Preparation and characterisation of palladium-loaded polypropylene porous hollow fibre membranes for hydrogenation of dissolved oxygen in water

Dissolved oxygen is one of the major components to be removed for the production of ultra-pure water. For the removal of oxygen to very low levels (less than 1 ppb for rinse water for the semiconductor industry), the catalytic reduction with hydrogen is an attractive method. The objective of this study was to integrate the palladium catalyst with the shell side of hydrophobic porous polypropylene membrane hollow fibre membranes to obtain a compact and efficient technique that preferably can be based on commercially available materials and modules. It was demonstrated that palladium could be deposited on a hydrophobic porous membrane hollow fibre, while maintaining its hydrophobic nature. Palladium loadings as low as 0.36% (w/w) were sufficient to catalyse the hydrogenation of dissolved oxygen while maintaining diffusion limited kinetics. Hence, a fast oxygen removal system is obtained that has the potential of maintaining removal rate, even at very low oxygen concentrations.