Cationic phenylene ethynylene polymers and oligomers exhibit efficient antiviral activity

The antiviral activities of poly(phenylene ethynylene) (PPE)-based cationic conjugated polyelectrolytes (CPE) and oligo-phenylene ethynylenes (OPE) were investigated using two model viruses, the T4 and MS2 bacteriophages. Under UV/visible light irradiation, significant antiviral activity was observed for all of the CPEs and OPEs; without irradiation, most of these compounds exhibited high inactivation activity against the MS2 phage and moderate inactivation ability against the T4 phage. Transmission electron microscopy (TEM) and SDS polyacrylamide gel electrophoresis (SDS-PAGE) reveal that the CPEs and OPEs exert their antiviral activity by partial disassembly of the phage particle structure in the dark and photochemical damage of the phage capsid protein under UV/visible light irradiation.     

An integrated technique using zero-valent iron and UV/H2O2 sequential process for complete decolorization and mineralization of C.I. Acid Black 24 wastewater

The zero-valent iron (ZVI) reduction succeeds for decolorization, while UV/H(2)O(2) oxidation process results into mineralization, so that this study proposed an integrated technique by reduction coupling with oxidation process in order to acquire simultaneously complete both decolorization and mineralization of C.I. Acid Black 24. From the experimental data, the zero-valent iron addition alone can decolorize the dye wastewater yet it demanded longer time than ZVI coupled with UV/H(2)O(2) processes (Red-Ox). Moreover, it resulted into only about 30% removal of the total organic carbon (TOC), which was capable to be effectively mineralized by UV/H(2)O(2) process. The proposed sequential ZVI-UV/H(2)O(2) integration system cannot only effectively remove color and TOC in AB 24 wastewater simultaneously but also save irradiation power and time demand. Furthermore, the decolorization rate constants were about 3.77-4.0 times magnitude comparing with that by UV/H(2)O(2) process alone.     

Photodegradation of Reactive Black 5, Direct Red 28 and Direct Yellow 12 using UV, UV/H(2)O(2) and UV/H(2)O(2)/Fe(2+): a comparative study

The photodegradation of three commercially available dyestuffs (C.I. Reactive Black 5, C.I. RB5, C.I. Direct Yellow 12, C.I. DY12, and C.I. Direct Red 28, C.I. DR28) by UV, UV/H(2)O(2) and UV/H(2)O(2)/Fe(II) processes was investigated in a laboratory-scale batch photoreactor equipped with an 16W immersed-type low-pressure mercury vapour lamp. The experimental results were assessed in terms of absorbance and total organic carbon (TOC) reduction. The initial concentration was kept constant at 100 mg l(-1) for all dyes. Initial results showed that, color removal efficiencies by UV or H(2)O(2) alone were negligible for all dyes. Almost complete disappearance of C.I. RB5 (99%) and DY12 (98%) in UV/H(2)O(2) process was possible to achieve after 60 min of irradiation. The maximum color removal efficiency of C.I. DR28 after 60 min of irradiation, however, was only 40% and reached a maximum value of 70% after 120 min of irradiation. Corresponding mineralization efficiencies were 50, 55 and 7-12%, respectively. The addition of Fe(II) to the system, so-called the photo-Fenton process, greatly enhanced the color removal, the efficiencies being 98, 88 and 85% for C.I. RB5, C.I. DY12 and C.I. DR28 only after 5 min of irradiation. Corresponding mineralization efficiencies were 98% for 45 min irradiation, 100% for 60 min irradiation and 98% for 90 min irradiation, respectively. However, marginal benefit was less significant in the higher range of both H(2)O(2) and Fe(II). Furthermore, decreases in both decolorization and mineralization were observed at higher concentrations of oxidant and catalyst due to the scavenging effect of excess H(2)O(2) and OH radicals. The degradation of all dyes was found to follow first-order reaction kinetics.     

