查找使用阿拉丁产品的科研文献

CoMn2O4 Catalyst Prepared Using the Sol-Gel Method for the Activation of Peroxymonosulfate and Degradation of UV Filter 2-Phenylbenzimidazole-5-sulfonic Acid (PBSA)

Chihao Lin,Dejian Shi,Zhentao Wu,Lingfeng Zhang,Zhicai Zhai,Yingsen Fang,Ping Sun,Ruirui Han,Jiaqiang Wu,Hui Liu

In this study, a bimetallic oxide catalyst of cobalt-manganese (CoMn2O4) was synthesized using the sol-gel method, and it was then characterized using a variety of techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) spectroscopy, X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption–desorption isotherms. The obtained novel catalyst, i.e., CoMn2O4, was then used as an activator of peroxymonosulfate (PMS) for the catalytic degradation of a commonly-used UV filter, 2-phenylbenzimidazole-5-sulfonic acid (PBSA) in water. The effects of various factors (e.g., catalyst dosage, PMS concentration, reaction temperature, and pH) in the process were also evaluated. Chemical scavengers and electron paramagnetic resonance (EPR) tests showed that the•OH and SO4•−were the main reactive oxygen species. Furthermore, this study showed that CoMn2O4is a promising catalyst for activating PMS to degrade the UV filters.Keywords:CoMn2O4;catalytic degradation;peroxymonosulfate;UV filters;2-phenylbenzimidazole-5-sulfonic acid (PBSA)

Growing Nano-SiO2 on the Surface of Aramid Fibers Assisted by Supercritical CO2 to Enhance the Thermal Stability, Interfacial Shear Strength, and UV Resistance

Luwei Zhang,Haijuan Kong,Mengmeng Qiao,Xiaoma Ding,Muhuo Yu

Aramid fibers (AFs) with their high Young′s modulus and tenacity are easy to degrade seriously with ultraviolet (UV) radiation that leads to reduction in their performance, causing premature failure and limiting their outdoor end use. Herein, we report a method to synthesize nano-SiO2on AFs surfaces in supercritical carbon dioxide (Sc-CO2) to simultaneously improve their UV resistance, thermal stability, and interfacial shear strength (IFSS). The effects of different pressures (10, 12, 14, 16 MPa) on the growth of nanoparticles were investigated. The untreated and modified fibers were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It was found that the nano-SiO2-decorated fibers exhibited improvement of thermal stability and mechanical properties, and the IFSS of the nano-SiO2modified fibers increases by up to 64% compared with the untreated fibers. After exposure to 216 h of UV radiation, the AFs-UV shows a less decrease in tensile strength, elongation to break and tensile modulus, retaining only 73%, 91%, and 85% of the pristine AFs, respectively, while those of AFs-SiO2-14MPa-UV retain 91.5%, 98%, and 95.5%. In short, this study presents a green method for growing nano-SiO2on the surface of AFs by Sc-CO2to enhance the thermal stability, IFSS, and UV resistance.Keywords:aramid fiber;nano-SiO2;supercritical CO2;thermal stability;interfacial shear strength;UV resistance

Effect of UV/TiO2 pretreatment on fouling alleviation and mechanisms of fouling development in a cross-flow filtration process using a ceramic UF membrane

