Dyes, aromatic

Ishi-i T, Shinkai S (2005) Dye-Based Organogels Stimuli-Responsive Soft Materials Based on One-Dimensional Self-Assembling Aromatic Dyes. 258 119-160... 

There are several chemical compounds found in the waste waters of a wide variety of industries that must be removed because of the danger they represent to human health. Among the major classes of contaminants, several aromatic molecules, including phenols and aromatic amines, have been reported. Enzymatic treatment has been proposed by many researchers as an alternative to conventional methods. In this respect, PX has the ability to coprecipitate certain difficult-to-remove contaminants by inducing the formation of mixed polymers that behave similarly to the polymeric products of easily removable contaminants. Thus, several types of PX, including HRP C, LiP, and a number of other PXs from different sources, have been used for treatment of aqueous aromatic contaminants and decolorization of dyes. Thus, LiP was shown to mineralize a variety of recalcitrant aromatic compounds and to oxidize a number of polycyclic aromatic and phenolic compounds. Furthermore, MnP and a microbial PX from Coprinus macrorhizus have also been observed to catalyze the oxidation of several monoaromatic phenols and aromatic dyes (Hamid and Khalil-ur-Rehman 2009). 

The first CEM system described by Griffing and West (84) consisted of an organic dye dispersed in an inert polymer film that is spin coated onto the surface of a resist and subsequently removed following exposure but prior to resist development. The chemistry of this system is based on the photoisomerization of an aromatic dye to an oxaziridine (87) (Figure 10). Other workers have evaluated polysilanes (88) and diazonium salt chemistry (89,90) for CEM applications. 

Chromosorb T shows the direct correlation of capacity with the oc-tanol-water partition coefficient expected of hydrophobic adsorbents (6). Its overall affinity for hydrophobic water contaminants is similar to that of Amberlite XAD-8 (Rohm and Haas), but it has additional affinity for humic acid and for water-soluble, cationic, aromatic dyes. Chromosorb T is more easily cleaned than the XAD resins, and it is more inert, contributing essentially no contaminants to eluates. Table IV illustrates the adsorption and recovery of a series of hydrophobic test solutes at 50 ppb in 8 L of synthetic hard water on a 50-mL bed of Chromosorb T. 

Fluorescence assays are considered among the most convenient, sensitive, and versatile of all laboratory techniques. However, the purine and pyrimidine bases yield only weak fluorescence spectra. Le Pecq and Paoletti (1967) showed that the fluorescence of a dye, ethidium bromide, is enhanced about 25-fold when it interacts with DNA. Ethidium bromide, which is a relatively small planar molecule (Figure El3.4), binds to DNA by insertion between stacked base pairs (intercalation). The process of intercalation is especially significant for aromatic dyes, antibiotics, and other drugs. Some dyes, when intercalated into DNA, show an enhanced fluorescence that can be used to detect DNA molecules after gel electrophoresis measurements (see Chapter 4 and Experiments 14 and 15) and to characterize the physical structure of DNA. Two analyses of DNA will be completed in this experiment ... 

Engle, A.R. Hyatt, J.A. Purdie, N. Induced circular dichroism study of the aqueous solution complexation of cello-oligosaccharides and related polysaccharides with aromatic dyes. Carbohydr. Res. 1994, 265, 181-195. 

The discovery of photoacidity was made by Forster more then 50 years ago . Forster correctly explained the unusual large Stokes shift found in the fluorescence of several classes of aromatic dyes, including 1- and 2-naphthol derivatives as an indication of excited state proton-transfer reaction which results in the formation of the molecular anion still in the excited state. Thus, it become clear that excited-state proton transfer may compete with other radiative and non-radiative decay routes of the photoacid. The main modern-day importance of photoacids lies in their ability to initiate and then to follow acid-base reactions so they may be regarded as optical probes for the study of general proton-transfer reactions. 

The interaction for the intercalation process seems to be based on an Interaction of flat aromatic dye molecules between the base pairs of DNA as reported by many investigatorsiZ-J. However, the exact steric location of the Intercalated dye and the heat of interaction between DNA and dye have not been established yet. 

Photodegradation process This part of study was consisted of a preliminary test and a further photodegradation test. The preliminary test was to examine the basic photodegradaton of sixteen commercial dyes while the further photodegradation test was to explore the reaction pathways and the decay rates of six purified Aromatic Dyes under different conditions. These conditions were aimed at studying including 1) the effect of initial pH 2) the effect of pH buffer 3) the quenching effect in the... 

Remediation of Chlorianted Aromatic Dyes (CADs) Polluted Soil by Surfactant Micellar/UV system. 

Hydrophobic dyes such as Chlorinated Aromatic Dyes (CADs) are one of the widely used dyes in dyeing industry today (Mishra G. and Tripathy M., 1993). In general, Hydrophobic compounds like CADs are slightly soluble to water in nature and readily sorbed onto soil or sediment in the disposal sites (Edwards D.A. et. al., 1994 Liu Z. and Shondali L., 1991 Miyamoto J. T., 1979). The remaining dyes escaping from treatment system may be discharged to rivers or harbours and eventually deposited in the sediment. Therefore, contamination of soils and sediments by CADs is an environmental concern. 

Up to now, no unique doctrine was concluded from previous researchers upon the pH effect on ozonation of some aromatic dyes. Green J.M. and Sokol C. (1985) explored the efficiency of ozonation in wastewater containing acid, disperse and direct dyes. The author found that the efficiency of dye removal was increased when the pH was lowered. Namboodri C.G (1994) also supported this doctrine. He concluded that ozonation can quickly and completely decolourized disperse, direct, acid and reactive dyes while lowered the pH and increased the conductivity of the solutions. 

Vigon B.W. and Rubin AJ. (1989) evaluated surfactant selection and dose optimization through evaluation of parameters such as surface tension, cmc. extent of hydrophilic-hydrophobic balance, solubilizaton efficiency, and partition coefficient. Chu W. and So W.S. (2000) has studied the surfactant aided soil washing of some contaminated non-chlorinated aromatic dyes. They concluded that dye concentration increased slightly until the surfactant monomers in the bulk solution was saturated the washing performance was 1 1 proportional to the monomer concentration. Above the effective critical micelle concentration (as the result of the sorption of surfactant monomer onto soil), the soilwashing performance increased linearly with increasing available surfactant micelles in the aqueous phase. 

Based on the evidences from literature review in Chapter 2, the optimal scientific and engineering approaches to remove Aromatic Dyes are still unclear. The optimal pH, sensitizer, oxidant concentration for Advanced Chemical Oxidation by UV-irradiation and ozonation were needed for further exploration. Moreover, there is still an unknown for the possible use of surfactants as facilitators of soil remediation, as both extracting agents and as a medium (i.e. micelle) in which to carry out photochemical decay within micellar solution of the solubilized Chlorinated Aromatic Dyes (CADs). More specifically, there is only little information in the photochemical decay of CADs at such micellar medium. In addition, the potential quenching or catalytic effect of humic materials in photochemical decay of CADs at micellar medium is still an unknown. Hence, in this research, the tasks were focused on the following areas ... 

Advanced Chemical Oxidation (ACO) treatment of dye wastewater, a. Ozonation of Aromatic Dyes... 

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