Removal of Oil from Oil-in-Water Emulsion by Poly (Sulfur/Soya Bean Oil) Composite Adsorbent: An Equilibrium Study

Abstract

This work describes synthesis of poly (sulfur/soya bean oil) composite material by co-polymerization of elemental sulfur and soya bean oil at 180 °C. The poly (sulfur/soya bean oil) (PSSBO) composite material was characterized by FTIR, XRD and SEM, BET, and TGA analysis. The surface area was found to be 4.063 m2 per g. The XRD analysis revealed that sulfur also existed as S8 in the polymer matrix also and therefore all the peaks of native elemental S8 were also found in the sample PSSBO (1:1). The SEM analysis indicated multilayered even surface. The PSSBO (1:1) composite was employed in batch mode experiments for the removal of oil from O/W emulsions, prepared in the range of 50 to 400 mg L−1 from Soya bean oil and distilled water. The adsorption data, obtained at 298 K, were interpreted in terms of various isotherm models. Based on the regression values, the order of fitness of these models was Langmuir > Freundlich > Temkin. The maximum oil sorption capacity was found to be 14285.71 mg per g dry polymer. The adsorbent was re-generated by washing with minimum quantity of ethanol and employed in five successive cycles for de-emulsification of water. A hydrophobic–hydrophobic interactions based mechanism was proposed to explain oil uptake by adsorbent PSSBO (1:1) composite. Considering zinc-based zeolitic imidazolate framework (ZIF-8) as a model adsorbent, it was found that Qo value of PSSBO (1:1) was almost three times greater than ZIF-8 and production cost of PSSBO (1:1) was almost 450 times less than ZIF-8.