Novel Adsorbent Synthesis Diffusion In Nanoporous Materials And Adsorption System Optimization

As nanomaterials get smaller, their properties increasingly diverge from their bulk material counterparts. Written from a materials science perspective, Adsorption and Diffusion in Nanoporous Materials describes the methodology for using single-component gas adsorption and diffusion measurements to characterize nanoporous solids. Concise, yet comprehensive, the book covers both equilibrium adsorption and adsorption kinetics in dynamic systems in a single source. It presents the theoretical and mathematical tools for analyzing microporosity, kinetics, thermodynamics, and transport processes of the adsorbent surface. Then it examines how these measurements elucidate structural and morphological characteristics of the materials. Detailed descriptions of the phenomena include diagrams, essential equations, and fully derived, concrete examples based on the author's own research experiences and insight. The book contains chapters on statistical physics, dynamic adsorption in plug flow bed reactors, and the synthesis and modification of important nanoporous materials. The final chapter covers the principles and applications of adsorption for multicomponent systems in the liquid phase. Connecting recent advances in adsorption characterization with developments in the transport and diffusion of nanoporous materials, this book is ideal for scientists involved in the research, development, and applications of new nanoporous materials.

This book provides researchers and graduate students with an overview of the latest developments in and applications of adsorption processes for water treatment and purification. In particular, it covers current topics in connection with the modeling and design of adsorption processes, and the synthesis and application of cost-effective adsorbents for the removal of relevant aquatic pollutants. The book describes recent advances and alternatives to improve the performance and efficacy of this water purification technique. In addition, selected chapters are devoted to discussing the reliable modeling and analysis of adsorption data, which are relevant for real-life applications to industrial effluents and groundwater. Overall, the book equips readers with a general perspective of the potential that adsorption processes hold for the removal of emerging water pollutants. It can readily be adopted as part of special courses on environmental engineering, adsorption and water treatment for upper undergraduate and graduate students. Furthermore, the book offers a valuable resource for researchers in water production control, as well as for practitioners interested in applying adsorption processes to real-world problems in water treatment and related areas.

In this work, a systematic computational study directed toward developing a molecular-level understanding of gas adsorption and diffusion characteristics in nano-porous materials is presented. Two different types of porous adsorbents were studied, one crystalline and the other amorphous. Physisorption and diffusion of hydrogen in ten iso-reticular metal-organic frameworks (IRMOFs) were investigated. A set of nine adsorbents taken from a class of novel, amorphous nano-porous materials composed of spherosilicate building blocks and isolated metal sites was also studied, with attention paid to the adsorptive and diffusive behavior of hydrogen, methane, carbon dioxide and their binary mixtures. Both classes of materials were modeled to correspond to experimentally synthesized materials. While much research has targeted adsorption in IRMOFs, very little has appeared for these amorphous silicates, which contain cubic silicate building blocks: Si8O20 [spherosilicate units], cross-linked by SiCl2O2 [silicon chloride] bridges and decorated with either -OTiCl3 [titanium chloride] or -OSiMe3 [trimethylsilyl] groups. Based only on physisorption, the amorphous silicates show competitive adsorptive capacities and selectivities with other commercial gas adsorbents. The tools employed in this dissertation were computational in nature. Adsorptive properties, such as adsorption isotherms, binding energies and selectivities, were generated from Grand Canonical Monte Carlo molecular (GCMC) simulations. Self-diffusivities and activation energies for diffusion were generated using Molecular Dynamics simulations. Adsorption isotherms are reported at temperatures of 77 K [Kelvin] and 300 K for pressures ranging up to 100 bar. The most favorable adsorption sites for all gases studied in the amorphous silicates are located in front of the faces of the spherosilicate cubes. Regardless of material, the hydrogen adsorption process is governed by entropic considerations at 300 K. At 77 K energetic considerations control hydrogen adsorption at low pressures and entropic effects dominate at high pressure. For methane and carbon dioxide at 300 K, the adsorption process is governed by energetic considerations at low pressure and by entropic (packing) constraints at high pressure. The amorphous silicates showed very high selectivity for carbon dioxide over hydrogen. The presence of titanium sitesdid not enhance physisorptive capacity or selectivity.

