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紫外分光光度法测定2,4-二氯苯酚 总被引:2,自引:0,他引:2
2,4-二氯苯酚被世界野生动物基金会列为潜在的内分泌修正化学物质,即环境荷尔蒙物质.这类物质在环境中虽然含量低,但却显示出超常的内分泌效应,因而对其的监测分析显得尤为重要.目前,分析2,4-二氯苯酚的方法有比色法[1]和色谱法[2].色谱法虽然快速、准确,但对仪器要求高,操作复杂,而比色法灵敏度低.用紫外分光光度法测定河水中的2,4-二氯苯酚. 相似文献
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《催化学报》2016,(4)
采用固态分散法成功制备了表面活性剂修饰的不同V_2O_5含量的二元氧化物催化剂,运用X射线衍射、漫反射光谱、红外光谱、扫描电镜和N_2吸附-脱附法对该纳米复合物进行了表征,并在紫外光照射下考察了其光催化降解2,4-二氯苯酚的性能.结果表明,50 wt%,V_2O_5-TiO_2(记为50V_2O_5-TiO_2)表现出比单纯V_2O_5,TiO_2和P25更高的光催化活性,V_2O_5和TiO_2之间的相互作用会影响二元氧化物催化剂的光催化效率.CTAB和HTAB的修饰显著增加了50V_2O_5-TiO_2样品的催化效率,其中(50V_2O_5-TiO_2)-CTAB催化剂在反应30 min后表现出最高的2,4-二氯苯酚降解率(100%)和反应速率(2.22 mg/(L·min)).表面活性剂的加入能修饰二元氧化物中V_2O_5和TiO_2的光学和电子性质,从而显著提高其光催化活性. 相似文献
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采用循环伏安法和原位红外光谱技术研究了2,4-二氯苯酚在Pt电极上的电化学氧化降解反应,结合Fukui函数值预测了2,4-二氯苯酚在电化学氧化过程中的反应位点. 结果表明,Pt电极对2,4-二氯苯酚有良好的电催化活性,2,4-二氯苯酚在电极表面反应主要有3个途径:直接通过电化学反应脱去氯离子,生成苯酚;在·OH的进攻下,C—Cl键断裂,4位Cl较2位Cl先脱去,生成苯二酚,并可进一步氧化生成苯醌以及不饱和羧酸;在·OH的进攻下发生苯环开环反应,生成含氯不饱和羧酸. 在1700 mV左右,2,4-二氯苯酚可经电化学氧化生成CO2. 相似文献
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鱼塘水中残留的2种除草剂(2,4-二氯-6-硝基苯酚和五氯酚)经GDX201固相萃取柱富集后,用二氯甲烷洗脱,洗脱液用N-(叔丁基二甲硅烷基)-N甲基三氟乙酰胺衍生化,所得衍生化产物溶于乙酸乙酯中,用气相色谱法测定,从而获得上述2种除草剂的含量。2,4-二氯-6-硝基苯酚和五氯酚的峰面积与其质量浓度均在10~200μg.L-1内呈线性关系,检出限(3S/N)分别为0.09μg.L-1和0.16μg.L-1。以鱼塘水为基体进行加标回收试验,测得回收率依次为98.3%,98.6%;测定值的相对标准偏差(n=5)分别为3.6%和4.3%。 相似文献
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以2,4-二甲基-6-叔丁基苯酚、多聚甲醛和三氯氧磷为原料,在四氯化碳溶剂中合成了6-叔丁基-3-氯甲基-2,4-二甲基苯酚并确定较佳的工艺条件,分别考察了物料配比、反应温度、反应时间和相转移催化剂用量对反应收率的影响。确定较佳工艺为:在四氯化碳溶剂中,反应温度为40℃,2,4-二甲基-6-叔丁基苯酚用量为60 g,多聚甲醛12 g,浓盐酸30 g,相转移催化剂4 g,三氯氧磷40 g。在上述条件下,6-叔丁基-3-氯甲基-2,4-二甲基苯酚的收率为95%,纯度>99%(HPLC面积归一化法),产品结构经IR、MS和~1H-NMR表征。 相似文献
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以2,4-二氯苯酚(DCP)与牛血清白蛋白的偶联物DCP-BSA为人工抗原,免疫新西兰大白兔,获得特异性的抗体.建立并优化了荧光免疫检测方法,工作曲线表明DCP在1~100 μg/L范围内呈良好的线性关系,回归方程为:IF=21.30lg ρ 29.13,相关系数r=0.991 5,DCP检出限为0.41 μg/L,抑制中质量浓度为9.18 μg/L,且对其它结构类似酚类化合物均有特异性识别.本法可应用于检测环境中微量的2,4-二氯苯酚. 相似文献
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《中国化学快报》2020,31(10):2769-2773
This study demonstrated interesting ultrafast activation of molecular O2 by copper oxide (CuO) particles and very rapid elimination of aqueous 2,4-dichlorophenol (2,4-DCP) within reaction time of 30 s. Electron paramagnetic resonance (EPR) characterization indicated that OH, Cu3+, 1O2 and O2− were generated in the CuO/O2 systems, wherein O2− would be the main reactive species responsible for 2,4-DCP degradation. It was further found that the catalytic ability of CuO for O2 activation was highly size dependent and nano-CuO was far reactive than micro-CuO. H2 temperature-programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM) analyses revealed that both the quantity and the reactivity of the surface reaction sites (surface Cu+ and O2) could determine the catalytic ability of CuO affecting efficient Cu+-based molecular oxygen activation. Moreover, the O2 activation ability of CuO would depend on not only the dimension, but also crystalline factors, for example, the exposed facets. 相似文献
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《中国化学快报》2021,32(8):2529-2533
