SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
·
IF 4.61
Guo-Qiang Li,Zheng-Yang Huo,Qian-Yuan Wu,Yun Lu,Hong-Ying Hu
An ultraviolet (UV)-based advanced oxidation process (AOP) for disinfecting water is introduced in this paper. This study aimed to evaluate the potential of UV light-emitting diodes (UV-LEDs)/chlorine AOP (UV/Cl 2 ) for Bacillus subtilis spore inactivation. Chlorine was combined with 265 and 280 nm LEDs (UV 265 /Cl 2 , UV 280 /Cl 2 ) and investigated. The addition of 4.0 mg/L of free chlorine at pH 7.0 in the presence of 125 mJ/cm 2 of UV irradiation resulted in an additional 1.8-log reduction in UV 265 /Cl 2 and 1.5-log reduction in UV 280 /Cl 2 . There was no observed enhancement in spore inactivation with the addition of a radical scavenger, t-BuOH, which indicated the role of • OH in the synergistic effect. To quantitatively evaluate the synergism, the primary treatment with UV/Cl 2 was followed by further UV or Cl 2 treatment. After UV/Cl 2 pretreatment at different pH levels, the 265 and 280 nm LEDs treatment enhanced an approximate 0.4–0.5-log reduction compared to UV only, and Cl 2 treatment enhanced an approximate 0.7–1.1-log reduction compared to Cl 2 only. In addition, at pH 7.0, in UV 265 /Cl 2 -Cl 2 and UV 280 /Cl 2 -Cl 2 , the inactivation rate constant k increased by approximately 2 and 1.5 times, respectively. The CT for the lag phases ( CT lag ) reduced to approximately 67 and 58%, respectively. Similar results were obtained at pH 7.5 and 8.0, and in the secondary effluent. The synergistic effect on spore inactivation suggested that the pathogen inactivation efficiency of sequential UV and chlorine disinfection processes, which are commonly applied, can be significantly enhanced by adding chlorine prior to UV treatment .
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HIGH PERFORMANCE POLYMERS
·
2018
·
IF 1.047
Lei Wang,Guifen Gong,Junyao Shen,Jinsong Leng
Polyimide (PI)/titanium dioxide (TiO2) composite nanofibers (NFs) with average diameters of 200–250 nm were synthesized via electrospinning. The total number density of dipoles decreased significantly, owing to the porous structures and compact interface between TiO2 NPs and PI matrix. All PI/TiO2 NFs maintain low dielectric constants and losses. For example, the dielectric constants of PI/TiO2-6% NFs are all lower than 2.6, being exposed to temperatures from 25°C to 200°C. Meantime, the dielectric losses of PI/TiO2-6% NFs are below 0.005. For ultraviolet (UV)-light shielding performance, the PI/TiO2 NFs exhibited good UV-light shielding and corresponding anti-photoaging properties. The reason can be ascribed from high UV-light absorption and scattering ability in the TiO2 NPs. The best UV-light absorption (average: 3.71) and corresponding absorption decay (15.13%) were achieved for optimized PI/TiO2-6% NFs. Other fundamental characteristics, such as the thermal stability, mechanical tensile property, and hydrophobicity, were also investigated. Such low dielectric constant PI/TiO2 composite NFs can be alternatively chosen under a longtime UV-light exposing condition.
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COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2018
·
IF 4.514
Yuewei Li,Jie Zhong,Lixin Wu,Zixiang Weng,Longhui Zheng,Shuqiang Peng,Xu Zhang
High performance stereolithography resin (SLR) nanocomposites with different amount of modified polyhedral oligomeric silsesquioxane (m-POSS) nanoparticles, which were synthesized through NH 2 -POSS and 2-isocyanatoethyl methacrylate, have been prepared. By copolymerization POSS nanoparticles can be grafted onto the polymer chains of the SLR matrix. The modified structure of POSS nanoparticles was characterized by Fourier transform infrared spectroscopy and 1 H NMR. The effects of m-POSS nanoparticles on morphologies, mechanical and thermal properties of SLR nanocomposites were investigated in detail. The results show that the tensile and flexible strength were improved by 36.2% and 40% respectively with the addition of 5% w/w m-POSS nanoparticles compared to pristine SLR. The nanoindentation analysis shows a significant amelioration in hardness and reduced modulus by the introduction of m-POSS nanoparticles. The results from thermal studies reveal that the incorporation of m-POSS nanoparticles can significantly enhance the glass transition temperature ( T g ), degradation temperature, char yield, and heat distortion temperature of nanocomposites. Moreover, the incorporation of m-POSS nanoparticles would not only improve the mechanical and thermal properties, but also maintain the high fabrication accuracy of the SLR for 3D stereolithography printing.