Ametryn degradation in the ultraviolet (UV) irradiation/hydrogen peroxide (H2O2) treatment

Ultraviolet (UV) irradiation (253.7nm) in the presence of hydrogen peroxide (H(2)O(2)) was used to decompose aqueous ametryn. The concentrations of ametryn were measured with time under various experiment conditions. The investigated factors included H(2)O(2) dosages, initial pH, initial ametryn concentrations, and a variety of inorganic anions. Results showed that ametryn degradation in UV/H(2)O(2) process was a pseudo-first-order reaction. Removal rates of ametryn were greatly affected by H(2)O(2) dosage and initial concentrations of ametryn, but appeared to be slightly influenced by initial pH. Furthermore, we investigated the effects of four anions (SO(4)(2-), Cl(-), HCO(3)(-), and CO(3)(2-)) on ametryn degradation by UV/H(2)O(2). The impact of SO(4)(2-) seemed to be insignificant; however, Cl(-), HCO(3)(-), and CO(3)(2-) considerably slowed down the degradation rate because they could strongly scavenge hydroxyl radicals (OH) produced during the UV/H(2)O(2) process. Finally, a preliminary cost analysis revealed that UV/H(2)O(2) process was more cost-effective than the UV alone in removal of ametryn from water.     

Photochemical mineralization of di-n-butyl phthalate with H2O2/Fe3+

This study evaluated the performance of photo-Fenton reaction initiated by the UV irradiation with H(2)O(2)/Fe(3+), denoted as UV/H(2)O(2)/Fe(3+), to decompose di-n-butyl phthalate (DBP) in the aqueous solution. The concentration of total organic carbon (TOC) was chosen as a mineralization index of the decomposition of DBP by the UV/H(2)O(2)/Fe(3+) process. A second-order kinetic model with respect to TOC was adequately adopted to represent the mineralization of DBP by the UV/H(2)O(2)/Fe(3+) process. The experimental results of this study suggested that the dosages with 4.74 x 10(-5) mol min(-1)L(-1) H(2)O(2) and initial Fe(3+) loading concentration of 4.50 x 10(-4) mol L(-1) in the solution at pH 3.0 with 120 microW cm(-2) UV (312 nm) provided the optimal operation conditions for the mineralization of DBP (5 mg L(-1)) yielding a 92.4% mineralization efficiency at 90 min reaction time.     

Reaction paths and efficiency of photocatalysis on TiO2 and of H2O2 photolysis in the degradation of 2-chlorophenol

The kinetics of 2-chlorophenol (2-CP) degradation and mineralization in the aqueous phase was investigated under irradiation at 254 nm, employing either photocatalysis in the presence of titanium dioxide, or hydrogen peroxide photolysis, to compare the efficiency of these photoinduced advanced oxidation techniques. Photocatalysis under 315-400 nm wavelength irradiation was also investigated. The concentration versus time profiles of the degradation intermediates catechol, chloro- and hydroxy-hydroquinone allowed the identification of the reaction paths prevailing under the different experimental conditions. Efficient CCl bond cleavage occurred as a consequence of direct light absorption by 2-CP, while hydroxyl radicals, photogenerated at the water-photocatalyst interface or during H(2)O(2) photolysis, were the main oxidation agents, able to attack both 2-CP and its degradation intermediates. Highest degradation and mineralization efficiencies were achieved under H(2)O(2) photolysis at 254 nm.     

纳米Cu2+/TiO2抗菌膜对禽流感病毒(H9N2)的灭活效应

利用病毒滴度测定和MDCK细胞电镜观察法,初步探讨了在365nm的黑光灯(UV)照射下,纳米Cu2+/TiO2抗菌膜对禽流感病毒(H9N2)的光催化灭活效应,并分别考察了UV强度、UV照射时间以及H9N2病毒量对H9N2病毒光催化灭活效应的影响.实验结果表明,在365nm黑光灯的照射下,纳米Cu2+/TiO2抗茵膜对H9N2病毒具有显著的灭活效应,在UV强度为0.5mW/cm2、UV照射时间为2.5h、病毒量为0.1ml时,H9N2病毒的灭活率达到了100%.研究结果表明,纳米Cu2+/TiO2抗菌膜在抑制禽流感(H9N2)病毒在环境媒介中的扩散与传播方面有潜在的应用价值.     

Degradation and by-product formation of diazinon in water during UV and UV/H(2)O(2) treatment

Kinetics and degradation products resulting from the application of UV and UV/H(2)O(2) to the US EPA Contaminant Candidate List pesticide diazinon were studied. Batch experiments were conducted with both monochromatic (low pressure [LP] UV 253.7 nm) and polychromatic (medium pressure [MP] UV 200-300 nm) UV sources alone or in the presence of up to 50 mg l(-1) H(2)O(2), in a quasi-collimated beam apparatus. Degradation of diazinon by both UV and UV/H(2)O(2) exhibited pseudo first order reaction kinetics, and quantum yield of 8.6 x 10(-2) and 5.8 x 10(-2) mol E(-1) for LP and MP lamps respectively. Photolysis studies under MP UV lamp showed 2-isopropyl-6-methyl-pyrimidin-4-ol (IMP) to be the main degradation product of diazinon at aqueous solution pH values of 4, 7 and 10. Trace levels up to 1.8 x 10(-3) microM of diazinon oxygen analogue diethyl 2-isopropyl-6-methylpyrimidin-4-yl phosphate (diazoxon) were detected only during the UV/H(2)O(2) reaction. Decay of both products was observed, as the UV/H(2)O(2) reaction prolonged, yet no mineralization was achieved over the UV fluence levels examined. Photolysis kinetics, quantum yield and UV/H(2)O(2) degradation of the reaction product IMP was determined using MP UV lamp at pH values of 4, 7 and 10.     