Tao Yang,Houfeng Xiong,Fen Liu,Qiyong Yang,Bingjie Xu,Changchao Zhan

In the application of ultrafiltration (UF) for removal of natural organic matter (NOM) from water, membrane fouling has always been considered a big issue. The influence of UV/TiO 2 photocatalysis as pretreatment to mitigate cross-flow ceramic UF membrane fouling caused by humic acid (HA) and the involved mechanisms of fouling development were investigated. The characterization of dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA), excitation-emission matrix (EEM), molecular weight (MW), hydrophilicity, fouling resistance, scanning electron microscopy (SEM) and model fitting using Hermia blocking models were performed. The dominant membrane fouling patterns can be predicated by the initial intermediate pore blocking, transition fouling and the final stage of limited cake growth. With extended UV/TiO 2 pretreatment time, a significant reduction of cake filtration coefficients and a slight decrease in pore blocking coefficients were observed. Longer UV/TiO 2 pretreatment achieved the remarkable effect of reversible fouling elimination as a result of reaching the final stage of limited cake growth earlier and aggregation forming a porous cake layer by TiO 2 particles mixed with more hydrophilic (HPI) and high MW (>50 kDa) humic-like substances. However, photocatalytic pretreatment exhibited a slight effect on the mitigation of irreversible fouling that was mainly dominated by HPI fractions, especially tryptophan-like protein (5–50 kDa) organics attaching to and/or blocking the membrane pores.

Comparison of the anti-inflammatory active constituents and hepatotoxic pyrrolizidine alkaloids in two Senecio plants and their preparations by LC–UV and LC–MS

Pinghong Chen,Yi Wang,Lulin Chen,Wei Jiang,Yan Niu,Qing Shao,Lu Gao,Quancheng Zhao,Licheng Yan,Shufang Wang

Two Senecio plants, Senecio cannabifolius Less. and its variety S. cannabifolius Less. var. integrifolius (Kiodz.) Kidam., were both used as the raw material of Feining granule, a traditional Chinese medicine product for treating respiratory diseases. In this study, the chemical profiles of these two plants were investigated and compared by liquid chromatography–mass spectrometry (LC–MS) and nuclear magnetic resonance (NMR). A total number of 83 constituents, including 55 organic acids, 11 flavonoids, 4 alkaloids, 3 terpenes and 10 other types of compounds, were characterized. The results indicated that the levels of most flavonoids were higher in S. cannabifolius than in S. cannabifolius var. integrifolius , however, the levels of hepatotoxic pyrrolizidine alkaloids (PAs) were higher in S. cannabifolius var. integrifolius than in S. cannabifolius . Fifteen constituents were evaluated on lipopolysaccharides (LPS) induced RAW 264.7 cells, and eleven of them showed inhibition effect against nitric oxide (NO) production. Finally, the levels of ten major constituents (including seven anti-inflammatory active ones) and two PAs in Feining granule from two Senecio plants were determined and compared by the LC–UV and LC–MS methods, respectively. It was found that one organic acid (homogentisic acid) and two PAs (seneciphylline and senecionine) had higher contents in the preparation of S. cannabifolius var. integrifolius than in that of S. cannabifolius , however, the situations were inverse for the levels of four organic acids and flavonoids (chlorogenic acid, hyperoside, isoquercitrin, and isochlorogenic acid B). Based on the above results, S. cannabifolius might be a better raw material for Feining granule than S. cannabifolius var. integrifolius , because it contained more anti-inflammatory constituents and less hepatotoxic PAs than the latter. However, more pharmacological evaluations should be carried out to support the selection. The results in this study were helpful for the quality control of Feining granule.

Effect of adjustable molecular chain structure and pure silica zeolite nanoparticles on thermal, mechanical, dielectric, UV-shielding and hydrophobic properties of fluorinated copolyimide composites