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JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2018
·
IF 2.891
Jia Deng,Guangxue Wu,Shoujun Yuan,Xinmin Zhan,Wei Wang,Zhen-Hu Hu
Ciprofloxacin (CIP) is a widely used third generation fluoroquinolone antibiotics, and has been often detected in wastewater treatment plants. Finding an effective way to remove them from wastewater is of great concern. Ultraviolet (UV)/chlorine advanced oxidation process (AOP) has many advantages in micropollutant removal. In this study, CIP degradation in UV/chlorine process was investigated. Only 41.2% of CIP was degraded by UV photolysis and 30.5% by dark chlorination in 30 min, while 98.5% of CIP was degraded by UV/chlorine process in 9 min. HCO 3 − had markedly inhibition, NO 3 − and SO 4 2- had slight inhibition, and Cl − had a marginal inhibition on CIP degradation in UV/chlorine system. The degradation of CIP in UV/chlorine process was mainly attributed to the attack of reactive species. The relative contributions of hydrated electrons (e aq ), hydroxyl radicals (HO ), chlorine atoms (Cl ), and UV photolysis were investigated. Under neutral condition in aqueous solution, CIP degradation had highest pseudo first-order reaction rate constant, in which e aq had the highest contribution, followed by Cl , HO , and UV photolysis. The intermediates and byproducts were identified and the degradation pathway was proposed. The total organic chlorine (TOCl) and biotoxicity were further assessed. CIP and natural organic matters (NOMs) were removed efficiently in real water. UV/chlorine showed the potential for the wastewater treatment containing CIP.
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CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Yin Xu,Ying Wu,Wei Zhang,Xiaohui Fan,Yan Wang,Hui Zhang
Sucralose (SUC) is ubiquitously present in aquatic ecosystems in many parts of the world, owing to its widespread usage and ineffective elimination in wastewater treatment plants. This study investigated the mineralization of SUC in aqueous solution via UV/O 3 process and found that SUC can be mineralized efficiently. Effect of several operating parameters like solution pH, O 3 concentration, gas flow rate and initial SUC concentration, on TOC removal were explored. Results indicated that the mineralization efficiency of SUC reached almost 90% in 120 min after UV/O 3 treatment at neutral pH. The intensity of hydroxyl radicals generated in sole O 3 and UV/O 3 processes were compared using the fluorescence spectra analysis. Toxicity tests carried out using Daphnia Magna indicated that the UV/O 3 process under the used experimental conditions was much more effective in the detoxification of the SUC solution than sole O 3 process. The presence of inorganic anion like NO 3 − exhibited an enhancement on the mineralization rate, while Cl − showed some positive effect at low concentration (1 mM) but inhibited SUC mineralization at higher concentrations (10–200 mM). Finally, the intermediates produced in UV/O 3 process were identified by LC-MS analysis and a possible transformation pathway was briefly discussed.
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JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2018
·Vol. 33
·期 2
·485-491
·
IF 0.524
Yuan Yan,Wu Haiqiang,Liu Jingcheng,Luo Jing,Liu Ren,Liu Xiaoya
A novel photosensitive copolymer P(SS-co-AA-g-GMA) (PSAG) was synthesized and utilized to noncovalently functionalize pristine single-walled carbon nanotubes (SCNTs). PSAG was highly effective for the solubilization of SCNTs in water and validated by UV-vis absorption spectra experiments, resulting in homogeneous and stable PSAG-SCNT aqueous dispersion. The microstructure of SCNTs was observed through Raman spectroscopy and transmission electron microscopy. In addition, compared with the two common polymeric dispersants of Triton X-100 and PSS, PSAG demonstrated more effective performances for dispersing SCNTs under identical conditions. Furthermore, the photosensitive PSAG-SCNTs can be crosslinked after UV irradiation, leading to significant improvement in the water resistance of SCNT films. UV-cured films can be transferred to plastic wrap to form a flexible film with high electrical conductivity.
