共查询到18条相似文献,搜索用时 250 毫秒
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增效磷在液相中的光化学降解研究 总被引:9,自引:0,他引:9
研究了增效磷在正己烷、甲醇、乙腈、丙酮及水溶液中以及在不同光源下的光化学降解, 结果表明: 在正己烷、甲醇、乙腈溶液中, 增效磷降解效应显著, 在汞灯下的半衰期分别为0. 98、1. 54、2. 11 h, 在紫外灯下, 半衰期分别为3. 59、3. 55、6. 01 h; 增效磷在丙酮溶剂中降解缓慢, 三种光源下的半衰期分别为8. 25、53. 32、990. 14 h; 增效磷在水中光解迅速, 高压汞灯下的光解半衰期为0. 33 h; 丙酮对增效磷在水中的光解有极显著的猝灭作用, 猝灭效率与丙酮的量具有显著的相关性, 猝灭效率最高达- 322. 34%。对反应体系的吸收光谱测定结果表明,增效磷在液相中的光解差异与吸收光谱的改变有一定程度的相关性。 相似文献
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溴虫腈在不同溶剂中的光化学降解 总被引:3,自引:3,他引:0
研究了高压汞灯光源下溴虫腈在不同溶剂中的光化学降解特性及其影响因素。在室内模拟条件下,初始质量浓度为2 mg/L的溴虫腈在纯水中的光解半衰期为25.86 min,在1~10 mg/L范围内,其光解速率随初始浓度的增大而降低;溴虫腈在pH值为5、7和9的缓冲溶液中的光解半衰期分别为42.52、24.49和32.39 min,即其在中性条件下光解最快;不同形态含氮离子(NO2-、NO3-、NH4+)对溴虫腈的光解均表现为抑制作用,且在离子质量浓度<20 mg/L时,NO3-、NO2-的抑制作用较强,≥20 mg/L时则NH4+的抑制作用较强;溴虫腈在不同有机溶剂中的光解速率从大到小依次为:正己烷>甲醇>乙酸乙酯>丙酮,其光解速率与有机溶剂的极性大小无关。研究结果可为溴虫腈的环境风险评价提供参考。 相似文献
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恶草酮在液相中的光化学降解研究 总被引:7,自引:1,他引:7
以高压汞灯为光源,研究了恶草酮在环己烷,甲醇,乙腈,丙酮及水溶液中的光化学降解,结果表明,在环己烷,甲醇,乙腈,水中,恶草酮光隆解效应显,其半衰期分别为4.45,15.34,57.58,54.69min;恶草酮在丙酮溶剂中降解缓慢,半衰期为293.83min,丙酮对恶草酮在水中的光解有显的光敏作用,光敏效应与丙酮的量显相关,光敏效率最高达95.84%。 相似文献
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丙炔氟草胺的水解及光解特性研究 总被引:1,自引:1,他引:0
为深入了解丙炔氟草胺的环境化学行为,通过室内模拟试验研究了其在不同条件下的水解和光解特性。结果表明:15℃下,初始质量浓度为2 mg/L的丙炔氟草胺在pH值为5、7和9的缓冲溶液中的水解半衰期分别为63.00、33.00和28.50 h,即其在碱性条件下水解最快;中性(pH 7)条件下,丙炔氟草胺在15、25和35℃下的水解半衰期分别为33.00、23.10和8.88 h,表明其水解受温度影响,温度越高,水解速率越快;丙炔氟草胺在河水中的水解速率高于在自来水和蒸馏水中的水解速率,3种条件下的半衰期分别为2.70、6.03和19.80 h。300 W汞灯照射下,丙炔氟草胺在碱性条件下的光解速率大于在酸性和中性条件下,半衰期分别为0.03、0.45和0.44 h;此外,丙炔氟草胺在不同有机溶剂中的光解速率顺序依次为甲醇 > 乙酸乙酯 > 正己烷 > 乙腈 > 丙酮;其在不同光源下的光解速率依次为500 W汞灯 > 300 W汞灯 > 氙灯。研究结果可为丙炔氟草胺的环境风险评价提供参考。 相似文献
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嘧菌酯在水和有机溶剂中的光化学降解 总被引:1,自引:0,他引:1
以500 W氙灯为光源,研究了嘧菌酯在水和有机溶剂中的光化学降解动态及其影响因素。结果表明:当质量浓度为5 mg/L时,嘧菌酯在纯水中光解的半衰期为5.8 h,在2~20 mg/L范围内,其光解速率随初始质量浓度的增大而降低;嘧菌酯在不同介质中的光解速率从大到小依次为乙腈水甲醇正己烷丙酮,其半衰期分别为4.8、5.8、11.5、12.1和23.5 h;硝酸盐对嘧菌酯在水中的光解具有光敏化作用,当NO-3质量浓度为1、2、10和20 mg/L时,其半衰期分别为5.5、5.1、4.5和3.9 h;在1~2 mg/L质量浓度下,NO-2对嘧菌酯在水中的光解具有光敏化作用,而在10~20 mg/L时则表现为光淬灭作用;Fe3+及表面活性剂十二烷基硫酸钠(SDS)对嘧菌酯在水中的光解具有光敏化作用,而腐殖酸和Fe2+则对其表现为光淬灭作用。研究结果可为嘧菌酯的科学合理使用及其环境风险评估提供参考。 相似文献
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噻呋酰胺的光解和水解特性研究 总被引:1,自引:1,他引:0
为了明确噻呋酰胺的环境行为规律,采用室内模拟试验方法,研究了噻呋酰胺在不同条件下的光解和水解特性。结果表明:紫外灯照射下,噻呋酰胺在碱性条件下光解速率大于中性和酸性条件下的;不同溶剂中,噻呋酰胺的光降解速率依次为正己烷 >乙腈 >甲醇 >乙酸乙酯 >超纯水;三价铁离子、二价铁离子以及腐殖酸均能抑制噻呋酰胺的光降解。中性条件下,噻呋酰胺水解速率最快,同时,噻呋酰胺的水解受温度影响,温度越高,水解速率越快,平均温度效应系数1.39~2.23;表面活性剂十六烷基三甲基溴化铵(CTAB)和十二烷基磺酸钠(SDS)均可抑制噻呋酰胺在水中的降解。 相似文献
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Nourrddine Chafik Mohammed Mansour Btissam Elamrani Karl‐Werner Schramm Antonius Kettrup M Khalid Elamrani 《Pest management science》2001,57(6):527-530
The photochemical fate of the herbicide triflusulfuron‐methyl in aqueous solution under UV light (λ > 290 nm) was investigated. Nine photoproducts were detected and tentatively identified by LC/MS and LC/MS/MS analysis. The main routes of degradation involve the cleavage and/or contraction of the sulfonylurea bridge with the elimination of sulfur dioxide, which increases the acidity of the reaction medium. On the basis of the results obtained a photodegradation pathway is proposed. © 2001 Society of Chemical Industry 相似文献
