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691.
思林水库荧光溶解性有机质的特征、来源及其转化动力学 总被引:1,自引:0,他引:1
利用三维荧光光谱(EEM)结合平行因子分析(PARAFAC),研究了思林水库冬季(1月)、春季(4月)、夏季(6月)和秋季(10月)上游入库水体、库区表层水(0 m)、库区深层水(20 m)、出库水体的荧光溶解性有机质(FDOM)不同组分的特征、来源及其转化动力学.结果表明,思林水库的溶解性有机质由3种荧光组分组成,分别是:陆源类腐殖质(C类,C1)、浮游植物源的微生物类腐殖质(M类,C2)和浮游植物源的类蛋白或类色氨酸或类酪氨酸(C3).其中陆源类腐殖质的荧光强度随着入库水、库区表层水、库区深层水和出库水逐渐减少,这表明由于光化学作用、微生物作用、大坝拦截效应等环境因素的影响,类腐殖质随着水体由入库向出库的流动而逐渐降解.相反,微生物类腐殖质(M类)的荧光强度结果表明,在入库-出库过程中,微生物类腐殖质处于产生及部分或完全降解的波动中,这表明微生物类腐殖质是浮游植物的原生产物,并且对于光化学作用、微生物作用和大坝拦截效应有很强的不稳定性.类蛋白或类色氨酸或类酪氨酸主要新产生于夏季和秋季的表层水体中,在冬季和春季表层和深层水体中也有产生;并在出库过程中逐渐减少.这表明类蛋白或类色氨酸或类酪氨酸是浮游植物的原生产物;并且它们受到光化学作用、微生物作用和大坝拦截效应的共同影响,在表层和深层水中生成和降解.因此,这些结果意味着通过平行因子分析确定的荧光溶解性有机质组分的方法,对于更好地理解溶解性有机质在水库水体的转化动力学机制至关重要. 相似文献
692.
Rashidul Alam Mubarak A. Khan Ruhul A. Khan Sushanta Ghoshal M. I. H. Mondal 《Journal of Polymers and the Environment》2008,16(3):213-219
Chitosan films were prepared from dried prawn shell via chitin and then tensile properties like tensile strength (TS) and
elongation at break (Eb) of the films were evaluated. Six formulations were developed using methyl methacylate (MMA) monomer
and aliphatic urethane diacrylate oligomer (M-1200) in methanol along with photoinitator (Darocur-1664). Then the films were
soaked in the formulations and irradiated under UV radiation at different doses for the improvement of physico-mechanical
properties of chitosan films. The cured films were characterized by measuring TS, Eb, polymer loading (PL), water absorption
and gel content properties. The formulation containing 43% MMA and 15% oligomer in methanol solution showed the best performance
at 20th UV pass for 4 min soaking time. 相似文献
693.
Nazia Umar Khan N. P. Bharathi Sheikh Shreaz Athar Adil Hashmi 《Journal of Polymers and the Environment》2011,19(3):607-614
This paper describes an ecofriendly development of a nanodrug delivery vehicle from seed oil. The entire synthesis, starting
from the ZnO nanoparticle to the polymeric vehicle is purely microwave assisted with minimal usage of organic solvents. Multifunctional
features like enhanced UV absorbance, antimicrobial properties and appreciable in vitro release can be attributed to the nanoparticle
loaded polymeric vehicle. Characterization of the synthesized species was done through FT-IR, 1HNMR, SEM and XRD. The physical characterizations were carried out using conventional laboratory techniques. 相似文献
694.
A simple and efficient ionic liquid-based ligandless microextraction method has been developed for preconcentration of cadmium ions (Cd2+) as a step prior to its determination by flame atomic absorption spectrometry (FAAS) with a micro-sample introduction system. In this approach, the ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] and ethanol were used as extractant and dispersive solvents to preconcentrate the Cd2+ in different waters, acid digested scalp hair, and nail samples. Some analytical parameters influencing the extraction efficiency of Cd2+ and its subsequent determination, including pH, IL volume, dispersant solvent volume, sample volume, temperature, incubation time, and matrix effect, were optimized. Under optimal conditions, the limit of detection (LOD), limit of quantification (LOQ), and enhancement factor (EF) were 0.4 μg L?1, 1.3 μg L?1, and 50, respectively. The relative standard deviation (RSD) of 100 μgL?1 Cd2+ was 4.3% (n = 6). The validity of the proposed method was checked by determining Cd2+ in certified reference material (TM-25.3 fortified water) and standard addition; the results showed sufficient recovery (>98%) of Cd2+ within the certified value. The method was applied for preconcentration and determination of cadmium in waters and biological samples. 相似文献
695.