超声协同控制污水厂紫外消毒出水大肠杆菌光复活的实验研究

污水厂出水经紫外(UV)消毒后存在微生物光复活现象,为此考查了超声(US)协同控制紫外消毒出水大肠杆菌光复活的效果。经研究发现:紫外辐照剂量与城市污水厂二级处理出水中的大肠杆菌灭活率具有良好的线性关系,相关系数达到0.99;超声作为预处理协同紫外作用时,在能耗相等时,使大肠杆菌1h内光复活率降低了59%,在光复活率基本相等的情况下,使能耗降低50%;从经济性及水质的微生物安全性考虑,可采用US-UV作为污水厂出水消毒的技术。     

Keggin型钨硅酸铯光电化学及光催化制氢性质的研究

本文成功制备了钨硅酸铯多相光电材料，利用IR、XRD、TG—DTA、UV—vis／DRS、TEM和N2吸附一脱附等技术对其进行了组成和结构表征。结果表明：它的分子式为Cs3HSiW12O40·5．5H2O，属于立方晶系，形貌为球形，粒径大小在100-300nm之间，其比表面积为124．6m2／g。在200-400nm有很强的紫外吸收。光催化制氢实验表明，在甲醇-水体系中，125W Hg灯照射下，平均产氢速率为10．8μmol／h，该催化剂在循环使用中活性基本保持不变。光电化学实验表明，钨硅酸铯是一个良好的光电材料。     

Photodegradation of methyl tert-butyl ether (MTBE) by UV/H2O2 and UV/TiO2

Two UV-based advanced oxidation processes (AOPs), UV/H2O2 and UV/TiO2, were tested in batch reactor systems to evaluate the removal efficiencies and optimal conditions for the photodegradation of methyl tert-butyl ether (MTBE). The optimal conditions at an initial MTBE concentration of 1 mM ([MTBE]0=1 mM) were acidic and 15 mM H2O2 in UV/H2O2 system, and pH 3.0 and 2.0 g/l TiO2 in UV/TiO2 suspended slurries system under 254-nm UV irradiation. Under the optimal conditions, MTBE photodegradation during the initial period of 60 min in UV/H2O2 and UV/TiO2 systems reached 98 and 80%, respectively. In both systems, MTBE photodegradation decreased with increasing [MTBE]0. While MTBE photodegradation rates increased with increasing dosage of H2O2 (5-15 mM) and TiO2 (0.5-3 g/l), further increase in the dosage of H2O2 (20 mM) or TiO2 (4 g/l) adversely reduced the MTBE photodegradation. Pseudo first-order kinetics with regard to [MTBE] can be used to describe the MTBE photodegradation in both systems. The pseudo first-order rate constants linearly increased with the increase in the molar ratio of [H2O2]0 to [MTBE]0 in UV/H2O2 system and linearly increased with the decrease in [MTBE]0 in UV/TiO2 system.     

Tandem mass spectrometry of intact proteins for characterization of biomarkers from Bacillus cereus T spores.

Intact protein biomarkers from Bacillus cereus T spores have been analyzed by high-resolution tandem Fourier transform ion cyclotron resonance mass spectrometry. Two techniques have been applied for excitation of the isolated multiply charged precursor ion species: sustained off-resonance irradiation/collisionally activated dissociation and electron capture dissociation. Fragmentation-derived sequence tags and BLAST sequence similarity proteome database searches allow unequivocal identification of the major biomarker protein with unprecedented specificity. Sequence-specific fragmentation patterns further confirm protein identification. Moreover, methodology combining accurate mass measurements of intact proteins with additional information contained in a proteome database permits tentative assignment of several other protein biomarkers isolated from the B. cereus T spores. We argue that approaches involving tandem MS of protein biomarkers, combined with bioinformatics, can drastically improve the specificity of individual microorganism identification, particularly in complex environments.     

