Remote-Controlled Magnetic Sponge Balls and Threads for Oil/Water Separation in a Confined Space and Anaerobic Reactions.

Magnetic sponges (MSs) and magnetic threads with hydrophilic and hydrophobic characteristics that can perform remote-controlled oil/water separation in a confined space and anaerobic reactions were prepared. For large amounts of water or oil, trainlike hydrophilic or hydrophobic MSs composed of more than three sponge balls moved as a group and quickly absorbed the water or oil droplets in oil or water by magnetic manipulation from outside of the tube. For the removal of heavy oils below the water in three-liquid multiphase solutions, the hydrophobic MS balls were moved to the heavy oil below the water, absorbed some of the heavy oil, and returned to the light oil layer to deliver the heavy oil by means of an external magnetic field. The mixed oils floating on the water were easily removed by a suction pump once the heavy oil had been completely delivered to the light oil layer via the round-trip process. Furthermore, our approach was demonstrated for use in an anaerobic reaction system due to the strong magnetic property that transfers the reactants/products, the porous structure providing a reaction site, and the prewetting ability containing the reactants/products of the MSs and the oil layer prohibiting oxygen contact.

One-Step Synthesis of Environmentally Friendly Superhydrophilic and Superhydrophobic Sponges for Oil/Water Separation.

Environmentally friendly superhydrophilic and superhydrophobic sponges were synthesized using a one-step approach for oil/water separation. A superhydrophilic or superhydrophobic sponge (MFS/CC-DKGM or MFS/CC-PDMS) was synthesized by one-step coating of melamine formaldehyde sponge (MFS) with a mixture of calcium carbonate (CC) rods and deacetylized Konjac glucomannan (DKGM) [or polydimethylsiloxane (PDMS)]. The MFS/CC-PDMS showed excellent absorption capacity, which reached 52⁻76 g/g following immersion into various types of oil/water mixtures. Furthermore, the MFS/CC-DKGM and MFS/CC-PDMS exhibited excellent water- and oil-flux performances, which reached 4,702 L/m² h and 19,591 L/m² h, respectively, when they were used as filters. The MFS/CC-DKGM and MFS/CC-PDMS maintained their wettability characteristics relatively well after the chemical, thermal, and mechanical stability tests.