Facile synthesis,characterization and application of magnetic Fe3O4-coir pith composites for the removal of methyl violet from aqueous solution: Kinetics,isotherm, thermodynamics and parametric optimization

Dyes are commonly used in coloring clothes; in fertilizers, as anti-freezers, as detergents and so on. The use of such dyes has carcinogenic and genotoxic effects. These dyes require proper removal from the environment. Subsequently, a green and low-cost approach promises to adhere to sustainability of the environment while maximum removal of these toxic dyes. The present study describes removal of methyl violet (MV) dye by adsorption process magnetically separable Fe₃O₄-coir pith composites. The study was evaluated in batch system taking the optimum conditions as: pH: 7, contact time: 12 h, stirring speed: 200 rpm, concentration of dye: 100 mg/L, adsorbent weight: 3 g/L, temp.: 308 K. The central composite design approach of response surface methodology in design-expert software showed maximum removal efficiency (>98%) for optimal parameters. The experimental equilibrium data fitted reasonably well to Langmuir isotherm model. ANOVA analysis along with Fisher's statistical test was also performed to validate the model. The predicted model was at par with the experimental values with adjusted R² of 0.9914. A thorough investigation of kinetic ($R_{\text{Pseudo second order}}^2$ = 0.99; $R_{\text{Pseudo second order}}^2=0.97;R_{\text{intra}?\text{particle diffusion}}^2=0.98)$, thermodynamic, adsorption isotherm $(R_{\text{Langmuir isotherm}}^2=0.997$ $R_{\text{Freundlich isotherm}}^2=0.99$ and eco-toxicological characteristics were performed for proper evaluations of the properties as well as sustainability of the adsorbent material. The whole research indicated encouraging potential of the developed material for adsorption, reusability and sustainability in applications for industrial scale wastewater treatment.     

Thermal stability of hybrid nanofluid with viscous dissipation and suction/injection applications: Dual branch framework

The thermal stability of nanomaterials is quite necessary for controlling the heat and cooling phenomenon. It is worthy observed that much research has been focused scientists towards the thermal significance of nanoparticles with multidisciplinary engineering and industrial applications. On this end, this report explores the improved thermal mechanism water base material with interaction of hybrid nanofluid stretching and shrinking surface. The cooling and heat phenomenon is observed in presence of viscous dissipation. The hybrid nanofluid characteristics are inspected with combination of copper $\left(Cu\right)$ and aluminum oxide $\left(A{l}_2{O}_3\right)$ nanoparticles with stable prospective. The consideration of such hybrid nanoparticles is due to impressive thermal characteristics and stable thermal performances. Although some studies are focused by researchers on hybrid nanofluid, however the measurement of thermal stability is not claimed yet. The stretching and shrinking configuration specify the porous medium features. The problem is compiled into dimensionless structure which is further preceded via bvp4c scheme. The resultant ODEs are successfully numerically solved using the bvp4c solver technique. Under restricting conditions, numerical findings are compared to previously published results. Non-dimensional profiles of velocity and temperature are shown graphically. Furthermore, graphs and tables show the effects of the physical parameters used on the reduced skin friction and heat transfer rate. Dual branches are found in specified domain of suction factor.     

Three dimensional nanofluid motion with convective boundary condition in presents of nonlinear thermal radiation via stretching sheet

In present work activation energy on 3D (“Three-Dimensional”) nanofluid (NFs) motion via stretching surface (SS) with slip condition: a statistical study. The slip velocity defined for NFs model are reduction in governing PDE’s were converted into a set of non-linear ODE’s by help of similarity transformations. Present Statistical model is taken three different systems: in which the statistical results are computed via R-K-F (“Range-Kutta-Fehlberg”) algorithm and tested these solutions with help of shooting technique and improved bvp 4th order analysis. Graphical comparisons and statistical (“Numerical”) tables are created to validation results for three different techniques. The emerging physical parameters on velocity (“axial and transverse directions”), $\theta \left(\eta \right)$ (“Temperature”) and $\phi \left(\eta \right)$ (“Concentration”). We found that, the $\theta \left(\eta \right)$ is more impact in NFs motion for enlarge statistical values of various physical parameters. Further, we compared statistical results of present study with previous results in up to six decimal places.     

Hall effects and entropy generation applications for peristaltic flow of modified hybrid nanofluid with electroosmosis phenomenon

The electroosmotic peristaltic flow of modified hybrid nanofluid in presence of entropy generation has been presented in this thermal model. The Hall impact and thermal radiation with help of nonlinear relations has also been used to modify the analysis. The assumed flow is considered due to a non-uniform trapped channel. The properties of modified hybrid nanofluid model are focused with interaction of three distinct types of nanoparticles namely copper ($Cu)$, silver ($Ag$) and aluminum oxide ($A{l}_2{O}_3).$ The mathematical modeling and significances of entropy generation and Bejan number are identified. With certain flow assumptions, the governing equations are attained for optimized peristaltic electroosmotic problem. Widely used assumptions of long wave length and low Reynolds number reduced the governing equations in ordinary differential equations. The ND solver is flowed for the solution process. The physical significant of results is observed by assigning the numerical values to parameters.