溶剂浮选光度法测定印染废水中的活性艳红X-3B

研究了溶剂浮选光度法测定水中活性艳红X-3B时的影响因素,并优化了溶剂浮选条件。实验表明,本法的浮选率大于96%,当染料含量在50~2 500μg/50mL范围时与离子缔合物的吸光度具有很好的线性关系,相关系数为0.9998,RSD为1.4%。该法与溶剂萃取法相比,分离富集效果更好,并已成功用于实际印染废水中活性艳红X-3B的测定。     

三种不同阳极上活性艳红X-3B的光电降

 分别以TiO2/Ti, SnxSb1-xO2/Ti和RuxPd1-xO2/Ti为阳极,钛网为阴极,NaCl为电解质,研究了活性艳红X-3B的光化学降解、电化学降解以及光电协同降解行为. 实验表明,经光电协同降解60 min后,三种电极体系中活性艳红X-3B的脱色率都超过了97%,三种电极上都存在显著的光电协同效应,即导体阳极与半导体阳极体系表现出相似的光电协同效应. SnxSb1-x-O2/Ti阳极体系先电解后光照和先光照后电解对比实验结果表明,电解生成的中间产物在光照3 min后使染料脱色率由17%迅速提高到75%,而先光照后电解则无此现象发生, 这说明电解中间产物经紫外光激发后对染料脱色有显著作用.     

负载型纳米TiO2光催化降解活性艳红X-3B染料

光催化氧化;负载型纳米光催化剂;负载型纳米TiO2光催化降解活性艳红X-3B染料     

丙酮酸钠/UV体系对模拟活性艳红X-3B废水的脱色

丙酮酸是大气中存在最丰富的酮酸之一,存在于气溶胶、雨水、城市大气、海洋及偏远地区[1]。有数据表明,大气中丙酮酸的主要消除过程是光解,同时也有与OH·自由基的反应[2]。丙酮酸在250-400nm波长范围内有较强吸收[3],光解产生包括OH·自由基在内的多种活性物种,其光解过程可用     

一阶导数光谱法同时测定水样中的罗丹明B和活性艳红X-3B

为解决罗丹明B(RB)和活性艳红X-3B(RBR)的零阶可见光谱重叠问题,建立了一阶导数光谱法同时检测水样中RB和RBR含量的方法.分别选择540 nm和553 nm作为RB和RBR的测定波长,RB和RBR分别在0.3～14 mg/L浓度范围内与一阶导数光谱呈现线性关系.检出限分别为0.19,0.06 mg/L.在 p...     

TiO2/SiO2的制备及其对染料X-3B溶液降解的光催化活性

以粗孔球形硅胶为载体,以聚乙二醇和二乙醇单乙醚的钛酸四丁酯无水乙醇溶液为浸涂液,用涂覆法制备了TiO     

活性艳红X-3B水溶液的光催化脱色及矿化过程研究

对染料活性艳红X-3B水溶液的光催化反应过程进行了初步研究.首先,利用紫外-可见吸收光谱、高效液相色谱和质谱对反应过程中溶液组成的变化进行了测试,并用重铬酸盐法测定了各反应时刻溶液的COD值;其次,使用红外吸收光谱对反应过程中催化剂表面的吸附物种进行了考察.研究结果表明,在本实验条件下,活性艳红X-3B水溶液的光催化脱色和矿化过程是同时进行的,脱色反应完成后,溶液中生成了难以降解的中间产物,致使矿化过程难以继续进行.     

活性艳红X-3B水溶液的光化学与光催化协同脱色反应

 对影响活性艳红X－3B水溶液光化学与光催化协同脱色反应的各种条件（如溶液的pH值,紫外光照强度,空气流量,催化剂用量及溶液的初始浓度等）进行了考察．结果表明,降解率随着紫外光照强度的增强而加快,随着X－3B初始浓度的增大而减慢;催化剂最佳用量为4g／L,空气最佳流量为4．3L／h．在X－3B水溶液的光催化脱色过程中,存在有光解反应,但它远不如光催化反应重要．因此,活性艳红X－3B水溶液的降解是光化学与光催化的协同脱色反应．     

TiO2/SiO2的制备及其对染料X-3B溶液降解的光催化活性

 以粗孔球形硅胶为载体,以聚乙二醇和二乙醇单乙醚的钛酸四丁酯无水乙醇溶液为浸涂液,用涂覆法制备了TiO2／SiO2光催化剂．用XRD,SEM和UV－Vis等对催化剂的物相、形貌及TiO2负载量进行了表征,并通过可溶性染料活性艳红X－3B的降解反应,考察了其光催化活性．实验结果表明,当选用16．79％TiO2／SiO2光催化剂时,活性艳红X－3B溶液的脱色率可达93％以上．     

Interaction of brilliant red X-3B with bovine serum albumin and application to protein assay

The interaction of brilliant red X-3B (BRX) with bovine serum albumin (BSA) in three pH media has been characterized by the spectral correction technique. The binding number maximum of BRX was determined to be 102 at pH 2.03, 82 at pH 3.25 and 38 at pH 4.35 and the binding mechanism was analyzed in detail. The effects of ionic strength from 0 to 1 mol L⁻¹ and temperature from 20 to 70 °C on the binding were investigated. The results showed that the interaction of BRX with BSA responded to the Langmuir adsorption isothermal model and the binding constant was determined. From the correlation between the binding number and the number of basic amino acid residues, the ion-pair attraction induced the union of non-covalent bonds including H-bond, van der Waals force and hydrophobic bond and the binding model was illustrated. The binding of BRX to BSA has resulted in change of the BSA conformation confirmed by means of circular dichroism. Using this interaction at pH 2.03, a sensitive method named the absorbance ratio difference spectrometry was established and applied to the protein assay and the limit of detection of protein was only 6 μg L⁻¹. Two samples were determined and the results were in agreement with those obtained by the classical coomassie brilliant blue colorimetry.     

