University of Idaho: Moscow, Idaho

Polyoxometalate Incorporation and Effects on Proton Transport in Hydrogel Polymers

August 7, 2020

Polyoxometalate clusters embedded into hydrogel biobeads may be able to solve the challenges posed by free proton generation during remediation of trichloroethylene by acting as buffers and reducing protons to hydrogen gas. In this thesis, the challenges posed by systems that contain both diffusion and reaction processes for protons are considered mathematically, and a computer simulation to was developed to prove the relationship between diaphragm cell lag period and reactive capabilities of membranes. Two polyoxometalate compounds, sodium decavanadate and alumina sulfate, were successfully incorporated into a poly(vinyl alcohol) hydrogel membrane, and the diffusivity changes associated with each compound was determined. It was found that the diffusivity of protons through an unmodified 10% w/v poly(vinyl alcohol) membrane was 1.76 × 10^-5 cm² s^-1 , the diffusivity through a 10%/2% w/w/v poly(vinyl alcohol)/sodium decavanadate membrane was 3.10 × 10^-6 cm² s^-1 , and the diffusivity through a 10%/2% w/w/v poly(vinyl alcohol)/alumina sulfate membrane was 3.32 × 10^-7 cm² s^-1 . Through analysis of the diaphragm cell lag period, it was found the incorporation of sodium decavanadate did not increase the reactivity of a poly(vinyl alcohol) hydrogel, and incorporation of alumina sulfate lowered the reactivity. These results indicate that polyoxometalate integration into hydrogel membranes is feasible, but does not provide any advantage to a bioremediation scenario.