Photophysical and Nonlinear Optical Properties of Azophloxine in Reverse Micelles

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. The photophysical and nonlinear optical properties of Azophloxine in Reverse micelle (RM) and dye-surfactant interaction were studied using Z-scan, spectrophotometer, and spectrofluorometer techniques. The different range of RM sizes and oil polarity is studied. RM is a mixture of water droplet in a continuous phase of oil and its polarity depends on oil polarity. The nonlinear absorption coefficient (β) and nonlinear refractive index (n2) of Azophloxine in RM depend on the polarity of bulk. By using the NMR instrument, it was observed that the Azophloxine dye is intercalated in the reverse micelles in AOT/Water/Benzene solution and its average location corresponds with the core of the micelle close to polar groups of the surfactant. The rule of charge and length scale of surfactant on the value of β and n2 of Azophloxine is studied. The results showed that the enhancement value of β and n2 is due to the solubility reduction of Azophloxine with the anionic surfactant in aqueous solutions or increase of oil length scale in RM. The quantum perturbation theory was used to study the ratio of excited to ground state dipole moment of Azophloxine in RM. By using dynamic light scattering, it was observed that the size of RM reduced with an increase of dye concentration in RM

Prediction of industrial catalysts deactivation rate using first principle model and operating data

Catalyst deactivation is the loss of catalytic activity and/or selectivity over the course of time. Catalyst deactivation is a considerable and enduring problem in the operation of industrial catalytic processes. It is very costly in terms of catalyst replacement and process shutdown. The deactivation phenomenon not only affects the final product quality but also negatively influences the efficiency of the downstream processes. Therefore, a practical method which can accurately predict the deactivation rate can be a quite advantage to the industrial processes. In this paper, the deactivation rate of the industrial catalyst is predicted using operating data and catalyst specifications. The first principle model (FPM) is employed to predict the catalysts deactivation rate. The devised model is implemented into an industrial catalyst, which is palladium supported on carbon (Pd/C) utilized for the purification process of terephthalic acid, to show its applicability. The whole programs to obtain the rate of catalyst deactivation have been coded into Matlab R2013a environment. The model validated against industrial data. For the proposed catalyst, the catalyst sintering order is calculated with less that 3 percent error, and the pre-exponential values and the activation energy for the deactivation were calculated 0.00092 h-1 and 5279 J mol-1. Moreover, the catalyst is deactivated after around 360 days of operation. The methods, which are devised in this study, can be applied to any industrial catalyst to calculate the rate of deactivation

Photophysical and Nonlinear Optical Properties of Azophloxine in Reverse Micelles

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. The photophysical and nonlinear optical properties of Azophloxine in Reverse micelle (RM) and dye-surfactant interaction were studied using Z-scan, spectrophotometer, and spectrofluorometer techniques. The different range of RM sizes and oil polarity is studied. RM is a mixture of water droplet in a continuous phase of oil and its polarity depends on oil polarity. The nonlinear absorption coefficient (β) and nonlinear refractive index (n2) of Azophloxine in RM depend on the polarity of bulk. By using the NMR instrument, it was observed that the Azophloxine dye is intercalated in the reverse micelles in AOT/Water/Benzene solution and its average location corresponds with the core of the micelle close to polar groups of the surfactant. The rule of charge and length scale of surfactant on the value of β and n2 of Azophloxine is studied. The results showed that the enhancement value of β and n2 is due to the solubility reduction of Azophloxine with the anionic surfactant in aqueous solutions or increase of oil length scale in RM. The quantum perturbation theory was used to study the ratio of excited to ground state dipole moment of Azophloxine in RM. By using dynamic light scattering, it was observed that the size of RM reduced with an increase of dye concentration in RM

Optical Properties of Methyl Orange-Doped Droplet and Photodynamic Therapy of Staphylococcus aureus