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Photolysis on soil surfaces of the organophosphorus insecticides diazinon, methidathion and profenofos was studied under artificial sunlight conditions. All three compounds were readily degraded under the conditions used. The rate of degradation decreased in the order diazinon, profenofos, methidathion and was always greater in moist than in dry soil. The same order of stability was also observed from photolysis studies in aqueous solution. The major photolysis products identified were 2-isopropyl-6-methylpyrimidin-4-ol from diazinon, 5-methoxy-3H-1,3,4-thiadiazol-2-one from methidathion and 4-bromo-2-chlorophenol and 4-bromo-2-chlorophenyl ethyl hydrogen phosphate from profenofos. The same compounds were formed in hydrolysis studies and also upon photodecomposition in aqueous solutions of diazinon and methidathion. Profenofos, however, showed a different photolytic reaction in aqueous systems, forming O-(2-chlorophenyl) O-ethyl S-propyl phosphorothioate. Soil photolysis studies together with hydrolysis experiments could be a useful quick method for obtaining early information on the chemical breakdown products which are to be expected in the soil environment. 相似文献
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Terence Clark David A. M. Watkins Deepthi K. Weerasinghe 《Pest management science》1983,14(4):449-452
The major product identified in the photochemical degradation of fluotrimazole, in aqueous suspension, as a thin film on glass, and sprayed on barley leaves, was 3-(trifluoromethyl)triphenylmethanol. This was also detected after photolysis in methanol, although methyl 3-trifluoromethyltrityl ether was the major product. Moreover, under all these conditions, 3-(trifluoromethyl)triphenylmethane was also present. 3-Trifluoromethylbenzophenone was produced only by irradiation of an aqueous suspension. The photolysis products, in contrast to fluotrimazole, were inactive at 1 mmol against barley powdery mildew (Erysiphe graminis). 相似文献
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采用溶胶-凝胶法制备了二氧化钛/多壁碳纳米管(TiO2/MWCNTs)复合材料,其m(TiO2)∶m(MWCNTs)=3∶4、表面平均孔径为5.724 nm。选用该复合材料对乐果进行光催化降解试验,探讨不同光源及光照时间、乐果初始浓度、复合材料添加量、温度等对其光催化降解能力的影响。结果表明:乐果在25℃、紫外光照30 min、初始质量浓度为5 mg/L和TiO2/MWCNTs复合材料添加量为0.25 g/L条件下的降解率为80.7%,TiO2/MWCNTs复合材料的最大吸附量为16.15 mg/g;在其他条件相同,仅将紫外光改为自然光条件下,乐果的催化降解率为79.2%,与紫外光下的催化降解率相差不大;而同等条件下,Ti O2对乐果在紫外光下的催化降解率比TiO2/MWCNTs低33.1%。因此,可以用自然光代替紫外光用于吸附试验,自然条件下采取该工艺可有效降解环境中乐果污染。 相似文献
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The use of acetone as a photosensitiser on the rate of photodegradation of atrazine, atraton and ametryne in diluted aqueous solutions increased degradation 3- to 11-fold. The mechanism of the sensitised photoreaction was studied. The photochemical stability increased in the order methylthio-<chloro-.<methoxy-l,3,5-triazines. Sensitised photolysis of atrazine, ametryne and atraton yielded the analogous two de-N-alkyl- and the de-NN′-dialkyl- products as well as the corresponding hydroxy-triazines; irradiation of ametryne also resulted in the formation of de(methylthio)-1,3,5-triazines. With the exception of de(methylthio)triazine formation, sensitised photodecomposition of these triazine herbicides yields no other breakdown products than those obtained by enzymatic and chemical reactions. 相似文献