气扩散电极(natural air diffusion electrode,NADE)为阴极,零价铁作为催化剂的电芬顿系统,深入探索了该系统对磺胺嘧啶(sulfadiazine,SD)的降解效果和机理.相较于其他系统,BDD-Fe-NADE系统降解优势明显.为进一步探索系统的作用机理,在BDD阳极和NADE阴极之间加入质子交换膜,构建双室降解系统,分别计算阳极室和阴极室中直接电子转移(direct electron transfer,DET)、H2O2、·OH、S2O82-和·SO4-等氧化性粒子对于磺胺嘧啶降解的贡献率.结果表明,在阳极室中,电极氧化和Fe2+催化S2O82-产生的·SO4-起主要氧化作用,贡献率分别为49.02%和35.29%;在阴极室中,Fe  相似文献   

10.
王婷婷  任刚  关健聪  余燕 《环境化学》2023,(7):2403-2410
本文以盐酸林可霉素(LCM)为研究对象,探究其在UV/H2O2降解作用下的降解情况,探讨了H2O2浓度、初始pH值和有机物等影响因素对LCM的影响及机制.实验结果表明,当H2O2浓度为50 mg·L-1,pH=7.3,LCM浓度为10 mg·L-1,反应30 min后,LCM去除率达到98%,且反应过程遵循准一级动力学.利用高效液相色谱串联飞行时间质谱仪(LCMS-TOF 5600+)鉴别出其在UV/H2O2降解过程中主要产物的分子结构式,进而推导出可能的降解路径.利用TEST对降解过程中的产物进行毒性预测,结果表明,中间产物的毒性高于母体,对水质安全保障造成潜在风险.  相似文献   

11.
• BiVO4/Fe3O4/rGO has excellent photocatalytic activity under solar light radiation. • It can be easily separated and collected from water in an external magnetic field. • BiVO4/Fe3O4/0.5% rGO exhibited the highest RhB removal efficiency of over 99%. • Hole (h+) and superoxide radical (O2) dominate RhB photo-decomposition process. • The reusability of this composite was confirmed by five successive recycling runs. Fabrication of easily recyclable photocatalyst with excellent photocatalytic activity for degradation of organic pollutants in wastewater is highly desirable for practical application. In this study, a novel ternary magnetic photocatalyst BiVO4/Fe3O4/reduced graphene oxide (BiVO4/Fe3O4/rGO) was synthesized via a facile hydrothermal strategy. The BiVO4/Fe3O4 with 0.5 wt% of rGO (BiVO4/Fe3O4/0.5% rGO) exhibited superior activity, degrading greater than 99% Rhodamine B (RhB) after 120 min solar light radiation. The surface morphology and chemical composition of BiVO4/Fe3O4/rGO were studied by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV–visible diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. The free radicals scavenging experiments demonstrated that hole (h+) and superoxide radical (O2) were the dominant species for RhB degradation over BiVO4/Fe3O4/rGO under solar light. The reusability of this composite catalyst was also investigated after five successive runs under an external magnetic field. The BiVO4/Fe3O4/rGO composite was easily separated, and the recycled catalyst retained high photocatalytic activity. This study demonstrates that catalyst BiVO4/Fe3O4/rGO possessed high dye removal efficiency in water treatment with excellent recyclability from water after use. The current study provides a possibility for more practical and sustainable photocatalytic process.  相似文献   