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PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2018
·
IF 3.441
Tao Lu,Ying Chen,Min Liu,Wenju Jiang
In this study, a batch experiment was used to investigate the degradation of real evaporative condensing liquid of shale gas wastewater (ECLSGW). We showed that compared to the O 3 , ultraviolet (UV), UV/TiO 2 , and O 3 /UV/TiO 2 processes, the O 3 /UV process has better performance in removing the chemical oxygen demand (COD) and total organic carbon (TOC) of ECLSGW under the same conditions. The effects of initial pH (3–12), ozone flow rate (0.1–0.5 L/min), UV power (15–50 W), and reaction time (0–60 min) on the degradation of ECLSGW via the O 3 /UV process were investigated using a single-factor experiment. Moreover, the optimal experimental conditions were obtained using a quadratic polynomial prediction model (R Adj 2 =0.9961) that was obtained from the central composite design (CCD) of the response surface methodology (RSM). Under optimal experimental conditions, the COD and TOC removal efficiency reached 93.12 and 95.5%, respectively. In addition, gas chromatography–mass spectrometry analysis showed that the O 3 /UV process could nearly completely mineralize organic pollutants in the ECLSGW. Hydrogen peroxide (H 2 O 2 ) and hydroxyl radical ( OH) were identified by manganese dioxide (MnO 2 ) and tert-butanol (TBA). The mechanism research showed that OH plays an important role in the degradation of organic pollutants. In summary, the O 3 /UV process is an effective method to degrade ECLSGW.
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RSC Advances
·
2018
·Vol. 8
·期 22
·12315-12321
·
IF 2.936
Lixian Xu,Di Wu,Bingrong Zhou,Yang Xu,Wenjuan Wang,Dinghua Yu,Dan Luo
Sunscreen is believed to protect human skin from photo damage due to UV exposure. However, substantial concerns remain associated with skin contact with UV filters and the subsequent reactive oxygen species from photoactivation of UV filters. Herein, we show that the microencapsulation of octyl p-methoxycinnamate (OMC), a typical UV filter, into the nanoporous structure of zeolitic imidazole frameworks (ZIF-8) prevents the skin exposure to UV filters while improving UV protection performance. Meanwhile, the UV filter photostability has been obviously improved due to the nanoconfinement effect. Microencapsulated OMC in ZIF-8 adhered to the stratum corneum could not only reduce OMC transdermal penetration, but also prevent skin exposure to the deleterious reactive oxygen species (ROS) from photoactivation of OMC. Therefore, this microencapsulated UV filter system based on a metal organic frameworks microporous polymer would find important applications in skin care products through providing safe and effective UV protection.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2015
·Vol. 23
·期 2
·1035-1043
·
IF 2.828
Yuan Yanan,Wang Yajie,Ding Wei,Li Jinjun,Wu Feng
Transformation of inorganic arsenic species has drawn great concern in recent decades because of worldwide and speciation-dependent pollution and the hazards that they pose to the environment and to human health. As(III) photooxidation in aquatic systems has received much attention, but little is known about photochemical transformation of arsenic species on top soil. As(III) photooxidation on natural montmorillonite under UV-A radiation was investigated by using a moisture- and temperature-controlled photochemical chamber with two black-light lamps. Initial As(III) concentration, pH, layer thickness, humic acid (HA) concentration, the presence of additional iron ions, and the contribution of reactive oxygen species (ROS) were examined. The results show that pH values of the clay layers greatly influenced As(III) photooxidation on montmorillonite. As(III) photooxidation followed the Langmuir–Hinshelwood model. HA and additional iron ions greatly promoted photooxidation, but excess Fe(II) competed with As(III) for oxidation by ROS. Scavenging experiments revealed that natural montmorillonite induced the conversion of As(III) to As(V) by generating ROS (mainly HO • and HO 2
• /O 2
•− ) and that HO • radical was the predominant oxidant in this system. Our work demonstrates that photooxidation on the surface of natural clay minerals in top soil can be important to As(III) transformation. This allows understanding and predicting the speciation and behavior of arsenic on the soil surface.
