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1.
The effects of the cuticle and epicuticular waxes of grapefruit, strawberry and apple on the photodegradation and penetration of chlorpyrifos-methyl were studied. Photodegradation experiments were conducted by exposing the insecticide to the light of a xenon lamp in the presence of a film of wax extracted from the fruit surface. The half-life of chlorpyrifos-methyl irradiated in absence of waxes was 9.6 min. The half-lives of pesticide irradiated in the presence of wax extracts of apple, grapefruit and strawberry were 83, 34 and 26 min, respectively. In penetration studies, fruit with and without wax layers were treated with an aqueous suspension of pesticide. The penetration of the pesticide from the cuticle to the pulp was measured after 24 h. Samples without wax contained a higher total amount of insecticide than those with wax. No pesticide was detected in samples of apple and grapefruit pulp. Residues were detected in all fractions of strawberry. The waxes and cuticle appear to have some effect on the photodegradation and penetration of chlorpyrifos-methyl in fruit samples. 相似文献
2.
Vincenzo Augugliaro Vittorio Loddo Ignacio Maldonado Raffaele Molinari 《Solar Energy》2005,79(4):402-408
The photocatalytic oxidation of a common antibiotic, the lincomycin was carried out in aqueous suspensions of polycrystalline TiO2 Degussa P25 irradiated by sunlight. In order to improve the performance of the lincomycin degradation a hybrid system consisting of a solar photoreactor with the photocatalyst in suspension coupled with a membrane module, used to confine both photocatalyst and pollutants in the reaction environment, was tested.A preliminary study was carried out in order to determine some kinetics parameters of the drug photodegradation. The influence of initial substrate concentration on the lincomycin photooxidation rate was investigated. The photooxidation rate follows a pseudo-first order kinetics with respect to the lincomycin concentration under the used experimental conditions. The presence of the membrane reactor allows the catalyst separation and to operate in continuous mode as the membranes rejection for lincomycin and its oxidation products was quite high. 相似文献
3.
Liyan Qiu Ajit Dattatray Phule Weipeng Zhong Shibao Wen Zhenxiu Zhang 《大分子材料与工程》2021,306(12):2100481
Development of industrialization has brought convenience to people's lives; however, it has also brought serious harm to the environment, where, water pollution is the most obvious. Here, a polybutylene adipate terephthalate (PBAT) open-cell foam doped with iron-pillared bentonite (IPB) is prepared by using sugar as a pore-forming agent and solution phase separation, and then combined with a solution dipping method to coat the foam surface with a polyacrylamide/SiO2, which makes the PBAT foam superhydrophilic. The static adsorption effect of superhydrophilic IPB-doped PBAT open-cell foam on methylene blue (MB) and Cu2+ is studied. The adsorption isotherm fitting shows that the adsorption conforms to the Langmuir model and it has biased toward monolayer adsorption. The adsorption kinetics fitting confirms that the adsorption process is in line with the pseudo-second-order adsorption model, which is dominated by chemical adsorption. The modified PBAT open-cell foam has an adsorption effect on Cu2+; however, it has weak cyclic adsorption capacity. It shows a good cyclic adsorption ability for the cationic dye MB and it has >95% photodegradation efficiency of the MB after five time's cyclic adsorption. The superhydrophilicity makes the foam to have better applications in oil–water separation. 相似文献
4.
含钛高炉渣作为固体废弃物,国内存量巨大,且其中的钛组元难以提取,导致含钛高炉渣综合利用一直没有得到有效解决。针对当前含钛高炉渣利用率低、附加值低等问题,基于含钛高炉渣成分特点,通过选择性析晶(CaTiO3优势析出)、碱激发,制备出CaTiO3-多孔地质聚合物的复合材料。试验结果表明,析晶温度1 400 ℃、保温1 h能够促进CaTiO3的优势析出,而剩余氧化物以玻璃相形式存在。制备出的CaTiO3-多孔地质聚合物材料结合了CaTiO3高光催化活性与多孔地质聚合物比表面积大的优点,对亚甲基蓝具有优异的吸附效果,最大吸附量可达60.4 mg/g。在投加量为50 mg,2 h吸附、3 h光降解条件下,对亚甲基蓝去除率可达94.5%,在治理有机污染领域有良好的应用前景。 相似文献
5.