Qing Li,Guangfu Liao,Shulai Zhang,Long Pang,Hao Tong,Wenzhe Zhao,Zushun Xu

A series of polyimide (PI) films, polyimide/pure silica zeolite nanoparticles (PSZN) blend films and polyimide/amine-functionalized pure silica zeolite nanoparticles (APSZN) composite films were successfully prepared by random copolycondensation. Thereinto, PSZN were synthesized by hydrothermal method. The polyimides were derived from 4,4′-diaminodiphenyl ether (ODA), and three adjustable molar ratios (3:1, 1:1, 1:3) of 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl] propane dianhydride (BPADA) and 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA). The effects of PSZN, APSZN and different chain structure on PI films were specifically evaluated in terms of morphology, thermal, mechanical, dielectric and UV-shielding properties, etc. Comparison was given among pure PI flims, PI/PSZN blend films and PI/APSZN composite flims. The results showed that the thermal and mechanical properties of PI films were drastically impaired after adding PSZN. On the contrary, the strength, toughness and thermal stability were improved after adding APSZN. Moreover, the dielectric constants of the PI/APSZN composite flims were lowered but UV-shielding properties were enhanced. Interestingly, we found that the greatest effects were obtained through introducing APSZN in PI derived by the 1:1 ratio of BPADA:6FDA. The corresponding PI/APSZN composite flim exhibited the most reinforced and toughened properties, the largest decrement of dielectric constant and the best UV-shielding efficiency, which made the composite flim be used as ultraviolet shielding material in outer space filled with high temperature and intensive ultraviolet light. Meanwhile, this work also provided a facile way to synthesize composite materials with adjustable performance.

Facile synthesis of UV-curable fluorosilicone polymers and coatings with good corrosive resistance on account of the reaction of disulfide bonds with vinyl groups

Zhen Yang,Yongping Bai,Binxiao Wei,Yutao Cui,Ruolin Wang,Wei Zhang,Yingying Li,Linghui Meng,Yu Wang

A new UV curing strategy is introduced into the curing field of fluorosilicone polymers. This strategy is predicated on the reaction of sulfur radicals generated from disulfide bonds with vinyl groups under the presence of UV light. Here, we engineered and synthesized a kind of novel fluorosilicone polymers (FS-SS) with disulfide bonds and vinyl groups. The disulfide bonds contained in FS-SS undergo photocleavage under ultraviolet irradiation, generating sulfide radicals, which can interact with vinyl groups to complete the curing reaction. Subsequently, the UV curing behavior of coatings on the basis of the novel polymers and photo-initiator 1173 was investigated by FT-IR spectroscopy and a possible UV-curable reaction mechanism based on disulfide bonds and vinyl groups was proposed. The results showed that curing reactions based on disulfide bonds and vinyl groups can reach a relatively high degree of reaction in a short period of time in terms of reaction rate. However, the lower conversion rate of the reaction may be due to the fact that the sulfur radicals generated by disulfide bonds are more inclined to form disulfide bonds rather than undergo addition reactions with vinyl groups. Subsequently, a series of fluorosilicone coatings with good optical transparency (transmittance above 90 %), good hydrophobicity (the lowest value of surface energy is 21.54 mN/m), lower roughness value (Ra values was in the region of 2.24 nm– 12.2 nm) and high temperature resistance were prepared by utilizing this curing strategy. Furthermore, the applicable experiment of fluorosilicone coatings to protect tinplate as anti-corrosive coatings was also performed. The corrosive resistance results formalize its practical value for possible application as preventive coatings.

Insights into enhanced degradation of antibiotic trimethoprim in water using a novel K doped g-C3N4 photocatalyst under vacuum-UV irradiation: Performance and mechanisms

Wen Lu,Aimin Wang,Yanyu Zhang,Songyu Ren,Zhongguo Zhang

In this work, an innovative strategy combining vacuum ultraviolet (VUV) and K doping graphite carbon nitride (K-g-C 3 N 4 ) was proposed for antibiotic removal in aqueous. The properties of K-g-C 3 N 4 were systematically characterized by XRD, FT-IR, BET, SEM, UV-vis DRS, and XPS, showing that K-g-C 3 N 4 possessed a larger specific surface and richer functional groups than g-C 3 N 4 . The catalytic efficiency of K-g-C 3 N 4 was investigated for the trimethoprim (TMP) removal under VUV irradiation. Compared with UVC photolysis, VUV photolysis, UVC/g-C 3 N 4 , VUV/g-C 3 N 4 , and UVC/K-g-C 3 N 4 processes, VUV/K-g-C 3 N 4 enhanced the pseudo-first-order reaction rate constant of TMP removal by 2.0–19.7 times and the mineralization rate by 9.0%-38.2%. Electron paramagnetic resonance results and quenching experiments validated that O 2 •- , • OH, 1 O 2 , h + , and e - were engaged in the VUV/K-g-C 3 N 4 process. The fluorescent spectra of O 2 •- -substituted and • OH-substituted products revealed that the K-g-C 3 N 4 greatly enhanced the quantity of O 2 •- and • OH during VUV irradiation. The VUV/K-g-C 3 N 4 system produced marginally more H 2 O 2 and • OH than the UVC/K-g-C 3 N 4 system, confirming that K-g-C 3 N 4 predominantly utilized the UVC and other ultraviolet–visible light emitted by the VUV lamp, with VUV having a minor effect. Furthermore, K-g-C 3 N 4 had exceptional stability and reusability, efficiently degrading various contaminants under VUV irradiation. This work offered a comprehensive insight into VUV/K-g-C 3 N 4 process as a novel approach for antibiotic removal from water.

