Modeling of Fe/Pd nanoparticle-based functionalized membrane reactor for PCB dechlorination at room temperature

This research deals with the modeling and experimental verification of polychlorinated biphenyl (PCB) dechlorination using a porous membrane reactor embedded with Fe/Pd nanoparticles. We synthesized core/shell Fe/Pd nanoparticles in polyvinylidene fluoride (PVDF) microfiltration membranes functionalized with poly(acrylic acid) (PAA). PAA functionalization was achieved by in situ free radical polymerization of acrylic acid in microfiltration membrane pores. Target ferrous ions were then introduced into the membranes by the ion exchange process. Subsequent reduction resulted in the in situ formation of 20-40 nm Fe nanoparticles. Bimetallic nanoparticles can be formed by post-deposition of Pd. The membranes and Fe/Pd nanoparticles were characterized by thermogravimetric analyzer (TGA), FTIR, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). 2,2′-Dichlorobiphenyl (PCB4) and 3,3′,4,4′-tertrachlorobiphenyl (PCB77) were chosen as the model compounds to investigate the catalytic properties of bimetallic nanoparticles, the reaction mechanism, and the intrinsic kinetics. A two-dimensional steady-state model was developed to correlate and simulate mass transfer and reaction in the membrane pores under pressure-driven convective flow conditions. The 2D model equations were solved by a finite element technique. The influence of changing parameters such as reactor geometry (i.e., membrane pore size) and Pd coating composition were evaluated by the model and compared well with the experimental data.