A comparative study on removal of boron via pervaporation and vacuum membrane distillation using zirconium metal–organic framework-loaded poly(lactic acid) membrane

Boron mineral is very important for the life. However, exceeding the standards of boron minerals, especially in water to be used as domestic water, causes health and environmental problems. The commercial method used to separate boron minerals from water is reverse osmosis. In recent years, promising results have been obtained with the membrane distillation (MD) method. However, another method that is as effective as this method is pervaporation (PV). The most important component that affects performance in both methods is the membranes. In this study, zirconium-based metal organic framework (MOF) material was synthesized and added to the polylactic acid (PLA) membrane and boron was removed by pervaporation and membrane distillation methods. While the selective layered asymmetric membrane was prepared for pervaporation, porous membranes were prepared for membrane distillation. The effect of MOF additive on the morphology, mechanical strength, and separation properties of the membrane was investigated. Additionally, the effects of boron concentration and temperature on the separation performance in both methods were examined. As a result, the mechanical strength of membranes with MOF added increased significantly from 2.41 to 8.20 MPa. 99.9% boron removal was achieved in both methods. While the highest flux value was calculated as 8 kg/m²h in pervaporation at 6 ppm boron concentration, it was calculated as 11.33 kg/m²h in membrane distillation.