Removal of heavy crude oil from water surfaces using a magnetic inorganic-organic hybrid powder and membrane system

摘要

Oil spills are among the most significant threats to aquatic ecosystems. The present work describes the synthesis of different organic-inorganic hybrid matrices with magnetic properties, obtained in the forms of powders and membranes. The powders were synthesized using the following biomass wastes to form the organic phase: coconut mesocarp, sugarcane bagasse, sawdust, and water hyacinth. The resulting powders were denoted HMG-CO, HMG-CN, HMG-SE, and HMG-AP, respectively, Membranes (denoted MHMG-PES) were prepared using polyethersulfone polymer. In both cases, the inorganic phase was cobalt ferrite. The materials were evaluated in terms of their efficiencies in removing crude oil from water surfaces. The presence of organic matter, polyethersulfone, and cobalt ferrite in the structures of the materials was confirmed by XRD and FTIR analyses. The efficiencies of the materials were determined using the Standard Test Method for Sorbent Performance of Adsorbents (ASTM F726-99). Among the hybrids in powder form, the HMG-CN material presented the highest oil removal efficiency (85%, adsorptive capacity of 17 g g(-1)), which could be attributed to the fibrous nature of the sugarcane bagasse. The MHMG-PES membrane was able to remove 35 times its own mass of oil (adsorptive capacity of 35 g g(-1)). In addition to this high removal efficiency, an important advantage of MHMG-PES, compared to the HMG-CN hybrid powder, was that the oil could be mechanically removed from the membrane surface, eliminating the need for subsequent time-consuming extraction steps requiring large volumes of organic solvents and additional energy expenditure. When the two materials were used simultaneously, it was possible to remove 45 times their own mass of oil (adsorptive capacity of 45 g g(-1)), with the adsorptive capacity of HMG-CN increasing by 23%. This high adsorptive capacity was due to the retaining barrier formed by the HMG-CN hybrid powder, which prevented the oil patch from spreading and enabled its homogeneous removal, which was not possible using MHMG-PES alone. It could be concluded that use of the magnetic hybrids synthesized using biomass wastes, together with the hybrid magnetic membrane, provided an effective and inexpensive technological alternative for the removal of oil from water surfaces.