Synergetic degradation of chitosan with gamma radiation and hydrogen peroxide

Chitosan samples were irradiated by ⁶⁰Co γ-rays in the presence of hydrogen peroxide with radiation dose from 10 kGy to 100 kGy. The degradation was monitored by gel permeation chromatography (GPC), revealing the existence of a synergetic effect on the degradation. Structures of the degraded products were characterized with Fourier-transform infrared spectra (FT-IR), ultraviolet-visible spectral (UV-vis) analysis, and X-ray diffraction (XRD). Results showed that the crystallinity of chitosan decreases with degradation, and the crystalline state of water-soluble chitosan is entirely different from that of water-insoluble chitosan. An elemental analysis method was employed to investigate changes in the element content of chitosan after degradation. Mechanism of chitosan radiation degradation with and without hydrogen peroxide was also discussed.     

Vitamin B3 as a high acid-alkali tolerant peroxidase mimic for colorimetric detection of hydrogen peroxide and glutathione

Small-molecule enzyme mimics as biocatalysts have been extensively applied in diverse colorimetric sensors fabrication. However, excavating potential organic enzyme mimics with high catalytic activity still remains challenging. In this study, the peroxidase mimicking activity of nicotinic acid (VB3) was demonstrated for the first time through chromogenic substrate 3, 3′, 5, 5′-tetramethylbenzidine (TMB) at the existence of hydrogen peroxide (H₂O₂). The catalytic activity of VB3 kept more than 80% of its optimum activity in a broad pH range of 3.0–9.0. In addition, the kinetic parameter (Michaelis constant, K_m = 0.037 mM) of VB3 catalysis to H₂O₂ is smaller than natural horseradish peroxidase (HRP) and previously reported peroxidase mimics. The catalytic mechanism of VB3 is mainly attributed to the active species of hydroxyl radical (OH) and partially attributed to the superoxide free radicals (O₂^?). A convenient and sensitive colorimetric method based on VB3-H₂O₂-TMB chromogenic system for H₂O₂ and glutathione detection was fabricated with the linear ranges of 5.0–100.0 μM and 5.0–50.0 μM, respectively. In short, this work will not only bring new enlightenment on the physiological functions and practical applications in the analytical field of VB3, but also provide a new type of structural reference for small-molecule enzyme mimics.     

Preparation of TiO<Subscript>2</Subscript>/activated carbon with Fe ions doping photocatalyst and its application to photocatalytic degradation of reactive brilliant red K2G

Titanium dioxide coated on activated carbon (AC) with Fe ions doping (Fe-TiO₂/AC) composite was prepared by an improved sol-gel method. The photocatalytic activities were tested by photocatalytic degradation of reactive brilliant red K2G in solution. The results show that in comparison with the agglomeration of pure TiO₂, the TiO₂ nanoparticles are well dispersed in the AC matrix, of which sizes are decreased with Fe ions doping. Additionally, the iron species on TiO₂ of composite are Fe₂O₃ and FeO, which do not affect the crystalline structures of TiO₂ nanoparticles. The AC matrix and iron doping content influence the fluorescence intensity of composite due to their effects on recombination probability of hole-electron pairs. Compared with TiO₂, 0.3% Fe-TiO₂, TiO₂/AC, 0.5% Fe-TiO₂/AC and 0.1% Fe-TiO₂/AC, the 0.3% Fe-TiO₂/AC shows the highest photoactivity with the complete mineralization of K2G for finite time due to the optimum Fe ions content and AC matrix. Furthermore, the kinetic constant (k = 0.0229 min⁻¹) of 0.3% Fe-TiO₂/AC composite is more than the sum of both TiO₂/AC (0.0154 min⁻¹) and 0.3% Fe-TiO₂ (0.0057 min⁻¹) because coexistence of the AC and Fe ions has an enlarging effect on improving the photoactivity of TiO₂. Supported by the Education Department Foundation of Hunan Province (Grant No. 08B063) and Science and Natural Science Foundation of Hunan Province (Grant No. 09JJ6101)     

Ultrasensitive fluorometric determination of hydrogen peroxide and glucose by using multiferroic BiFeO3 nanoparticles as a catalyst

BiFeO₃ magnetic nanoparticles (BFO MNPs) are used as a catalyst to develop an ultrasensitive method for the determination of H₂O₂. It is found that BFO MNPs can catalyze the decomposition of H₂O₂ to produce OH radicals, which in turn oxidize the weakly fluorescent benzoic acid to a strongly fluorescent hydroxylated product with a maximum emission at 405 nm. This makes it possible to sensitively quantify traces of H₂O₂. Under optimized conditions, the fluorescence intensity is observed to be well linearly correlated with H₂O₂ concentration from 2.0 × 10⁻⁸ to 2.0 × 10⁻⁵ mol L⁻¹ with a detection limit of 4.5 × 10⁻⁹ mol L⁻¹ (S/N = 3). In addition, a selective method for glucose determination is developed by using both glucose oxidase and BFO MNPs, which has a linear range for glucose concentration from 1.0 × 10⁻⁶ to 1.0 × 10⁻⁴ mol L⁻¹ with a detection limit of 5.0 × 10⁻⁷ mol L⁻¹. These new methods have been successfully applied for the determination of H₂O₂ in rainwater and glucose in human serum samples.