12.
Fe2O3-CeO2-Bi2O3/γ-Al2O3, an environmental friendly material, was investigated. The catalyst exhibited good catalytic performance in the CWAO of cationic red GTL. The apparent activation energy for the reaction was 79 kJ·mol−1. HO2· and O2· appeared as the main reactive species in the reaction. The Fe2O3-CeO2-Bi2O3/γ-Al2O3 catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation (CWAO) of cationic red GTL under mild operating conditions in a batch reactor. The catalyst was prepared by wet impregnation, and characterized by special surface area (BET measurement), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Fe2O3-CeO2-Bi2O3/γ-Al2O3 catalyst exhibited good catalytic activity and stability in the CWAO under atmosphere pressure. The effect of the reaction conditions (catalyst loading, degradation temperature, solution concentration and initial solution pH value) was studied. The result showed that the decolorization efficiency of cationic red GTL was improved with increasing the initial solution pH value and the degradation temperature. The apparent activation energy for the reaction was 79 kJ·mol1. Hydroperoxy radicals (HO2·) and superoxide radicals (O2·) appeared as the main reactive species upon the CWAO of cationic red GTL.  相似文献   

13.
为研究乌鲁木齐市米东区大气降水中的化学组分特征及来源,对2017-2019年降水中主要离子浓度及来源进行了分析.研究结果显示,米东区2017-2019年降水的雨量加权pH年均值为7.95,雨量加权平均电导率年均值为16.15 mS·m-1,雨量加权平均总离子浓度为72.75-95.89 μeq·L-1,年均浓度为81....  相似文献   

14.
The adsorption of direct fast black onto acid-thermal modified sepiolite was investigated. Batch adsorption experiments were performed to evaluate the influences of experimental parameters such as initial dye concentration, initial solution pH and adsorbent dosage on the adsorption process. The three-factor and three-level Box-Behnken response surface methodology (RSM) was utilized for modeling and optimization of the adsorption conditions for direct fast black onto the acid-thermal modified sepiolite. The raw sepiolite was converted to acid-thermal modified sepiolite, and changes in the fourier transform infrared spectrum (FTIR) adsorption bands of the sample were noted at 3435 cm-1 and 1427 cm-1. The zeolitic water disappeared and the purity of sepiolite was improved by acid-thermal modification. The decolorization rate of direct fast black adsorbed increased from 68.2% to 98.9% on acid-thermal modified sepiolite as the initial solution pH decreased from 10 to 2. When the adsorbent dosage reached to 2.5 g·L-1, 2.0 g·L-1, 1.5 g·L-1 and 1.0 g·L-1, the decolorization rate was 90.3%, 86.7%, 61.0% and 29.8%, respectively. When initial dye concentration increased from 25 to 200 mg·L-1, the decolorization rate decreased from 91.9% to 60.0%. The RSM results showed that the interaction between adsorbent dosage and pH to be a significant factor. The optimum conditions were as follows: the adsorbent dosage 1.99 g·L-1, pH 4.22, and reaction time 5.2 h. Under these conditions, the decolorization rate was 95.1%. The three dimensional fluorescence spectra of direct fast black before and after treatment showed that the direct fast black was almost all adsorbed by the acid-thermal modified sepiolite.  相似文献   

15.
陈晨  李北罡 《环境化学》2021,(3):799-807
以天然高分子化合物海藻酸钠(sodium alginate,SA)为骨架,结合磁性Fe3O4和稀土铈离子Ce(Ⅲ)通过溶液反应制备出一种新型的磁性海藻酸铈复合微球(Fe3O4@SA;Ce).采用X射线衍射(XRD)、孔结构比表面积分析(BET)、扫描电子显微镜(SEM)、红外光谱(FT-IR)及振动样品强磁计(VSM)对Fe3O4@SA;Ce的结构进行了表征,并以直接桃红12B(direct red 12B,DR 12B)和直接橙S(direct orange S,DO S)两种染料为吸附对象,探讨了Fe3O4@SA;Ce的吸附剂性能、吸附动力学和热力学.结果表明,Fe3O4@SA;Ce对室温下自然pH染料溶液中DR 12B和DO S均表现出良好的吸附效果,吸附量分别可达464 mg·g-1和730 mg·g-1.在不同温度下(298、313、328 K),Fe3O4@SA;Ce对DR 12B和DO S的吸附过程均可用拟二级吸附动力学方程准确描述.通过等温吸附研究,发现Fe3O4@SA;Ce对两种染料的等温吸附较好地符合Freundlich模型.各种表征结果表明,SA与Ce(Ⅲ)和Fe3O4交联反应后生成的Fe3O4@SA;Ce凝胶球表面有大量深浅不一的褶皱沟纹,形貌发生了显著变化.作为一种绿色环保、制备方法简单、可高效吸附的磁性高分子复合吸附剂,Fe3O4@SA;Ce对高浓度染料具有很好的吸附效果,期望能够在染料废水处理中得到广泛应用.  相似文献   

