Novel supramolecular organo-oil gelators for fast and effective oil trapping: Mechanism and applications

In this paper, for the sorption of oil from oil polluted soil/water systems, nine new supramolecular organo-oil gelators were synthesized using three distinct diisocyanates and alcohols. The manufactured gelators were characterized using various techniques. The Fourier transform infrared (FTIR) and mass spectra confirmed the successful formation of the oil gelators. The synthesis of the proposed gelators was confirmed by the 1H NMR, which exhibited three singlets that were attributed to an aliphatic side chain containing 29 protons. The scanning electron microscopy (SEM) analysis exhibited porous, sheets, prisms, and fibrous structures for the supramolecular oil gelators. The oil uptake data analysis was subjected to the Langmuir and Freundlich isotherm models which showed the R2 value of 0.99 and a maximum adsorption capacity (qmax) of 45 mLg-1. From the mechanistic point of view, it was proposed that the organo-oil gel initially leads to self-assembly and further entanglements forming the fibers, which finally make a trap for the oil molecules. Among all the nine gelators and different combinations used, the combination of ditetradecyl (TDI 14: DMI14: HMI 14) gelators in the ratio of 1:2:1 exhibited maximum oil uptake of ∼58% initially which further boosted to ∼99% using gasoline as the co-congealed solvent. Interestingly, the complete gelation of the oil from the oil-water mixture was achieved within 30 min of application with high oil recovery. The presented study confirmed that the oil removal by organo-oil gelator is a simple, novel, and facile technique, which could be employed for treating oil-contaminated soil/water mixture.