© 2019, Springer Science+Business Media, LLC, part of Springer Nature. Dye-doped droplets are known as mixtures of dyes with uniform solutions of water droplets in a continuous phase of oils with surfactants. To observe the relationship between water droplet structures and surfactant types on optical properties of dyes, a mixture of methyl orange (MO)-doped droplet prepared with benzane and hexane as oils and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as a surfactant was thus examined using Z-scan instrument, spectrophotometer, and fluorimeter in the present study. The findings revealed that nonlinear refractive (NLR) index, nonlinear absorption (NLA) coefficient, as well as fluorescence intensity of the MO had enhanced following a reduction in the droplet water content induced by changes in the non-centrosymmetric charge density distribution of this pH indicator. Moreover, the MO-doped droplet in a continuous phase of benzene investigated by 1H nuclear magnetic resonance (NMR) spectroscopy indicated that the MO had been located in the droplet in the vicinity of the hydrophilic part of the surfactant. Furthermore, the MO-doped droplets along with laser radiation were employed to perform antibacterial photodynamic therapy (APDT) of Staphylococcus aureus (S. aureus). It was ultimately concluded that the bacteria colony had also extremely diminished in the group treated by the MO-doped droplet

Optical Properties of Methyl Orange-Doped Droplet and Photodynamic Therapy of Staphylococcus aureus

© 2019, Springer Science+Business Media, LLC, part of Springer Nature. Dye-doped droplets are known as mixtures of dyes with uniform solutions of water droplets in a continuous phase of oils with surfactants. To observe the relationship between water droplet structures and surfactant types on optical properties of dyes, a mixture of methyl orange (MO)-doped droplet prepared with benzane and hexane as oils and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as a surfactant was thus examined using Z-scan instrument, spectrophotometer, and fluorimeter in the present study. The findings revealed that nonlinear refractive (NLR) index, nonlinear absorption (NLA) coefficient, as well as fluorescence intensity of the MO had enhanced following a reduction in the droplet water content induced by changes in the non-centrosymmetric charge density distribution of this pH indicator. Moreover, the MO-doped droplet in a continuous phase of benzene investigated by 1H nuclear magnetic resonance (NMR) spectroscopy indicated that the MO had been located in the droplet in the vicinity of the hydrophilic part of the surfactant. Furthermore, the MO-doped droplets along with laser radiation were employed to perform antibacterial photodynamic therapy (APDT) of Staphylococcus aureus (S. aureus). It was ultimately concluded that the bacteria colony had also extremely diminished in the group treated by the MO-doped droplet

Modeling study on CO2 and H2S simultaneous removal using MDEA solution

This study presents a rate-based model of an absorber packed column for simultaneous absorptions of acid gases into methyldiethanolamine (MDEA) aqueous solution. The model is in good agreement with experimental data. The parametric study showed that the concentration of acid gases in the sweet gas stream increases by decrease in the specific surface area of packing. The peak of selectivity factor decreases with the increase in the mole ratio of CO2/H2S in the gas feed along the packed column. The sensitivity analysis reveals that selecting the accurate correlations of the gas-side mass transfer coefficient and specific surface area is vital

A generic hybrid model development for process analysis of industrial fixed-bed catalytic reactors

Catalyst deactivation is one of the major concerns in industrial catalytic reactors. The capability to perform detailed analysis of the catalytic process and its deactivation phenomenon is therefore vital in maintaining high productivity and product quality. Analysis and prediction of the catalyst deactivation mechanism and the rate of deactivation are among the most challenging endeavors in the area of the catalytic reactor modeling. Hence, the catalyst deactivation phenomenon requires detailed dynamic modeling to enable its performance to be closely scrutinized. In this paper, a hybrid model incorporating first principle model and artificial neural network (ANN) has been used to develop a generic framework to model the industrial fixed-bed catalytic reactors (FBCRs) experiencing catalyst deactivation. The model does not consider the complicated mechanism of catalyst deactivation, and its effect is incorporated employing ANN, which utilizes the catalytic process data. The generic modeling steps have been extensively described, and the developed model has been applied on two industrial case studies. The validation of each model was carried out signifying that the generalized model developed has acceptable accuracy. The model enabled the lifetime of the industrial Pd/C and CuO-ZnO-Al2O3 catalysts and the effects of the operating parameters on the hydropurification process and methanol production reactors to be predicted. The generic strategy presented can be utilized for the performance analysis of any FBCR disregarding the type of catalyst