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ACS Applied Materials & Interfaces
·
2014
·
IF 5.9
Jianzhong Du,Hui Sun
Presented in this paper is a hybrid polymer/titanium dioxide (TiO2) vesicle that has excellent UV-screening efficacy and strong capacity to encapsulate antioxidant agents. Poly(ethylene oxide)-block-poly(2-(dimethylamino)ethyl methacrylate)-block-polystyrene (PEO-b-PDMAEMA-b-PS) triblock terpolymer was synthesized by atom transfer radical polymerization (ATRP) and then self-assembled into vesicles. Those vesicles showed excellent UV-screening property due to the scattering by vesicles and the absorption by PS vesicle membrane. The selective deposition of solvophobic tetrabutyl titanate in the PDMAEMA shell and the PS membrane of the vesicles led to the formation of polymer/TiO2 hybrid vesicles, resulting in an enhanced UV-screening property by further reflecting and scattering UV radiation. The vesicles can effectively encapsulate antioxidant agents such as ferulic acid (up to 57%), showing a rapid antioxidant capability (within 1 min) and a long-lasting antioxidant effect.
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CHROMATOGRAPHIA
·
2015
·Vol. 78
·期 11
·833-837
·
IF 1.411
Zhang Mingyu,Qiu Danye,Kang Jingwu
A simple, sensitive and environmentally friendly capillary electrophoresis method for the determination of free sulfate anions in heparin and low-molecular-weight heparin with indirect UV detection is reported. The background electrolyte consists of 20 mM nitrate (pH 5.5) containing 0.2 mM CTAB. The use of nitrate as the probe anion is based on the consideration that nitrate has a very close electrophoretic mobility to that of sulfate, leading to a very narrow peak shape. Moreover, the apparent molar absorptivity of nitrate at 202 nm (8413 L mol −1 cm −1 ) is much higher than that of the commonly used probe anion chromate at 254 nm (2400 L mol −1 cm −1 ). The combination of the narrow peak shape with the high apparent molar absorptivity of the probe ion improved the limit of detection by 2.4 times and the limit of quantitation by 3.2 times. The effect of various CE parameters on the separation of sulfate from chloride was investigated and optimized. The method displays linearity in the range from 0.05 to 20 mM. The RSD % for intraday ( n = 6), and interday ( n = 3) repeatability in terms of migration times and peak areas were all less than 3 %. The limit of detection ( S / N = 3) and limit of quantitation ( S / N = 10) for sulfate were determined as 18 and 53 µM, respectively. The method was successfully applied for the quantification of sulfate anions in heparin and low-molecular-weight heparins.
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PROGRESS IN ORGANIC COATINGS
·
2013
·
IF 1.848
Ren Liu,Jiajia Zhu,Jing Luo,Xiaoya Liu
With a view to developing high performance UV curable coatings with high renewable contents, acrylated epoxidized soybean oil (AESO) was combined with a novel kind of biorenewable tannic acid-based hyperbranched methacrylates (TAHAs). The TAHAs were synthesized by ring-opening reaction of glycidyl methacrylate (GMA), glycidyl ester of Versatic acid (CE10) and natural tannic acid (TA). The epoxy groups of GMA and CE10 were involved in the ring-opening reaction with the hydroxyl groups of TA while residual methacrylate groups can carry out photopolymerization . By controlling the ratio of GMA and CE10, TAHAs with varying degree of methacrylate groups have been prepared. The synthesized TAHAs were formulated into acrylated epoxidized soybean oil (AESO) based UV curable coatings to produce the biorenewable materials based UV curable coatings. The effects of TAHAs on AESO coated film properties of pendulum hardness, flexibility and adhesion were investigated. Mechanical properties , thermal properties and biodegradability of the cured films were also evaluated. With the incorporation of TAHAs, the hardness, adhesion, tensile strength of the cured coating films were remarkably improved, which were attributed to the unique structure of hyperbranched methacrylates. Meanwhile, the biorenewable content was not greatly decreased due to the biorenewable character of tannic acid in TAHAs. These results showed that TAHAs as efficient toughening agents could produce UV-curable coatings of balanced coating performance with reasonably high biorenewable content. Moreover, the environment degradability of AESO-based cured films was also enhanced after the addition of TAHAs.
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