The aim of this study was to prepare poly-N-isopropylmethacrylamide-co-acrylic acid-acrylamide [p-(NIPMAM-co-AA-AAm)] via precipitation polymerization in an aqueous medium. Rhodium nanoparticles were formed in the microgel network by an in-situ reduction technique with the addition of sodium borohydride as a reducing agent. Pure p-(NIPMAM-co-AA-AAm) and hybrid microgels [Rh-(p-NIPMAM-co-AA-AAm)] microgels were examined by using UV–Visible, FTIR (Fourier Transform Infrared), SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), DLS (Dynamic Light Scattering) and XRD (X-Ray Diffraction) techniques. The catalytic activities of the hybrid microgel [Rh-(p-NIPMAM-co-AA-AAm)] for the degradation of azo dyes such as alizarin yellow (AY), congo red (CR), and methyl orange (MO) were compared and the mechanism of the catalytic action by this system was examined. Various parameters including the catalyst amount and dye concentration influenced the catalytic decomposition of azo dyes. In order to maximize the reaction conditions for the dye's quick and efficient decomposition, the reaction process was monitored by spectroscopic analysis. The rate constants for reductive degradation of azo dyes were measured under various conditions. When kapp values were compared for dyes, it was found that [Rh-(p-NIPMAM-co-AA-AAm)] hybrid microgels showed superior activity for the degradation of MO dyes compared to the reductive degradation of CR and AY.
Asphaltene precipitation and its subsequent deposition always remain a major concern for Oil industry. Formulation of a comprehensive and reliable risk management system for asphaltene prone wells and fields is a challenging task because of the influence of diverse factors. In this study, a decision support system is developed for the asphaltene risk assessment in wells and fields. Since, the data present in the literature is scarce and not consistent, therefore, a hypothetical data of fields and their wells was considered to conduct the study comprehensively. Three hypothetical fields namely; Field A, Field B and Field C were assumed and in each field ten wells were taken into consideration. A decision support system for assessing the risk of asphaltene prone wells was developed using one of the popular and powerful multi-criteria decision making technique i.e. Fuzzy Technique for Order of Preference by Similarity to Ideal Solution (Fuzzy TOPSIS) coupled with Analytic Hierarchy process (AHP). The risk of wells was evaluated using three criteria namely; Detection, Severity and Controls. These criteria were further sub-divided into sub-criteria and their data was assumed. The assumed data was transformed into Triangular fuzzy numbers for calculations. According to the final outcomes, Field A was proved be the most risky field followed by Field B and in the last comes Field C. The outcomes were further validated by other method namely; Fuzzy Complex Proportional Assessment (COPRAS) and all TOPSIS outcomes were found in good relationship with Fuzzy COPRAS. The proposed methodology proposed in this study will be landmark in risk ranking of asphaltene prone wells and fields.
Crystal violet dye (CVD) is one of the most stable and toxic dyes, whose adverse consequencus in the aquatic and hence other components of the environment are well documented. Consequently, th remediation of water contaminated by this dye, has several advantages to industries that discharge dye rich-wastes to the aquatic environment. In this study, advantages of using nanoparticles that are ecofriendly and cost effective was implemented by converting CaCO3 in oyster shells to calcium oxide nanoparticles (CaO-NP). The synthesized CaO-NP were characterized using UV-visible, XRD, FTIR, SEM, EDX, DLS and XPS techniques.The XRD profile indicated peaks typical to CaO-NP with principal peak observed at 2θ= 34.19 ° and crystalline size equal to 27.70 nm. Information deduced from EDX and XPS also confirmed the composition and electron releasing profile of the CaO-NP. The DLS measurement indicated the average diameter of the CaO-NP as 50.24 nm, which confirms its fitness as a mesoporous nanoparticles. The application of the CaO-NP as a catalyst for the photodegradation of CVD in water showed a strong dependency on some physicochemical parameters but showed an optimum efficiency of 99% at initial dye concentration of 50 ppm, catalyst dosage of 1.5 g and pH of 11. The degradation kinetics showed a good degree of fitness for the Langmuir-Hinshelwood, modified Freundlich, first order and parabolic diffusion models. The theoretically evaluated bandgap (≈ 4.4 eV) for the nanoparticles agrees with the experimental value and indicates that the material is a semiconductor that absorb in the UV region. The observation of the XPS of the CaO-NP before and after photocatalysis indicated that electrons were consumed during the photodegradation process. Also, the conduction band potential of the CaO-NP (ECond(p)=−1.7eV) was found to be more negative than that of O2/O2− (-0.282 eV), which indicated that the photodegradation reaction is limited by the ability of electrons to reduce the O2 in the dye solution to superoxide O2−.
Flow in a rotating cone for magnetized Prandtl fluid model is inspected in this investigation. The momentum equation of Prandtl model is derived under the consideration of Hall and ion slip effects and heat transport phenomenon is considered with Joule heating and viscous dissipation effects. The model of Hamilton Crosser and Yamada Ota are considered for the empirical relations of nanofluid mixture. The flow presenting expression of Prandtl fluid model with thermal transport is modeled under boundary layer approximation in the form of partial differential equations (PDEs). The derived PDEs have been converted into set of coupled nonlinear ordinary differential equations (ODEs) by engaging an appropriate scaling group transformation and these converted nonlinear set of ODEs have been tackled numerically via finite element scheme (FES). Impact of different emerging parameters has been displayed graphically and the physics behind the observed phenomena is explained in detail. The convergence of FES is established by carrying the grid independent survey. From the performed investigation, it is recorded that the parameters appear due to Hall and Ion slip currents enhance the fluid velocity but the inverse behavior is recorded for temperature profile.
Syngas has been utilized in the production of chemicals and fuels, as well as in the creation of electricity. Feedstock impurities, such as nitrogen, sulfur, chlorine, and ash, in syngas have a negative impact on downstream processes. Fischer–Tropsch synthesis is a process that relies heavily on temperature to increase the production of liquid fuels (FTS). In this study, waste biomass converted into activated carbon and then a carbon-supported iron-based catalyst was prepared. The catalyst at 200 °C and 350 °C was used to investigate the influence of temperature on the subsequent application of syngas to liquid fuels. Potassium (K) was used as a structural promoter in the Fe-C catalyst to boost catalyst activity and structural stability (Fe-C-K). Low temperatures (200 °C) cause 60% and 80% of diesel generation, respectively, without and with potassium promoter. At high temperatures (350 °C), the amount of gasoline produced is 36% without potassium promoter, and 72% with promoter. Iron carbon-supported catalysts with potassium promoter increase gasoline conversion from 36.4% (Fe-C) to 72.5% (Fe-C-K), and diesel conversion from 60.8% (Fe-C) to 80.0% (Fe-C-K). As seen by SEM pictures, iron particles with potassium promoter were found to be equally distributed on the surface of activated carbon.
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