Pd-based catalytic hydrogenation has emerged as a promising and sustainable technology for the removal of waterborne contaminants. Catalyst supports are indispensable because they prevent Pd nanoparticle aggregation and enhance catalyst recovery after use. Electrospun nanofibers act as a great catalyst support due to their large surface area, highly porous structure, and tunable physicochemical properties. Our previous study used a one-pot synthesis and fabricated Pd on electrospun nanofiber catalysts with uniform Pd distribution, however the majority of Pd nanoparticles were embedded in the nanofibers (~97 %, based on CO chemisorption and ICP-MS tests) and resulted in a low activity. The objective of this study is to tailor the properties of electrospun PAN nanofibers as the Pd catalyst support and load Pd nanoparticles exclusively on nanofiber surface via incipient wetness to improve catalytic activity for waterborne contaminant removal (e.g., nitrite, bromate, <i>N</i>-nitrosodimethylamine). Hydrolysis of electrospun PAN nanofibers by NaOH creates hydrophilic groups (e.g., carboxylic and hydroxyl groups) and the addition of MWCNTs treated by concentrated nitric acid (a-MWCNTs) into PAN nanofibers also introduces hydrophilic groups. Both strategies are expected to improve Pd<sup>2+</sup> chelation, reduce Pd nanoparticle size, and improve catalytic activity. Our preliminary results showed that Pd on PAN/a-MWCNTs increased nitrite reduction kinetics up to 6.2 folds compared to its counterpart without a-MWCNT addition. The nanofiber diameter and porosity, surface functional groups, and Pd nanoparticle size will be evaluated. Electrospun catalytic nanofibers and their non-woven membrane structures will pave a new avenue to increase catalytic activity and reusability to address the challenges in practical applications.

Enhancement of reduction kinetics of waterborne contaminants on electrospun nanofibrous Pd-polyacrylonitrile (Pd-PAN) catalysts

251st National Meeting (2016)

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