High performance Ni-based porous catalytically activated absorbers and establishment of kinetic model for complex solar methane dry reforming reaction system

Highly selective adsorption of Hg (II) from aqueous solution by three-dimensional porous N-doped starch-based carbon

For the first time, N-doped carbon materials with 3D porous-layered skeleton structure was synthesized through a one-step co-pyrolysis method, which was fabricated by co-pyrolysis of natural corn starch and melamine using metal catalysts (Ni (II) and Mn (II)). The 3D-NC possessed a heterogeneously meso-macroporous surface with a hierarchically connected sheet structure inside. Batch adsorption experiments suggested that highly selective adsorption of Hg (II) by the 3D-NC could be completed within 90 min and had maximum adsorption capacities as high as 403.24 mg/g at 293 K, pH = 5. The adsorption mechanism for Hg (II) was carefully evaluated and followed the physical adsorption, electrostatic attraction, chelation, and ion exchange. Besides, thermodynamic study demonstrated that the Hg (II) adsorption procedure was spontaneous, endothermic, and randomness. More importantly, the 3D-NC could be regenerated and recovered well after adsorption-desorption cycles, showing a promising prospect in the remediation of Hg (II)-contaminated wastewater.

Evaluation of promoted Ni-based nanocatalysts in wall-coated microchannel reactor on the dry reforming of methane and effect of ultrasound waves on physiochemical properties of synthesized nanocatalysts

The deactivation of nickel catalysts in the dry reforming of methane (DRM) process has been one of the issues of interest to researchers. In this research, the effect of active phase and support promoter uses and synthesis method on synthesized Ni–Co/Al2O3–MgO nanocatalysts efficiency in wall coated microreactor on dry reforming of methane process studied. To determine the characteristics of the synthesized samples, XRD, BET, FESEM, and Ft-IR analyses have been performed. Analyses show that the use of ultrasound waves in the synthesis of catalysts improves the catalyst surface morphology so that about 82% of the particles of the synthesized sample are smaller than 100 nm and , increases the specific surface area to an average of 10%, and makes its structure smaller. Also, the total pore volume on the surface of the samples also shows a 10% increase. The use of promoters increases the catalyst activity and makes it more stable up to 18 h on stream. The use of a wall-coated microreactor improves heat transfer, easier access of reactants to active sites, no pressure drop, and higher activity than a conventional U-type fixed bed reactor. Nanocatalysts with Ni/Co = 5 and Al/Mg = 5 has shown the highest and most stable activity throughout the temperature range in the DRM process.