Preparation, characterization and laboratory-scale application of modified hydrophobic aluminum oxide hollow fiber membrane for CO₂ capture using H₂O as low-cost absorbent

The objective of this work was to apply the modified hydrophobic metal oxide hollow fiber membrane in a laboratory-scale gas-liquid membrane contacting process for CO₂ capture applications using H₂O as low-cost absorbent at room temperature. With this aim, the porous aluminum oxide (α-Al₂O₃) hollow fiber membranes were prepared by a phase inversion spinning technique and a sintering method. In order to render the hydrophilic surface of prepared Al₂O₃ hollow fiber membrane without changing its physical properties, a fluoroalkylsilanes (FAS) film was used. The fluoroalkylsilanized Al₂O₃ hollow fiber membrane surface was studied by performing thermal gravimetric analysis (TG), scanning electron microscopy (SEM), X-ray diffractometer (XRD). In addition, the hydrophobicity nature of modified Al₂O₃ hollow fiber membrane surfaces was measured by water drop contact angle test and break through pressure measurement. This work, for what we believe to be the first time, has successfully realized a room-temperature laboratory-scale gas-liquid membrane contactors using a single fluoroalkylsilanized Al₂O₃ hollow fiber membrane for CO₂ capture. According to the experimental results, the correlations between water and gas flow rate, and CO₂ mass transfer through the modified hydrophobic Al₂O₃ hollow fiber membranes are given. In addition, a comparative review was made between our modified hydrophobic aluminum oxide and traditional polymeric hollow fiber membrane for application in the field of CO₂ absorption in water. The results indicated that studied fluoroalkylsilanized Al₂O₃ hollow fiber membrane may be possible candidates for the development of new gas-liquid membrane contactors for CO₂ capture.