Magnetic adsorbent used in combination with ultrafiltration membrane for the removal of surfactants from water

Powdered activated carbon (PAC)/iron oxide composite (MAC13) was prepared and was characterized by surface area analyzer, powdered X-ray diffraction, and sigma bulk magnetization. The adsorptive parameters of the prepared adsorbent and PAC were determined for Triton X-100, N-dodecylpyridinium chloride, and sodium dodecylbenzene sulfonate. The equilibrium adsorption data matched well to Langmuir model in various concentration ranges. The effects on contact time of adsorbates on adsorbents were determined. Both adsorbents were used in hybrid manner in pilot plant with ultrafiltration membrane (UF) system. The UF membrane parameters were determined for both PAC/UF and MAC13/UF process. Although the percent retention for PAC/UF was high, was associated with some secondary problems like cake formation over membrane and blacking of pipes. These secondary problems were not observed for MAC13, as MAC13 was removed from the slurry after use through magnet. Improved permeate fluxes were observed for MAC13 as the decline in permeate flux caused by cake formation was not encountered for magnetic adsorbent. The back wash time for PAC and MAC13 was compared and was found high for PAC.