This work centers on recycling of Rh catalysts and utilizing ion exchange to separate nuclear waste. In the area of Rh-type catalyst supports, non-porous zirconium phosphate nanoplatelets (ZrP) were utilized to provide sufficient outside surface area while still being easily separable from the reaction mixtures. First, a phosphine linker containing an ethoxysilyl group, (EtO)3Si(CH2)3PPh2, is reacted with ZrP. Addition of Wilkinson's catalyst ClRh(PPh3)3 to the phosphine-modified ZrP gives the immobilized catalyst. In the absence of pore diffusion, the catalytic hydrogenation of 1-dodecene using the Rhtype immobilized catalyst proceeds with unprecedented speed and the catalyst can be recovered and recycled 15 times.
New materials were synthesized that are comprised of Zr/Sn phosphonate-phosphate hybrids. The general formula for these materials is M(O3PC6H4PO3)1-x/2(APO4)x•nH2O, where M = Zr^4+, Sn^4+; A = H, Na, K; and x = 0, 0.5, 0.8, 1.0, 1.33, 1.6. These materials have a preference for ions of high charge (3+, 4+) over those with lower charge (1+, 2+). From this charge-based affinity and pH modification, separations can be achieved with Nd^3+/Cs^+ separation factors ≥ 100. The stability of these materials to 3.18 MGy gamma radiation was also observed with performance and structure retained. Greater than 99% removal of radioactive Am(III) from solution was obtained. Similar materials have also been utilized to explore rare earth recovery from Compact Fluorescent Lamps and Cr(VI) removal from wastewater solutions