A comprehensive study on the impact of UV aging time on the adsorption and desorption behaviors of antibiotics on degradable and non-degradable microplastics

Wenrui He,Sui’an Wan,Meng Xu,Wei Wei,Dongfang Wang,Chuan Yi,Yufeng Zhao

The extensive use of microplastics (MPs) and antibiotics has not only exacerbated environmental pollution, but the composite pollutants formed by them also pose escalating ecological risks. This study investigated the impact of aging time on the biodegradable polylactic acid (PLA) and non-degradable polyvinyl chloride (PVC), as well as the adsorption/desorption behavior of norfloxacin (NOR), ciprofloxacin (CIP), and sulfamethoxazole (SMZ) onto these MPs. The effects of ultraviolet (UV) aging (30, 60, and 90 days) on MPs’ physicochemical properties and adsorption performance were systematically evaluated. The results showed that UV aging altered MPs’ surface morphology, crystallinity, and surface charge, enhancing their adsorption capacity. Adsorption kinetics followed the pseudo-second-order model, while isotherms aligned with the Freundlich model, indicating multilayer adsorption governed by physical and chemical interactions (e.g., hydrogen bonding, electrostatic, hydrophobic, and π-π interactions). The adsorption capacities followed the order NOR > CIP > SMZ, with aged PLA exhibiting superior performance (PLA-90d > PLA-60d > PLA-30d > pristine PLA > PVC-90d > PVC-60d > PVC-30d > pristine PVC). PLA exhibited a higher adsorption capacity for antibiotics than PVC, indicating that biodegradable MPs have a stronger ability to adsorb organic pollutants. Desorption experiments were conducted in different pH and waters. The results revealed that PLA-90d and PVC-90d exhibited the highest NOR release rates (30.43 % and 24.64 %, respectively) at pH 11, with seawater promoting greater desorption than lake or ultrapure water due to ionic competition. These findings highlight the critical role of aging in amplifying MPs’ environmental risks as carriers of antibiotics.

Wane-and-wax mechanism of nitrogenous disinfection byproducts with constant Cl/N peak under UV/chlorine treatment: Implication for new drinking water disinfection strategy

Jinxiu Lou,Lu Yin,Feilong Dong,Zhanfei He,Huijie Lu,Shuangxi Fang,Xiangliang Pan

Nitrogenous disinfection byproducts (N-DBPs) are notorious for their serious health risks, yet nitrate (NO 3 - ) mediates N-DBPs generation during UV/chlorine treatment remains unexplored. This study investigated the interaction of chlorine and NO 3 - on N-DBPs formation and developed a specific fragment-based screening method using UPLC-QTOF-MS to explore the underlying mechanism. Results showed that the chlorine-to-nitrogen (Cl/NO 3 - -N) molar ratio significantly affects dichloroacetonitrile (DCAN) and dichloroacetamide (DCAM) generation, with peak concentrations at a Cl/NO 3 - -N molar ratio of around 15. NO 3 - promotes the production of HO • , which positively correlates with DCAN and DCAM concentrations, also peaking at this ratio. Utilizing our developed method, three key hydroxyl-substituted intermediates that circumvent the previously reported “limiting-steps” in DCAN formation were identified. This reaction proceeds via a stepwise mechanism involving hydroxylation and chlorine substitution to produce hydroxyl-phenylacetonitrile and hydroxyl-chlorine-phenylacetonitrile. The conversion rate of hydroxyl-chlorine-phenylacetonitrile to DCAN was 8.6 times higher at Cl/NO 3 - -N molar ratio of 15 compared to conditions without NO 3 - , attributed to the weakened bond strength of the side chain, as supported by density functional theory calculations. This study provides novel insights into the mechanistic pathways of DCAN and DCAM formation, critical for developing more effective drinking water disinfection technologies to control N-DBPs.