16.
• Strong metal-support interaction exists on Pt/Fe3O4 catalysts. • Pt metal particles facilitate the formation of oxygen vacancies on Fe3O4. • Fe3O4 supports enhance the strength of CO adsorption on Pt metal particles. The self-inhibition behavior due to CO poisoning on Pt metal particles strongly impairs the performance of CO oxidation. It is an effective method to use reducible metal oxides for supporting Pt metal particles to avoid self-inhibition and to improve catalytic performance. In this work, we used in situ reductions of chloroplatinic acid on commercial Fe3O4 powder to prepare heterogeneous-structured Pt/Fe3O4 catalysts in the solution of ethylene glycol. The heterogeneous Pt/Fe3O4 catalysts achieved a better catalytic performance of CO oxidation compared with the Fe3O4 powder. The temperatures of 50% and 90% CO conversion were achieved above 260°C and 290°C at Pt/Fe3O4, respectively. However, they are accomplished on Fe3O4 at temperatures higher than 310°C. XRD, XPS, and H2-TPR results confirmed that the metallic Pt atoms have a strong synergistic interaction with the Fe3O4 supports. TGA results and transient DRIFTS results proved that the Pt metal particles facilitate the release of lattice oxygen and the formation of oxygen vacancies on Fe3O4. The combined results of O2-TPD and DRIFTS indicated that the activation step of oxygen molecules at surface oxygen vacancies could potentially be the rate-determining step of the catalytic CO oxidation at Pt/Fe3O4 catalysts. The reaction pathway involves a Pt-assisted Mars-van Krevelen (MvK) mechanism.  相似文献   

17.
A study of the decolorization of reactive brilliant blue in an aqueous solution using Fe-Mn-sepiolite as a heterogeneous Fenton-like catalyst has been performed. The Fourier transform infrared (FTIR) spectra of the catalyst showed bending vibrations of the Fe-O. The X-ray diffraction (XRD) patterns of the catalyst showed characteristic diffraction peaks of α-Fe2O3, γ-Fe2O3 and MnO. A four factor central composite design (CCD) coupled with response surface methodology (RSM) was applied to evaluate and optimize the important variables (catalyst addition, hydrogen peroxide dosage, initial pH value and initial dye concentration). When the reaction conditions were catalyst dosage= 0.4 g, [H2O2]= 0.3 mL, pH= 2.5, [reactive brilliant blue]o = 50 mg·L−1, and volume of solution= 500 mL at room temperature, the decolorization efficiency of reactive brilliant blue was 91.98% within 60 min. Moreover, the Fe-Mn-sepiolite catalyst had good stability for the degradation of reactive brilliant blue even after six cycles. Leaching of iron ions (<0.4 mg·L−1) was observed. The decoloring process was reactive brilliant blue specific via a redox reaction. The benzene ring and naphthalene ring were first oxidized to open ring; these were then oxidized to the alcohol and carboxylic acid. The reactive brilliant blue was decomposed mainly by the attack of ·OH radicals including surface-bound ·OH radicals generated on the catalyst surface.  相似文献   