Bimetallic nanoparticles modified hollow-structured nanoporous carbons (NPCs) have been fabricated via a convenient one-step carbonizing strategy derived from covalent organic framework. The Pd/Fe/NPCs, Pt/Fe/NPCs and Rh/Fe/NPCs were obtained and can be used as Fenton-like catalysts with good stability and reusability. The catalytic activity was evaluated by the degradation of 2,4-dichlorophenl (2,4-DCP). These fabricated bimetallic catalysts exhibited much higher catalytic activity than Fe/NPCs at room temperature. The enhancement of catalytic ability was benefited from synergetic catalytic effect of bimetallic nanoparticles and accelerated mass transfer of hollow structure. Additionally, the enhanced catalytic mechanism of bimetallic catalysts was studied in detail and the reasonable reaction pathway was proposed. Besides, the bimetallic catalysts were successfully used for degradation of 2,4-DCP in actual industrial wastewater and the removal efficiency could reach 74.3% within 120 min, which demonstrated the promising potential application of bimetallic catalysts in the removal of pollutants in environment. 相似文献
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T. López M. Alvarez F. Tzompantzi M. Picquart 《Journal of Sol-Gel Science and Technology》2006,37(3):207-211
Because of its semiconductor properties, sol-gel zirconia can be used as a photocatalyst. When zirconia is doped with transition
metals, its electronic properties are modified. In this work, sol-gel Mn/ZrO2 and ZrO2 materials were tested for photocatalytic degradation of 2,4-dichlorophenoxiacetic acid and 2,4,6-trichlorophenol. The powders
were characterized by XRD, UV-Vis and Raman spectroscopy. The apparent rate constants were calculated assuming pseudo-first
order kinetics. The results reveal that ZrO2 is effective as a photocatalyst; moreover, its photocatalytic properties improve when it is doped with manganese. 相似文献
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A combined cluster and periodic study has been carried out to elucidate the stability of hydrated species on the vanadia/titania
catalyst. First, the hydration of a V2O5 cluster was analyzed for the successive adsorption of one to four water molecules. The dimeric skeleton is found to be preserved
at a low water concentration. However, after the adsorption of four water molecules on the dimer, it is found to break to
generate stable monomeric OV(OH)3 units. The two moieties are related by the equation:
Such OV(OH)3 units have been taken as a monomer model for the periodic representation of the vanadia/titania catalyst. On the (100) surface,
the OV(OH)3 moieties are anchored by three V–O–Ti bonds to the support surface in a pyramidal arrangement. The vanadyl V=O bond is found
to be very stable. 相似文献
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分别采用普通浸渍法(VWTi-con)和超声辅助浸渍法(VWTi-HUST)制备了V2O5/WO3-TiO2催化剂,并用X射线衍射、扫描电镜、拉曼光谱和X射线光电子能谱等技术对催化剂进行了表征,评价了水热老化前后两种催化剂的NH3-SCR脱除模拟柴油车尾气中NOx的反应活性,并与国外成熟商品催化剂进行了比较.结果表明,制备方法可影响V2O5/WO3-TiO2催化剂的水热稳定性,VWTi-con催化剂老化后几乎完全失活,而VWTi-HUST具有优异的水热稳定性,与国外成熟商品催化剂性能相当.与传统浸渍法相比,超声辅助浸渍法增强了活性物种和载体的相互作用,提高了活性组分的分散性等.采用该法制备的VWTi-HUST催化剂将具有较强的商业应用性;台架试验正在进行中,以期满足柴油车国IV排放标准的要求. 相似文献