Efficient photodegradation of Acid Red B by immobilized ferrocene in the presence of UVA and H2O2

SiO2-C2H4-ferrocene (SiCFe) was synthesized by covalent grafting of ferrocene on functionalized silica gel with a -C2H4- linkage. On the basis of characterization by diffuse reflectance UV-vis spectra (DRS) and Fourier transform infrared spectra (FT-IR), ferrocene has been successfully anchored on the silica gel. Under UVA (lambdamax=365 nm) irradiation, the catalyst exhibited high photocatalytic activity in the degradation of Acid Red B (ARB), especially in the presence of H2O2. Meanwhile, the catalytic activity of SiCFe was maintained effectively even after reused for 4 times without any significant destruction of ferrocene. The influence of initial solution pH and wavelength of UV light on the catalyst's activity was also investigated. Electron spin resonance (ESR) studies revealed that both OH and HO2/O2- radicals were involved as the active species in the ARB degradation process. Furthermore, results of total organic carbon (TOC) and FT-IR analysis indicated that ARB degradation proceeded by the cleavage of NN, followed by hydroxylation and opening of phenyl rings to form aliphatic acids and further oxidization of the aliphatic acids to produce carbon dioxide and water. A possible reaction mechanism was proposed on the basis of all the information obtained under various experimental conditions.     

铜及其氧化物薄膜对大肠杆菌的强抑制作用

采用直流磁控溅射,靶材为金属铜靶,调节氧气和氩气流量,制备了以石英玻璃为基底颗粒大小在20～50nm之间的Cu和Cu2O纳米薄膜,研究了大肠杆菌与纳米铜系氧化物薄膜的相互作用。通过紫外可见分光光度计,掠入射小角X射线衍射(GIXRD),SEM分别对样品的光学性能、晶体结构、形貌特征进行了研究,发现纳米Cu和Cu2O薄膜均对大肠杆菌具有强抑制作用。在光照下,Cu2O薄膜除了具有金属离子抗菌效应外,光催化抗菌效应表现强烈;Cu薄膜表面有部分被氧化为Cu2O,有助于协同抗菌。     

Application of artificial neural networks for modeling of the treatment of wastewater contaminated with methyl tert-butyl ether (MTBE) by UV/H2O2 process

During the last two decades, methyl tert-butyl ether (MTBE) has been widely used as an additive to gasoline (up to 15%) both to increase the octane number and as a fuel oxygenate to improve air quality by reducing the level of carbon monoxide in vehicle exhausts. The present work mainly deals with photooxidative degradation of MTBE in the presence of H2O2 under UV light illumination (30W). We studied the influence of the basic operational parameters such as initial concentration of H2O2 and irradiation time on the photodegradation of MTBE. The oxidation rate of MTBE was low when the photolysis was carried out in the absence of H2O2 and it was negligible in the absence of UV light. The addition of proper amount of hydrogen peroxide improved the degradation, while the excess hydrogen peroxide could quench the formation of hydroxyl radicals (OH). The semi-log plot of MTBE concentration versus time was linear, suggesting a first order reaction. Therefore, the treatment efficiency was evaluated by figure-of-merit electrical energy per order (E(Eo)). Our results showed that MTBE could be treated easily and effectively with the UV/H2O2 process with E(Eo) value 80 kWh/m3/order. The proposed model based on artificial neural network (ANN) could predict the MTBE concentration during irradiation time in optimized conditions. A comparison between the predicted results of the designed ANN model and experimental data was also conducted.     

Photodegradation of nitrobenzene using 172 nm excimer UV lamp

Photodegradation of nitrobenzene (NB) using an excimer UV lamp at a wavelength of 172 nm is investigated. Experimental results show that high concentration nitrobenzene can be efficiently degraded with irradiation by excimer UV lamp, and confirm that degradation of nitrobenzene is more efficient by UV/H(2)O(2) combination than UV only. In the case of using UV only, 60 min of treatment was found to be sufficient to degrade the major part of NB solution with a concentration of less than 4mM. In the case of using the combination of UV/H(2)O(2) with a H(2)O(2) concentration of 7:1 molar ratio to NB, 4.07 mM NB solution drastically decreased to 0.41 mM after treatment for only 20 min. Degradation intermediate products are identified by analyzing the degradation products with GC/HRMS and possible degradation pathways of nitrobenzene are suggested.     