18.
Metabolites of algae such as geosmin, 2-methylisoborneol etc. are reported to induce pungent odors into drinking water and attract additional scientific attention. Recently, in China, taste and odor outbreaks in drinking water supply have become increasingly common. In source water affected by eutrophication, dimethyl trisulfide, speculated to be produced by decayed algae, was found to be the source of taste and odor issues and can be removed effectively by usual oxidation agents. In this experimental study, batch scale tests were carried out focusing on the removal of dimethyl trisulfide. Reaction kinetics of dimethyl trisulfide oxidized by potassium permanganate in water had been studied; influence factors such as pH, organic substrate, other existed taste, and odor contaminant in equivalent concentration were also discussed. Results showed that dimethyl trisulfide can be removed by potassium permanganate efficiently; the ratio can reach more than 70% with oxidant dosage of 4 mg·L-1 and contact time prolonged to 120 min. The dimethyl trisulfide decomposition followed a second-order kinetics pattern with a rate constant k = 0.00213 L·(min·mg)-1. Typically, the degradation rate of dimethyl trisulfide was increased with the increasing KMnO4 dosage, but dramatically dropped with the increasing levels of humic acid (1.8–4.5 mg·L-1) and other odor-causing compounds (e.g. β-cyclocitral, 0–1886.0 μg·L-1). Solution pH (5.2–9.0) and initial dimethyl trisulfide concentration did not significantly affected the degradation. This study demonstrates that KMnO4 oxidation is an effective option to remove dimethyl trisulfide from water.  相似文献   

19.
• Cu0.15-ACF performs the best for H2S and PH3 simultaneous removal. • 550°C and 90°C are separately calcination and reaction temperatures. • The reason why Cu0.15/ACF shows better performance was found. • The accumulation of H2PO4 and SO42−(H2O)6 is the deactivation cause of Cu0.15/ACF. Poisonous gases, such as H2S and PH3, produced by industrial production harm humans and damage the environment. In this study, H2S and PH3 were simultaneously removed at low temperature by modified activated carbon fiber (ACF) catalysts. We have considered the active metal type, content, precursor, calcination, and reaction temperature. Experimental results exhibited that ACF could best perform by loading 15% Cu from nitrate. The optimized calcination temperature and reaction temperature separately were 550°C and 90°C. Under these conditions, the most removal capacity could reach 69.7 mg/g and 132.1 mg/g, respectively. Characterization results showed that moderate calcination temperature (550°C) is suitable for the formation of the copper element on the surface of ACF, lower or higher temperature will generate more cuprous oxide. Although both can exhibit catalytic activity, the role of the copper element is significantly greater. Due to the exceptional dispersibility of copper (oxide), the ACF can still maintain the advantages of larger specific surface area and pore volume after loading copper, which is the main reason for better performance of related catalysts. Finally, increasing the copper loading amount can significantly increase the crystallinity and particle size of copper (oxide) on the ACF, thereby improving its catalytic performance. In situ IR found that the reason for the deactivation of the catalyst should be the accumulation of generated H2PO4 and SO42−(H2O)6 which could poison the catalyst.  相似文献   

20.
Chemical looping combustion is a promising technology for energy conversion due to its low-carbon, high-efficiency, and environmental-friendly feature. A vital issue for CLC process is the development of oxygen carrier, since it must have sufficient reactivity. The mechanism and kinetics of CO reduction on iron-based oxygen carriers namely pure Fe2O3 and Fe2O3 supported by alumina (Fe2O3/Al2O3) were investigated using thermo-gravimetric analysis. Fe2O3/Al2O3 showed better reactivity over bare Fe2O3 toward CO reduction. This was well supported by the observed higher rate constant for Fe2O3/Al2O3 over pure Fe2O3 with respective activation energy of 41.1±2.0 and 33.3±0.8 kJ·mol−1. The proposed models were compared via statistical approach comprising Akaike information criterion with correction coupled with F-test. The phase-boundary reaction and diffusion control models approximated to 95% confidence level along with scanning electron microscopy results; revealed the promising reduction reactions of pure Fe2O3 and Fe2O3/Al2O3. The boosting recital of iron-based oxygen carrier support toward efficient chemical looping combustion could be explained accurately through the present study.  相似文献   

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