Facile fabrication of ceramic-polymeric nanocomposite membrane with special surface wettability using amino decorated NH₂-SiO₂@SiC nanopowder for production of clean water from oily wastewater

Given the huge market potential of treating oily wastewater, a ceramic membrane with special surface wettability was fabricated by covalently decorating amino-functionalized silicon carbide (NH₂-SiO₂@SiC) as an active layer on alumina support. The NH₂-SiO₂@SiC was synthesized by growing a layer of silicon dioxide (SiO₂) on silicon carbide (SiC) leading to silicon dioxide loaded silicon carbide (SiO₂@SiC). Then amino (-NH₂) functionalization of SiO₂@SiC was carried out through 3-triethoxysilylpropylamine (APTES) yielding NH₂-SiO₂@SiC. The NH₂-SiO₂@SiC was covalently deposited as active layer on alumina support through interfacial polymerization with terephthaloyl chloride (TPC) leading to SiO₂@SiC/polyamide nanocomposite decorated on alumina (SiO₂@SiC/PA@Al₂O₃) ceramic membrane. The SiO₂@SiC/PA@Al₂O₃ ceramic membrane was thoroughly characterized by several membrane characterization techniques including water and oil contact angles, SEM (scanning electron microscopy), elemental mapping, EDX analysis (energy dispersive x-ray) and ATR-FTIR (Attenuated Total Reflectance Fourier Transform Infrared spectroscopy). The SiO₂@SiC/PA@Al₂O₃ ceramic membrane was applied for sepraration of surfactant stabalized oil-in-water (O/W) emulsion feed. The effect of increasing O/W emulsion concentration (33.75–250 ppm) was studied by varying the amount of oil in the emulsion. The ceramic membrane was able to maintain a separation efficiency of > 98 % with permeate flux of 270 L/m².h at a transmembrane pressure of 2 bar. The long-term filtration tests revealed that SiO₂@SiC/PA@Al₂O₃ ceramic membrane retained its separation efficiency at > 98 % for 420 min when 125 ppm O/W emulsion was used as feed. The SiO₂@SiC/PA@Al₂O₃ ceramic membrane showed a potential of treating a high concentration (250 ppm) surfactant stabalized O/W emulsion.