Tailored Macroporous Hydrogels With Catalytic Nanoparticles for Chemical Engineering Processes

点击翻译按钮获取中文摘要

Transition metal (gold, silver, etc.) nanoparticles (NPs) for heterogeneous catalysis have revealed a wide array of possibilities in the last 20 years. From water treatment applications (e.g. degradation of azo dyes and nitro compounds), to “greener” processes (e.g. the oxidation of alcohols, classically involving toxic compounds), and new synthesis pathways (e.g. aromatic amines for the pharmaceutical industry), NPs offer significant potential for chemical processes at mild conditions (room T and p, aqueous media). NPs come in various shapes, sizes, and compositions i.e. tunable reactivity , and are easy to synthesize. The successful integration of NPs in chemical engineering processes requires (1) preventing their agglomeration and coalescence to maintain reactivity, and (2) to design an efficient process allowing reuse and easy NPs separation.Hydrogels can help achieve these goals since they efficiently entrap and inhibit NPs agglomeration, while allowing reactants and products diffusion to and from NPs surface due to their liquid-like diffusivity properties. However, the reactivity of hybrid gel-NPs materials is typically low due to diffusion-limited mass transfer. One way to significantly enhance mass transfer is to use macroporous hydrogels, which contain networks of interconnected pores (diam. > 50 nm, IUPAC) - the main challenges being to achieve precise control over pore size, distribution and interconnectivity, with the possibility of scaling up the fabrication process. Recently, we have developed a scalable method to synthesize macroporous gels from cocontinuous polymer blends, with a high level of control over the porosity features, and displaying enhanced mass transfer properties. The general goal of this program is to develop morphologically tailored, mechanically robust macroporous gels containing catalytic NPs, such as gold, at controlled loading and reactivity levels. Three specific objectives are proposed : (1) To quantify the impacts of polymer blend, porous polymer mold, and gel morphologies, on the catalytic and mechanical properties of NP-loaded macroporous gels, and to strengthen their mechanical properties; (2) to control the nucleation and growth of NPs in porous gels, to correlate their properties to reactivity and microstructure, and to extend synthesis to multicomponent/anisotropic NPs; (3) To quantify the flow properties and reaction yield in continuous flow conditions, as a function of microstructure. To realize this program, 3 PhD and 5 undergraduate student interns will be hired, working at the interface of polymer/gel processing, nanomaterials synthesis, and catalytic processes projects encompassing multiple aspects of chemical engineering. The long-term objective is to integrate these materials in continuous-flow and membrane reactors for the development of new catalytic, high performance chemical engineering processes.