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Cetyltrimethyl ammonium bromide (CTAB) was used in a sol-gel route to synthesize porous lanthanum titanate. The materials are composed of perovskite La2Ti2O7 in monoclinic system. The addition of CTAB does not cause phase transformation, but leads to a slight decreasing tendency of La2Ti2O7 crystallite size. Both the pore volume and pore size distribution range are enlarged after using CTAB. The sample obtained with 4 g CTAB has the maximum BET specific surface area of 42.4 m2/g. When the amount of CTAB is less than 4 g, the increase in photocatalytic degradation efficiency is almost in linear relationship to the amount of CTAB. The reaction rate constants are 0.0032, 0.0116 and 0.0237 min−1 on the La2Ti2O7 samples obtained using 0, 2 and 4 g CTAB. The functional groups in azophloxine molecule are decomposed during photocatalytic oxidation with extending irradiation time. 相似文献
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Simple and fast spectrophotometric determination of H(2)O(2) in photo-Fenton reactions using metavanadate 总被引:1,自引:0,他引:1
This work proposes a spectrophotometric method for the determination of hydrogen peroxide during photodegradation reactions. The method is based on the reaction of H2O2 with amonium metavanadate in acidic medium, which results in the formation of a red-orange color peroxovanadium cation, with maximum absorbance at 450 nm. The method was optimized using the multivariate analysis providing the minimum concentration of vanadate (6.2 mmol L−1) for the maximum absorbance signal. Under these conditions, the detection limit is 143 μmol L−1. The reaction product showed to be very stable for samples of peroxide concentrations up to 3 mmol L−1 at room temperature during 180 h. For higher concentrations however, samples must be kept refrigerated (4 °C) or diluted. The method showed no interference of Cl− (0.2-1.3 mmol L−1), NO3− (0.3-1.0 mmol L−1), Fe3+ (0.2-1.2 mmol L−1) and 2,4-dichlorophenol (DCP) (0.2-1.0 mmol L−1). When compared to iodometric titration, the vanadate method showed a good agreament. The method was applied for the evaluation of peroxide consumption during photo-Fenton degradation of 2,4-dichlorophenol using blacklight irradiation. 相似文献
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采用表面改性法制备了负载型复合半导体材料V2O5-TiO2/SiO2,并用X射线衍射、比表面积测定、拉曼光谱、程序升温还原和紫外-可见漫反射光谱等技术对固体材料的结构和光响应性能进行了表征. 结果表明,V2O5和TiO2在负载型复合半导体V2O5-TiO2/SiO2表面有相互修饰的作用. 一方面,V2O5能扩展TiO2的光响应范围,使TiO2的吸光区域由紫外光区拓宽至可见光区,从而提高了复合半导体对光能的利用率; 另一方面,TiO2则有助于提高V2O5在载体表面的分散程度,抑制VOx的聚合,减小V2O5的微晶尺寸,提高固体材料的能隙值和氧化还原能力. 相似文献
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Cu/V2O5-TiO2的光催化丙烯和二氧化碳合成MAA反应性能 总被引:4,自引:0,他引:4
用IR、TPD、UV-Vis和微型光反应器技术研究了CO2和C3H6在Cu/V2O5-TiO2表面上的吸附特性和光催化反应性能.实验结果表明:在Cu/V2O5-TiO2催化剂表面存在金属位Cu、Lewis酸位V^5 和Ti^4 以及Lewis碱位V-O-Ti的桥氧和V=O的端氧三类活性中心;在金属位Cu和Lewis酸位Ti^4 (或V^5 )协同作用下.CO2形成活性较高的卧式吸附态Cu-(CO)-O→Ti^4 (或V^5 ).C3H6的β-H和β-C分别吸附在Lewis碱位V=O与金属位Cu上形成Cu-C(CH2CH3)-H→O=V吸附态;Cu/V2O5-TiO2催化剂的吸光阈值红移和光吸收量的提高均有利于其光催化活性的提高;担载10%V2O5的光催化剂催化活性优于其它含量的催化剂,其光量子效率达到15.1%;C3H6转化率为5.5%,MAA选择性超过95%.根据实验结果.提出了光促表面催化合成反应的机理. 相似文献