As nanomaterials get smaller, their properties increasingly diverge from their bulk material counterparts. Written from a materials science perspective, Adsorption and Diffusion in Nanoporous Materials describes the methodology for using single-component gas adsorption and diffusion measurements to characterize nanoporous solids.

The development of metal-organic frameworks (MOFs) have received an increasing attention due to their potential applications for environmental remediation. Because of their ultrahigh micropore volume and large specific surface area, MOFs are specifically applicable for gas adsorption and separation. However, these applications are often limited due to their high cost, restricted mass transfer, and inadequate selectivity. The main objective of this dissertation is the synthesis and characterization of novel nanoporous materials based on ZIF-67 and Cu-BTC MOF frameworks. The first main chapter of this dissertation focuses on the synthesis of small crystals of ZIF-67 using cetyltrimethylammonium bromide (CTAB) surfactant as a capping agent to obtain composites of ZIF-67 and microporous carbon applicable for gas adsorption, including CO2 adsorption. The next chapter focuses on the synthesis of composites consisting of ZIF-67 and gamma alumina (GA) with and without its modification with imidazole-containing silanes. A significant improvement is observed in dye adsorption (Rhodamine B) on the composites as compared to ZIF-67 and GA alone. The composites consisting of GA modified with imidazole show higher adsorption capacity for Rhodamine B. The other two chapters deal with the synthesis and characterization of novel composites of Cu-BTC and nanoporous carbons as well as with improvement of CO2 adsorption properties of Cu-BTC. The aforementioned composites exhibit a synergistic effect of the structure parameters derived from the both parent materials. As compared to the parent materials, the composites of Cu-BTC and porous carbons, show higher specific surface area and microporosity due to the newly created micropores at the interface, which enhance their CO2 adsorption capacity at ambient conditions. This work shows that a further improvement of the CO2 adsorption properties of Cu-BTC is possible by adjusting the molar ratio of Cu to BTC during synthesis. Namely, the ratio of 1.09:1.0 Cu to BTC produces MOF with improved textural properties and a remarkably high CO2 adsorption of 9.33 mmol/g at 0 oC and 1 bar.

Organic and Inorganic pollutants from a number of sources are introduced into the water reservoirs limiting the usability and placing burden on natural resources. This manuscript is an attempt based on the applied bench scale research proposing novel adsorbents for the removal of aqueous pollutants. Nitrates and Phenols are persistent in the media and are difficult to be removed. Adsorption offers a viable and technological doable option for decontamination of industrial pollutants. Nanomaterials based on silica and alumina are synthesized using different procedures and to determine the efficacy of these small particles, meso sized materials are also applied for comparison. Twelve series of batch experiment was conducted at variables of contact time, pH of the medium, adsorbent dose, and adsorbate concentration. More research in this direction is required as nanotechnology has the potential to be equally applied for remediation. This piece of work can serve a guideline for researchers in the field of synthetic chemistry, environmentalists, and policy makers.

During the last years, the authors have synthesized, characterized, and studied the adsorption properties of nitroprussides, Prussian blue analogues, akaganeites, MeAPOs, metal,Äìorganic frameworks, and extremely high specific surface amorphous silica, which allowed the storage of about 11¬†wt.% of hydrogen in the form of ammonia. In this sense, using the solid-state reaction method, sol,Äìgel methodologies, together with aluminosilicate, high silica and non-aluminosilicate zeolite synthesis methods, were described, moreover was explained how to prepare active carbons along with the synthesis of Prussian blue analogues (PBAs) and nitroprussides (NPs). In addition, the characterization of the materials of interest applying X-ray diffraction, thermogravimetric analysis, DRIFTS, and room-temperature Mossbauer spectrometry was discussed. Besides, the concepts that define physical adsorption and examples of adsorption data, which were tested with the help of the Dubinin, osmotic adsorption and Langmuir-type isotherms, were defined. Later, the methodology was described for the measurement of adsorption data with the help of the volumetric method. Moreover, a description of the thermodynamics of adsorption, along with the methodology for the calculation of calorimetric data with the help of heat flow calorimeters together with the measurement of differential heats of adsorption data was developed. Finally, the different interaction forces that make possible adsorption were discussed.