Influence of Alkalinization Over Metal Organic Frameworks MIL-100(Fe) for Enhanced Volatile Organic Compounds (VOCs) Adsorbents

Substantial attempts have been undertaken for the improvement of the air quality over decades; and Volatile Organic Compounds (VOCs) from the chemical and textile industries are truly listed as severe issue to be controlled. To come up with modus operandi for this issue, a novel composite of metal organic frameworks (MOFs) MIL-100(Fe) with salient tuned features of natrite was designed by a green and facile method. Mineralized composite MOFs exhibited enhanced crystallinity than pure MIL-100(Fe) as well showcased a higher surface area of 1300 m2 g−1. Through dynamic acetone pressure swing adsorption setup, MIL-0.05Na (MIL-100(Fe) synthesized with 0.05 mM Na2CO3 solution) revealed an enhanced acetone adsorption of 210 mg g 1 at room temperature. Gas phase adsorption isotherms confirmed the mono layer adsorption behavior. The kinetics models evaluated that the external mass transfer was the rate limiting step for surface adsorption. The thermodynamic study manifested that the adsorption reaction was spontaneous and exothermic. The proposed mechanism of adsorption was the act of physisorption which enriched the adsorbents reusability. This research work provides a futuristic vista to design mineralized Fe-MOFs composites for an energy saving adsorbents for VOCs removal.

Gas Phase Lubrication Study with an Organic Friction Modifier

Friction modifier additive technologies play a crucial role in controlling friction and wear of lubricated tribological systems. Novel additives are usually evaluated using formulations of varying concentrations. It can be very difficult to understand the underlying mechanisms in those laboratory tests because of the interaction of base oil with the additives. It thus can be insightful to perform model experiments in a controllable atmosphere. This can be achieved for instance by integrating a tribometer into a vacuum system comprising in-situ surface analytical methods.In this work, a nitrogen containing organic friction modifier is adsorbed from the gas phase onto a Fe2O3 surface. Different coating thicknesses are prepared by varying the duration of the vapor deposition, so that the influence of the coating thickness on the friction behavior can be investigated. The chemical composition of the coated surfaces is also analyzed by coupling to an XPS photoelectron spectrometer.Contrary to the assumption that layers are formed, this friction modifier accumulates in droplets on the Fe2O3 surface. The number of droplets as well as the radii of droplets increase with evaporation time. The chemical composition of the additive does not change as a result of the gas phase deposition. In the friction tests, the smallest friction values are found for a very low coverage of droplets. For larger droplets, friction increases due to a capillary neck of additive that forms between the sliding surfaces and is dragged along during the friction test.Using gas phase adsorption of a nitrogen containing organic friction modifier it was possible to establish a correlation between droplet morphology and the friction behavior.

Influence of alkalinization over MIL-100(Fe) for enhanced VOCs adsorbents

Substantial attempts have been undertaken for the improvement of the air quality over decades; and Volatile Organic Compounds (VOCs) from the chemical and textile industries are truly listed as severe issue to be controlled. To come up with modus operandi for this issue, a novel composite of metal organic frameworks (MOFs) MIL-100(Fe) with salient tuned features of natrite was designed by a green and facile method. Mineralized composite MIL-100(Fe) exhibited enhanced crystallinity than pure MIL-100(Fe) as well showcased a higher surface area of 1300 m2g− 1. Through dynamic acetone pressure swing adsorption setup, MIL-0.05Na revealed an enhanced acetone adsorption of 210 mg g− 1 at room temperature. Gas phase adsorption isotherms confirmed the mono layer adsorption behavior. The kinetics models evaluated that the external mass transfer was the rate limiting step for surface adsorption. The thermodynamic study manifested that the adsorption reaction was spontaneous and exothermic. The proposed mechanism of adsorption was the act of physisorption which enriched the adsorbents reusability. This research work provides a futuristic vista to design mineralized Fe-MOFs composites for an energy saving adsorbents for VOCs removal.

Application of cyanated asphaltenes in gas-phase adsorption processes for removal of volatile organic compounds

The paper presents an innovative, chemically modified (methylcyanated) asphaltene-based adsorbent that can be an interesting low-cost alternative for traditional adsorbents. Adsorption properties of adsorbents were examined by inverse gas chromatography technique, adsorption isotherms, and breakthrough curves. A significant increase in retention volume for pyridine, 2-pentanone, nitropropane, toluene, and 1-butanol was observed. Rohrschneider–McReynolds constants revealed an increase in strength of interactions as a result of the modification, especially in strong proton–acceptor interaction (by a factor of 4.6). The surface-free energy of asphaltene adsorbents increased from 136.71 to 169.95 mJ m−2 after modification. It is similar to the surface-free energy of silica or alumina. Moreover, modified adsorbent shows very high adsorption potential for pyridine. Adsorption isotherms revealed that monolayer adsorption capacity for pyridine increased 1.5 times after modification. Breakthrough curves of pyridine indicate that chemical modification increased the adsorption capacity, removal efficiency, and throughput. Scale-up calculations revealed that adsorption column packed with modified asphaltene adsorbent would be almost two times smaller compared to a column packed with unmodified one. Graphic abstract

A dry chemical method for dispersing Ir nanoparticles in the pores of activated carbon and their X-ray absorption spectroscopy analysis

Ir nanoparticles are finely dispersed inside the pores of activated carbon (AC) via the gas phase adsorption of an organoiridium complex in the AC and subsequent heat treatment. X-ray absorption spectroscopy reveals the structure of the supported Ir.