▎ 摘　　要

NOVELTY - Preparing (M1) oxidized graphene flakes (OGF) incorporated reduced graphene oxide (rGO) coated PU foam comprises: preparing surface of the mold for anti-sticking property; weighing 5-30 wt.% OGF measured to the total weight of polyol and isocyanate; uniformly mixing OGF with polyol; adding di-isocyanate to the homogeneous mixture of the OGF with polyol and mixing for polymerizing; pouring the mixed OGF, polyol and diisocyanate mixture to the mold; packing the mold tightly to prevent leakage of the expanding mixture during polymerization to ensure obtaining least rejection and high quality OGF incorporated PU foam; cutting the OGF incorporated PU foam into blocks of particular thickness; twice dip coating the OGF incorporated PU foam blocks with graphene oxide (GO) by dipping the OGF incorporated PU foam blocks in GO liquid solution; and thermally treating the GO dip coated OGF incorporated PU foam blocks obtain the rGO dip coated oxidized graphene flakes (OGF) incorporated PU foam. USE - The method is useful for preparing oxidized graphene flakes (OGF) incorporated reduced graphene oxide (rGO) coated PU foam, which is useful in porous filter media based filtration device for separating oil from the oil water emulsion in both gravity fed system and pressure fed system. ADVANTAGE - The method: provides porous filter media having high oil absorption capacity; reduces oil ppm level of an oil water emulsion liquid to below 10 ppm; has low cost of synthesis of filter media due to less use of chemicals; eliminates crosslinking requirement of graphene oxide on foam surface and cheaper alternative of materials used; and adopts porous media which is super hydrophobic and superoleophilic in nature, OGF is waste derived and hence ads to the circular economy of the nation, oil water separation column which is economical compared to the existing available systems, and oil water separation column which is recyclable and reusable. DETAILED DESCRIPTION - INDEPENDENT CLAIMs are also included for: (1) nanocomposite PU foam-based oil separation column (100), comprising many porous filter media blocks stacked together having interconnected pores to break the oil water emulsion and separate oil from the oil water emulsion, a membrane to firmly wrap around the stacked porous filter media blocks preventing the leakage of oil outside the stacked porous filter media blocks, a housing (101) of a rigid hollow pipe structure similar to the shape of the porous filter media blocks to house the membrane wrapped stacked porous filter media blocks, an upper end cap (102) fixed with an interference fit longitudinally on the top side of the housing, a lower end cap (103) is fixed with an interference fit longitudinally on the bottom side of the housing, an inlet connector (104) is fixed on the upper end cap either by threading or fitting or welding to enable attachment of feed water supply line, an outlet connector is fixed on the lower end cap either by threading or fitting or welding to enable attachment of permeate water supply line, and many polymer washers is placed in-between the end caps, and connectors; (2) assembling (M2) the nanocomposite PU foam-based oil separation column, comprising gluing, each face of the porous filter media blocks on flat side where the glue is applied in a thin ring manner on the periphery of the face of each porous filter media blocks, placing, each glued porous filter media blocks on top of each other to form a single porous filter media, gluing a side of flat membrane, wrapping, the membrane completely around the periphery of the porous filter media having membrane glued side towards the porous filter media leaving the longitudinal ends open, gluing, the outer periphery of the membrane wrapped porous filter media, inserting, the glued membrane wrapped porous filter media into the housing so that the open extension is equivalent or exceeding the top open end, sealing the top and bottom ends of the housing with Teflon(RTM: PTFE) tape or sealing liquid to prevent leakage of fluid, fixing the inlet connector and outlet connector to the upper end cap and lower end cap respectively intermediate with polymer washers to prevent leakage of fluid, and fixing the upper end cap and lower end cap on the top and bottom end of the housing ensuring interference fit; (3) nanocomposite PU foam-based oil separation column comprising manyporous filter media blocks is stacked together having interconnected pores to break the oil water emulsion and separate oil from the oil water emulsion, a membrane to firmly wrap around the stacked porous filter media blocks preventing the leakage of oil outside the stacked porous filter media blocks, a housing of a rigid hollow pipe structure similar to the shape of the porous filter media blocks to house the membrane is wrapped stacked porous filter media blocks, many polymer seals around the periphery of membrane wrapped porous filter media block for each porous filter media block to prevent the leakage of feed water directly to the outlet, an upper end cap fixed with an interference fit longitudinally on the top side of the housing, a lower end cap is fixed with an interference fit longitudinally on the bottom side of the housing, an inlet connector fixed on the upper end cap either by threading or fitting or welding to enable attachment of feed water supply line, an outlet connector is fixed on the lower end cap either by threading or fitting or welding to enable attachment of permeate water supply line, and a plurality of polymer washers placed in-between the end caps, and connectors; and (4) nanocomposite PU foam-based oil separation column. DESCRIPTION OF DRAWING(S) - The figure shows an isometric view of the oil separation column. 100Nanocomposite PU foam-based oil separation column 101Housing 102Upper end cap 103Lower end cap 104Inlet connector