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Organic Chemicals
Published in Eliot Epstein, LAND APPLICATION of SEWAGE SLUDGE and BIOSOLIDS, 2002
Many organic compounds will degrade in the soil. This process is extremely important as a means of removing several toxic organic compounds. There is extensive literature on the degradation of pesticides in soil. Organic matter can either accelerate or possibly inhibit biodegradation. Guthrie and Pfaender (1998) determined that biodegradation was the main means of removing pyrene. Accelerated biodegradation could occur through the enhancement of the microbial population and its activity. Organic matter can also tie up compounds, thus reducing or delaying their assimilation by the microbial population. Adding compost to soils accelerates the degradation of toxic organic compounds. Stegmann et al. (1991), Atlas (1991), and Hupe et al. (1996) showed that compost added to soils was effective in hydrocarbon degradation.
Self-Assemblies of Macromolecular Systems Containing Green Polymers
Published in Neha Kanwar Rawat, Tatiana G. Volova, A. K. Haghi, Applied Biopolymer Technology and Bioplastics, 2021
Andreea Irina Barzic, Raluca Marinica Albu, Cristian Logigan
Fluorescence spectroscopy is one of the most common methods used in determination of the CMC [38, 39]. Pyrene is often preferred fluorescent probe given its strong fluorescence in nonpolar domains and its poor radiation in polar media. The shift of the excitation peak is monitored to prove the transfer of pyrene molecules into an increasingly nonpolar micellar medium. The ratio of intensities of the excitation maxima at 339 and 333 nm is changing with concentration. This leads to a plot with where a sudden variation of the data is noted. The crossover of the lines having distinct slopes represents the CMC value.
Polynuclear Aromatic Hydrocarbons
Published in Michael J. Kennish, Ecology of Estuaries: Anthropogenic Effects, 2019
Because of its carcinogenicity in mammals,78-80 benzo(a)pyrene has been the target of much research on environmental PAH contamination of estuarine and marine waters. About 70 metric tons of benzo(a)pyrene enter the aquatic environment each year, leading to its broad geographic distribution.3 Combustion effluents generate a large quantity of airborne benzo(a)pyrene that ultimately settle to water surfaces via fallout or rainout.80
Investigation of mechanistic interactions between Rifampicin and bovine serum albumin in the presence of different surfactants
Published in Journal of Dispersion Science and Technology, 2023
Sampat R. Shingda, Parvez S. Ali, Nilesh V. Gandhare, Naziyanaz B. Pathan, Nizamul H. Ansari
Fluorescence is a convenient and accurate method, which has been widely used to investigate the interaction between proteins and small molecules. Pyrene is a very hydrophobic molecule with a low aqueous solubility.[22] The fluorescence spectrum of pyrene is related to its vibrionic fine structure and the relative peak intensity detection wavelengths of I1 = 373 nm, I3 = 384 nm, and IE = 475 nm is strongly dependent on the microenvironment polarity. With increasing polarity, intensity of the first band (I1) and third band (I3) was enhanced. This feature is often used to study the changes in environmental polarity of surfactant-drug upon association in solution. Therefore, the ratio of I1/I3 was used to determine the critical micelle concentration (CMC) of surfactants and to examine the interaction between surfactants and drug. One of the most important properties of surfactants is to form micelles in aqueous solution.
Synthesis, characterization and properties of novel nonionic hydrocarbon/fluorocarbon hybrid surfactants containing a short fluoroalkyl chain
Published in Journal of Dispersion Science and Technology, 2023
Yutang Zhou, Yichao Shen, Liangjie Shi, Yong Jin, Shuangquan Lai, Yujia Tang
The steady-state fluorescence measurement was employed to further study the micellization properties of Hm-Fn in aqueous solution. Pyrene has been used as fluorescent probe. The intensity ratio of the first (373 nm, I1) to the third (384 nm, I3) emission peaks in the pyrene emission spectrum is wildly used for the excellent index to investigate the aggregation of surfactant solution.[31]Figure 4 shows the emission spectra of pyrene in aqueous solution with various concentrations of Hm-Fn (represented by H16-F6 and H16-F4) and the variations of I1/I3 values at different concentration. It is obvious that the plot of the I1/I3 versus the concentration of these two surfactants has the sigmoidal shape and the concentration corresponding to the middle of the curve drop is regarded as the critical micelle concentration (cmc).[32] The cmc values determined by steady-state fluorescence measurement are 0.052 mM and 0.676 mM for H16-F6 and H16-F4, respectively, which are slightly smaller than those obtained from surface tension measurement. The reason may be explained that different cmc test methods have own limitations and different sensitivity.
Biodegradation performance and diversity of enriched bacterial consortia capable of degrading high-molecular-weight polycyclic aromatic hydrocarbons
Published in Environmental Technology, 2022
Dongqi Wang, Lu Qin, Enyu Liu, Guodong Chai, Zhenduo Su, Jiaqi Shan, Zhangjie Yang, Zhe Wang, Hui Wang, Haiyu Meng, Xing Zheng, Huaien Li, Jiake Li, Yishan Lin
It was previously demonstrated that elevated PAH concentration would result in the inhibition of microbial growth and degradation capability due to toxic effects of high-level PAHs and their metabolic byproducts [16]. As shown in Figure 2(d), the higher the initial pyrene concentration, the slower the degradation rate. A lag phase was observed when the initial pyrene concentration was above 200 mg/L. But still, consortium TC could function well even at the pyrene concentration of 1000 mg/L, with a degradation efficiency of 75% after 21 d. Some PAH-degraders were found to effectively remove pyrene at high concentrations. Habe et al. [42] found that Mycobacterium sp. strain MHP-1 could utilize ∼50% of pyrene at an initial concentration of 1000 mg/L. Sarma et al. [43] reported the complete degradation of pyrene (initial concentration of up to 1000 mg/L) could be achieved when employing the immobilized cells of Mycobacterium frederiksbergense in the presence of non-ionic surfactant Tween-80. The finding in our study is in agreement with those previous reports, indicating consortium TC’s potential application in the sites contaminated with high levels of HMW PAHs.