(376ae) PVDF Membrane Pore Functionalization Approaches with Applications to Pollutant Remediation

Authors: 
Islam, M. S., University of Kentucky
Wan, H., University of Kentucky
Bhattacharyya, D., University of Kentucky
Responsive membranes provide a highly tunable platform through ease of functionalization, accessibility with charged groups (-COOH, -OH) and tuning of pore size. Specifically, polyvinylidene fluoride (PVDF) microfiltration membranes have distinct advantage for open structure in terms of high internal surface area and ease of access in the pore domain. This give an edge to functionalize PVDF membrane with suitable responsive (pH, temperature) polymer and further incorporating Pd-Fe bimetallic nanoparticles for degradation of chlorinated organic compounds (COCs). However, making responsive membranes with specific responsive factor and precise amount of nanoparticle loading is a function of type of membrane and polymerization conditions. Specially, role of polymerization condition during making membrane is very critical to control membrane mass gain, water permeability, nanoparticle size and loading and finally,
the rate of degradation of COCs. Unfortunately, in literature this aspect is somehow overlooked. To address this aspect of making pH responsive membrane this study has demonstrated the effects of changing monomer and cross-linker concentrations matrix on the mass gain, water permeability, Pd-Fe nanoparticle (NP) loading, and the rate of degradation of one of COCs. Here, 3,3',4,4',5-pentachlorobiphenyl (PCB 126) was used as a model compound. The results revealed precise information on mass gain, water permeability, NPs size and loading on pH responsive functionalized membrane. The NPs functionalized membranes were then tested for use as a platform for the degradation of PCB 126. The observed batch reaction rate (Kobs) for PCB 126 degradation for per mg of catalyst loading was found 0.08~0.1 hr-1. Degradation study in convective flow mode shows 98.6% PCB 126 is degraded at a residence time of 46.2 seconds. The corresponding surface area normalized reaction rate (Ksa) is found about two times higher than Ksa of batch degradation; suggesting overcoming the effect of diffusion resistance for degradation of PCB 126 in convective flow mode operation. Lastly, statistical analysis based on experimental results allows us to portray responsive model behavior of functionalized membrane.

We like to thank NIH-NIEHS-SRC and Chevron for funding this research project.