Development of adsorbent hollow fibres for environmental applications

In this paper, new generic synthesis routes for the single step prodn. of adsorbent composite hollow fibers, based on polymer dry/wet spinning followed by a phase inversion process, is presented. This prepn. technique avoids impregnation of precursors or the use of chems. for zeolite deposition while prodn. times and costs are dramatically reduced. Primary factors (such as type of solvent and viscosity), affecting the structure and adsorption performance of the mol. sieving hollow fibers are studied. The produced fibers show very good quality and reveal an asym. structure with a porosity between 37% and 45%. The adsorptive/sepn. properties of silicalite fibers and their particulate counterparts have been obtained in a lab.-scale flow system using n-butane as the adsorbate. The fibers prepd. from three different solvents, N, N-Dimethylformamide (DMF), N, N-dimethylacetamide (DMAc) and 1-methyl-2-pyrrolidone (NMP), are compared. The hollow fiber prepd. from 1-methyl-2-pyrrolidone (NMP) solvent gave the sharpest breakthrough curve and the longest breakthrough time compared to fibers prepd. from N, N-dimethylacetamide (DMAc), N, N-Dimethylformamide (DMF) and com. pellets. With this new method, membranes with unique adsorbent properties and a high surface area per unit vol. ratio can be achieved with a range of adsorbents to target a range of pollutants. The proposed method is not limited to silicalite; in principle many adsorbent materials or catalytic or metallic powders may be used. This means that this method can pave the way for a new generation of adsorbent fiber membranes with low mass transfer resistance. [on SciFinder (R)]