Li-Piin Sung Joan Jasmin Xiaohong Gu Tinh Nguyen Jonathan W. Martin 《Journal of Coatings Technology and Research》2004,1(4):267-276
Laser scanning confocal microscopy (LSCM) has been used to characterize the changes in film thickness and local surface morphology
of polymer coatings during the UV degradation process. With the noninvasive feature of LSCM, one can obtain thickness information
directly and nondestructively at various exposure times without destroying the specimens or deriving the thickness values
from IR measurement by assuming uniform film ablation. Two acrylic polymer coatings were chosen for the study, and the physical
and chemical changes of the two systems at various exposure times were measured and analyzed. Those measurable physical changes
caused by UV exposure include film ablation, formation of pits and other surface defects, and increases in surface roughness.
It was found in both coatings that changes in measured film thickness by LSCM were not correlated linearly to the predicted
thickness loss using the changes in the CH band obtained by the Fourier Transform Infrared (FTIR) spectroscopy measurements
in the later degradation stages. This result suggested it was not a uniform film ablation process during the UV degradation.
At later stages, where surface deformation became severe, surface roughness and profile information using LSCM were also proven
to be useful for analyzing the surface degradation process
Presented at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 13–14, 2004 in Philadelphia,
PA. 相似文献
6.
C.?M.?SeubertEmail author M.?E.?Nichols A.?V.?Kucherov 《Journal of Coatings Technology and Research》2005,2(7):529-538
The long-term weathering performance of two UV-curable clearcoat systems was studied using in-plane microtomy in combination
with infrared spectroscopy, UV spectroscopy, and ESR spectroscopy. Oxygen transport characteristics were also studied using
the half-time method. The photooxidation versus depth profile was highly dependant on the presence of hindered amine light
stabilizers (HALS) for both coating systems. Ultraviolet light absorbers (UVA) had little effect on the photooxidation profile.
A photooxidation gradient was formed in both clearcoats due to a reduction in oxygen solubility when compared to standard
thermoset clearcoats. This gradient was only seen in formulations not containing HALS.
Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago,
IL. 相似文献
7.
8.
9.
Aziz Rezig Tinh Nguyen David Martin Lipiin Sung Xiaohong Gu Joan Jasmin Jonathan W. Martin 《Journal of Coatings Technology and Research》2006,3(3):173-184
The relationship between chemical degradation and thickness loss of an unpigmented, non UV-stabilized, crosslinked amine-cured
epoxy coating exposed to three UV conditions was investigated. Spin-coated samples having a thickness of approximately 7 μm
on an Si substrate were prepared from a stochiometric mixture of a bisphenol A epoxy resin and a tetra-functional amine curing
agent. Samples were exposed outdoors and to two accelerated laboratory UV environments. Chemical degradation and thickness
loss were measured by transmission Fourier transform infrared spectroscopy (FTIRS) and laser scanning confocal microscopy
(LSCM), respectively. In addition, surface roughness and morphological changes were measured by atomic forcemicrosocopy (AFM)
and LSCM. Substantial chemical degradation, thickness loss, and morpholocal changes occurred in the exposed films, and the
rate of chemical degradation was greater than that due to the thickness loss. This additional chemical loss was attributed
to an inhomogeneous degradation process in which nanoscale localized depressions initiate at certain sites on the surface,
which then enlarge and deepen with exposure time. The results of this study provide a better understanding of the degradation
mechanism and should lead to the development of scientific-based models for predicting the service life of crosslinked amine-cured
epoxy coatings.
Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago,
IL 相似文献
10.
制备了离子液体1-乙基-3-甲基咪唑溴盐([emin]Br),以该离子液体为模板剂,采用水热法制备了亚微米级棒状ZnO粉体。经扫描电子显微镜(SEM)、X射线衍射(XRD)、傅立叶转换红外光谱(FT-IR)等对样品进行了表征和分析。结果表明,该方法制备出具有六方纤锌矿结构的棒状亚微米级ZnO粉体,棒长为2~3μm,直径为500~600 nm;以高压汞灯为光源,以ZnO粉体为光催化剂,对有机染料罗丹明B进行了光降解实验,光降解90 min后,其去除率达到93.3%。 相似文献