Li2NaB3S2O12: A Deep-UV Transparent Borosulfate with Moderate Birefringence Derived from the [B3S2O12]∞ Infinite Chain Designed by the High Boron-to-Sulfur Ratio Strategy

Zichang Wang,Jianyi Zuo,Qingyu Liu,Xueling Hou,Minqiang Gai

The first mixed alkali metal borosulfate compound, Li2NaB3S2O12 (LNBSO), which contains [BO3] groups, was designed and synthesized by using a high boron-to-sulfur ratio strategy through the high temperature solution method. LNBSO exhibits a birefringence of 0.057@546.1 nm in experiments, which was mainly contributed by the [BO3] groups, and possesses a short absorption edge at 184 nm, and the space group of LNBSO is P21/c. This newly synthesized borosulfate compound holds potential as a promising birefringent material within the deep-ultraviolet wavelength range. Moreover, the investigation on the relationship among the ratio of boron to sulfur, the dimensionality of the anionic framework, and the formation of [BO3] groups has been conducted on available borosulfate, providing insights for the synthesis of borosulfate with desirable performances.

Synthesis of photosensitive polyimide for liquid crystal alignment under non-polarised UV ageing lamp irradiation and a study on the possible mechanism of alignment

Gang Zhu,Fei Wang,Wenjie Liu,Xinjian Gong,Pengfei Geng,Zhenwei Gao,Yinghan Wang

Effect of operating conditions and water matrix on the performance of UV combined electrochemical process for treating Chloride-containing solution and its reaction mechanism

Jia-Ying Li,Rui Hu,Lili Shan,Zheng-Qian Liu,Sui-Qin Yang,Jingjing Yang,Fengyi Sun,Yu-Hong Cui

The performance of ultraviolet combined electrochemical (EC) process for treating chloride-containing (UV/EC/Cl - ) solution was evaluated based on the N, N-Diethyl-m-toluamide (DEET) degradation. The influences of operating conditions and water matrix on the DEET degradation were investigated, and the reaction mechanism of UV/EC/Cl - process was discussed based on the analysis of DEET degradation pathway, the detection of the steady-state concentrations of active free radicals and the analysis of free radicals scavenging. The observed reaction rate constant of DEET degradation in UV/EC/Cl - process (0.093 min −1 ) is significantly higher than that of UV/Cl 2 process (0.036 min −1 ), and the synergistic effect on the DEET degradation is remarkable in UV/EC/Cl - process. The current and chloride concentration have remarkable impact on the DEET degradation, while the initial pH, reaction temperature, and initial DEET concentration have slight influence on the DEET degradation. The impact of alkalinity on DEET degradation is more significant than that of ammonia, while sulfate and phosphate have slight effect on the DEET degradation. The active points attacked by free radicals on DEET molecule were predicted basing on density functional theory. During the DEET degradation, small molecular products are produced through a series of reactions such as hydrogen abstraction, substitution, dealkylation, and ring-opening. The steady-state concentrations of HO • and Cl • in UV/EC/Cl - process (1.57 × 10 -13 M and 2.37 × 10 -14 M, respectively) are higher than those of UV/Cl 2 process (1.23 × 10 -13 M and 1.07 × 10 -14 M, respectively), and HO • and Cl • play key roles in the DEET degradation during the UV/EC/Cl - process.