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The paper investigates two-dimensional, steady, nonlinear laminar boundary layer heat and mass transfer MHD flow past a stretching porous surface embedded in a porous medium under the action of internal heat generation with the consideration of viscous and joules heat dissipation in the presence of a transverse magnetic field. The two-dimensional governing equations are solved by using MATLAB built in bvp4c solver technique for different values of physical parameters. The numerical values of various flow parameters such as velocity, temperature, concentration are calculated numerically and analysed graphically for various values of the non-dimensional physical parameters of the problem followed by conclusions. The study concludes opposite behaviour of transverse and longitudinal velocity under the action of suction velocity in addition to the effects of heat source on fluid velocities, temperature and concentration.

The paper investigates two-dimensional, steady, nonlinear laminar boundary layer heat and mass transfer MHD flow past a stretching porous surface embedded in a porous medium under the action of internal heat generation with the consideration of viscous and joules heat dissipation in the presence of a transverse magnetic field. The two-dimensional governing equations are solved by using MATLAB built in bvp4c solver technique for different values of physical parameters. The numerical values of various flow parameters such as velocity, temperature, concentration are calculated numerically and analysed graphically for various values of the non-dimensional physical parameters of the problem followed by conclusions. The study concludes opposite behaviour of transverse and longitudinal velocity under the action of suction velocity in addition to the effects of heat source on fluid velocities, temperature and concentration. [ABSTRACT FROM AUTHOR]

The superior electrocatalytic hydrodechlorination (EHDC) performance on Pd/U-TiO 2 catalyst is attributed to the electron-rich Pd regulated by urchin-like yolk/shell TiO 2 support, enhanced adsorption and activation of 2,4-dichlorophenol, faster mass diffusion behavior and high current efficiency toward EHDC. [Display omitted] • Pd supported on urchin-like yolk/mesoporous shell TiO 2 (Pd/U-TiO 2) is prepared. • Pd/U-TiO 2 affords high efficiency and durability in EHDC of 2,4-DCP. • Pd/U-TiO 2 affords a higher H* utilization efficiency of 48.6 % than single Pd. • U-TiO 2 support boosts the mass diffusion of 2,4-DCP around Pd nanoparticles. • The pollutant adsorption and activation are enhanced on U-TiO 2 -supported Pd. Improving the utilization of hydrogen radicals (H*) is of great significance for effective Pd-mediated electrocatalytic hydrodechlorination (EHDC) in detoxifying chlorinated organic pollutants (COPs). However, the limited H* utilization by single Pd arises from its inadequate performance in adsorbing/activating COPs and inferior mass transfer of low-concentration COPs. In this study, an urchin-like yolk/shell TiO 2 spheres with mesoporous structure are developed for supporting Pd nanoparticles (Pd/U-TiO 2), which exhibits superior EHDC activity and selectivity for 2,4-DCP reduction. Notably, the prepared Pd/U-TiO 2 catalyst achieves a mass activity of 4.2 min−1 g Pd -1 and a specific activity of 1.94 min−1 mol Pd -1 when detoxifying 50 mg/L of 2,4-DCP at −0.85 V, surpassing the most reported catalysts. Furthermore, the Pd/U-TiO 2 catalyst consistently demonstrates higher H* utilization efficiency compared to single Pd, regardless of the 2,4-DCP concentration or reaction mode (batch or continuous-flow). This enhanced H* utilization efficiency is attributed to two key factors: the urchin-like and yolk/shell structure of U-TiO 2 enhances the mass diffusion of 2,4-DCP, and the strong interactions between Pd and U-TiO 2 generate electron-rich Pd species that enhance the adsorption and activation of COPs. Overall, this work highlights the synergistic effects of strong metal-support interactions and mass diffusion in enhancing atomic H* utilization. This study lays a significant experimental and theoretical foundation for designing efficient electrocatalysts for the detoxification of chlorinated organic pollutants and various other halogenated organic pollutants. [ABSTRACT FROM AUTHOR]

Heavy metal pollution treatment in industrial wastewater is crucial for protecting biological and environmental safety. However, the highly efficient and selective removal of heavy metal ions from multiple cations in wastewater is a significant challenge. This work proposed a pulse electrochemical method with a low-/high-voltage periodic appearance to selectively recover heavy metal ions from complex wastewater. It exhibited a higher recovery efficiency for heavy metal ions (100% for Pb 2+ and Cd 2+ , >98% for Mn 2+ ) than other alkali and alkaline earth metal ions (Na + , Ca 2+ , and Mg 2+ were kept below 3.6, 1.3, and 2.6%, respectively) in the multicomponent solution. The energy consumption was only 34-77% of that of the direct current electrodeposition method. The results of characterization and experiment unveil the mechanism that the low-/high-voltage periodic appearance can significantly suppress the water-splitting reaction and break the mass-transfer limitation between heavy metal ions and electrodes. In addition, the plant study demonstrates the feasibility of treated wastewater for agricultural use, further proving the high sustainability of the method. Therefore, it provides new insights into the selective recovery of heavy metals from industrial wastewater.