Characterization and Photocatalytic Efficiency of TiO2 /Ti Beads Fabricated by Simple Heat-Treatment

The goal of the present study was to investigate the photocatalytic efficiency of titanium dioxide (TiO 2) formed on titanium (Ti) bead substrate (referred herein as TiO 2 /Ti beads) by heat treatment when exposing to ultraviolet (UV) light irradiation.Escherichia coli was used as the model test organism.The results show 4-log and 7-log decrease in bacterial concentration after a test time of 15 and 120 min,respectively,using TiO 2 /Ti beads irradiated with UV light in a tin-foil covered beaker.This article presents the potential of TiO 2 on Ti bead substrate formed by simple heat-treatment together with UV light for bacterial inactivation.     

Degradation of C.I. Reactive Red 2 (RR2) using ozone-based systems: comparisons of decolorization efficiency and power consumption

This study investigated the decolorization efficiency of C.I. Reactive Red 2 (RR2) in O3, O3/H2O2, O3/Fe3+, O3/H2O2/Fe3+, UV/O3, UV/O3/Fe3+, UV/O3/H2O2 and UV/O3/H2O2/Fe3+ systems at various pHs. The effective energy consumption constants and the electrical energy per order of pollutant removal (EE/O) were also determined. The experimental results indicated that the energy efficiency was highest at [H2O2]0=1000mg/l and [Fe3+]0=25mg/l. Accordingly, the H2O2 and Fe3+ doses in the hybrid ozone- and UV/ozone-based systems were controlled at these values. This work suggests that the dominant reactant in O3, O3/Fe3+ and O3/H2O2 systems was O3 and that in the O3/H2O2/Fe3+ system was H2O2/Fe3+. The experimental results revealed that the combinations of Fe3+ or H2O2/Fe3+ with O3 at pH 4 and of H2O2 or H2O2/Fe3+ with UV/O3 at pH 4 or 7 yielded a higher decolorization rate than O3 and UV/O3, respectively. At pH 4, the EE/O results demonstrated that the UV/O3/H2O2/Fe3+ system reduced 85% of the energy consumption compared with the UV/O3 system. Moreover, the O3/H2O2/Fe3+ system reduced 62% of the energy consumption compared with the O3 system. At pH 7, the EE/O results revealed that the UV/O3/H2O2/Fe3+ system consumed half the energy of the UV/O3 system.     

The effect of microwave-assisted for photo-catalytic degradation of rhodamine B in aqueous nano TiO2 particles dispersions

The photo-catalytic decomposition of rhodamine B was examined in aqueous nano TiO2 particles dispersions to assess effects of the microwave radiation assisted photo-catalytic process driven by UV radiation. The results of photo-catalytic degradation of rhodamine B showed that the decomposition rate increased with the microwave intensity, UV intensity, TiO2 particle dosages and the circulating fluid velocity. Addition of oxygen gas in the photo-catalytic degradation of rhodamine B increased the reaction rate. The effect of addition of H2O2 was not significant when photo-catalysis was used without additional microwave radiation or when microwave was irradiated without the use of photo-catalysts. When H2O2 was added under simultaneous use of photo-catalysis and microwave irradiation, however, considerably higher degradation reaction rates were observed. This study demonstrates that the microwave irradiation can play a very important role in photo-catalytic degradation.     

Degradation of natural organic matter in surface water using vacuum-UV irradiation

The use of vacuum-UV (VUV) radiation to degrade natural organic matter (NOM) and the main variables affecting the efficiency of this process were investigated using an annular photoreactor. After 180 min of irradiation with VUV, the total organic carbon (TOC) decreased from 4.95 ppm to 0.3 ppm. Also, decadic absorption coefficients of the water at 185 nm and 254 nm decreased from 3.2 cm(-1) to 2.85 cm(-1), and 0.225 cm(-1) to 0 cm(-1), respectively. The reactor operation was kinetically controlled for Reynolds numbers greater than 600, changes of pH between 5 and 9 had little effect, and increases in alkalinity decreased the process efficacy. Additionally, H(2)O(2)/VUV and VUV processes were compared to H(2)O(2)/UV and UV processes, where the formers showed greater effectiveness with complete mineralization of NOM as opposed to partial oxidation with H(2)O(2)/UV, and no mineralization with UV alone. Modeling and analysis of the photon flux and absorption in the reactor showed that 99% of the 185 nm radiation was absorbed by the water in the reactor. In comparison, only 48% of the 254 nm radiation was absorbed by the water. The overall quantum efficiency of the mineralization for VUV was 0.10 for 50% TOC reduction.