Nusrat Sharmin Ruhul A. Khan Stephane Salmieri Dominic Dussault Monique Lacroix 《Journal of Polymers and the Environment》2012,20(3):698-705
Chitosan was dissolved in 2?% aqueous acetic acid solution and the films were prepared by solution casting. Values of tensile strength (TS), tensile modulus (TM), elongation at break (Eb?%) and water vapor permeability (WVP) of the chitosan films were found to be 30?MPa, 450?MPa, 8?% and 4.7?g?mm/m2?day?kPa, respectively. Poly(caprolactone) (PCL) films were prepared from its granules by compression molding and the values of TS, TM, Eb and WVP were 14?MPa, 220?MPa, 70?% and 1.54?g?mm/m2?day?kPa, respectively. PCL was reinforced with chitosan films, and composite films were prepared by compression molding. Amount of chitosan in the composite films varied from 10 to 50?% (w/w). It was found that with the incorporation of chitosan films in PCL, both the values of TS and TM of composite films increased significantly. The highest mechanical properties were found at 50?% (w/w) of chitosan content. The Oxygen transmission rate (OTR) of composite film was found to decrease significantly than PCL films. Thermal properties of the composite were also improved as compared to PCL. The water uptake test of the composite also showed promising results with a good stability of composite films. The interface of the composite was investigated by scanning electron microscopy and showed good interfacial adhesion between PCL and chitosan films. 相似文献
696.
Han Il Yoo Keunje Kang Bo Ram No Jee Hyun Wee Gui Nam Khan Muhammad Imran Jeong Tae Young Lee Tae Kwon 《Environmental geochemistry and health》2018,40(1):451-460
Environmental Geochemistry and Health - Improper decisions concerning animal carcass disposal sites pose grave threats to environmental biosecurity. However, only a few studies have focused on the... 相似文献
697.
Asim Jilani Mohd Hafiz Dzarfan Othman Mohammad Omaish Ansari Syed Zajif Hussain Ahmad Fauzi Ismail Imran Ullah Khan Inamuddin 《Environmental Chemistry Letters》2018,16(4):1301-1323
Graphene was discovered in 2004 and has attracted intensive interests because of its unique mechanical, electric, thermal, optical, and structural properties, which makes graphene a potential candidate for various applications. Graphene is being used as a composite or filler material with metals, metal oxides, and polymers for potential advanced applications in solar cells, lithium-ion batteries, photocatalysis and sensing. These applications depend upon the distinctive properties of graphene, which in turn depend on the adopted synthetic approach. This article reviews the recent developments in synthesis of graphene and related composite materials. The synthesis of graphene through exfoliation, epitaxial growth and direct growth via carbon source, and modification approaches by covalent and noncovalent methodologies are discussed. Graphene-based metal and metal oxide composites for the purification of wastewater using photolytic process are also presented. 相似文献
698.
Ali Iftikhar Khan Muhammad Jamil Shah Azizullah Deeba Farah Hussain Haziq Yazdan Fazal Khan Mati Ullah Khan Muhammad Daud 《Environmental science and pollution research international》2022,29(25):37765-37776
Environmental Science and Pollution Research - Natural resources, especially agrarian soils, have been much contaminated with various pollutants including heavy metals since industrial revolution,... 相似文献
699.
Huibo Wang Awan Rehmat Ullah Qayyum Abdul Munir Arshad Khan Jamal Gulzar Fatima 《Environmental science and pollution research international》2022,29(10):14355-14370
Environmental Science and Pollution Research - The construction of green finance index is a three-tiered process that involves macroeconomic, ecological, and monetary indicators. Therefore, this... 相似文献
700.
Rabbany Md Ghulam Mehmood Yasir Hoque Fazlul Sarker Tanwne Hossain Kh Zulfikar Khan Arshad Ahmad Hossain Mohammad Shakhawat Roy Rana Luo Jianchao 《Environmental science and pollution research international》2022,29(1):444-456
Environmental Science and Pollution Research - This study analyzes the effects of credit constraints on technical efficiency of Boro rice growers in the district of Pabna in Bangladesh. Using a... 相似文献